TBA (16S147)

Detection of antibiotic resistance using faecal samples in Helicobacter pylori infection: A validation study.

Author(s)

Denise Brennan, Joseph Omorogbe, Mary Hussey, Donal Tighe, Colm O’Morain, Sinead Smith*, Deirdre McNamara*. preprocess

Department(s)/Institutions

Trinity Academic Gastroenterology Group (TAGG), Department of Clinical Medicine, Trinity College Dublin. *Joint senior authors. preprocess

Introduction

The GenoType HelicoDR assay- which enables the detection of antibiotic resistant strains of Helicobacter pylori in gastric biopsy samples- is an attractive alternative to standard culture and susceptibility testing, which can be troublesome. Analysis of H. pylori DNA from faecal samples instead of gastric biopsies represents a novel, non-invasive method of determining antibiotic resistance. However, this method requires validation. preprocess

Aims/Background

A validation study was carried out to evaluate the GenoType HelicoDR test for the detection of antibiotic resistance-mediating DNA mutations in faecal samples from H. pylori-infected patients. preprocess

Method

Following ethical approval and informed consent, DNA was isolated from gastric biopsies and stool samples from H. pylori positive adult patients (by histology) and from H. pylori negative (by UBT) patients. DNA was analysed using the GenoType HelicoDR assay (Hain Life Sciences) and resistance profiles from stool and biopsy samples were compared. preprocess

Results

In all, 20 stool and biopsy samples from H. pylori positive patients (mean age 46.8 years; 50% male) and 2 from H. pylori negative patients have been analysed. Firstly, the ability of the assay to detect H. pylori DNA in each sample was assessed. The GenoType HelicoDR assay detected H. pylori DNA in gastric biopsies from all (n=20) of the CLO-test positive patients tested. Concordance between results obtained using biopsy and stool samples for detection of H. pylori DNA was 90% (18/20). The sensitivity of the GenoType HelicoDR assay using stool samples in detecting clarithromycin and levofloxacin resistance was 50%. The specificity of the GenoType HelicoDR assay using stool samples in detecting clarithromycin and levofloxacin resistance was also 50%. The samples from 2 H. pylori negative patients showed no presence of H. pylori DNA. preprocess

Conclusions

Detection of antibiotic resistance in H. pylori infection using the Helico DR assay on DNA extracted from stool is not the optimum technique. The presence of other bacteria or substances in stool samples may impact the sensitivity of the test. Further studies are needed to optimise the detection of antibiotic-resistant H. pylori infection by non-invasive methods. preprocess

Click to access the login or register cheese