Prospective Study
Copyright ©The Author(s) 2016. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Gastroenterol. Nov 7, 2016; 22(41): 9214-9221
Published online Nov 7, 2016. doi: 10.3748/wjg.v22.i41.9214
Molecular detection of Helicobacter pylori antibiotic resistance in stool vs biopsy samples
Denise E Brennan, Joseph Omorogbe, Mary Hussey, Donal Tighe, Grainne Holleran, Colm O’Morain, Sinéad M Smith, Deirdre McNamara
Denise E Brennan, Joseph Omorogbe, Mary Hussey, Donal Tighe, Grainne Holleran, Colm O’Morain, Sinéad M Smith, Deirdre McNamara, Department of Clinical Medicine, School of Medicine, Trinity College Dublin, 2 Dublin, Ireland
Sinéad M Smith, School of Pharmacy and Pharmaceutical Sciences, Trinity College Dublin, 2 Dublin, Ireland
Author contributions: Smith SM and McNamara D contributed equally this work; Brennan DE, Omorogbe J, Hussey M, Tighe D, Holleran G, O’Morain C and McNamara D recruited patients and collected samples for the study; Brennan DE and Smith SM conducted experiments, analysed data and wrote the manuscript; all authors critically reviewed and approved the manuscript prior to publication.
Institutional review board statement: The study was reviewed and approved by the Adelaide and Meath Hospital Research Ethics Committee.
Conflict-of-interest statement: No potential conflicts of interest relevant to this article were reported.
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. Sinéad M Smith, PhD, Assistant Professor, Department of Clinical Medicine, School of Medicine, Trinity College Dublin, Tallaght, 2 Dublin, Ireland. smithsi@tcd.ie
Telephone: +35-318-961385 Fax: +35-318-962988
Received: August 9, 2016
Peer-review started: August 11, 2016
First decision: September 12, 2016
Revised: September 27, 2016
Accepted: October 19, 2016
Article in press: October 19, 2016
Published online: November 7, 2016
Abstract
AIM

To compare (1) demographics in urea breath test (UBT) vs endoscopy patients; and (2) the molecular detection of antibiotic resistance in stool vs biopsy samples.

METHODS

Six hundred and sixteen adult patients undergoing endoscopy or a UBT were prospectively recruited to the study. The GenoType HelicoDR assay was used to detect Helicobacter pylori (H. pylori) and antibiotic resistance using biopsy and/or stool samples from CLO-positive endoscopy patients and stool samples from UBT-positive patients.

RESULTS

Infection rates were significantly higher in patients referred for a UBT than endoscopy (overall rates: 33% vs 19%; treatment-naïve patients: 33% vs 14.7%, respectively). H. pylori-infected UBT patients were younger than H. pylori-infected endoscopy patients (41.4 vs 48.4 years, respectively, P < 0.005), with a higher percentage of H. pylori-infected males in the endoscopy-compared to the UBT-cohort (52.6% vs 33.3%, P = 0.03). The GenoType HelicoDR assay was more accurate at detecting H. pylori infection using biopsy samples than stool samples [98.2% (n = 54/55) vs 80.3% (n =53/66), P < 0.005]. Subset analysis using stool and biopsy samples from CLO-positive endoscopy patients revealed a higher detection rate of resistance-associated mutations using stool samples compared to biopsies. The concordance rates between stool and biopsy samples for the detection of H. pylori DNA, clarithromycin and fluoroquinolone resistance were just 85%, 53% and 35%, respectively.

CONCLUSION

Differences between endoscopy and UBT patients provide a rationale for non-invasive detection of H. pylori antibiotic resistance. However, the GenoType HelicoDR assay is an unsuitable approach.

Keywords: Helicobacter pylori, Antibiotic resistance, Clarithromycin, Fluoroquinolone, Molecular methods

Core tip: The successful detection of clarithromycin and/or fluoroquinolone resistant Helicobacter pylori (H. pylori) infections by non-invasive methods would enable a widespread assessment of resistance rates. Here we evaluate the GenoType HelicoDR assay for the detection of clarithromycin and fluoroquinolone resistance using DNA isolated from stool samples compared to biopsy samples. Although results using this assay on biopsy tissue have previously been shown to correspond well with culture and antimicrobial susceptibility testing, there was weak correlation between results obtained using biopsy vs stool samples in our study. Further studies are required to optimise the non-invasive detection of clarithromycin and fluoroquinolone resistant H. pylori infection.