Detection of primary clarithromycin resistance of Helicobacter pylori and association between cagA + status and clinical outcome

Abstract

Helicobacter pylori was examined in 110 patients (82 (74.5) with gastritis, 18 (16.4) with duodenitis, six (5.5) with duodenal ulcer and gastroesophageal reflux, and four (3.6%) with normal) with gastrointestinal problems living in rural area, no history of macrolide use, and detected by culture (71.8) or direct detection from gastric biopsies by PCR (82.7%). Also, cagA gene was identified using PCR and was found positive in 68/91 (74.7%) strains. The prevalence of clarithromycin-resistant H. pylori was investigated by two methods including PCR-RFLP (7.7 (A2142G 1.1 and A2143G 6.6%)) and twofold agar dilution (8.9%) to detect phenotypic and genotypic status simultaneously. Among all the H. pylori positive patients, eight (8.8%) isolates were found to be resistant to clarithromycin by at least one of the AD and/or PCR-RFLP methods. H. pylori positive rates were significantly correlated with patients' sex, age, and endoscopic findings (p = 0.040, <0.001 and <0.001, respectively). There were no differences in gender or endoscopic findings related to cagA (+) and cagA (-) patients. The gene of cagA was not significantly helpful in predicting the clinical outcome of H. pylori infection alone. In conclusion, we revealed that there was a low prevalence of primer clarithromycin resistance in patients living in rural area with no history of macrolide use. The prevalence of mutant strains among the macrolide-resistant H. pylori varies even geographically between close provinces.