ANTIMICROBIAL SUSCEPTIBILITY OF HELICOBACTER PYLORI ISOLATED FROM GASTRIC BIOPSIES OF DUODENAL ULCER PATIENTS

Abstract

Introduction: Helicobacter pylori is the microorganism most frequently found in the human gastric mucosa in association with gastric epithelial cells and is associated with gastrointestinal diseases including gastritis and peptic ulcers. Despite its significance, there is a scarcity of antimicrobial susceptibility testing (AST) data available for this microorganism. Objectives: The aim of this study was to assess the AST profile and identify factors associated with H. pylori culture positivity in a cohort of patients with refractory H. pylori undergoing gastric biopsies. Methods: Gastric biopsy specimens were retrospectively reviewed received for culture between July 2006 and July 2008. We analyzed specimen transport time, Gram smear results, direct urease test findings, culture positivity and AST profiles. Using gradient strip methodology on Antimicrobial Susceptibility Testing breakpoints, AST was conducted for amoxicillin, clarithromycin, metronidazole, levofloxacin and tetracycline. Results: Of 382 biopsy samples received for H. pylori culture, 228 (39.4%) tested positive. Samples transported within <1 h had significantly higher odds (1.81 times, P < 0.015) of being culture positive compared to those with longer transport times. Smear-positive samples had substantially higher odds (18.8 times, P < 0.001) of culture positivity compared to smear-negative. Urease-positive samples demonstrated notably higher odds (7.7 times, P < 0.001) of culture positivity compared to ureasenegative samples. The collection of isolates from gastric biopsies showed susceptibility rates of 97.3% to amoxicillin, 99.1% to tetracycline, 50.4% to levofloxacin, 25.9% to metronidazole and 12.9% to clarithromycin. Conclusions: In this cohort of refractory H. pylori cases, susceptibility rates were high for amoxicillin and tetracycline and low for clarithromycin, metronidazole and levofloxacin.