Basic Study
Copyright ©The Author(s) 2017. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Gastroenterol. Feb 21, 2017; 23(7): 1163-1170
Published online Feb 21, 2017. doi: 10.3748/wjg.v23.i7.1163
Effect of biofilm formation by clinical isolates of Helicobacter pylori on the efflux-mediated resistance to commonly used antibiotics
Bahareh Attaran, Tahereh Falsafi, Nassim Ghorbanmehr
Bahareh Attaran, Tahereh Falsafi, Department of Microbiology, Faculty of Biological Sciences, Alzahra University, Tehran 1993893973, Iran
Nassim Ghorbanmehr, Department of Biotechnology, Faculty of Biological Sciences, Alzahra University, Tehran 1993893973, Iran
Author contributions: Attaran B and Falsafi T designed the study, wrote the manuscript, and provided vital analytical tools; Attaran B performed all experiments; Ghorbanmehr N participated in providing analytical tools and reading of the manuscript.
Institutional review board statement: The H. pylori strains used for this study were isolated from the patients who were admitted to Medical Centers for their persistent upper gastrointestinal problems, and for this reason they underwent endoscopy for biopsy. All routine biopsy specimens from the patients were taken after informed consent and the protocols, under which the biopsies for culture were obtained, were in accordance with the Helsinki Declaration of 1975.
Conflict-of-interest statement: The authors have no conflict of interest.
Data sharing statement: No additional data are available.
Open-Access: This article is an open-access article which was selected by an in-house editor and fully peer-reviewed by external reviewers. It is distributed in accordance with the Creative Commons Attribution Non Commercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is non-commercial. See: http://creativecommons.org/licenses/by-nc/4.0/
Correspondence to: Dr. Tahereh Falsafi, Professor, Department of Microbiology, Faculty of Biological Sciences, Alzahra University, Vanak Village Street, Tehran 1993893973, Iran. falsafi.tahereh@yahoo.com
Telephone: +98-21-88044040
Received: September 23, 2016
Peer-review started: September 25, 2016
First decision: October 20, 2016
Revised: November 11, 2016
Accepted: January 4, 2017
Article in press: January 4, 2017
Published online: February 21, 2017
Processing time: 149 Days and 21.1 Hours
Abstract
AIM

To evaluate the role of biofilm formation on the resistance of Helicobacter pylori (H. pylori) to commonly prescribed antibiotics, the expression rates of resistance genes in biofilm-forming and planktonic cells were compared.

METHODS

A collection of 33 H. pylori isolates from children and adult patients with chronic infection were taken for the present study. The isolates were screened for biofilm formation ability, as well as for polymerase chain reaction (PCR) reaction with HP1165 and hp1165 efflux pump genes. Susceptibilities of the selected strains to antibiotic and differences between susceptibilities of planktonic and biofilm-forming cell populations were determined. Quantitative real-time PCR (qPCR) analysis was performed using 16S rRNA gene as a H. pylori-specific primer, and two efflux pumps-specific primers, hp1165 and hefA.

RESULTS

The strains were resistant to amoxicillin, metronidazole, and erythromycin, except for one strain, but they were all susceptible to tetracycline. Minimum bactericidal concentrations of antibiotics in the biofilm-forming cells were significantly higher than those of planktonic cells. qPCR demonstrated that the expression of efflux pump genes was significantly higher in the biofilm-forming cells as compared to the planktonic ones.

CONCLUSION

The present work demonstrated an association between H. pylori biofilm formation and decreased susceptibility to all the antibiotics tested. This decreased susceptibility to antibiotics was associated with enhanced functional activity of two efflux pumps: hp1165 and hefA.

Keywords: Helicobacter pylori; Biofilm; Antibiotic resistance; Efflux genes; hp1165; hefA

Core tip: The current study has addressed the co-incidence of biofilm formation by Helicobacter pylori (H. pylori) and decreased susceptibility to antibiotics. The results demonstrated a significantly higher expression of two efflux pump genes, hp1165 and hefA (involved in the specific resistance to tetracycline and multidrug resistance, respectively), in the biofilm-forming cells as compared to the planktonic cells. There was also association between H. pylori biofilm formation and decreased susceptibility to antibiotics. This event would probably be involved in the failure of H. pylori eradication and might be beneficial for developing new therapeutic approaches for this infection.