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Lyon LM, Marroquin SM, Thorstenson JC, Joyce LR, Fuentes EJ, Doran KS, Horswill AR. Genome-wide mutagenesis identifies factors involved in MRSA vaginal colonization. Cell Rep 2025; 44:115421. [PMID: 40085646 DOI: 10.1016/j.celrep.2025.115421] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2024] [Revised: 01/17/2025] [Accepted: 02/20/2025] [Indexed: 03/16/2025] Open
Abstract
Methicillin-resistant Staphylococcus aureus (MRSA) is an opportunistic pathogen that colonizes various body sites, including the nares, skin, and vagina. During pregnancy,colonization can lead to dysbiosis, adverse pregnancy outcomes, and invasive disease. To identify genes contributing to MRSA vaginal fitness, we performed transposon sequencing (Tn-seq) using a murine model of vaginal colonization, identifying over 250 conditionally essential genes. Five genes were validated in our murine model, including those encoding the aerobic respiration protein QoxB, bacillithiol biosynthesis component BshB2, sialic acid catabolism enzyme NanE, and staphylococcal regulator of respiration SrrAB. RNA sequencing and comparative analysis identified over 30 SrrAB-regulated genes potentially important for fitness in vaginal-like conditions, particularly under oxygen stress. These findings highlight pathways such as aerobic respiration, bacillithiol biosynthesis, sialic acid catabolism, and transcriptional regulation that support MRSA's competitive fitness in the vaginal tract.
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Affiliation(s)
- Laurie M Lyon
- University of Colorado Anschutz Medical Campus, Department of Immunology and Microbiology, Aurora, CO, USA
| | - Stephanie M Marroquin
- University of Colorado Anschutz Medical Campus, Department of Immunology and Microbiology, Aurora, CO, USA
| | - John C Thorstenson
- University of Colorado Anschutz Medical Campus, Department of Immunology and Microbiology, Aurora, CO, USA
| | - Luke R Joyce
- University of Colorado Anschutz Medical Campus, Department of Immunology and Microbiology, Aurora, CO, USA
| | - Ernesto J Fuentes
- Department of Biochemistry and Molecular Biology, University of Iowa Carver College of Medicine, Iowa City, IA, USA
| | - Kelly S Doran
- University of Colorado Anschutz Medical Campus, Department of Immunology and Microbiology, Aurora, CO, USA
| | - Alexander R Horswill
- University of Colorado Anschutz Medical Campus, Department of Immunology and Microbiology, Aurora, CO, USA; Department of Veterans Affairs Eastern, Colorado Healthcare System, Aurora, CO, USA.
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Roman-Rodriguez F, Kim J, Parker D, Boyd JM. An effective response to respiratory inhibition by a Pseudomonas aeruginosa excreted quinoline promotes Staphylococcus aureus fitness and survival in co-culture. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2025:2025.03.12.642861. [PMID: 40161799 PMCID: PMC11952440 DOI: 10.1101/2025.03.12.642861] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 04/02/2025]
Abstract
Pseudomonas aeruginosa and Staphylococcus aureus are primary bacterial pathogens isolated from the airways of cystic fibrosis patients. P. aeruginosa produces secondary metabolites that negatively impact the fitness of S. aureus, allowing P. aeruginosa to become the most prominent bacterium when the species are co-cultured. Some of these metabolites inhibit S. aureus respiration. SrrAB is a staphylococcal two-component regulatory system (TCRS) that responds to alterations in respiratory status and helps S. aureus transition between fermentative and respiratory metabolisms. We used P. aeruginosa mutant strains and chemical genetics to demonstrate that P. aeruginosa secondary metabolites, HQNO in particular, inhibit S. aureus respiration, resulting in modified SrrAB stimulation. Metabolomic analyses found that the ratio of NAD + to NADH increased upon prolonged culture with HQNO. Consistent with this, the activity of the Rex transcriptional regulator, which senses and responds to alterations in the NAD + / NADH ratio, had altered activity upon HQNO treatment. The presence of SrrAB increased fitness when cultured with HQNO and increased survival when challenged with P. aeruginosa. S. aureus strains with a decreased ability to maintain redox homeostasis via fermentation had decreased fitness when challenged with HQNO and decreased survival when challenged with P. aeruginosa . These findings led to a model wherein P. aeruginosa secreted HQNO inhibits S. aureus respiration, stimulating SrrAB, which promotes fitness and survival by increasing carbon flux through fermentative pathways to maintain redox homeostasis. Importance Cystic fibrosis (CF) is a hereditary respiratory disease that predisposes patients to bacterial infections, primarily caused by Staphylococcus aureus and Pseudomonas aeruginosa . P. aeruginosa excreted secondary metabolites decrease S. aureus fitness during co-infection, ultimately eliminating it. The genetic mechanisms that S. aureus uses to detect and respond to these metabolites are unknown. The S. aureus SrrAB two-component regulatory system senses flux through respiratory pathways and increases transcription of genes utilized for adaption to low-respiration environments. This study demonstrates that SrrAB responds to the P. aeruginosa -produced respiratory toxin HQNO and responds by increasing fermentation increasing competition. This study describes interactions between these two bacterial pathogens, which could be exploited to decrease pathogen burden in individuals living with cystic fibrosis.
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Affiliation(s)
- Franklin Roman-Rodriguez
- Department of Biochemistry and Microbiology, Rutgers, The State University of New Jersey, New Brunswick, NJ 08901, USA
| | - Jisun Kim
- Department of Pathology, Immunology and Laboratory Medicine, Center for Immunity and Inflammation, Rutgers New Jersey Medical School, Newark, NJ 07103, USA
| | - Dane Parker
- Department of Pathology, Immunology and Laboratory Medicine, Center for Immunity and Inflammation, Rutgers New Jersey Medical School, Newark, NJ 07103, USA
| | - Jeffrey M. Boyd
- Department of Biochemistry and Microbiology, Rutgers, The State University of New Jersey, New Brunswick, NJ 08901, USA
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3
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Liu D, Lu Y, Li Z, Pang X, Gao X. Quorum Sensing: Not Just a Bridge Between Bacteria. Microbiologyopen 2025; 14:e70016. [PMID: 40159675 PMCID: PMC11955508 DOI: 10.1002/mbo3.70016] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2024] [Revised: 02/18/2025] [Accepted: 03/07/2025] [Indexed: 04/02/2025] Open
Abstract
The study of quorum sensing (QS) has gained critical importance, offering insights into bacterial and microorganism communication. QS, regulated by autoinducers, synchronizes collective bacterial behaviors across diverse chemical signals and target genes. This review highlights innovative approaches to regulating QS, emphasizing the potential of quorum quenching and QS inhibitors to mitigate bacterial pathogenicity. These strategies have shown promise in aquaculture and plant resistance, disrupting QS pathways to combat infections. QS also provides opportunities for developing biosensors for early disease detection and preventing biofilm formation, which is critical to overcoming antimicrobial resistance. The applications of QS extend to cancer therapy, with targeted drug delivery systems utilizing QS mechanisms. Advancements in QS regulation, such as the use of nanomaterials, hydrogels, and microplastics, provide novel methods to modulate QS systems. This review explores the latest developments in QS, recognizing its significance in controlling bacterial behavior and its broad impacts on human health and disease management. Integrating these insights into therapeutic strategies and diagnostics represents a pivotal opportunity for medical progress.
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Affiliation(s)
- Derun Liu
- Medical Science and Technology Innovation CenterShandong First Medical University & Shandong Academy of Medical SciencesjinanChina
| | - Yonglin Lu
- Medical Science and Technology Innovation CenterShandong First Medical University & Shandong Academy of Medical SciencesjinanChina
| | - Ziyun Li
- State Key Laboratory of Microbial TechnologyShandong UniversityQingdaoChina
| | - Xin Pang
- State Key Laboratory of Microbial TechnologyShandong UniversityQingdaoChina
| | - Xueyan Gao
- Medical Science and Technology Innovation CenterShandong First Medical University & Shandong Academy of Medical SciencesjinanChina
- State Key Laboratory of Microbial TechnologyShandong UniversityQingdaoChina
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Burke Ó, Zeden MS, O'Gara JP. The pathogenicity and virulence of the opportunistic pathogen Staphylococcus epidermidis. Virulence 2024; 15:2359483. [PMID: 38868991 DOI: 10.1080/21505594.2024.2359483] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2024] [Accepted: 05/19/2024] [Indexed: 06/14/2024] Open
Abstract
The pervasive presence of Staphylococcus epidermidis and other coagulase-negative staphylococci on the skin and mucous membranes has long underpinned a casual disregard for the infection risk that these organisms pose to vulnerable patients in healthcare settings. Prior to the recognition of biofilm as an important virulence determinant in S. epidermidis, isolation of this microorganism in diagnostic specimens was often overlooked as clinically insignificant with potential delays in diagnosis and onset of appropriate treatment, contributing to the establishment of chronic infection and increased morbidity or mortality. While impressive progress has been made in our understanding of biofilm mechanisms in this important opportunistic pathogen, research into other virulence determinants has lagged S. aureus. In this review, the broader virulence potential of S. epidermidis including biofilm, toxins, proteases, immune evasion strategies and antibiotic resistance mechanisms is surveyed, together with current and future approaches for improved therapeutic interventions.
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Affiliation(s)
- Órla Burke
- Microbiology, School of Biological and Chemical Sciences, University of Galway, Galway, Ireland
| | | | - James P O'Gara
- Microbiology, School of Biological and Chemical Sciences, University of Galway, Galway, Ireland
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Hauserman MR, Sullivan LE, James KL, Ferraro MJ, Rice KC. Response of Staphylococcus aureus physiology and Agr quorum sensing to low-shear modeled microgravity. J Bacteriol 2024; 206:e0027224. [PMID: 39120147 PMCID: PMC11411946 DOI: 10.1128/jb.00272-24] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2024] [Accepted: 07/11/2024] [Indexed: 08/10/2024] Open
Abstract
Staphylococcus aureus is commonly isolated from astronauts returning from spaceflight. Previous analysis of omics data from S. aureus low Earth orbit cultures indicated significantly increased expression of the Agr quorum sensing system and its downstream targets in spaceflight samples compared to ground controls. In this current study, the rotary cell culture system (RCCS) was used to investigate the effect of low-shear modeled microgravity (LSMMG) on S. aureus physiology and Agr activity. When cultured in the same growth medium and temperature as the previous spaceflight experiment, S. aureus LSMMG cultures exhibited decreased agr expression and altered growth compared to normal gravity control cultures, which are typically oriented with oxygenation membrane on the bottom of the high aspect rotating vessel (HARV). When S. aureus was grown in an inverted gravity control orientation (oxygenation membrane on top of the HARV), reduced Agr activity was observed relative to both traditional control and LSMMG cultures, signifying that oxygen availability may affect the observed differences in Agr activity. Metabolite assays revealed increased lactate and decreased acetate excretion in both LSMMG and inverted control cultures. Secretomics analysis of LSMMG, control, and inverted control HARV culture supernatants corroborated these results, with inverted and LSMMG cultures exhibiting a decreased abundance of Agr-regulated virulence factors and an increased abundance of proteins expressed in low-oxygen conditions. Collectively, these studies suggest that the orientation of the HARV oxygenation membrane can affect S. aureus physiology and Agr quorum sensing in the RCCS, a variable that should be considered when interpreting data using this ground-based microgravity model.IMPORTANCES. aureus is commonly isolated from astronauts returning from spaceflight and from surfaces within human-inhabited closed environments such as spacecraft. Astronaut health and immune function are significantly altered in spaceflight. Therefore, elucidating the effects of microgravity on S. aureus physiology is critical for assessing its pathogenic potential during long-term human space habitation. These results also highlight the necessity of eliminating potential confounding factors when comparing simulated microgravity model data with actual spaceflight experiments.
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Affiliation(s)
- Matthew R. Hauserman
- Department of Microbiology and Cell Science, IFAS, University of Florida, Gainesville, Florida, USA
| | - Leia E. Sullivan
- Department of Microbiology and Cell Science, IFAS, University of Florida, Gainesville, Florida, USA
| | - Kimberly L. James
- Department of Biological Sciences, Florida Gulf Coast University, Fort Myers, Florida, USA
| | - Mariola J. Ferraro
- Department of Microbiology and Cell Science, IFAS, University of Florida, Gainesville, Florida, USA
| | - Kelly C. Rice
- Department of Microbiology and Cell Science, IFAS, University of Florida, Gainesville, Florida, USA
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6
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Suzuki Y, Kawada-Matsuo M, Le MNT, Eng S, Hisatsune J, Sugai M, Sakaguchi T, Komatsuzawa H. The two-component regulatory systems GraRS and SrrAB mediate Staphylococcus aureus susceptibility to Pep5 produced by clinical isolate of Staphylococcus epidermidis. Appl Environ Microbiol 2024; 90:e0030024. [PMID: 38832774 PMCID: PMC11267926 DOI: 10.1128/aem.00300-24] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2024] [Accepted: 05/08/2024] [Indexed: 06/05/2024] Open
Abstract
Staphylococcus aureus is a common bacterium on the skin and in the nose that sometimes causes severe illness. Bacteriocins, antimicrobial peptides, or proteins produced by bacteria are candidates for the treatment of S. aureus infection. In this study, we found that a clinical Staphylococcus epidermidis strain, KSE112, produced the lantibiotic Pep5, which showed anti-S. aureus activity. The complete nucleotide sequence of the Pep5-encoding plasmid was determined. Several S. aureus two-component regulatory systems (TCSs) are known to be involved in bacteriocin susceptibility. Therefore, susceptibility tests were performed using TCS-inactivated S. aureus mutants to determine which TCS is responsible for Pep5 susceptibility; the ΔgraRS mutant exhibited increased susceptibility to Pep5, while the ΔsrrAB mutant exhibited decreased susceptibility. GraRS is known to regulate dltABCD and mprF in concert with vraFG, and Pep5 susceptibility was significantly increased in the ΔdltABCD, ΔmprF, and ΔvraFG mutants. Regarding the ΔsrrAB mutant, cross-resistance to aminoglycosides was observed. As aminoglycoside activity is known to be affected by aerobic respiration, we focused on qoxABCD and cydAB, which are quinol oxidase genes that are necessary for aerobic respiration and have downregulated the expression in the ΔsrrAB mutant. We constructed ΔqoxABCD and ΔcydAB mutants and found that qoxABCD inactivation decreased susceptibility to Pep5 and aminoglycosides. These results indicate that reduced aerobic respiration due to the reduced qoxABCD expression in the ΔsrrAB mutant decreased Pep5 activity.IMPORTANCEThe emergence of drug-resistant bacteria, including MRSA, is a severe health problem worldwide. Thus, the development of novel antimicrobial agents, including bacteriocins, is needed. In this report, we found a Pep5-producing strain with anti-S. aureus activity. We determined the complete sequence of the Pep5-encoding plasmid for the first time. However, in S. aureus, GraRS and its effectors conferred decreased susceptibility to Pep5. We also revealed that another TCS, SrrAB, affects susceptibility Pep5 and other lantibiotics by controlling aerobic respiration. In our study, we investigated the efficacy of Pep5 against S. aureus and other Gram-positive bacteria and revealed that respiratory constancy regulated by TCS is required for the antimicrobial activity of nisin, nukacin, and Pep5. These findings provide important information for the clinical application of bacteriocins and suggest that they have different properties among similar pore-forming lantibiotics.
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Affiliation(s)
- Yujin Suzuki
- Department of Bacteriology, Hiroshima University Graduate School of Biomedical and Health Sciences, Hiroshima, Japan
- Department of Virology, Hiroshima University Graduate School of Biomedical and Health Sciences, Hiroshima, Japan
- Antimicrobial Resistance Research Center, National Institute of Infectious Diseases, Higashi Murayama, Japan
| | - Miki Kawada-Matsuo
- Department of Bacteriology, Hiroshima University Graduate School of Biomedical and Health Sciences, Hiroshima, Japan
- Project Research Centre for Nosocomial Infectious Diseases, Hiroshima University, Hiroshima, Japan
| | - Mi Nguyen-Tra Le
- Department of Bacteriology, Hiroshima University Graduate School of Biomedical and Health Sciences, Hiroshima, Japan
- Project Research Centre for Nosocomial Infectious Diseases, Hiroshima University, Hiroshima, Japan
| | - Sopongselamuny Eng
- Department of Bacteriology, Hiroshima University Graduate School of Biomedical and Health Sciences, Hiroshima, Japan
| | - Junzo Hisatsune
- Antimicrobial Resistance Research Center, National Institute of Infectious Diseases, Higashi Murayama, Japan
- Project Research Centre for Nosocomial Infectious Diseases, Hiroshima University, Hiroshima, Japan
| | - Motoyuki Sugai
- Antimicrobial Resistance Research Center, National Institute of Infectious Diseases, Higashi Murayama, Japan
- Project Research Centre for Nosocomial Infectious Diseases, Hiroshima University, Hiroshima, Japan
| | - Takemasa Sakaguchi
- Department of Virology, Hiroshima University Graduate School of Biomedical and Health Sciences, Hiroshima, Japan
| | - Hitoshi Komatsuzawa
- Department of Bacteriology, Hiroshima University Graduate School of Biomedical and Health Sciences, Hiroshima, Japan
- Project Research Centre for Nosocomial Infectious Diseases, Hiroshima University, Hiroshima, Japan
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7
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Hallier M, Bronsard J, Dréano S, Sassi M, Cattoir V, Felden B, Augagneur Y. RNAIII is linked with the pentose phosphate pathway through the activation of RpiRc in Staphylococcus aureus. mSphere 2024; 9:e0034823. [PMID: 38591898 PMCID: PMC11237564 DOI: 10.1128/msphere.00348-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2023] [Accepted: 03/18/2024] [Indexed: 04/10/2024] Open
Abstract
Staphylococcus aureus RNAIII is a dual-function regulatory RNA that controls the expression of multiple virulence genes and especially the transition from adhesion to the production of exotoxins. However, its contribution to S. aureus central metabolism remains unclear. Using MS2-affinity purification coupled with RNA sequencing, we uncovered more than 50 novel RNAIII-mRNA interactions. Among them, we demonstrate that RNAIII is a major activator of the rpiRc gene, encoding a regulator of the pentose phosphate pathway (PPP). RNAIII binds the 5' UTR of rpiRc mRNA to favor ribosome loading, leading to an increased expression of RpiRc and, subsequently, of two PPP enzymes. Finally, we show that RNAIII and RpiRc are involved in S. aureus fitness in media supplemented with various carbohydrate sources related to PPP and glycolysis. Collectively, our data depict an unprecedented phenotype associated with the RNAIII regulon, especially the direct implication of RNAIII in central metabolic activity modulation. These findings show that the contribution of RNAIII in Staphylococcus aureus adaptation goes far beyond what was initially reported. IMPORTANCE Staphylococcus aureus is a major human pathogen involved in acute and chronic infections. Highly recalcitrant to antibiotic treatment, persistent infections are mostly associated with the loss of RNAIII expression, a master RNA regulator responsible for the switch from colonization to infection. Here, we used the MS2 affinity purification coupled with RNA sequencing approach to identify novel mRNA targets of RNAIII and uncover novel functions. We demonstrate that RNAIII is an activator of the expression of genes involved in the pentose phosphate pathway and is implicated in the adjustment of bacterial fitness as a function of carbohydrate sources. Taken together, our results demonstrate an unprecedented role of RNAIII that goes beyond the knowledge gained so far and contributes to a better understanding of the role of RNAIII in bacterial adaptation expression and the coordination of a complex regulatory network.
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Affiliation(s)
- Marc Hallier
- QCPS (Quality Control in Protein Synthesis), IGDR UMR CNRS 6290, Université de Rennes 1, Rennes, France
- BRM (Bacterial Regulatory RNAs and Medicine), UMR_S 1230, Université de Rennes 1, Rennes, France
| | - Julie Bronsard
- BRM (Bacterial Regulatory RNAs and Medicine), UMR_S 1230, Université de Rennes 1, Rennes, France
| | - Stéphane Dréano
- Molecular Bases of Tumorigenesis: VHL Disease Team, CNRS UMR 6290 IGDR, BIOSIT, Université de Rennes 1, Rennes, France
| | - Mohamed Sassi
- BRM (Bacterial Regulatory RNAs and Medicine), UMR_S 1230, Université de Rennes 1, Rennes, France
| | - Vincent Cattoir
- BRM (Bacterial Regulatory RNAs and Medicine), UMR_S 1230, Université de Rennes 1, Rennes, France
| | - Brice Felden
- BRM (Bacterial Regulatory RNAs and Medicine), UMR_S 1230, Université de Rennes 1, Rennes, France
| | - Yoann Augagneur
- BRM (Bacterial Regulatory RNAs and Medicine), UMR_S 1230, Université de Rennes 1, Rennes, France
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Ali L, Abdel Aziz MH. Crosstalk involving two-component systems in Staphylococcus aureus signaling networks. J Bacteriol 2024; 206:e0041823. [PMID: 38456702 PMCID: PMC11025333 DOI: 10.1128/jb.00418-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/09/2024] Open
Abstract
Staphylococcus aureus poses a serious global threat to human health due to its pathogenic nature, adaptation to environmental stress, high virulence, and the prevalence of antimicrobial resistance. The signaling network in S. aureus coordinates and integrates various internal and external inputs and stimuli to adapt and formulate a response to the environment. Two-component systems (TCSs) of S. aureus play a central role in this network where surface-expressed histidine kinases (HKs) receive and relay external signals to their cognate response regulators (RRs). Despite the purported high fidelity of signaling, crosstalk within TCSs, between HK and non-cognate RR, and between TCSs and other systems has been detected widely in bacteria. The examples of crosstalk in S. aureus are very limited, and there needs to be more understanding of its molecular recognition mechanisms, although some crosstalk can be inferred from similar bacterial systems that share structural similarities. Understanding the cellular processes mediated by this crosstalk and how it alters signaling, especially under stress conditions, may help decipher the emergence of antibiotic resistance. This review highlights examples of signaling crosstalk in bacteria in general and S. aureus in particular, as well as the effect of TCS mutations on signaling and crosstalk.
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Affiliation(s)
- Liaqat Ali
- Fisch College of Pharmacy, The University of Texas at Tyler, Tyler, Texas, USA
| | - May H. Abdel Aziz
- Fisch College of Pharmacy, The University of Texas at Tyler, Tyler, Texas, USA
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9
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Sato'o Y, Hisatsune J, Aziz F, Tatsukawa N, Shibata-Nakagawa M, Ono HK, Naito I, Omoe K, Sugai M. Coordination of prophage and global regulator leads to high enterotoxin production in staphylococcal food poisoning-associated lineage. Microbiol Spectr 2024; 12:e0292723. [PMID: 38319074 PMCID: PMC10913437 DOI: 10.1128/spectrum.02927-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2023] [Accepted: 01/05/2024] [Indexed: 02/07/2024] Open
Abstract
Staphylococcus species in food produce Staphylococcal enterotoxins (SEs) that cause Staphylococcal food poisoning (SFP). More than 20 SE types have been reported, among which Staphylococcal enterotoxin A (SEA) has been recognized as one of the most important SEs associated with SFP. However, the regulatory mechanisms underlying its production remain unclear. Previously, we identified a major SFP clone in Japan, CC81 subtype-1, which exhibits high SEA production. In this study, we attempted to identify the factors contributing to this phenomenon. Thus, we demonstrated that the attenuation of the activity of endogenous regulator, Staphylococcal accessory regulator S (SarS), and the lysogenization of a high SEA-producing phage contributed to this phenomenon in CC81 subtype-1. Furthermore, our results indicated that SarS could directly bind to the promoter upstream of the sea gene and suppress SEA expression; this low SarS repression activity was identified as one of the reasons for the high SEA production observed. Therefore, we revealed that both exogenous and endogenous factors may probably contribute to the high SEA production. Our results confirmed that SE production is a fundamental and critical factor in SFP and clarified the associated production mechanism while enhancing our understanding as to why a specific clone frequently causes SFP. IMPORTANCE The importance of this study lies in its unveiling of a molecular regulatory mechanism associated with the most important food poisoning toxin and the evolution of Staphylococcal food poisoning (SFP)-associated clone. SFP is primarily caused by Staphylococcus aureus, with Staphylococcal enterotoxin A (SEA) being commonly involved in many cases. Thus, SEA has been recognized as a major toxin type. However, despite almost a century since its discovery, the complete mechanism of SEA production is as yet unknown. In this study, we analyzed an SEA-producing SFP clone isolated in East Asia and discovered that this strain, besides acquiring the high SEA-producing phage, exhibits remarkably high SEA production due to the low activity of SarS, an intrinsic regulatory factor. This is the first report documenting the evolution of the SFP clone through the coordinated action of exogenous mobile genetic factors and endogenous regulators on this notorious toxin.
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Affiliation(s)
- Yusuke Sato'o
- Department of Bacteriology, Hiroshima University Graduate School of Biomedical & Health Sciences, Hiroshima, Japan
| | - Junzo Hisatsune
- Department of Bacteriology, Hiroshima University Graduate School of Biomedical & Health Sciences, Hiroshima, Japan
- Antimicrobial Resistance Research Center, National Institute of Infectious Diseases (NIID), Tokyo, Japan
| | - Fatkhanuddin Aziz
- Department of Bacteriology, Hiroshima University Graduate School of Biomedical & Health Sciences, Hiroshima, Japan
| | - Nobuyuki Tatsukawa
- Department of Bacteriology, Hiroshima University Graduate School of Biomedical & Health Sciences, Hiroshima, Japan
| | - Mari Shibata-Nakagawa
- Department of Veterinary Medicine, Faculty of Agriculture, Iwate University, Morioka city, Japan
| | - Hisaya K. Ono
- Department of Veterinary Medicine, Faculty of Agriculture, Iwate University, Morioka city, Japan
- Laboratory of Zoonoses, Kitasato University School of Veterinary Medicine, Towada city, Japan
| | - Ikunori Naito
- Department of Veterinary Medicine, Faculty of Agriculture, Iwate University, Morioka city, Japan
| | - Katsuhiko Omoe
- Department of Veterinary Medicine, Faculty of Agriculture, Iwate University, Morioka city, Japan
| | - Motoyuki Sugai
- Department of Bacteriology, Hiroshima University Graduate School of Biomedical & Health Sciences, Hiroshima, Japan
- Antimicrobial Resistance Research Center, National Institute of Infectious Diseases (NIID), Tokyo, Japan
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10
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Brandwein JN, Sculthorpe TS, Ridder MJ, Bose JL, Rice KC. Factors impacting the regulation of nos gene expression in Staphylococcus aureus. Microbiol Spectr 2023; 11:e0168823. [PMID: 37747881 PMCID: PMC10580903 DOI: 10.1128/spectrum.01688-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2023] [Accepted: 07/29/2023] [Indexed: 09/27/2023] Open
Abstract
Staphylococcus aureus nitric oxide synthase (saNOS) contributes to oxidative stress resistance, antibiotic tolerance, virulence, and modulation of aerobic and nitrate-based cellular respiration. Despite its involvement in these essential processes, the genetic regulation of nos expression has not been well characterized. 5' rapid amplification of cDNA ends on nos RNA isolated from S. aureus UAMS-1 (USA200 strain) and AH1263 (USA300 strain) revealed that the nos transcriptional start site mapped to an adenine nucleotide in the predicted Shine-Dalgarno site located 11 bp upstream of the nos ATG start codon, suggesting that the nos transcript may have a leaderless organization or may be subject to processing. The SrrAB two-component system (TCS) was previously identified as a positive regulator of nos RNA levels, and experiments using a β-galactosidase reporter plasmid confirmed that SrrAB is a positive regulator of nos promoter activity. In addition, the quorum-sensing system Agr was identified as a negative regulator of low-oxygen nos expression in UAMS-1, with activity epistatic to SrrAB. Involvement of Agr was strain dependent, as nos expression remained unchanged in an AH1263 agr mutant, which has higher Agr activity compared to UAMS-1. Furthermore, nos promoter activity and RNA levels were significantly stronger in AH1263 relative to UAMS-1 during late-exponential low-oxygen growth, when nos expression is maximal. Global regulators Rex and MgrA were also implicated as negative regulators of low-oxygen nos promoter activity in UAMS-1. Collectively, these results provide new insight into factors that control nos expression.IMPORTANCEBacterial nitric oxide synthase (bNOS) has recently emerged in several species as a key player in resistance to stresses commonly encountered during infection. Although Staphylococcus aureus (sa)NOS has been suggested to be a promising drug target in S. aureus, an obstacle to this in practice is the existence of mammalian NOS, whose oxygenase domain is like bacterial NOS. Increased understanding of the nos regulatory network in S. aureus could allow targeting of saNOS through its regulators, bypassing the issue of also inhibiting mammalian NOS. Furthermore, the observed strain-dependent differences in S. aureus nos regulation presented in this study reinforce the importance of studying bacterial NOS regulation and function at both the strain and species levels.
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Affiliation(s)
- Jessica N. Brandwein
- Department of Microbiology & Cell Science, Institute of Food and Agricultural Sciences, University of Florida, Gainesville, Florida, USA
| | - Tiffany S. Sculthorpe
- Department of Microbiology & Cell Science, Institute of Food and Agricultural Sciences, University of Florida, Gainesville, Florida, USA
| | - Miranda J. Ridder
- Department of Microbiology, Molecular Genetics and Immunology, University of Kansas Medical Center, Kansas City, Kansas, USA
| | - Jeffrey L. Bose
- Department of Microbiology, Molecular Genetics and Immunology, University of Kansas Medical Center, Kansas City, Kansas, USA
| | - Kelly C. Rice
- Department of Microbiology & Cell Science, Institute of Food and Agricultural Sciences, University of Florida, Gainesville, Florida, USA
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Schlievert PM, Gaitán AV, Kilgore SH, Roe AL, Maukonen J, Lehtoranta L, Leung DYM, Marsman DS. Inhibition of Toxic Shock Syndrome-Associated Staphylococcus aureus by Probiotic Lactobacilli. Microbiol Spectr 2023; 11:e0173523. [PMID: 37404182 PMCID: PMC10434015 DOI: 10.1128/spectrum.01735-23] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2023] [Accepted: 06/21/2023] [Indexed: 07/06/2023] Open
Abstract
Staphylococcus aureus is a human pathogen with many infections originating on mucosal surfaces. One common group of S. aureus is the USA200 (CC30) clonal group, which produces toxic shock syndrome toxin-1 (TSST-1). Many USA200 infections occur on mucosal surfaces, particularly in the vagina and gastrointestinal tract. This allows these organisms to cause cases of menstrual TSS and enterocolitis. The current study examined the ability of two lactobacilli, Lactobacillus acidophilus strain LA-14 and Lacticaseibacillus rhamnosus strain HN001, for their ability to inhibit the growth of TSST-1 positive S. aureus, the production of TSST-1, and the ability of TSST-1 to induce pro-inflammatory chemokines from human vaginal epithelial cells (HVECs). In competition growth experiments, L. rhamnosus did not affect the growth of TSS S. aureus but did inhibit the production of TSST-1; this effect was partially due to acidification of the growth medium. L. acidophilus was both bactericidal and prevented the production of TSST-1 by S. aureus. This effect appeared to be partially due to acidification of the growth medium, production of H2O2, and production of other antibacterial molecules. When both organisms were incubated with S. aureus, the effect of L. acidophilus LA-14 dominated. In in vitro experiments with HVECs, neither lactobacillus induced significant production of the chemokine interleukin-8, whereas TSST-1 did induce production of the chemokine. When the lactobacilli were incubated with HVECs in the presence of TSST-1, the lactobacilli reduced chemokine production. These data suggest that these two bacteria in probiotics could reduce the incidence of menstrual and enterocolitis-associated TSS. IMPORTANCE Toxic shock syndrome (TSS) Staphylococcus aureus commonly colonize mucosal surfaces, giving them the ability to cause TSS through the action of TSS toxin-1 (TSST-1). This study examined the ability of two probiotic lactobacilli to inhibit S. aureus growth and TSST-1 production, and the reduction of pro-inflammatory chemokine production by TSST-1. Lacticaseibacillus rhamnosus strain HN001 inhibited TSST-1 production due to acid production but did not affect S. aureus growth. Lactobacillus acidophilus strain LA-14 was bactericidal against S. aureus, partially due to acid and H2O2 production, and consequently also inhibited TSST-1 production. Neither lactobacillus induced the production of pro-inflammatory chemokines by human vaginal epithelial cells, and both inhibited chemokine production by TSST-1. These data suggest that the two probiotics could reduce the incidence of mucosa-associated TSS, including menstrual TSS and cases originating as enterocolitis.
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Affiliation(s)
- Patrick M. Schlievert
- Department of Microbiology and Immunology, University of Iowa; Carver College of Medicine, Iowa City, Iowa, USA
| | | | - Samuel H. Kilgore
- Department of Microbiology and Immunology, University of Iowa; Carver College of Medicine, Iowa City, Iowa, USA
| | - Amy L. Roe
- The Procter & Gamble Company, Cincinnati, Ohio, USA
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12
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Patel H, Rawat S. A genetic regulatory see-saw of biofilm and virulence in MRSA pathogenesis. Front Microbiol 2023; 14:1204428. [PMID: 37434702 PMCID: PMC10332168 DOI: 10.3389/fmicb.2023.1204428] [Citation(s) in RCA: 23] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2023] [Accepted: 05/30/2023] [Indexed: 07/13/2023] Open
Abstract
Staphylococcus aureus is one of the most common opportunistic human pathogens causing several infectious diseases. Ever since the emergence of the first methicillin-resistant Staphylococcus aureus (MRSA) strain decades back, the organism has been a major cause of hospital-acquired infections (HA-MRSA). The spread of this pathogen across the community led to the emergence of a more virulent subtype of the strain, i.e., Community acquired Methicillin resistant Staphylococcus aureus (CA-MRSA). Hence, WHO has declared Staphylococcus aureus as a high-priority pathogen. MRSA pathogenesis is remarkable because of the ability of this "superbug" to form robust biofilm both in vivo and in vitro by the formation of polysaccharide intercellular adhesin (PIA), extracellular DNA (eDNA), wall teichoic acids (WTAs), and capsule (CP), which are major components that impart stability to a biofilm. On the other hand, secretion of a diverse array of virulence factors such as hemolysins, leukotoxins, enterotoxins, and Protein A regulated by agr and sae two-component systems (TCS) aids in combating host immune response. The up- and downregulation of adhesion genes involved in biofilm formation and genes responsible for synthesizing virulence factors during different stages of infection act as a genetic regulatory see-saw in the pathogenesis of MRSA. This review provides insight into the evolution and pathogenesis of MRSA infections with a focus on genetic regulation of biofilm formation and virulence factors secretion.
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Affiliation(s)
| | - Seema Rawat
- Microbiology Laboratory, School of Life Sciences, Central University of Gujarat, Gandhinagar, Gujarat, India
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13
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Walsh SK, Imrie RM, Matuszewska M, Paterson GK, Weinert LA, Hadfield JD, Buckling A, Longdon B. The host phylogeny determines viral infectivity and replication across Staphylococcus host species. PLoS Pathog 2023; 19:e1011433. [PMID: 37289828 PMCID: PMC10284401 DOI: 10.1371/journal.ppat.1011433] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2022] [Revised: 06/21/2023] [Accepted: 05/18/2023] [Indexed: 06/10/2023] Open
Abstract
Virus host shifts, where a virus transmits to and infects a novel host species, are a major source of emerging infectious disease. Genetic similarity between eukaryotic host species has been shown to be an important determinant of the outcome of virus host shifts, but it is unclear if this is the case for prokaryotes where anti-virus defences can be transmitted by horizontal gene transfer and evolve rapidly. Here, we measure the susceptibility of 64 strains of Staphylococcaceae bacteria (48 strains of Staphylococcus aureus and 16 non-S. aureus species spanning 2 genera) to the bacteriophage ISP, which is currently under investigation for use in phage therapy. Using three methods-plaque assays, optical density (OD) assays, and quantitative (q)PCR-we find that the host phylogeny explains a large proportion of the variation in susceptibility to ISP across the host panel. These patterns were consistent in models of only S. aureus strains and models with a single representative from each Staphylococcaceae species, suggesting that these phylogenetic effects are conserved both within and among host species. We find positive correlations between susceptibility assessed using OD and qPCR and variable correlations between plaque assays and either OD or qPCR, suggesting that plaque assays alone may be inadequate to assess host range. Furthermore, we demonstrate that the phylogenetic relationships between bacterial hosts can generally be used to predict the susceptibility of bacterial strains to phage infection when the susceptibility of closely related hosts is known, although this approach produced large prediction errors in multiple strains where phylogeny was uninformative. Together, our results demonstrate the ability of bacterial host evolutionary relatedness to explain differences in susceptibility to phage infection, with implications for the development of ISP both as a phage therapy treatment and as an experimental system for the study of virus host shifts.
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Affiliation(s)
- Sarah K. Walsh
- Centre for Ecology and Conservation; Faculty of Environment, Science, and Economy; Biosciences; University of Exeter; Cornwall; United Kingdom
- Environment and Sustainability Institute; University of Exeter; Cornwall; United Kingdom
| | - Ryan M. Imrie
- Centre for Ecology and Conservation; Faculty of Environment, Science, and Economy; Biosciences; University of Exeter; Cornwall; United Kingdom
| | - Marta Matuszewska
- Department of Medicine; University of Cambridge; Cambridge; United Kingdom
| | - Gavin K. Paterson
- Royal (Dick) School of Veterinary Studies and the Roslin Institute; University of Edinburgh;Edinburgh; United Kingdom
| | - Lucy A. Weinert
- Department of Veterinary Medicine; University of Cambridge; Cambridge; United Kingdom
| | - Jarrod D. Hadfield
- Institute of Evolutionary Biology; The University of Edinburgh; Edinburgh; United Kingdom
| | - Angus Buckling
- Centre for Ecology and Conservation; Faculty of Environment, Science, and Economy; Biosciences; University of Exeter; Cornwall; United Kingdom
- Environment and Sustainability Institute; University of Exeter; Cornwall; United Kingdom
| | - Ben Longdon
- Centre for Ecology and Conservation; Faculty of Environment, Science, and Economy; Biosciences; University of Exeter; Cornwall; United Kingdom
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14
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Schlievert PM, Kilgore SH, Beck LA, Yoshida T, Klingelhutz AJ, Leung DYM. Host Cationic Antimicrobial Molecules Inhibit S. aureus Exotoxin Production. mSphere 2023; 8:e0057622. [PMID: 36598227 PMCID: PMC9942567 DOI: 10.1128/msphere.00576-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2022] [Accepted: 12/02/2022] [Indexed: 01/05/2023] Open
Abstract
Innate immune molecules, including antimicrobial peptides (for example, defensins) and lysozyme, function to delay or prevent bacterial infections. These molecules are commonly found on mucosal and skin surfaces. Staphylococcus aureus is a common pathogen and causes millions of infections annually. It is well known that innate immune molecules, such as defensins and lysozyme, either poorly inhibit or do not inhibit the growth of S. aureus. Our current studies show that the α-defensin human neutrophil α-defensin-1 (HNP-1) and lysozyme inhibit exotoxin production, both hemolysins and superantigens, which are required for S. aureus infection. HNP-1 inhibited exotoxin production at concentrations as low as 0.001 μg/mL. Lysozyme inhibited exotoxin production at 0.05 to 0.5 μg/mL. Both HNP-1 and lysozyme functioned through at least one two-component system (SrrA/B). The β-defensin human β-defensin 1 (HBD-1) inhibited hemolysin but not superantigen production. The cation chelator S100A8/A9 (calprotectin), compared to EDTA, was tested for the ability to inhibit exotoxin production. EDTA at high concentrations inhibited exotoxin production; these were the same concentrations that interfered with staphylococcal growth. S100A8/A9 at the highest concentration tested (10 μg/mL) had no effect on S. aureus growth but enhanced exotoxin production. Lower concentrations had no effect on growth or exotoxin production. Lysostaphin is regularly used to lyse S. aureus. The lytic concentrations of lysostaphin were the only concentrations that also inhibited growth and exotoxin production. Our studies demonstrate that a major activity of innate defensin peptides and lysozyme is inhibition of staphylococcal exotoxin production but not inhibition of growth. IMPORTANCE Staphylococcus aureus causes large numbers of both relatively benign and serious human infections, which are mediated in large part by the organisms' secreted exotoxins. Since 1921, it has been known that lysozyme and, as shown later in the 1900s, other innate immune peptides, including human neutrophil α-defensin-1 (HNP-1) and human β-defensin 1 (HBD-1), are either not antistaphylococcal or are only weakly inhibitory to growth. Our study confirms those findings but, importantly, shows that at subgrowth inhibitory concentrations, these positively charged innate immune peptides inhibit exotoxin production, including both hemolysins and the superantigen toxic shock syndrome toxin-1. The data show that the principal activity of innate immune peptides in the host is likely to be inhibition of exotoxin production required for staphylococcal mucosal or skin colonization rather than growth inhibition.
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Affiliation(s)
- Patrick M. Schlievert
- Department of Microbiology and Immunology, Carver College of Medicine, University of Iowa, Iowa City, Iowa, USA
| | - Samuel H. Kilgore
- Department of Microbiology and Immunology, Carver College of Medicine, University of Iowa, Iowa City, Iowa, USA
| | - Lisa A. Beck
- Department of Dermatology, University of Rochester Medical Center, Rochester, New York, USA
| | - Takeshi Yoshida
- Department of Dermatology, University of Rochester Medical Center, Rochester, New York, USA
| | - Aloysius J. Klingelhutz
- Department of Microbiology and Immunology, Carver College of Medicine, University of Iowa, Iowa City, Iowa, USA
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15
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Costa MDOCE, do Nascimento APB, Martins YC, dos Santos MT, Figueiredo AMDS, Perez-Rueda E, Nicolás MF. The gene regulatory network of Staphylococcus aureus ST239-SCC mecIII strain Bmb9393 and assessment of genes associated with the biofilm in diverse backgrounds. Front Microbiol 2023; 13:1049819. [PMID: 36704545 PMCID: PMC9871828 DOI: 10.3389/fmicb.2022.1049819] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2022] [Accepted: 12/19/2022] [Indexed: 01/12/2023] Open
Abstract
Introduction Staphylococcus aureus is one of the most prevalent and relevant pathogens responsible for a wide spectrum of hospital-associated or community-acquired infections. In addition, methicillin-resistant Staphylococcus aureus may display multidrug resistance profiles that complicate treatment and increase the mortality rate. The ability to produce biofilm, particularly in device-associated infections, promotes chronic and potentially more severe infections originating from the primary site. Understanding the complex mechanisms involved in planktonic and biofilm growth is critical to identifying regulatory connections and ways to overcome the global health problem of multidrug-resistant bacteria. Methods In this work, we apply literature-based and comparative genomics approaches to reconstruct the gene regulatory network of the high biofilm-producing strain Bmb9393, belonging to one of the highly disseminating successful clones, the Brazilian epidemic clone. To the best of our knowledge, we describe for the first time the topological properties and network motifs for the Staphylococcus aureus pathogen. We performed this analysis using the ST239-SCCmecIII Bmb9393 strain. In addition, we analyzed transcriptomes available in the literature to construct a set of genes differentially expressed in the biofilm, covering different stages of the biofilms and genetic backgrounds of the strains. Results and discussion The Bmb9393 gene regulatory network comprises 1,803 regulatory interactions between 64 transcription factors and the non-redundant set of 1,151 target genes with the inclusion of 19 new regulons compared to the N315 transcriptional regulatory network published in 2011. In the Bmb9393 network, we found 54 feed-forward loop motifs, where the most prevalent were coherent type 2 and incoherent type 2. The non-redundant set of differentially expressed genes in the biofilm consisted of 1,794 genes with functional categories relevant for adaptation to the variable microenvironments established throughout the biofilm formation process. Finally, we mapped the set of genes with altered expression in the biofilm in the Bmb9393 gene regulatory network to depict how different growth modes can alter the regulatory systems. The data revealed 45 transcription factors and 876 shared target genes. Thus, the gene regulatory network model provided represents the most up-to-date model for Staphylococcus aureus, and the set of genes altered in the biofilm provides a global view of their influence on biofilm formation from distinct experimental perspectives and different strain backgrounds.
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Affiliation(s)
| | - Ana Paula Barbosa do Nascimento
- Departamento de Análises Clínicas e Toxicológicas, Faculdade de Ciências Farmacêuticas, Universidade de São Paulo, São Paulo, Brazil
| | | | | | - Agnes Marie de Sá Figueiredo
- Instituto de Investigaciones en Matemáticas Aplicadas y en Sistemas, Universidad Nacional Autónoma de México, Unidad Académica Yucatán, Merida, Mexico
| | - Ernesto Perez-Rueda
- Laboratório de Biologia Molecular de Bactérias, Instituto de Microbiologia Paulo de Goés, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil,*Correspondence: Ernesto Perez-Rueda ✉
| | - Marisa Fabiana Nicolás
- Laboratório Nacional de Computação Científica (LNCC), Petrópolis, Brazil,Marisa Fabiana Nicolás ✉
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16
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Peng Q, Tang X, Dong W, Sun N, Yuan W. A Review of Biofilm Formation of Staphylococcus aureus and Its Regulation Mechanism. Antibiotics (Basel) 2022; 12:antibiotics12010012. [PMID: 36671212 PMCID: PMC9854888 DOI: 10.3390/antibiotics12010012] [Citation(s) in RCA: 68] [Impact Index Per Article: 22.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2022] [Revised: 11/23/2022] [Accepted: 11/25/2022] [Indexed: 12/24/2022] Open
Abstract
Bacteria can form biofilms in natural and clinical environments on both biotic and abiotic surfaces. The bacterial aggregates embedded in biofilms are formed by their own produced extracellular matrix. Staphylococcus aureus (S. aureus) is one of the most common pathogens of biofilm infections. The formation of biofilm can protect bacteria from being attacked by the host immune system and antibiotics and thus bacteria can be persistent against external challenges. Therefore, clinical treatments for biofilm infections are currently encountering difficulty. To address this critical challenge, a new and effective treatment method needs to be developed. A comprehensive understanding of bacterial biofilm formation and regulation mechanisms may provide meaningful insights against antibiotic resistance due to bacterial biofilms. In this review, we discuss an overview of S. aureus biofilms including the formation process, structural and functional properties of biofilm matrix, and the mechanism regulating biofilm formation.
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Affiliation(s)
- Qi Peng
- Guangzhou Key Laboratory for Clinical Rapid Diagnosis and Early Warning of Infectious Diseases, KingMed School of Laboratory Medicine, Guangzhou Medical University, Guangzhou 510180, China
| | - Xiaohua Tang
- Guangzhou Key Laboratory for Clinical Rapid Diagnosis and Early Warning of Infectious Diseases, KingMed School of Laboratory Medicine, Guangzhou Medical University, Guangzhou 510180, China
| | - Wanyang Dong
- Guangzhou Key Laboratory for Clinical Rapid Diagnosis and Early Warning of Infectious Diseases, KingMed School of Laboratory Medicine, Guangzhou Medical University, Guangzhou 510180, China
| | - Ning Sun
- Guangzhou First People’s Hospital, School of Medicine, South China University of Technology, Guangzhou 510180, China
- Correspondence: (N.S.); (W.Y.)
| | - Wenchang Yuan
- Guangzhou Key Laboratory for Clinical Rapid Diagnosis and Early Warning of Infectious Diseases, KingMed School of Laboratory Medicine, Guangzhou Medical University, Guangzhou 510180, China
- Correspondence: (N.S.); (W.Y.)
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17
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The Intersection of the Staphylococcus aureus Rex and SrrAB Regulons: an Example of Metabolic Evolution That Maximizes Resistance to Immune Radicals. mBio 2021; 12:e0218821. [PMID: 34781744 PMCID: PMC8593685 DOI: 10.1128/mbio.02188-21] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
Staphylococcus aureus is the most pathogenic member of the Staphylococcaceae. While it acquired an arsenal of canonical virulence determinants that mediate pathogenicity, it has also metabolically adapted to thrive at sites of inflammation. Notably, it has evolved to grow in the presence of nitric oxide (NO·). To this end, we note that the Rex regulon, composed of genes encoding dehydrogenases, metabolite transporters, and regulators, is much larger in S. aureus than other Staphylococcus species. Here, we demonstrate that this expanded Rex regulon is necessary and sufficient for NO· resistance. Preventing its expression results in NO· sensitivity, and the closely related species, Staphylococcus simiae, also possesses an expanded Rex regulon and exhibits NO· resistance. We hypothesize that the expanded Rex regulon initially evolved to provide efficient anaerobic metabolism but that S. aureus has co-opted this feature to thrive at sites of inflammation where respiration is limited. One distinguishing feature of the Rex regulon in S. aureus is that it contains the srrAB two-component system. Here, we show that Rex blocks the ability of SrrA to auto-induce the operon, thereby preventing maximal SrrAB expression. This results in NO·-responsive srrAB expression in S. aureus but not in other staphylococci. Consequently, higher expression of cytochromes and NO· detoxification are also observed in S. aureus alone, allowing for continued respiration at NO· concentrations beyond that of S. simiae. We therefore contend that the intersection of the Rex and SrrAB regulons represents an evolutionary event that allowed S. aureus to metabolically adapt to host inflammatory radicals during infection.
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18
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Price EE, Román-Rodríguez F, Boyd JM. Bacterial approaches to sensing and responding to respiration and respiration metabolites. Mol Microbiol 2021; 116:1009-1021. [PMID: 34387370 DOI: 10.1111/mmi.14795] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2021] [Revised: 08/03/2021] [Accepted: 08/09/2021] [Indexed: 11/29/2022]
Abstract
Bacterial respiration of diverse substrates is a primary contributor to the diversity of life. Respiration also drives alterations in the geosphere and tethers ecological nodes together. It provides organisms with a means to dissipate reductants and generate potential energy in the form of an electrochemical gradient. Mechanisms have evolved to sense flux through respiratory pathways and sense the altered concentrations of respiration substrates or byproducts. These genetic regulatory systems promote efficient utilization of respiration substrates, as well as fine tune metabolism to promote cellular fitness and negate the accumulation of toxic byproducts. Many bacteria can respire one or more chemicals, and these regulatory systems promote the prioritization of high energy metabolites. Herein we focus on regulatory paradigms and discuss systems that sense the concentrations of respiration substrates and flux through respiratory pathways. This is a broad field of study, and therefore we focus on key fundamental and recent developments and highlight specific systems that capture the diversity of sensing mechanisms.
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Affiliation(s)
- Erin E Price
- Department of Biochemistry & Microbiology, Rutgers, The State University of New Jersey, New Brunswick, NJ, 08901, USA
| | - Franklin Román-Rodríguez
- Department of Biochemistry & Microbiology, Rutgers, The State University of New Jersey, New Brunswick, NJ, 08901, USA
| | - Jeffrey M Boyd
- Department of Biochemistry & Microbiology, Rutgers, The State University of New Jersey, New Brunswick, NJ, 08901, USA
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19
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Gilpin D, Hoffman LR, Ceppe A, Muhlebach MS. Phenotypic characteristics of incident and chronic MRSA isolates in cystic fibrosis. J Cyst Fibros 2021; 20:692-698. [PMID: 34103251 DOI: 10.1016/j.jcf.2021.05.015] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2020] [Revised: 05/19/2021] [Accepted: 05/22/2021] [Indexed: 01/02/2023]
Abstract
BACKGROUND Chronic methicillin resistant Staphylococcus aureus (MRSA) in CF is associated with worse outcomes compared to early or intermittent infection. This observation could be related to adaptive bacterial changes such as biofilm formation or anaerobic growth. METHODS MRSA isolates stored from incident and during chronic (>2 years) infection were included at two study sites. MRSA isolates were characterised by spa-typing, antimicrobial susceptibility testing, biofilm formation and haemolysis under aerobic and anaerobic culture conditions. RESULTS Paired MRSA isolates from 49 patients were included. Mean age at incident infection was 9.7±1.2 years with mild to moderate lung disease (FEV1 74±4% predicted). Twenty-five subjects showed progression of disease/symptoms after onset of MRSA with significantly increased use of antibiotics. Most isolates belonged to t002 (38%) and t008 (36%) spa-types and 8 patients had a change in spa-type over time. Antimicrobial susceptibility testing showed few differences between incident and late isolates but significantly lower MIC under anaerobic vs. aerobic conditions for vancomycin, fusidic acid, rifampin but higher MIC for trimethoprim-sulfamethoxazole. Biofilm formation and haemolysis did not differ by stage of infection or disease course but both were lower under anaerobic conditions (biofilm p=0.018; haemolysis p=0.002) in multi-variate analyses that included study site, growth condition and stage of infection. CONCLUSIONS Persistent MRSA infection is frequently associated with clinical decline. Anaerobic growth conditions, which occur in CF airways, affect the expression of virulence factors and antibiotic susceptibility of MRSA more than duration of infection.
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Affiliation(s)
- Deirdre Gilpin
- Department of Pharmacy Services, Queens University, Belfast, UK.
| | - Lucas R Hoffman
- Department of Pediatrics, University of Washington, Seattle Children's Hospital, Seattle, WA, USA.
| | - Agathe Ceppe
- Marisco Lung Institute, University of North Carolina, Chapel Hill, NC, USA.
| | - Marianne S Muhlebach
- Marisco Lung Institute, University of North Carolina, Chapel Hill, NC, USA; Department of Pediatrics, University of North Carolina, Chapel Hill, NC, USA.
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20
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Hu DL, Li S, Fang R, Ono HK. Update on molecular diversity and multipathogenicity of staphylococcal superantigen toxins. ANIMAL DISEASES 2021. [DOI: 10.1186/s44149-021-00007-7] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
AbstractStaphylococcal superantigen (SAg) toxins are the most notable virulence factors associated with Staphylococcus aureus, which is a pathogen associated with serious community and hospital acquired infections in humans and various diseases in animals. Recently, SAg toxins have become a superfamily with 29 types, including staphylococcal enterotoxins (SEs) with emetic activity, SE-like toxins (SEls) that do not induce emesis in primate models or have yet not been tested, and toxic shock syndrome toxin-1 (TSST-1). SEs and SEls can be subdivided into classical types (SEA to SEE) and novel types (SEG to SElY, SE01, SE02, SEl26 and SEl27). The genes of SAg toxins are located in diverse accessory genetic elements and share certain structural and biological properties. SAg toxins are heat-stable proteins that exhibit pyrogenicity, superantigenicity and capacity to induce lethal hypersensitivity to endotoxin in humans and animals. They have multiple pathogenicities that can interfere with normal immune function of host, increase the chances of survival and transmission of pathogenic bacteria in host, consequently contribute to the occurrence and development of various infections, persistent infections or food poisoning. This review focuses on the following aspects of SAg toxins: (1) superfamily members of classic and novelty discovered staphylococcal SAgs; (2) diversity of gene locations and molecular structural characteristics; (3) biological characteristics and activities; (4) multi-pathogenicity of SAgs in animal and human diseases, including bovine mastitis, swine sepsis, abscesses and skin edema in pig, arthritis and septicemia in poultry, and nosocomial infections and food-borne diseases in humans.
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21
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Grispoldi L, Karama M, Armani A, Hadjicharalambous C, Cenci-Goga BT. Staphylococcus aureus enterotoxin in food of animal origin and staphylococcal food poisoning risk assessment from farm to table. ITALIAN JOURNAL OF ANIMAL SCIENCE 2021. [DOI: 10.1080/1828051x.2020.1871428] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Affiliation(s)
| | - Musafiri Karama
- Department of Paraclinical Sciences, University of Pretoria, Onderstepoort, South Africa
| | - Andrea Armani
- Department of Veterinary Sciences, University of Pisa, Pisa, Italy
| | | | - Beniamino T. Cenci-Goga
- Department of Veterinary Medicine, Perugia, Italy
- Department of Paraclinical Sciences, University of Pretoria, Onderstepoort, South Africa
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22
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Identification of CD4 + T cell epitopes from Staphylococcus aureus secretome using immunoinformatic prediction and molecular docking. BIOTECHNOLOGIA 2021; 102:43-54. [PMID: 36605712 PMCID: PMC9642919 DOI: 10.5114/bta.2021.103761] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2020] [Revised: 08/25/2020] [Accepted: 10/23/2020] [Indexed: 01/09/2023] Open
Abstract
One major reason for the lack of clinical success of Staphylococcus aureus vaccine candidates is the inability of the antigens to develop a CD4+ T cell-mediated immune response. Hence, it is important to identify CD4+ T cell antigens from S. aureus. CD4+ T cells are activated following the presentation of epitopes derived from exogenous proteins on HLA class II molecules. Fifty-nine secretory proteins of S. aureus were analyzed computationally for the presence of HLA class II binding peptides. Fifteen-mer peptides were generated, and their binding to 26 HLA class II alleles was predicted. The structural feasibility of the peptides binding to HLA-II was studied using molecular docking. Of the 16,724 peptides generated, 6991 (41.8%) were predicted to bind to any one of the alleles with an IC50 value below 50 nM. Comparative sequence analysis revealed that only 545 of the strong binding peptides are non-self in the human system. Approximately 50% of the binding peptides were monoallele-specific. Moreover, approximately 95% of the predicted strong binding non-self peptides interacted with the binding groove of at least one HLA class II molecule with a glide score better than -10 kcal/mol. On the basis of the analysis of the strength of binding, non-self presentation in the human host, propensity to bind to a higher number of alleles, and energetically favorable interactions with HLA molecules, a set of 11 CD4+ T cell epitopes that can be used as vaccine candidates was identified.
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23
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Schulze A, Mitterer F, Pombo JP, Schild S. Biofilms by bacterial human pathogens: Clinical relevance - development, composition and regulation - therapeutical strategies. MICROBIAL CELL (GRAZ, AUSTRIA) 2021; 8:28-56. [PMID: 33553418 PMCID: PMC7841849 DOI: 10.15698/mic2021.02.741] [Citation(s) in RCA: 97] [Impact Index Per Article: 24.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/08/2020] [Revised: 01/08/2021] [Accepted: 01/12/2021] [Indexed: 12/19/2022]
Abstract
Notably, bacterial biofilm formation is increasingly recognized as a passive virulence factor facilitating many infectious disease processes. In this review we will focus on bacterial biofilms formed by human pathogens and highlight their relevance for diverse diseases. Along biofilm composition and regulation emphasis is laid on the intensively studied biofilms of Vibrio cholerae, Pseudomonas aeruginosa and Staphylococcus spp., which are commonly used as biofilm model organisms and therefore contribute to our general understanding of bacterial biofilm (patho-)physiology. Finally, therapeutical intervention strategies targeting biofilms will be discussed.
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Affiliation(s)
- Adina Schulze
- Institute of Molecular Biosciences, University of Graz, Humboldtstrasse 50, 8010 Graz, Austria
- A.S. and F.M. contributed equally to this work
| | - Fabian Mitterer
- Institute of Molecular Biosciences, University of Graz, Humboldtstrasse 50, 8010 Graz, Austria
- A.S. and F.M. contributed equally to this work
| | - Joao P. Pombo
- Institute of Molecular Biosciences, University of Graz, Humboldtstrasse 50, 8010 Graz, Austria
| | - Stefan Schild
- Institute of Molecular Biosciences, University of Graz, Humboldtstrasse 50, 8010 Graz, Austria
- BioTechMed Graz, Austria
- Field of Excellence Biohealth – University of Graz, Graz, Austria
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Linzner N, Loi VV, Fritsch VN, Antelmann H. Thiol-based redox switches in the major pathogen Staphylococcus aureus. Biol Chem 2020; 402:333-361. [PMID: 33544504 DOI: 10.1515/hsz-2020-0272] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2020] [Accepted: 11/05/2020] [Indexed: 12/15/2022]
Abstract
Staphylococcus aureus is a major human pathogen, which encounters reactive oxygen, nitrogen, chlorine, electrophile and sulfur species (ROS, RNS, RCS, RES and RSS) by the host immune system, during cellular metabolism or antibiotics treatments. To defend against redox active species and antibiotics, S. aureus is equipped with redox sensing regulators that often use thiol switches to control the expression of specific detoxification pathways. In addition, the maintenance of the redox balance is crucial for survival of S. aureus under redox stress during infections, which is accomplished by the low molecular weight (LMW) thiol bacillithiol (BSH) and the associated bacilliredoxin (Brx)/BSH/bacillithiol disulfide reductase (YpdA)/NADPH pathway. Here, we present an overview of thiol-based redox sensors, its associated enzymatic detoxification systems and BSH-related regulatory mechanisms in S. aureus, which are important for the defense under redox stress conditions. Application of the novel Brx-roGFP2 biosensor provides new insights on the impact of these systems on the BSH redox potential. These thiol switches of S. aureus function in protection against redox active desinfectants and antimicrobials, including HOCl, the AGXX® antimicrobial surface coating, allicin from garlic and the naphthoquinone lapachol. Thus, thiol switches could be novel drug targets for the development of alternative redox-based therapies to combat multi-drug resistant S. aureus isolates.
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Affiliation(s)
- Nico Linzner
- Freie Universität Berlin, Institute of Biology-Microbiology, Königin-Luise-Straße 12-16, D-14195Berlin, Germany
| | - Vu Van Loi
- Freie Universität Berlin, Institute of Biology-Microbiology, Königin-Luise-Straße 12-16, D-14195Berlin, Germany
| | - Verena Nadin Fritsch
- Freie Universität Berlin, Institute of Biology-Microbiology, Königin-Luise-Straße 12-16, D-14195Berlin, Germany
| | - Haike Antelmann
- Freie Universität Berlin, Institute of Biology-Microbiology, Königin-Luise-Straße 12-16, D-14195Berlin, Germany
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25
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Schelin J, Cohn MT, Frisk B, Frees D. A Functional ClpXP Protease is Required for Induction of the Accessory Toxin Genes, tst, sed, and sec. Toxins (Basel) 2020; 12:E553. [PMID: 32872362 PMCID: PMC7551677 DOI: 10.3390/toxins12090553] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2020] [Revised: 08/21/2020] [Accepted: 08/26/2020] [Indexed: 01/09/2023] Open
Abstract
Staphylococcal toxic shock syndrome is a potentially lethal illness attributed to superantigens produced by Staphylococcus aureus, in particular toxic shock syndrome toxin 1 (TSST-1), but staphylococcal enterotoxins (SEs) are also implicated. The genes encoding these important toxins are carried on mobile genetic elements, and the regulatory networks controlling expression of these toxins remain relatively unexplored. We show here that the highly conserved ClpXP protease stimulates transcription of tst (TSST-1), sec (SEC), and sed (SED) genes in the prototypical strains, SA564 and RN4282. In the wild-type cells, the post-exponential upregulation of toxin gene transcription was proposed to occur via RNAIII-mediated downregulation of the Rot repressor. Contradictive to this model, we showed that the post-exponential induction of tst, sed, and sec transcription did not occur in cells devoid of ClpXP activity, despite the Rot level being diminished. To identify transcriptional regulators with a changed expression in cells devoid of ClpXP activity, RNA sequencing was performed. The RNAseq analysis revealed a number of global virulence regulators that might act downstream of ClpXP, to control expression of tst and other virulence genes. Collectively, the results extend our understanding of the complex transcriptional regulation of the tst, sed, and sec genes.
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Affiliation(s)
- Jenny Schelin
- Division of Applied Microbiology, Department of Chemistry, Lund University, SE-221 00 Lund, Sweden; (J.S.); (B.F.)
| | - Marianne Thorup Cohn
- Department of Veterinary and Animal Sciences, University of Copenhagen, 1870 Frederikberg C, Denmark;
| | - Barbro Frisk
- Division of Applied Microbiology, Department of Chemistry, Lund University, SE-221 00 Lund, Sweden; (J.S.); (B.F.)
| | - Dorte Frees
- Department of Veterinary and Animal Sciences, University of Copenhagen, 1870 Frederikberg C, Denmark;
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26
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Butrico CE, Cassat JE. Quorum Sensing and Toxin Production in Staphylococcus aureus Osteomyelitis: Pathogenesis and Paradox. Toxins (Basel) 2020; 12:toxins12080516. [PMID: 32806558 PMCID: PMC7471978 DOI: 10.3390/toxins12080516] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2020] [Revised: 08/04/2020] [Accepted: 08/10/2020] [Indexed: 01/18/2023] Open
Abstract
Staphylococcus aureus is a Gram-positive pathogen capable of infecting nearly every vertebrate organ. Among these tissues, invasive infection of bone (osteomyelitis) is particularly common and induces high morbidity. Treatment of osteomyelitis is notoriously difficult and often requires debridement of diseased bone in conjunction with prolonged antibiotic treatment to resolve infection. During osteomyelitis, S. aureus forms characteristic multicellular microcolonies in distinct niches within bone. Virulence and metabolic responses within these multicellular microcolonies are coordinated, in part, by quorum sensing via the accessory gene regulator (agr) locus, which allows staphylococcal populations to produce toxins and adapt in response to bacterial density. During osteomyelitis, the Agr system significantly contributes to dysregulation of skeletal homeostasis and disease severity but may also paradoxically inhibit persistence in the host. Moreover, the Agr system is subject to complex crosstalk with other S. aureus regulatory systems, including SaeRS and SrrAB, which can significantly impact the progression of osteomyelitis. The objective of this review is to highlight Agr regulation, its implications on toxin production, factors that affect Agr activation, and the potential paradoxical influences of Agr regulation on disease progression during osteomyelitis.
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Affiliation(s)
- Casey E. Butrico
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University Medical Center, Nashville, TN 37232, USA;
| | - James E. Cassat
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University Medical Center, Nashville, TN 37232, USA;
- Department of Pediatrics, Division of Pediatric Infectious Diseases, Vanderbilt University Medical Center, Nashville, TN 37232, USA
- Vanderbilt Center for Bone Biology, Vanderbilt University Medical Center, Nashville, TN 37232, USA
- Department of Biomedical Engineering, Vanderbilt University, Nashville, TN 37232, USA
- Vanderbilt Institute for Infection, Immunology, and Inflammation (VI4), Vanderbilt University Medical Center, Nashville, TN 37232, USA
- Correspondence: ; Tel.: +1-615-936-6494
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27
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Zaatout N, Ayachi A, Kecha M. Staphylococcus aureus persistence properties associated with bovine mastitis and alternative therapeutic modalities. J Appl Microbiol 2020; 129:1102-1119. [PMID: 32416020 DOI: 10.1111/jam.14706] [Citation(s) in RCA: 52] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2020] [Revised: 04/15/2020] [Accepted: 05/09/2020] [Indexed: 12/12/2022]
Abstract
Staphylococcus aureus is an important agent of contagious bovine intramammary infections in dairy cattle. Its ability to persist inside the udder is based on the presence of important mechanisms such as its ability to form biofilms, polysaccharide capsules small colony variants, and their ability to invade professional and nonprofessional cells, which will protect S. aureus from the innate and adaptive immune response of the cow, and from antibiotics that are no longer considered to be sufficient against S. aureus bovine mastitis. In this review, we present the recent research outlining S. aureus persistence properties inside the mammary gland, including its regulation mechanisms, and we highlight alternative therapeutic strategies that were tested against S. aureus isolated from bovine mastitis such as the use of probiotic bacteria, bacteriocins and bacteriophages. Overall, the persistence of S. aureus inside the mammary gland remains a pressing veterinary problem. A thorough understanding of staphylococcal persistence mechanisms will elucidate novel ways that can help in the identification of novel treatments.
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Affiliation(s)
- N Zaatout
- Laboratory of Applied Microbiology, Faculty of Nature and Life Sciences, University of Bejaia, Bejaia, Algeria
| | - A Ayachi
- Institute of Veterinary and Agricultural Sciences, University of Batna, Batna, Algeria
| | - M Kecha
- Laboratory of Applied Microbiology, Faculty of Nature and Life Sciences, University of Bejaia, Bejaia, Algeria
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28
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Abstract
In the 1980s, menstrual toxic shock syndrome (mTSS) became a household topic, particularly among mothers and their daughters. The research performed at the time, and for the first time, exposed the American public as well as the biomedical community, in a major way, to understanding disease progression and investigation. Those studies led to the identification of the cause, Staphylococcus aureus and the pyrogenic toxin superantigen TSS toxin 1 (TSST-1), and many of the risk factors, for example, tampon use. Those studies in turn led to TSS warning labels on the outside and inside of tampon boxes and, as important, uniform standards worldwide of tampon absorbency labeling. This review addresses our understanding of the development and conclusions related to mTSS and risk factors. We leave the final message that even though mTSS is not commonly in the news today, cases continue to occur. Additionally, S. aureus strains cycle in human populations in roughly 10-year intervals, possibly dependent on immune status. TSST-1-producing S. aureus bacteria appear to be reemerging, suggesting that physician awareness of this emergence and mTSS history should be heightened.
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29
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Chamon RC, Marques LM, Timenetsky J, da Costa Rachid CT, Ferreira RB, de Oliveira TL, Glatthardt T, de Oliveira Moreira L, dos Santos KR. Genome Sequence of a Highly Virulent pvl-positive Vancomycin intermediate- resistant Staphylococcus aureus Sequence Type 30. Curr Genomics 2020; 21:128-137. [PMID: 32655307 PMCID: PMC7324871 DOI: 10.2174/1389202921666200327105756] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2020] [Revised: 03/16/2020] [Accepted: 03/16/2020] [Indexed: 11/22/2022] Open
Abstract
Background:
Staphylococcus aureus isolates expressing the Panton-Valentine Leukocidin
(PVL) have been related to a wide range of diseases. Recently, pvl-positive community-associated
methicillin-resistant S. aureus belonging to USA1100 (ST30/CC30/SCCmec IV) lineage has emerged
in Brazilian hospitals.
Objective:
The aim of this work was to sequence the genome of a pvl-positive USA1100 Vancomycin-
Intermediate-Resistant S. aureus (VISA) isolate from Rio de Janeiro, Brazil.
Methods:
The 13420 genome was sequenced using the HiSeq 2500 platform. The draft genome, plasmids
annotation, and genome analysis were performed using RAST. Comparison of the relative pvl
gene expression of six S. aureus isolates was performed by qRT-PCR.
Results:
The isolate presented the ϕPVL phage codifying for the H2b PVL protein isoform, and another
prophage carrying a PVL variant named lukF and lukS-PV.2. The 13420 genome presented a
high number of virulence determinants, such as genes codifying for serine-protease proteins, enterotoxins
(egc), the immune evasion cluster (IEC), adhesion proteins, spermine/spermidine acetyltransferase
gene (blt), superantigen-like proteins, as well as the ica operon. Point mutations at vraS, tcaA,
and tcaB genes were detected. Moreover, the PVL mRNA relative expression of the 13420 isolate was
five times higher than mRNA PVL levels of the USA300/ST8 reference strain.
Conclusion:
We described for the first time the genome sequence of a VISA isolate harboring two
pvl-associated genes and other virulence factors that may improve the USA1100/ST30 lineage fitness
and impact its pathogenicity and spreading at Brazilian hospitals.
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Affiliation(s)
- Raiane C. Chamon
- Laboratorio de Infeccao Hospitalar, Departamento de Microbiologia Medica, Instituto de Microbiologia Paulo de Goes, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
| | - Lucas M. Marques
- Instituto Multidisciplinar em Saúde, Universidade Federal da Bahia, Bahia, Brazil
| | - Jorge Timenetsky
- Instituto de Ciencias Biomedicas, Universidade de Sao Paulo, Sao Paulo, Brazil
| | - Caio T.C. da Costa Rachid
- Departamento de Microbiologia Geral, Instituto de Microbiologia Paulo de Goes, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
| | - Rosana B.R. Ferreira
- Laboratorio de Infeccao Hospitalar, Departamento de Microbiologia Medica, Instituto de Microbiologia Paulo de Goes, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
| | - Tamara L.R. de Oliveira
- Laboratorio de Infeccao Hospitalar, Departamento de Microbiologia Medica, Instituto de Microbiologia Paulo de Goes, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
| | - Thais Glatthardt
- Laboratorio de Infeccao Hospitalar, Departamento de Microbiologia Medica, Instituto de Microbiologia Paulo de Goes, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
| | - Lilian de Oliveira Moreira
- Laboratorio de Bacteriologia e Imunologia Clinica, Departamento de Analises Clínicas e Toxicologicas, Faculdade de Farmacia, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
| | - Kátia R.N. dos Santos
- Laboratorio de Infeccao Hospitalar, Departamento de Microbiologia Medica, Instituto de Microbiologia Paulo de Goes, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
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30
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Rudra P, Boyd JM. Metabolic control of virulence factor production in Staphylococcus aureus. Curr Opin Microbiol 2020; 55:81-87. [PMID: 32388086 DOI: 10.1016/j.mib.2020.03.004] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2019] [Revised: 03/09/2020] [Accepted: 03/10/2020] [Indexed: 12/27/2022]
Abstract
As investigators decipher the underlining mechanisms of Staphylococcus aureus pathogenesis, it is becoming apparent that perturbations in central metabolism alter virulence factor production and infection outcomes. It is also evident that S. aureus has the ability to metabolically adapt to improve colonization and overcome challenges imparted by the immune system. Altered metabolite pools modify virulence factor production suggesting that proper functioning of a core metabolic network is necessary for successful niche colonization and pathogenesis. Herein we discuss four examples of transcriptional regulators that monitor metabolic status. These regulatory systems sense perturbations in the metabolic network and respond by altering the transcription of genes utilized for central metabolism, energy generation and pathogenesis.
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Affiliation(s)
- Paulami Rudra
- Department of Biochemistry and Microbiology, Rutgers, the State University of New Jersey, New Brunswick, NJ 08901, USA
| | - Jeffrey M Boyd
- Department of Biochemistry and Microbiology, Rutgers, the State University of New Jersey, New Brunswick, NJ 08901, USA.
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31
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The SrrAB two-component system regulates Staphylococcus aureus pathogenicity through redox sensitive cysteines. Proc Natl Acad Sci U S A 2020; 117:10989-10999. [PMID: 32354997 DOI: 10.1073/pnas.1921307117] [Citation(s) in RCA: 54] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Staphylococcus aureus infections can lead to diseases that range from localized skin abscess to life-threatening toxic shock syndrome. The SrrAB two-component system (TCS) is a global regulator of S. aureus virulence and critical for survival under environmental conditions such as hypoxic, oxidative, and nitrosative stress found at sites of infection. Despite the critical role of SrrAB in S. aureus pathogenicity, the mechanism by which the SrrAB TCS senses and responds to these environmental signals remains unknown. Bioinformatics analysis showed that the SrrB histidine kinase contains several domains, including an extracellular Cache domain and a cytoplasmic HAMP-PAS-DHp-CA region. Here, we show that the PAS domain regulates both kinase and phosphatase enzyme activity of SrrB and present the structure of the DHp-CA catalytic core. Importantly, this structure shows a unique intramolecular cysteine disulfide bond in the ATP-binding domain that significantly affects autophosphorylation kinetics. In vitro data show that the redox state of the disulfide bond affects S. aureus biofilm formation and toxic shock syndrome toxin-1 production. Moreover, with the use of the rabbit infective endocarditis model, we demonstrate that the disulfide bond is a critical regulatory element of SrrB function during S. aureus infection. Our data support a model whereby the disulfide bond and PAS domain of SrrB sense and respond to the cellular redox environment to regulate S. aureus survival and pathogenesis.
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32
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Schurig-Briccio LA, Parraga Solorzano PK, Lencina AM, Radin JN, Chen GY, Sauer JD, Kehl-Fie TE, Gennis RB. Role of respiratory NADH oxidation in the regulation of Staphylococcus aureus virulence. EMBO Rep 2020; 21:e45832. [PMID: 32202364 DOI: 10.15252/embr.201845832] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2018] [Revised: 02/21/2020] [Accepted: 02/26/2020] [Indexed: 01/28/2023] Open
Abstract
The success of Staphylococcus aureus as a pathogen is due to its capability of fine-tuning its cellular physiology to meet the challenges presented by diverse environments, which allows it to colonize multiple niches within a single vertebrate host. Elucidating the roles of energy-yielding metabolic pathways could uncover attractive therapeutic strategies and targets. In this work, we seek to determine the effects of disabling NADH-dependent aerobic respiration on the physiology of S. aureus. Differing from many pathogens, S. aureus has two type-2 respiratory NADH dehydrogenases (NDH-2s) but lacks the respiratory ion-pumping NDHs. Here, we show that the NDH-2s, individually or together, are not essential either for respiration or growth. Nevertheless, their absence eliminates biofilm formation, production of α-toxin, and reduces the ability to colonize specific organs in a mouse model of systemic infection. Moreover, we demonstrate that the reason behind these phenotypes is the alteration of the fatty acid metabolism. Importantly, the SaeRS two-component system, which responds to fatty acids regulation, is responsible for the link between NADH-dependent respiration and virulence in S. aureus.
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Affiliation(s)
| | - Paola K Parraga Solorzano
- Department of Microbiology, University of Illinois, Urbana, IL, USA.,Departamento de Ciencias de la Vida, Universidad de las Fuerzas Armada ESPE, Sangolquí, Ecuador
| | - Andrea M Lencina
- Department of Biochemistry, University of Illinois, Urbana, IL, USA
| | - Jana N Radin
- Department of Microbiology, University of Illinois, Urbana, IL, USA
| | - Grischa Y Chen
- Department of Medical Microbiology and Immunology, University of Wisconsin-Madison, Madison, WI, USA
| | - John-Demian Sauer
- Department of Medical Microbiology and Immunology, University of Wisconsin-Madison, Madison, WI, USA
| | - Thomas E Kehl-Fie
- Department of Microbiology, University of Illinois, Urbana, IL, USA.,Carl R. Woese Institute for Genomic Biology, University of Illinois, Urbana, IL, USA
| | - Robert B Gennis
- Department of Biochemistry, University of Illinois, Urbana, IL, USA
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33
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Effect of non-absorbent intravaginal menstrual/contraceptive products on Staphylococcus aureus and production of the superantigen TSST-1. Eur J Clin Microbiol Infect Dis 2019; 39:31-38. [PMID: 31853743 DOI: 10.1007/s10096-019-03685-x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2019] [Accepted: 08/22/2019] [Indexed: 10/25/2022]
Abstract
Tampons are associated with toxic shock syndrome (mTSS). One reason for this association is oxygen introduction within tampons into the anaerobic vagina. Oxygen is required for Staphylococcus aureus to produce TSS toxin-1 (TSST-1). There have been changes in use of medical devices to control menstrual flow, including increased use of menstrual discs and cups. These devices composed of solid, flexible materials do not absorb menstrual fluid and thus do not trap oxygen. This study evaluates tampons and non-absorbent devices for effect on S. aureus and TSST-1 production. There are three in vitro tests to evaluate devices for effect on TSST-1 production: (1) stationary flask, (2) shake flask, and (3) tampon sac. In this study, 100% rayon and 100% cotton tampons with three absorbencies, contraceptive diaphragms, and menstrual discs and cups were tested for effect on S. aureus growth and TSST-1 production. Product composition did not affect bacterial growth or TSST-1 production. Tampons showed no effect on S. aureus growth compared with no-tampon controls, but tampons showed enhanced TSST-1 production as a function of trapped oxygen in stationary cultures and tampon sacs but not in shake flasks. The non-absorbent devices showed no enhanced S. aureus growth or TSST-1 production compared with no-device controls. These studies are consistent with the association of tampons with mTSS as a function of absorbency, but they suggest the occasional association of mTSS with non-absorbent devices may be coincidental as opposed to co-causative.
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34
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Analysis of the influence of cyclo (L-phenylalanine-L-proline) on the proteome of Staphylococcus aureus using iTRAQ. ANN MICROBIOL 2019. [DOI: 10.1007/s13213-019-01508-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
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35
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Influence of protein and vitamin B2 as nutrients of chicken meat on staphylococcal enterotoxin genes expression via virulence regulators. Lebensm Wiss Technol 2019. [DOI: 10.1016/j.lwt.2019.05.097] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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36
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The ClpCP Complex Modulates Respiratory Metabolism in Staphylococcus aureus and Is Regulated in a SrrAB-Dependent Manner. J Bacteriol 2019; 201:JB.00188-19. [PMID: 31109995 DOI: 10.1128/jb.00188-19] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2019] [Accepted: 05/17/2019] [Indexed: 01/13/2023] Open
Abstract
The staphylococcal respiratory regulator (SrrAB) modulates energy metabolism in Staphylococcus aureus Studies have suggested that regulated protein catabolism facilitates energy homeostasis. Regulated proteolysis in S. aureus is achieved through protein complexes composed of a peptidase (ClpQ or ClpP) in association with an AAA+ family ATPase (typically, ClpC or ClpX). In the present report, we tested the hypothesis that SrrAB regulates a Clp complex to facilitate energy homeostasis in S. aureus Strains deficient in one or more Clp complexes were attenuated for growth in the presence of puromycin, which causes enrichment of misfolded proteins. A ΔsrrAB strain had increased sensitivity to puromycin. Epistasis experiments suggested that the puromycin sensitivity phenotype of the ΔsrrAB strain was a result of decreased ClpC activity. Consistent with this, transcriptional activity of clpC was decreased in the ΔsrrAB mutant, and overexpression of clpC suppressed the puromycin sensitivity of the ΔsrrAB strain. We also found that ClpC positively influenced respiration and that it did so upon association with ClpP. In contrast, ClpC limited fermentative growth, while ClpP was required for optimal fermentative growth. Metabolomics studies demonstrated that intracellular metabolic profiles of the ΔclpC and ΔsrrAB mutants were distinct from those of the wild-type strain, supporting the notion that both ClpC and SrrAB affect central metabolism. We propose a model wherein SrrAB regulates energy homeostasis, in part, via modulation of regulated proteolysis.IMPORTANCE Oxygen is used as a substrate to derive energy by the bacterial pathogen Staphylococcus aureus during infection; however, S. aureus can also grow fermentatively in the absence of oxygen. To successfully cause infection, S. aureus must tailor its metabolism to take advantage of respiratory activity. Different proteins are required for growth in the presence or absence of oxygen; therefore, when cells transition between these conditions, several proteins would be expected to become unnecessary. In this report, we show that regulated proteolysis is used to modulate energy metabolism in S. aureus We report that the ClpCP protein complex is involved in specifically modulating aerobic respiratory growth but is dispensable for fermentative growth.
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37
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Zhao H, Xu S, Yang H, He C, Xu X, Hu F, Shu W, Gong F, Zhang C, Liu Q. Molecular Typing and Variations in Amount of tst Gene Expression of TSST-1-Producing Clinical Staphylococcus aureus Isolates. Front Microbiol 2019; 10:1388. [PMID: 31275293 PMCID: PMC6594356 DOI: 10.3389/fmicb.2019.01388] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2019] [Accepted: 06/03/2019] [Indexed: 12/25/2022] Open
Abstract
The toxic shock syndrome toxin-1 (TSST-1), encoded by tst gene, has been proposed to cause staphylococcal toxic shock syndrome (TSS) in a susceptible host, which highlights the need to evaluate the level of tst gene expression and molecular genetic characteristics of the tst-positive isolates. A total of 916 S. aureus isolates collected from seven hospitals in China were screened for the tst gene. The tst positive isolates were characterized by spa, SCCmec, PFGE, and agr typing. Representative strains were also subjected to MLST typing. qRT-PCR was used to quantify tst and major virulence regulator genes expression. We also sequenced the regions of promoter and open reading frame (ORF) of tst to investigate whether they correlate with the variation in tst expression. We found 208 (22.7%) of surveyed isolates including 198 (29.8%) of MRSA and 10 (4.0%) of MSSA isolates harbored the tst gene. The most common clone among tst positive MRSA isolates belonged to ST5 (CC5)-agr2-t002-SCCmecII. The amount of tst mRNA varied 8.4-folds among clinical S. aureus isolates. Sequencing the tst promoter revealed a base T deletion in tst high expressed isolates. As for major virulence regulators, srrA, sarT, RNAIII, and ccpA in four tst differentially expressed strains were detected to be highly expressed, respectively. Our study revealed high prevalence of ST5 (CC5)-agr2-t002-SCCmecII clone among tst positive MRSA in hospitals from China. The levels of tst expression among clinical S. aureus isolates varied, which may be associated with tst promoter and variations in specific virulence regulators.
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Affiliation(s)
- Huanqiang Zhao
- Department of Clinical Laboratory, Shanghai General Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China
| | - Su Xu
- Institute of Antibiotics, Huashan Hospital, Fudan University, Shanghai, China
| | - Han Yang
- Department of Clinical Laboratory, Shanghai General Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China
| | - Chunyan He
- Department of Clinical Laboratory, Shanghai General Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China
| | - Xiaogang Xu
- Institute of Antibiotics, Huashan Hospital, Fudan University, Shanghai, China
| | - Fupin Hu
- Institute of Antibiotics, Huashan Hospital, Fudan University, Shanghai, China
| | - Wen Shu
- Department of Clinical Laboratory, Shanghai General Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China
| | - Fang Gong
- Department of Clinical Laboratory, the Third Hospital Affiliated to Nantong University, Wuxi, China
| | - Chuanling Zhang
- Department of Clinical Laboratory, Xiaoshan Hospital, Hangzhou, China
| | - Qingzhong Liu
- Department of Clinical Laboratory, Shanghai General Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China
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Graf AC, Leonard A, Schäuble M, Rieckmann LM, Hoyer J, Maass S, Lalk M, Becher D, Pané-Farré J, Riedel K. Virulence Factors Produced by Staphylococcus aureus Biofilms Have a Moonlighting Function Contributing to Biofilm Integrity. Mol Cell Proteomics 2019; 18:1036-1053. [PMID: 30850421 PMCID: PMC6553939 DOI: 10.1074/mcp.ra118.001120] [Citation(s) in RCA: 68] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2018] [Revised: 02/19/2019] [Indexed: 12/11/2022] Open
Abstract
Staphylococcus aureus is the causative agent of various biofilm-associated infections in humans causing major healthcare problems worldwide. This type of infection is inherently difficult to treat because of a reduced metabolic activity of biofilm-embedded cells and the protective nature of a surrounding extracellular matrix (ECM). However, little is known about S. aureus biofilm physiology and the proteinaceous composition of the ECM. Thus, we cultivated S. aureus biofilms in a flow system and comprehensively profiled intracellular and extracellular (ECM and flow-through (FT)) biofilm proteomes, as well as the extracellular metabolome compared with planktonic cultures. Our analyses revealed the expression of many pathogenicity factors within S. aureus biofilms as indicated by a high abundance of capsule biosynthesis proteins along with various secreted virulence factors, including hemolysins, leukotoxins, and lipases as a part of the ECM. The activity of ECM virulence factors was confirmed in a hemolysis assay and a Galleria mellonella pathogenicity model. In addition, we uncovered a so far unacknowledged moonlighting function of secreted virulence factors and ribosomal proteins trapped in the ECM: namely their contribution to biofilm integrity. Mechanistically, it was revealed that this stabilizing effect is mediated by the strong positive charge of alkaline virulence factors and ribosomal proteins in an acidic ECM environment, which is caused by the release of fermentation products like formate, lactate, and acetate because of oxygen limitation in biofilms. The strong positive charge of these proteins most likely mediates electrostatic interactions with anionic cell surface components, eDNA, and anionic metabolites. In consequence, this leads to strong cell aggregation and biofilm stabilization. Collectively, our study identified a new molecular mechanism during S. aureus biofilm formation and thus significantly widens the understanding of biofilm-associated S. aureus infections - an essential prerequisite for the development of novel antimicrobial therapies.
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Affiliation(s)
- Alexander C Graf
- From the ‡Institute of Microbiology, Department of Microbial Physiology and Molecular Biology
| | - Anne Leonard
- §Institute of Biochemistry, Department of Cellular Biochemistry and Metabolomics
| | - Manuel Schäuble
- From the ‡Institute of Microbiology, Department of Microbial Physiology and Molecular Biology
| | - Lisa M Rieckmann
- From the ‡Institute of Microbiology, Department of Microbial Physiology and Molecular Biology
| | - Juliane Hoyer
- ¶Institute of Microbiology, Department of Microbial Proteomics; University of Greifswald, Germany
| | - Sandra Maass
- ¶Institute of Microbiology, Department of Microbial Proteomics; University of Greifswald, Germany
| | - Michael Lalk
- §Institute of Biochemistry, Department of Cellular Biochemistry and Metabolomics
| | - Dörte Becher
- ¶Institute of Microbiology, Department of Microbial Proteomics; University of Greifswald, Germany
| | - Jan Pané-Farré
- From the ‡Institute of Microbiology, Department of Microbial Physiology and Molecular Biology
| | - Katharina Riedel
- From the ‡Institute of Microbiology, Department of Microbial Physiology and Molecular Biology;
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39
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Ming T, Geng L, Feng Y, Lu C, Zhou J, Li Y, Zhang D, He S, Li Y, Cheong L, Su X. iTRAQ-Based Quantitative Proteomic Profiling of Staphylococcus aureus Under Different Osmotic Stress Conditions. Front Microbiol 2019; 10:1082. [PMID: 31191466 PMCID: PMC6549500 DOI: 10.3389/fmicb.2019.01082] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2018] [Accepted: 04/29/2019] [Indexed: 02/03/2023] Open
Abstract
Staphylococcus aureus (S. aureus) is an extremely halotolerant pathogenic bacterium with high osmotic stress tolerance, and it is frequently encountered in aquatic production and preservation. However, the mechanism underlying the extremely high osmotic stress tolerance of S. aureus remains unclear. In this study, the isobaric tags for relative and absolute quantification (iTRAQ) method was used to identify the differentially expressed proteins (DEPs) under different sodium chloride (NaCl) concentrations. Compared with the control group (0% NaCl), the 10 and 20% NaCl groups had 484 DEPs and 750 DEPs, respectively. Compared with the 10% NaCl group, the 20% NaCl group had 361 DEPs. Among the DEPs, proteins involved in fatty acid synthesis, proline/glycine betaine biosynthesis and transportation, stress tolerance, cell wall biosynthesis and the TCA cycle were upregulated, whereas proteins associated with biofilm formation and pathogenic infections were downregulated. The results obtained in this study indicate that under extremely high osmotic stress, modification of the cell membrane structure, increased biosynthesis and transportation of osmotic protectants, and redistribution of energy metabolism contribute to the osmotic stress tolerance of S. aureus, and the infectious ability of the bacteria may be limited. The aim of this study was to provide new insight into how S. aureus tolerates the high-salt conditions involved in aquatic production and preservation.
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Affiliation(s)
- Tinghong Ming
- School of Marine Sciences, Ningbo University, Ningbo, China.,College of Food and Pharmaceutical Sciences, Ningbo University, Ningbo, China
| | - Lingxin Geng
- School of Marine Sciences, Ningbo University, Ningbo, China.,College of Food and Pharmaceutical Sciences, Ningbo University, Ningbo, China
| | - Ying Feng
- School of Marine Sciences, Ningbo University, Ningbo, China
| | - Chenyang Lu
- School of Marine Sciences, Ningbo University, Ningbo, China
| | - Jun Zhou
- School of Marine Sciences, Ningbo University, Ningbo, China
| | - Yanyan Li
- Department of Biological and Environmental Science and Engineering, King Abdullah University of Science and Technology, Thuwal, Saudi Arabia
| | - Dijun Zhang
- Zhejiang Zhengli Antuo Biotechnology Co., Ltd, Ningbo, China
| | - Shan He
- School of Marine Sciences, Ningbo University, Ningbo, China
| | - Ye Li
- School of Marine Sciences, Ningbo University, Ningbo, China
| | - Lingzhi Cheong
- College of Food and Pharmaceutical Sciences, Ningbo University, Ningbo, China
| | - Xiurong Su
- School of Marine Sciences, Ningbo University, Ningbo, China
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40
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Jenul C, Horswill AR. Regulation of Staphylococcus aureus Virulence. Microbiol Spectr 2019; 7:10.1128/microbiolspec.gpp3-0031-2018. [PMID: 30953424 PMCID: PMC6452892 DOI: 10.1128/microbiolspec.gpp3-0031-2018] [Citation(s) in RCA: 301] [Impact Index Per Article: 50.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2018] [Indexed: 01/15/2023] Open
Abstract
Staphylococcus aureus is a Gram-positive opportunistic pathogen that has evolved a complex regulatory network to control virulence. One of the main functions of this interconnected network is to sense various environmental cues and respond by altering the production of virulence factors necessary for survival in the host, including cell surface adhesins and extracellular enzymes and toxins. Of these S. aureus regulatory systems, one of the best studied is the accessory gene regulator (agr), which is a quorum-sensing system that senses the local concentration of a cyclic peptide signaling molecule. This system allows S. aureus to sense its own population density and translate this information into a specific gene expression pattern. Besides agr, this pathogen uses other two-component systems to sense specific cues and coordinates responses with cytoplasmic regulators of the SarA protein family and alternative sigma factors. These divergent regulatory systems integrate the various environmental and host-derived signals into a network that ensures optimal pathogen response to the changing conditions. This article gives an overview of the most important and best-studied S. aureus regulatory systems and summarizes the functions of these regulators during host interactions. The regulatory systems discussed include the agr quorum-sensing system; the SaeRS, SrrAB, and ArlRS two-component systems, the cytoplasmic SarA-family regulators (SarA, Rot, and MgrA); and the alternative sigma factors (SigB and SigH).
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Affiliation(s)
- Christian Jenul
- Department of Immunology and Microbiology, University of Colorado Anschutz Medical Campus, Aurora, CO 80045
| | - Alexander R Horswill
- Department of Immunology and Microbiology, University of Colorado Anschutz Medical Campus, Aurora, CO 80045
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41
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Marincola G, Wencker FDR, Ziebuhr W. The Many Facets of the Small Non-coding RNA RsaE (RoxS) in Metabolic Niche Adaptation of Gram-Positive Bacteria. J Mol Biol 2019; 431:4684-4698. [PMID: 30914292 DOI: 10.1016/j.jmb.2019.03.016] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2019] [Revised: 03/13/2019] [Accepted: 03/13/2019] [Indexed: 01/01/2023]
Abstract
Small regulatory RNAs (sRNAs) are increasingly recognized as players in the complex regulatory networks governing bacterial gene expression. RsaE (synonym RoxS) is an sRNA that is highly conserved in bacteria of the Bacillales order. Recent analyses in Bacillus subtilis, Staphylococcus aureus and Staphylococcus epidermidis identified RsaE/RoxS as a potent riboregulator of central carbon metabolism and energy balance with many molecular RsaE/RoxS functions and targets being shared across species. Similarities and species-specific differences in cellular processes modulated by RsaE/RoxS suggest that this sRNA plays a prominent role in the adaptation of Gram-positive bacteria to niches with varying nutrient availabilities and environmental cues. This review summarizes recent findings on the molecular function of RsaE/RoxS and its interaction with mRNA targets. Special emphasis will be on the integration of RsaE/RoxS into metabolic regulatory circuits and, derived from this, the role of RsaE/RoxS as a putative driver to generate phenotypic heterogeneity in bacterial populations. In this respect, we will particularly discuss heterogeneous RsaE expression in S. epidermidis biofilms and its possible contribution to metabolic niche diversification, programmed bacterial lysis and biofilm matrix production.
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Affiliation(s)
- Gabriella Marincola
- Institute of Molecular Infection Biology, University of Würzburg, Josef-Schneider-Str. 2, 97080 Würzburg, Germany
| | - Freya D R Wencker
- Institute of Molecular Infection Biology, University of Würzburg, Josef-Schneider-Str. 2, 97080 Würzburg, Germany
| | - Wilma Ziebuhr
- Institute of Molecular Infection Biology, University of Würzburg, Josef-Schneider-Str. 2, 97080 Würzburg, Germany.
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Abstract
Menstrual toxic shock syndrome (TSS) is a serious infectious disease associated with vaginal colonization by Staphylococcus aureus producing the exotoxin TSS toxin 1 (TSST-1). We show that menstrual TSS occurs after TSST-1 interaction with an immune costimulatory molecule called CD40 on the surface of vaginal epithelial cells. Other related toxins, where the entire family is called the superantigen family, bind to CD40, but not with a high-enough apparent affinity to cause TSS; thus, TSST-1 is the only exotoxin superantigen associated. Once the epithelial cells become activated by TSST-1, they produce soluble molecules referred to as chemokines, which in turn facilitate TSST-1 activation of T lymphocytes and macrophages to cause the symptoms of TSS. Identification of small-molecule inhibitors of the interaction of TSST-1 with CD40 may be useful so that they may serve as additives to medical devices, such as tampons and menstrual cups, to reduce the incidence of menstrual TSS. Mucosal and skin tissues form barriers to infection by most bacterial pathogens. Staphylococcus aureus causes diseases across these barriers in part dependent on the proinflammatory properties of superantigens. We showed, through use of a CRISPR-Cas9 CD40 knockout, that the superantigens toxic shock syndrome toxin 1 (TSST-1) and staphylococcal enterotoxins (SEs) B and C stimulated chemokine production from human vaginal epithelial cells (HVECs) through human CD40. This response was enhanced by addition of antibodies against CD40 through an unknown mechanism. TSST-1 was better able to stimulate chemokine (IL-8 and MIP-3α) production by HVECs than SEB and SEC, suggesting this is the reason for TSST-1’s exclusive association with menstrual TSS. A mutant of TSST-1, K121A, caused TSS in a rabbit model when administered vaginally but not intravenously, emphasizing the importance of the local vaginal environment. Collectively, our data suggested that superantigens facilitate infections by disruption of mucosal barriers through their binding to CD40, with subsequent expression of chemokines. The chemokines facilitate TSS and possibly other epithelial conditions after attraction of the adaptive immune system to the local environment.
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Bronesky D, Desgranges E, Corvaglia A, François P, Caballero CJ, Prado L, Toledo-Arana A, Lasa I, Moreau K, Vandenesch F, Marzi S, Romby P, Caldelari I. A multifaceted small RNA modulates gene expression upon glucose limitation in Staphylococcus aureus. EMBO J 2019; 38:e99363. [PMID: 30760492 PMCID: PMC6418428 DOI: 10.15252/embj.201899363] [Citation(s) in RCA: 39] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2018] [Revised: 12/17/2018] [Accepted: 01/21/2019] [Indexed: 01/10/2023] Open
Abstract
Pathogenic bacteria must rapidly adapt to ever-changing environmental signals resulting in metabolism remodeling. The carbon catabolite repression, mediated by the catabolite control protein A (CcpA), is used to express genes involved in utilization and metabolism of the preferred carbon source. Here, we have identified RsaI as a CcpA-repressed small non-coding RNA that is inhibited by high glucose concentrations. When glucose is consumed, RsaI represses translation initiation of mRNAs encoding a permease of glucose uptake and the FN3K enzyme that protects proteins against damage caused by high glucose concentrations. RsaI also binds to the 3' untranslated region of icaR mRNA encoding the transcriptional repressor of exopolysaccharide production and to sRNAs induced by the uptake of glucose-6 phosphate or nitric oxide. Furthermore, RsaI expression is accompanied by a decreased transcription of genes involved in carbon catabolism pathway and an activation of genes involved in energy production, fermentation, and nitric oxide detoxification. This multifaceted RNA can be considered as a metabolic signature when glucose becomes scarce and growth is arrested.
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Affiliation(s)
- Delphine Bronesky
- Architecture et Réactivité de l'ARN, CNRS, Université de Strasbourg, Strasbourg, France
| | - Emma Desgranges
- Architecture et Réactivité de l'ARN, CNRS, Université de Strasbourg, Strasbourg, France
| | - Anna Corvaglia
- Genomic Research Laboratory, Department of Medical Specialties, Geneva University Hospitals, University of Geneva, Geneva, Switzerland
| | - Patrice François
- Genomic Research Laboratory, Department of Medical Specialties, Geneva University Hospitals, University of Geneva, Geneva, Switzerland
| | | | - Laura Prado
- Instituto de Agrobiotecnología (IdAB), CSIC-UPNA-GN, Navarra, Spain
| | | | - Inigo Lasa
- Navarrabiomed-Universidad Pública de Navarra-Departamento de Salud, IDISNA, Pamplona, Spain
| | - Karen Moreau
- CIRI, Centre international de Recherche en Infectiologie, Inserm, U1111, Université Claude Bernard Lyon 1, CNRS, UMR5308, École Normale Supérieure de Lyon, Hospices Civils de Lyon, Univ Lyon, Lyon, France
| | - François Vandenesch
- CIRI, Centre international de Recherche en Infectiologie, Inserm, U1111, Université Claude Bernard Lyon 1, CNRS, UMR5308, École Normale Supérieure de Lyon, Hospices Civils de Lyon, Univ Lyon, Lyon, France
| | - Stefano Marzi
- Architecture et Réactivité de l'ARN, CNRS, Université de Strasbourg, Strasbourg, France
| | - Pascale Romby
- Architecture et Réactivité de l'ARN, CNRS, Université de Strasbourg, Strasbourg, France
| | - Isabelle Caldelari
- Architecture et Réactivité de l'ARN, CNRS, Université de Strasbourg, Strasbourg, France
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Schoenfelder SMK, Lange C, Prakash SA, Marincola G, Lerch MF, Wencker FDR, Förstner KU, Sharma CM, Ziebuhr W. The small non-coding RNA RsaE influences extracellular matrix composition in Staphylococcus epidermidis biofilm communities. PLoS Pathog 2019; 15:e1007618. [PMID: 30870530 PMCID: PMC6435200 DOI: 10.1371/journal.ppat.1007618] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2018] [Revised: 03/26/2019] [Accepted: 02/04/2019] [Indexed: 12/15/2022] Open
Abstract
RsaE is a conserved small regulatory RNA (sRNA) which was previously reported to represent a riboregulator of central carbon flow and other metabolic pathways in Staphylococcus aureus and Bacillus subtilis. Here we show that RsaE contributes to extracellular (e)DNA release and biofilm-matrix switching towards polysaccharide intercellular adhesin (PIA) production in a hypervariable Staphylococcus epidermidis isolate. Transcriptome analysis through differential RNA sequencing (dRNA-seq) in combination with confocal laser scanning microscopy (CLSM) and reporter gene fusions demonstrate that S. epidermidis protein- and PIA-biofilm matrix producers differ with respect to RsaE and metabolic gene expression. RsaE is spatiotemporally expressed within S. epidermidis PIA-mediated biofilms, and its overexpression triggers a PIA biofilm phenotype as well as eDNA release in an S. epidermidis protein biofilm matrix-producing strain background. dRNA-seq and Northern blot analyses revealed RsaE to exist as a major full-length 100-nt transcript and a minor processed species lacking approximately 20 nucleotides at the 5'-end. RsaE processing results in expansion of the mRNA target spectrum. Thus, full-length RsaE interacts with S. epidermidis antiholin-encoding lrgA mRNA, facilitating bacterial lysis and eDNA release. Processed RsaE, however, interacts with the 5'-UTR of icaR and sucCD mRNAs, encoding the icaADBC biofilm operon repressor IcaR and succinyl-CoA synthetase of the tricarboxylic acid (TCA) cycle, respectively. RsaE augments PIA-mediated biofilm matrix production, most likely through activation of icaADBC operon expression via repression of icaR as well as by TCA cycle inhibition and re-programming of staphylococcal central carbon metabolism towards PIA precursor synthesis. Additionally, RsaE supports biofilm formation by mediating the release of eDNA as stabilizing biofilm matrix component. As RsaE itself is heterogeneously expressed within biofilms, we consider this sRNA to function as a factor favoring phenotypic heterogeneity and supporting division of labor in S. epidermidis biofilm communities. Bacterial biofilms are highly organized structures which functionally emulate multicellular organisms, last but not least through heterogeneous gene expression patterns displayed by biofilm subpopulations. Here we analyzed the functions of the non-coding RNA RsaE in Staphylococcus epidermidis biofilm communities. RsaE exerted unexpected influences on S. epidermidis biofilm matrix composition by triggering localized eDNA release and facilitating PIA expression. RsaE accomplishes these effects by targeting mRNAs involved in bacterial lysis control, icaADBC expression and TCA cycle activity, with RsaE undergoing processing to exploit its full target potential. Interestingly, RsaE interaction with lysis-engaged lrgA mRNA is specific for S. epidermidis lrgA, but does not occur with lrgA mRNA from S. aureus, suggesting species-specific differences in staphylococcal lysis control. We speculate that RsaE-mediated bacterial lysis might represent a form of bacterial altruism contributing to biofilm structuring by providing nutrients to neighboring bacterial cells as well as by releasing eDNA as stabilizing biofilm matrix component. Due to its heterogeneous expression, we consider RsaE as a supporting factor that facilitates population diversity. Together, the data give insight into an unanticipated role of sRNAs as players in S. epidermidis biofilm organization.
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Affiliation(s)
| | - Claudia Lange
- University of Würzburg, Institute of Molecular Infection Biology, Würzburg, Germany
| | | | - Gabriella Marincola
- University of Würzburg, Institute of Molecular Infection Biology, Würzburg, Germany
| | - Maike F. Lerch
- University of Würzburg, Institute of Molecular Infection Biology, Würzburg, Germany
| | - Freya D. R. Wencker
- University of Würzburg, Institute of Molecular Infection Biology, Würzburg, Germany
| | - Konrad U. Förstner
- University of Würzburg, Institute of Molecular Infection Biology, Würzburg, Germany
| | - Cynthia M. Sharma
- University of Würzburg, Institute of Molecular Infection Biology, Würzburg, Germany
| | - Wilma Ziebuhr
- University of Würzburg, Institute of Molecular Infection Biology, Würzburg, Germany
- * E-mail:
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45
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Brüggemann H, Poehlein A, Brzuszkiewicz E, Scavenius C, Enghild JJ, Al-Zeer MA, Brinkmann V, Jensen A, Söderquist B. Staphylococcus saccharolyticus Isolated From Blood Cultures and Prosthetic Joint Infections Exhibits Excessive Genome Decay. Front Microbiol 2019; 10:478. [PMID: 30915059 PMCID: PMC6423177 DOI: 10.3389/fmicb.2019.00478] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2019] [Accepted: 02/25/2019] [Indexed: 12/27/2022] Open
Abstract
The slow-growing, anaerobic, coagulase-negative species Staphylococcus saccharolyticus is found on human skin and in clinical specimens but its pathogenic potential is unclear. Here, we investigated clinical isolates and sequenced the genomes of seven strains of S. saccharolyticus. Phylogenomic analyses showed that the closest relative of S. saccharolyticus is Staphylococcus capitis with an average nucleotide identity of 80%. Previously sequenced strains assigned to S. saccharolyticus are misclassified and belong to S. capitis. Based on single nucleotide polymorphisms of the core genome, the population of S. saccharolyticus can be divided into two clades that also differ in a few larger genomic islands as part of the flexible genome. An unexpected feature of S. saccharolyticus is extensive genome decay, with over 300 pseudogenes, indicating ongoing reductive evolution. Many genes of the core metabolism are not functional, rendering the species auxotrophic for several amino acids, which could explain its slow growth and need for fastidious growth conditions. Secreted proteins of S. saccharolyticus were determined; they include stress response proteins such as heat and oxidative stress-related factors, as well as immunodominant staphylococcal surface antigens and enzymes that can degrade host tissue components. The strains secrete lipases and a hyaluronic acid lyase. Hyaluronidase as well as urease activities were detected in biochemical assays, with clade-specific differences. Our study revealed that S. saccharolyticus has adapted its genome, possibly due to a recent change of habitat; moreover, the data imply that the species has tissue-invasive potential and might cause prosthetic joint infections.
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Affiliation(s)
| | - Anja Poehlein
- Department of Genomic and Applied Microbiology, Institute of Microbiology and Genetics, University of Göttingen, Göttingen, Germany
| | - Elzbieta Brzuszkiewicz
- Department of Genomic and Applied Microbiology, Institute of Microbiology and Genetics, University of Göttingen, Göttingen, Germany
| | - Carsten Scavenius
- Department of Molecular Biology and Genetics, Aarhus University, Aarhus, Denmark
| | - Jan J Enghild
- Department of Molecular Biology and Genetics, Aarhus University, Aarhus, Denmark
| | - Munir A Al-Zeer
- Department of Applied Biochemistry, Institute of Biotechnology, Technical University of Berlin, Berlin, Germany
| | - Volker Brinkmann
- Microscopy Core Facility, Max Planck Institute for Infection Biology, Berlin, Germany
| | - Anders Jensen
- Department of Biomedicine, Aarhus University, Aarhus, Denmark
| | - Bo Söderquist
- Department of Laboratory Medicine, Clinical Microbiology, Faculty of Medicine and Health, Örebro University, Örebro, Sweden
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Abstract
Staphylococcus aureus is clearly the most pathogenic member of the Staphylococcaceae. This is in large part due to the acquisition of an impressive arsenal of virulence factors that are coordinately regulated by a series of dedicated transcription factors. What is becoming more and more appreciated in the field is the influence of the metabolic state of S. aureus on the activity of these virulence regulators and their roles in modulating metabolic gene expression. Here I highlight recent advances in S. aureus metabolism as it pertains to virulence. Specifically, mechanisms of nutrient acquisition are outlined including carbohydrate and non-carbohydrate carbon/energy sources as well as micronutrient (Fe, Mn, Zn and S) acquisition. Additionally, energy producing strategies (respiration versus fermentation) are discussed and put in the context of pathogenesis. Finally, transcriptional regulators that coordinate metabolic gene expression are outlined, particularly those that affect the activities of major virulence factor regulators. This chapter essentially connects many recent observations that link the metabolism of S. aureus to its overall pathogenesis and hints that the mere presence of a plethora of virulence factors may not entirely explain the extraordinary pathogenic potential of S. aureus.
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Affiliation(s)
- Anthony R Richardson
- Department of Microbiology and Molecular Genetics, University of Pittsburgh, Pittsburgh, PA 15219
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47
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Interplay of Nitric Oxide Synthase (NOS) and SrrAB in Modulation of Staphylococcus aureus Metabolism and Virulence. Infect Immun 2019; 87:IAI.00570-18. [PMID: 30420450 DOI: 10.1128/iai.00570-18] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2018] [Accepted: 10/26/2018] [Indexed: 12/15/2022] Open
Abstract
Staphylococcus aureus nitric oxide synthase (saNOS) is a major contributor to virulence, stress resistance, and physiology, yet the specific mechanism(s) by which saNOS intersects with other known regulatory circuits is largely unknown. The SrrAB two-component system, which modulates gene expression in response to the reduced state of respiratory menaquinones, is a positive regulator of nos expression. Several SrrAB-regulated genes were also previously shown to be induced in an aerobically respiring nos mutant, suggesting a potential interplay between saNOS and SrrAB. Therefore, a combination of genetic, molecular, and physiological approaches was employed to characterize a nos srrAB mutant, which had significant reductions in the maximum specific growth rate and oxygen consumption when cultured under conditions promoting aerobic respiration. The nos srrAB mutant secreted elevated lactate levels, correlating with the increased transcription of lactate dehydrogenases. Expression of nitrate and nitrite reductase genes was also significantly enhanced in the nos srrAB double mutant, and its aerobic growth defect could be partially rescued with supplementation with nitrate, nitrite, or ammonia. Furthermore, elevated ornithine and citrulline levels and highly upregulated expression of arginine deiminase genes were observed in the double mutant. These data suggest that a dual deficiency in saNOS and SrrAB limits S. aureus to fermentative metabolism, with a reliance on nitrate assimilation and the urea cycle to help fuel energy production. The nos, srrAB, and nos srrAB mutants showed comparable defects in endothelial intracellular survival, whereas the srrAB and nos srrAB mutants were highly attenuated during murine sepsis, suggesting that SrrAB-mediated metabolic versatility is dominant in vivo.
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48
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Queiroux C, Bonnet M, Saraoui T, Delpech P, Veisseire P, Rifa E, Moussard C, Gagne G, Delbès C, Bornes S. Dialogue between Staphylococcus aureus SA15 and Lactococcus garvieae strains experiencing oxidative stress. BMC Microbiol 2018; 18:193. [PMID: 30466395 PMCID: PMC6251228 DOI: 10.1186/s12866-018-1340-3] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2017] [Accepted: 11/14/2018] [Indexed: 02/02/2023] Open
Abstract
Background Staphylococcus aureus is an important foodborne pathogen. Lactococcus garvieae is a lactic acid bacterium found in dairy products; some of its strains are able to inhibit S. aureus growth by producing H2O2. Three strains of L. garvieae from different origins were tested for their ability to inhibit S. aureus SA15 growth. Two conditions were tested, one in which H2O2 was produced (high aeration) and another one in which it was not detected (low aeration). Several S. aureus genes related to stress, H2O2-response and virulence were examined in order to compare their level of expression depending on the inoculated L. garvieae strain. Simultaneous L. garvieae H2O2 metabolism gene expression was followed. Results The results showed that under high aeration condition, L. garvieae strains producing H2O2 (N201 and CL-1183) inhibited S. aureus SA15 growth and impaired its ability to deal with hydrogen peroxide by repressing H2O2-degrading genes. L. garvieae strains induced overexpression of S. aureus stress-response genes while cell division genes and virulence genes were repressed. A catalase treatment partially or completely restored the SA15 growth. In addition, the H2O2 non-producing L. garvieae strain (Lg2) did not cause any growth inhibition. The SA15 stress-response genes were down-regulated and cell division genes expression was not affected. Under low aeration condition, while none of the strains tested exhibited H2O2-production, the 3 L. garvieae strains inhibited S. aureus SA15 growth, but to a lesser extent than under high aeration condition. Conclusion Taken together, these results suggest a L. garvieae strain-specific anti-staphylococcal mechanism and an H2O2 involvement in at least two of the tested L. garvieae strains. Electronic supplementary material The online version of this article (10.1186/s12866-018-1340-3) contains supplementary material, which is available to authorized users.
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Affiliation(s)
| | - Muriel Bonnet
- Université Clermont Auvergne, INRA, UMRF, F-15000, Aurillac, France
| | - Taous Saraoui
- Université Clermont Auvergne, INRA, UMRF, F-15000, Aurillac, France
| | - Pierre Delpech
- Université Clermont Auvergne, INRA, UMRF, F-15000, Aurillac, France
| | | | - Etienne Rifa
- Université Clermont Auvergne, INRA, UMRF, F-15000, Aurillac, France
| | - Cécile Moussard
- Université Clermont Auvergne, INRA, UMRF, F-15000, Aurillac, France
| | - Geneviève Gagne
- Université Clermont Auvergne, INRA, UMRF, F-15000, Aurillac, France
| | - Céline Delbès
- Université Clermont Auvergne, INRA, UMRF, F-15000, Aurillac, France.
| | - Stéphanie Bornes
- Université Clermont Auvergne, INRA, UMRF, F-15000, Aurillac, France
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Staphylococcus aureus Biofilm Growth on Cystic Fibrosis Airway Epithelial Cells Is Enhanced during Respiratory Syncytial Virus Coinfection. mSphere 2018; 3:3/4/e00341-18. [PMID: 30111629 PMCID: PMC6094059 DOI: 10.1128/msphere.00341-18] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
The airways of individuals with cystic fibrosis (CF) are commonly chronically infected, and Staphylococcus aureus is the dominant bacterial respiratory pathogen in CF children. CF patients also experience frequent respiratory virus infections, and it has been hypothesized that virus coinfection increases the severity of S. aureus lung infections in CF. We investigated the relationship between S. aureus and the CF airway epithelium and observed that coinfection with respiratory syncytial virus (RSV) enhances S. aureus biofilm growth. However, iron, which was previously found to be a significant factor influencing Pseudomonas aeruginosa biofilms during virus coinfection, plays a minor role in S. aureus coinfections. Transcriptomic analyses provided new insight into how bacterial and viral pathogens alter host defense and suggest potential pathways by which dampening of host responses to one pathogen may favor persistence of another in the CF airways, highlighting complex interactions occurring between bacteria, viruses, and the host during polymicrobial infections. Staphylococcus aureus is a major cause of chronic respiratory infection in patients with cystic fibrosis (CF). We recently showed that Pseudomonas aeruginosa exhibits enhanced biofilm formation during respiratory syncytial virus (RSV) coinfection on human CF airway epithelial cells (AECs). The impact of respiratory viruses on other bacterial pathogens during polymicrobial infections in CF remains largely unknown. To investigate if S. aureus biofilm growth in the CF airways is impacted by virus coinfection, we evaluated S. aureus growth on CF AECs. Initial studies showed an increase in S. aureus growth over 24 h, and microscopy revealed biofilm-like clusters of bacteria on CF AECs. Biofilm growth was enhanced when CF AECs were coinfected with RSV, and this observation was confirmed with S. aureus CF clinical isolates. Apical conditioned medium from RSV-infected cells promoted S. aureus biofilms in the absence of the host epithelium, suggesting that a secreted factor produced during virus infection benefits S. aureus biofilms. Exogenous iron addition did not significantly alter biofilm formation, suggesting that it is not likely the secreted factor. We further characterized S. aureus-RSV coinfection in our model using dual host-pathogen RNA sequencing, allowing us to observe specific contributions of S. aureus and RSV to the host response during coinfection. Using the dual host-pathogen RNA sequencing approach, we observed increased availability of nutrients from the host and upregulation of S. aureus genes involved in growth, protein translation and export, and amino acid metabolism during RSV coinfection. IMPORTANCE The airways of individuals with cystic fibrosis (CF) are commonly chronically infected, and Staphylococcus aureus is the dominant bacterial respiratory pathogen in CF children. CF patients also experience frequent respiratory virus infections, and it has been hypothesized that virus coinfection increases the severity of S. aureus lung infections in CF. We investigated the relationship between S. aureus and the CF airway epithelium and observed that coinfection with respiratory syncytial virus (RSV) enhances S. aureus biofilm growth. However, iron, which was previously found to be a significant factor influencing Pseudomonas aeruginosa biofilms during virus coinfection, plays a minor role in S. aureus coinfections. Transcriptomic analyses provided new insight into how bacterial and viral pathogens alter host defense and suggest potential pathways by which dampening of host responses to one pathogen may favor persistence of another in the CF airways, highlighting complex interactions occurring between bacteria, viruses, and the host during polymicrobial infections.
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Wermser C, Lopez D. Identification of Staphylococcus aureus genes involved in the formation of structured macrocolonies. MICROBIOLOGY-SGM 2018; 164:801-815. [PMID: 29638209 DOI: 10.1099/mic.0.000660] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
The human pathogen Staphylococcus aureus causes difficult-to-eradicate biofilm-associated infections that generally become chronic. Understanding the genetic regulation of biofilm formation in S. aureus is central to a precise definition of the conditions and genes involved in development of chronic biofilm-associated infections. Biofilm-related genes have been detected by comparing mutants using the classical submerged biofilm formation assay, in which cells adhere to the bottom of a well containing culture medium. We recently developed an alternative biofilm formation model for S. aureus, based on macrocolony formation on agar plates, comparable to an assay used to study biofilm formation in a few other bacterial species. As organism features are the result of environmental conditions as well as of genes, we used a genome-wide collection of transposon-mapped mutants in this macrocolony assay to seek S. aureus developmental genes and pathways not identified by the classical biofilm formation assay. We identified routes related to glucose and purine metabolism and clarified their regulatory link to macrocolony formation. Our study demonstrates that formation of microbial communities must be correlated to specific growth conditions, and the role of metabolism must be considered in S. aureus biofilm formation and thus, in the development of chronic infections.
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Affiliation(s)
- Charlotte Wermser
- Research Centre for Infectious Diseases (ZINF), University of Würzburg, Würzburg 97080, Germany.,Institute for Molecular Infection Biology (IMIB), University of Würzburg, Würzburg 97080, Germany
| | - Daniel Lopez
- Research Centre for Infectious Diseases (ZINF), University of Würzburg, Würzburg 97080, Germany.,Institute for Molecular Infection Biology (IMIB), University of Würzburg, Würzburg 97080, Germany.,National Centre for Biotechnology, Spanish National Research Council (CNB-CSIC), Madrid 28049, Spain
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