Abstract
Background and Objectives: Increasing Helicobacter pylori resistance to common antibiotics has created various treatment methods in different geographical areas. This study aimed at determining in vitro susceptibility of H. pylori to clarithromycin, metronidazole, amoxicillin and tetracycline, the four antibiotics commonly used in eradication therapies.
Materials and Methods: Patients with chronic dyspepsia referred to our clinic for upper endoscopy were included. Patients with history of antibiotic or proton pump inhibitor consumption in recent two weeks prior to the endoscopy, and those with malignancy were excluded. Endoscopy samples were prepared for histology, rapid urease test, culture and antibiogram. Antibiotic resistance was evaluated with two methods; agar dilution and disc diffusion tests.
Results: Among 185 patients, 124 cases (67%) were histologically positive. Sensitivity and specificity of culture, compared to the histology, was 66.1% and 100%, respectively. Reported resistance was 17.1 % for clarithromycin, 64.6% for metronidazole and 9.8% for amoxicillin. No resistance was observed for tetracycline. Resistance to metronidazole was more common in patients younger than 50 years (P=0.01). Sixty four percent of the specimens with resistance to clarithromycin showed co-resistance to metronidazole.
Conclusion: According to high resistance to metroniazole in our study, especially in young patients, this drug is not recommended for H. pylori as the first line treatment in Iran. We suggest that in patients who failed to respond to clarithromycin, culturing and determining microbial susceptibility to other antibiotics be performed.