• Clostridioides difficile/enzymology
• Clostridioides difficile/isolation & purification
• Clostridioides difficile/immunology
• Humans
• Glutamate Dehydrogenase/analysis
• Glutamate Dehydrogenase/immunology
• Bacterial Toxins/analysis
• Bacterial Toxins/immunology
• Feces/microbiology
• Clostridium Infections/diagnosis
• Clostridium Infections/microbiology
• Bacterial Proteins/analysis
• Fluoroimmunoassay/methods
• Sensitivity and Specificity
• Immunoenzyme Techniques/methods
• Antigens, Bacterial/analysis
• Enterotoxins/analysis

• Clostridioides difficile
• Diagnosis
• Identification
• Sequence Type 1

• Clostridioides difficile/genetics
• Clostridioides difficile/isolation & purification
• Humans
• Real-Time Polymerase Chain Reaction
• Feces/microbiology
• Polymerase Chain Reaction/methods
• Clostridium Infections/diagnosis
• Clostridium Infections/microbiology
• Virulence/genetics
• Sensitivity and Specificity

• C. difficile
• Clostridioides difficile infection
• asymptomatic carriers
• asymptomatic colonization
• asymptomatic infection
• cancer

• Humans
• Asymptomatic Infections/epidemiology
• Bacterial Toxins
• Clostridioides difficile/genetics
• Genotype
• Prospective Studies
• Neoplasms/complications
• Clostridium Infections/epidemiology

• Biomarker
• Clostridioides difficile
• Diagnostic
• Prognostic
• microRNA

• Humans
• MicroRNAs
• Clostridioides difficile/genetics
• Reproducibility of Results
• Clostridium Infections/diagnosis
• Feces

Antibiotic-associated diarrhea (AAD) describes any unexplained diarrhea associated with the use of antibiotics. AAD develops through diverse mechanisms, ranging from pharmacologic effects on gut motility to disturbance of the function and carbohydrate metabolism of the indigenous intestinal flora and overgrowth by pathogenic micro-organisms. Clostridioides difficile-associated diarrhea (CDAD) is a subset of AAD; however, it accounts only for a small percentage of diarrhea caused by antibiotics. Diarrhea has been reported as a side effect of daptomycin use, nevertheless, it's thought to be mild and carries significantly less risk of diarrhea than other alternative treatments of S. aureus bacteremia, i.e., vancomycin or cefazolin. The authors present an interesting case of daptomycin-associated diarrhea presenting with a protracted and severe course. Patient symptoms didn’t improve with empiric Clostridioides difficile therapy and CDAD testing was negative. Diarrhea promptly resolved after discontinuation of daptomycin. Furthermore, a thorough literature review was conducted and discussed in this article to raise awareness of this under-recognized complication. Clinicians should be mindful of daptomycin-associated diarrhea along with its presentation and treatment. Further studies are needed to identify the pathophysiology of daptomycin-associated diarrhea and other forms of AAD. Understanding their mechanism could help prevent, treat, and reduce the significant medical costs associated with antibiotic adverse events.

• Concentration gradient
• Electroosmosis
• Electrophoresis
• Nanopore
• Transferrin

To describe the epidemiology and risk factors for Clostridioides difficile (C. difficile) colonization among young children in eight low-resource settings.

We tested 41 354 monthly non-diarrhoeal and diarrhoeal stools for C. difficile toxin genes (TcdA and TcdB) using quantitative PCR (qPCR) in 1715 children from birth to age two years in a multisite birth cohort study. We estimated the prevalence, cumulative incidence, and seasonality of C. difficile colonization and investigated the associations of C. difficile detection with risk factors of infection, markers of enteropathy, and growth.

The prevalence of C. difficile detection was lower in diarrhoeal (2.2%; n = 151/6731) compared to non-diarrhoeal stools (6.1%; n = 2106/34 623). By 24 months of age, the cumulative incidence of C. difficile varied widely by site, with 17.9% (n = 44; Pakistan) to 76.3% (n = 148; Peru) of children having at least one positive stool. Only Bangladesh and Pakistan had seasonal differences in C. difficile detection. Female sex (adjusted risk ratio (aRR): 1.18; 95% CI: 1.02–1.35), cephalosporin use in the past 15 days (aRR: 1.73; 95% CI: 1.39–2.16), and treated water (aRR: 1.24; 95% CI: 1.02–1.50) were risk factors for C. difficile positivity. The presence of C. difficile was significantly associated with elevated faecal myeloperoxidase, neopterin, and α-1-antitrypsin, but no associations were found between C. difficile and child growth at 24 months of age.

C. difficile colonization among children ages 0–2 years was variable across low-resource settings. Significant elevation of intestinal inflammation and barrier disruption markers associated with C. difficile detection suggests a subclinical impact of colonization.

To reduce health care facility–onset (HCFO) Clostridioides difficile infection (CDI) incidence by improving diagnostic stewardship and reducing the inappropriate testing of C difficile assays.

A multidisciplinary team conducted a quality improvement initiative from January 1, 2020, through March 31, 2021. Clostridioides difficile infection and inappropriate testing were identified via electronic health records using predefined criteria related to stool quantity/caliber, confounding medications, and laboratory data. An intervention bundle was designed including (1) provider education, (2) implementation of an appropriate testing algorithm, (3) expert review of C difficile orders, and (4) batch testing of assays to facilitate review and cancellation if inappropriate.

Compared with a baseline period from January to September 2020, implementation of our intervention bundle from December 2020 to March 2021 resulted in an 83.6% reduction in inappropriate orders tested and a 41.7% reduction in HCFO CDI incidence.

A novel prevention bundle improved C difficile diagnostic stewardship and HCFO CDI incidence by reducing testing of inappropriate orders. Such initiatives targeting HCFO CDI may positively affect patient safety and hospital reimbursement.

• ATA, appropriate testing algorithm
• CDC, Centers for Disease Control and Prevention
• CDI, Clostridioides difficile infection
• CMS, Centers for Medicare & Medicaid Services
• COVID, coronavirus disease
• HAI, health care–associated infection
• HCFO, health care facility–onset
• IDSA, Infectious Diseases Society of America
• IPAC, infection prevention and control
• PCR, polymerase chain reaction
• QI, quality improvement
• SIR, standardized infection ratio

• Clostridium
• diarrhea
• nucleic acid amplification
• recurrence
• treatment

The application of modern PCR approaches for the diagnosis of bacterial gastrointestinal pathogens is on the rise due to their rapidly available results combined with high sensitivity. While multiple studies describe the ongoing implementation of this technique for routine diagnostic purposes in laboratories in Western industrialized countries, reports on successful and also sustainable respective approaches in resource-poor tropical settings are still scarce. In order to shed light on potential reasons for this marked discrepancy, this narrative review summarizes identified challenges for the application of diagnostic PCR targeting bacterial gastrointestinal pathogens from stool samples in the tropics. The identified and discussed issues comprise the lack of generally accepted definitions for (1) minimum standards regarding sample acquisition, storage and transport time for diagnostic PCR analyses in the tropics, (2) nucleic acid extraction standards allowing an optimum detection of all types of pathogens which may be responsible for gastroenteritis in the tropics, (3) validation standards to ensure comparable quality of applied diagnostic assays, and (4) cut-offs for a reliable discrimination of infection and mere colonization in areas where semi-immunity due to repeated exposition associated with poor hygiene conditions has to be expected. Further implementation research is needed to solve those issues.

• PCR
• colonization
• diagnostics
• gastroenteritis
• infection
• interpretation
• nucleic acid extraction
• pre-analytics
• tropics
• validation

• Clostridioides difficile
• Clostridium difficile
• clinical outcomes
• ribotype
• whole-genome sequencing

• D-index
• allogeneic hematopoietic stem cell transplantation
• bacteremia
• bloodstream infection
• neutropenia

• Amidase
• Antimicrobial Resistance
• Cell Wall Peptidoglycan
• Gram Positive

• Clostridioides difficile
• Enzymatic immunoassay
• Immunochromatographic test
• Polymerase chain reaction

While early empiric antibiotic therapy is beneficial for patients presenting with sepsis, the presentation of sepsis from Clostridioides difficile (formerly Clostridium difficile) infection (CDI) has not been well studied in large cohorts. We sought to determine whether the combination of extreme leukocytosis and diarrhea was strongly predictive of CDI in a cohort of 8659 patients admitted to the intensive care unit. We found that CDI was present in 15.0% (95% CI, 12.1–18.3%) of patients with extreme leukocytosis and diarrhea and that mortality for those with CDI, diarrhea, and extreme leukocytosis was 33.8% (95% CI, 23.2–44.3%). These data support consideration of empiric treatment for CDI in unstable critically ill patients with extreme leukocytosis and diarrhea, along with treatment of other possible sources of sepsis as appropriate. Empiric treatment for CDI can usually be discontinued promptly, along with narrowing of other broad-spectrum antimicrobial coverage, if a sensitive C. difficile test is negative.

• Clostridioides difficile
• Clostridium difficile
• critical care medicine
• leukocytosis
• sepsis

The aim of the study was a comparative evaluation of in-house real-time PCR and commercial real-time PCR (Fast Track Diagnostics (FTD), ampliCube/Mikrogen) targeting enteropathogenic bacteria from stool in preparation of Regulation (EU) 2017/746 on in vitro diagnostic medical devices.

Both 241 stool samples from patients and 100 samples from German laboratory control schemes (“Ringversuche”) were used to comparatively assess in-house real-time PCR, the FTD bacterial gastroenteritis kit, and the ampliCube gastrointestinal bacterial panels 1&2 either with the in-house PCRs as gold standard and as a test comparison without gold standard applying latent class analysis. Sensitivity, specificity, intra- and inter-assay variation and Cohen’s kappa were assessed.

In comparison with the gold standard, sensitivity was 75–100% for strongly positive samples, 20–100% for weakly positive samples, and specificity ranged from 96 to 100%. Latent class analysis suggested that sensitivity ranges from 81.2 to 100% and specificity from 58.5 to 100%. Cohen’s kappa varied between moderate and nearly perfect agreement, intra- and inter-assay variation was 1–3 to 1–4 Ct values.

Acceptable agreement and performance characteristics suggested replaceability of the in-house PCR assays by the commercial approaches.

• comparative evaluation
• gastrointestinal pathogens
• nucleic acid amplification testing
• real-time PCR

• Clostridium difficile
• Bezlotoxumab
• Clostridiodes difficile
• Diarrhoea associated to C. difficile
• Fecal Material Transplantation (FMT)
• Fidaxomicin
• Metronidazole
• Monoclonal antibodies
• Probiotics
• Vaccines
• Vancomycin

• Anti-Bacterial Agents/therapeutic use
• Clostridioides difficile/isolation & purification
• Clostridium Infections/diagnosis
• Clostridium Infections/drug therapy
• Continuity of Patient Care
• Cost-Benefit Analysis
• Diarrhea/microbiology
• Feces/microbiology
• Female
• Humans
• Male
• Microbial Sensitivity Tests
• Probiotics/therapeutic use
• Secondary Prevention
• Societies, Medical/standards
• Spain
• Specimen Handling/methods

• Clostridium difficile
• cytotoxicity
• diagnosis
• diarrhea
• enzyme immunoassay
• nucleic acid tests
• toxigenic culture
• toxins

Rapid diagnostic tests (RDTs) for infectious diseases, with a turnaround time of less than 2 hours, are promising tools that could improve patient care, antimicrobial stewardship and infection prevention in the emergency department (ED) setting. Numerous RDTs have been developed, although not necessarily for the ED environment. Their successful implementation in the ED relies on their performance and impact on patient management.

The aim of this narrative review was to provide an overview of currently available RDTs for infectious diseases in the ED.

PubMed was searched through August 2019 for available studies on RDTs for infectious diseases. Inclusion criteria included: commercial tests approved by the US Food and Drug Administration (FDA) or Conformité Européenne (CE) in vitro diagnostic devices with data on clinical samples, ability to run on fully automated systems and result delivery within 2 hours.

A nonexhaustive list of representative commercially available FDA- or CE-approved assays was categorized by clinical syndrome: pharyngitis and upper respiratory tract infection, lower respiratory tract infection, gastrointestinal infection, meningitis and encephalitis, fever in returning travellers and sexually transmitted infection, including HIV. The performance of tests was described on the basis of clinical validation studies. Further, their impact on clinical outcomes and anti-infective use was discussed with a focus on ED-based studies.

Clinicians should be familiar with the distinctive features of each RDT and individual performance characteristics for each target. Their integration into ED work flow should be preplanned considering local constraints of given settings. Additional clinical studies are needed to further evaluate their clinical effectiveness and cost-effectiveness.

• Clinical impact
• ED
• Infections
• POC test
• RDT
• Rapid diagnosis

A proportion of patients suspected of Clostridium difficile infection are unnecessarily placed in contact isolation. By introducing a random-access glutamate dehydrogenase (GDH) test for C. difficile, we aimed to reduce isolation time. In addition, we investigated whether the result of the toxin A&B enzyme immunoassay (EIA) was associated with the decision to initiate antibiotic treatment against C. difficile. This retrospective pre- and post-implementation study was from June 3, 2016, to June 4, 2018. Pre-implementation, only a NAAT was performed. In the post-implementation period, a GDH test was performed; if positive, a toxin A&B EIA followed the same day and subsequently a NAAT. Contact isolation for CDI was discontinued when the GDH test was negative. Median time in isolation was 50.8 h pre-implementation (n = 189) versus 28.0 h post-implementation (n = 119), p < 0.001. The GDH test had a negative predictive value of 98.8% (95% CI 97.9–99.4). In 7/31 (22.6%) patients with a positive NAAT and GDH test and a negative toxin A&B EIA, no antibiotics against C. difficile were initiated versus 4/28 (14.3%) patients who were NAAT, GDH and toxin A&B EIA positive. Introducing a random-access screening test resulted in a significant decrease in patient isolation time. The GDH test had a high negative predictive value making it suitable to determine whether contact isolation can be discontinued. Furthermore, the result of a toxin A&B EIA had limited added value on the percentage of patients in whom antibiotic treatment against C. difficile was initiated.

• Clostridium difficile
• Isolation
• Toxin A&B EIA and GDH test

The aim of this study was to evaluate the clinical application of three methods for detecting Clostridium difficile in fecal samples.

One hundred and fifty fecal specimens were collected and tested for C. difficile using three methods: (1) the toxigenic culture (TC); (2) the VIDAS enzyme immunoassay (EIA): the VIDAS glutamate dehydrogenase (GDH) assay and toxin A/B assay were used to detect GDH antigen and A/B toxin; and (3) the GeneXpert PCR assay. The toxigenic culture was used as a reference to evaluate the performance of the VIDAS EIA and the GeneXpert PCR assay.

Of 150 specimens, 26 carried both A and B toxin genes, and none of the samples were positive for the binary toxin gene. Toxin-producing C. difficile using three methods: (1) the toxigenic culture (TC); (2) the VIDAS enzyme immunoassay (EIA): the VIDAS glutamate dehydrogenase (GDH) assay and toxin A/B assay were used to detect GDH antigen and A/B toxin; and (3) the GeneXpert PCR assay. The toxigenic culture was used as a reference to evaluate the performance of the VIDAS EIA and the GeneXpert PCR assay. C. difficile using three methods: (1) the toxigenic culture (TC); (2) the VIDAS enzyme immunoassay (EIA): the VIDAS glutamate dehydrogenase (GDH) assay and toxin A/B assay were used to detect GDH antigen and A/B toxin; and (3) the GeneXpert PCR assay. The toxigenic culture was used as a reference to evaluate the performance of the VIDAS EIA and the GeneXpert PCR assay.

The VIDAS GDH assay is useful for initial screening of C. difficile using three methods: (1) the toxigenic culture (TC); (2) the VIDAS enzyme immunoassay (EIA): the VIDAS glutamate dehydrogenase (GDH) assay and toxin A/B assay were used to detect GDH antigen and A/B toxin; and (3) the GeneXpert PCR assay. The toxigenic culture was used as a reference to evaluate the performance of the VIDAS EIA and the GeneXpert PCR assay.

• Clostridioides difficile
• biosecurity
• breakroom
• farm worker
• swine
• zoonotic transmission

The advanced technologies described in this chapter should allow for full inventories to be made of bacterial genes, their time- and place-dependent expression, and the resulting proteins as well as their outcome metabolites. The evolution of these molecular technologies will continue, not only in the microbial pathogens but also in the context of host-pathogen interactions targeting human genomics and transcriptomics. Their performance characteristics and limitations must be clearly understood by both laboratory personnel and clinicians to ensure proper utilization and interpretation.

• Adolescent
• Adult
• Aged
• Amino Acids/metabolism
• Animals
• Clostridioides difficile/physiology
• Clostridium Infections/microbiology
• Diarrhea/complications
• Diarrhea/microbiology
• Disease Susceptibility
• Dysbiosis/complications
• Dysbiosis/microbiology
• Fecal Microbiota Transplantation
• Female
• Gastrointestinal Microbiome
• Germ-Free Life
• Humans
• Male
• Mice
• Middle Aged
• Risk Factors
• Young Adult

• R03 DK111850 NIDDK NIH HHS
• R01 DK085025 NIDDK NIH HHS
• K08 DK100638 NIDDK NIH HHS
• K23 DK103911 NIDDK NIH HHS
• P30 DK084567 NIDDK NIH HHS
• R01 DK114007 NIDDK NIH HHS
• R01 CA179243 NCI NIH HHS

• Aeromonas
• Complication
• Rehospitalization
• Relapse

• Adolescent
• Adult
• Aged
• Aged, 80 and over
• Bacteria/classification
• Bacteria/isolation & purification
• Bacterial Infections/epidemiology
• Bacterial Infections/microbiology
• Bacteriological Techniques
• Feces/microbiology
• Female
• Follow-Up Studies
• Hospitalization
• Humans
• Inflammatory Bowel Diseases/microbiology
• Male
• Middle Aged
• Polymerase Chain Reaction
• Retrospective Studies
• Young Adult

• Clostridium difficile
• capillary electrophoresis
• characterization
• detection
• multiplex PCR

• Bunyaviridae/genetics
• Bunyaviridae Infections/diagnosis
• Bunyaviridae Infections/virology
• Computational Biology/methods
• Flaviviridae/genetics
• Flaviviridae Infections/diagnosis
• Flaviviridae Infections/virology
• Humans
• Oligonucleotide Array Sequence Analysis
• Phylogeny
• Real-Time Polymerase Chain Reaction

• CDI
• Clostridium difficile
• Diagnosis
• Epidemiology
• FMT
• Fecal microbiota transplantation

• clostridium difficile
• enzyme immunoassay
• genexpert pcr assay

• Clostridium difficile
• asymptomatic infections
• bacteria
• community-acquired infections
• healthcare settings
• hospital infections
• nosocomial infections
• theoretical models
• transmission

• Aged
• Carrier State/epidemiology
• Carrier State/microbiology
• Carrier State/transmission
• Clostridioides difficile/isolation & purification
• Clostridioides difficile/pathogenicity
• Clostridioides difficile/physiology
• Communicable Disease Control/methods
• Community-Acquired Infections
• Cross Infection/epidemiology
• Cross Infection/microbiology
• Cross Infection/transmission
• Enterocolitis, Pseudomembranous/epidemiology
• Enterocolitis, Pseudomembranous/microbiology
• Enterocolitis, Pseudomembranous/transmission
• Female
• Hospitals
• Humans
• Incidence
• Long-Term Care
• Male
• Middle Aged
• Models, Statistical
• Prevalence
• United States/epidemiology

• S10 RR019895 NCRR NIH HHS
• S10 RR029676 NCRR NIH HHS
• RR029676 NCRR NIH HHS
• RR19895 NCRR NIH HHS

• Clostridium difficile infection (CDI)
• Rapid testing
• TcdA
• TcdB

Since every single test has some limitations for detecting toxigenic Clostridium difficile, multistep algorithms are recommended. This study aimed to compare the current, representative diagnostic algorithms for detecting toxigenic C. difficile, using VIDAS C. difficile toxin A&B (toxin ELFA), VIDAS C. difficile GDH (GDH ELFA, bioMérieux, Marcy-l’Etoile, France), and Xpert C. difficile (Cepheid, Sunnyvale, California, USA). In 271 consecutive stool samples, toxigenic culture, toxin ELFA, GDH ELFA, and Xpert C. difficile were performed. We simulated two algorithms: screening by GDH ELFA and confirmation by Xpert C. difficile (GDH + Xpert) and combined algorithm of GDH ELFA, toxin ELFA, and Xpert C. difficile (GDH + Toxin + Xpert). The performance of each assay and algorithm was assessed. The agreement of Xpert C. difficile and two algorithms (GDH + Xpert and GDH+ Toxin + Xpert) with toxigenic culture were strong (Kappa, 0.848, 0.857, and 0.868, respectively). The sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) of algorithms (GDH + Xpert and GDH + Toxin + Xpert) were 96.7%, 95.8%, 85.0%, 98.1%, and 94.5%, 95.8%, 82.3%, 98.5%, respectively. There were no significant differences between Xpert C. difficile and two algorithms in sensitivity, specificity, PPV and NPV. The performances of both algorithms for detecting toxigenic C. difficile were comparable to that of Xpert C. difficile. Either algorithm would be useful in clinical laboratories and can be optimized in the diagnostic workflow of C. difficile depending on costs, test volume, and clinical needs.

• Clostridium difficile
• cell cytotoxicity assay
• diagnostic algorithms
• enzyme immune assay
• laboratory diagnosis
• nucleic acid amplification tests
• toxigenic culture

• Clostridium difficile infection
• diagnosis
• guideline
• recommendations
• review

• Clostridium difficile
• PCR assay (GeneXpert®)
• antibiotic-associated diarrhea
• glutamate dehydrogenase
• toxin A/B

Establishing a specific etiology for gastrointestinal infections can be challenging because of the common clinical features and wide variety of causative microorganisms. In many cases, the etiologic agent cannot be determined using traditional diagnostic methods and may result in unnecessary antibiotic use or prolonged periods of illness. Molecular tests provide many advantages over traditional laboratory methods but, with the exception of a few analytes, are still largely in the developmental phase for gastrointestinal pathogens and are not widely used. The main advantages of molecular tests include increased sensitivity and the ability to detect agents which will not grow in culture. To test for all possible gastrointestinal pathogens at one time would require a large panel that would include a variety of bacterial, viral and parasitic agents. Challenges inherent in developing diagnostic molecular panels include ensuring that all variants of a particular microorganism can be detected as well as the rapid evolution of pathogens. In this chapter, the diagnostic merit of molecular tests as well as available tests will be presented for the major groups of gastrointestinal pathogens.

• Clostridium difficile
• Detection method
• RT-PCR
• Vegetative cells

• Clostridium difficile
• Culture
• Cytotoxin assay
• Diagnostic accuracy
• Immunoassay
• Nucleic acid amplification test

• Adult
• Clostridioides difficile/drug effects
• Clostridium Infections/diagnosis
• Clostridium Infections/drug therapy
• Clostridium Infections/epidemiology
• Cross Infection/diagnosis
• Cross Infection/drug therapy
• Cross Infection/epidemiology
• Enterocolitis, Pseudomembranous/diagnosis
• Enterocolitis, Pseudomembranous/drug therapy
• Enterocolitis, Pseudomembranous/epidemiology
• Humans
• Infection Control/methods

• Adolescent
• Adult
• Aged
• Aged, 80 and over
• Antibodies/therapeutic use
• Bacteremia/epidemiology
• Bacteremia/microbiology
• Child
• Clostridioides difficile/isolation & purification
• Clostridium Infections/drug therapy
• Clostridium Infections/epidemiology
• Clostridium Infections/etiology
• Comorbidity
• Cross Infection/epidemiology
• Cross Infection/microbiology
• Female
• Gastrointestinal Tract/microbiology
• Gastrointestinal Tract/surgery
• Humans
• Male
• Medical Records/statistics & numerical data
• Microbial Sensitivity Tests
• Middle Aged
• Postoperative Complications/epidemiology
• Postoperative Complications/microbiology
• Retrospective Studies
• Wounds and Injuries/epidemiology
• Wounds and Injuries/microbiology
• Young Adult

Clostridium difficile is the main cause of nosocomial diarrhea, but is also found in asymptomatic subjects that are potentially involved in transmission of C. difficile infection. A sensitive and accurate detection method of C. difficile, especially toxigenic strains is indispensable for the epidemiological investigation.

TaqMan-based quantitative-PCR (qPCR) method for targeting 16S rRNA, tcdB, and tcdA genes of C. difficile was developed. The detection limit and accuracy of qPCR were evaluated by analyzing stool samples spiked with known amounts of C. difficile. A total of 235 stool specimens collected from 82 elderly nursing home residents were examined by qPCR, and the validity was evaluated by comparing the detection result with that by C. difficile selective culture (CDSC).

The analysis of C. difficile-spiked stools confirmed that qPCR quantified whole C. difficile (TcdA⁺TcdB⁺, TcdA⁻TcdB⁺, and TcdA⁻TcdB⁻ types), TcdB-producing strains (TcdA⁺TcdB⁺ and TcdA⁻TcdB⁺ types), and TcdA-producing strains (TcdA⁺TcdB⁺ type), respectively, with a lower detection limit of 10³ cells/g of stool. Of the 235 specimens examined, 12 specimens (5.1%) were C. difficile-positive by qPCR: TcdA⁺TcdB⁺ strain in six specimens and TcdA⁻TcdB⁻ strain in the other six. CDSC detected C. difficile in 9 of the 12 specimens, and toxigenic types of the isolates from the 9 specimens were consistent with those identified by qPCR, supporting the validity of our qPCR method. Moreover, the qPCR examination revealed that the carriage rate of whole C. difficile and that of toxigenic strains in the 82 subjects over a 6-month period ranged from 2.4 to 6.8% and 1.2 to 3.8%, respectively. An average qPCR count of C. difficile detected was 10^4.5 cells/g of stool, suggesting that C. difficile constituted a very small fraction of intestinal microbiota.

Our qPCR method should be an effective tool for both clinical diagnosis and epidemiological investigation of C. difficile.

• Aged
• Aged, 80 and over
• Clostridioides difficile/genetics
• Clostridioides difficile/isolation & purification
• DNA Primers/metabolism
• Feces/microbiology
• Female
• Genes, Bacterial
• Humans
• Immunoassay
• Limit of Detection
• Male
• Nursing Homes
• RNA, Ribosomal, 16S/genetics
• Real-Time Polymerase Chain Reaction/methods
• Taq Polymerase/metabolism