Helicobacter pylori infection: Correlation to disease severity and Clarithromycin resistance in a Sri Lankan setting

Abstract

Background: Helicobacter pylori is a causative agent of gastritis, gastric ulcer, duodenal ulcer and gastric cancer. Clarithromycin is often used in the treatment of H. pylori infections in Sri Lanka. Although resistance of H. pylori to clarithromycin has been reported in other countries the situation in Sri Lanka is an enigma. We determined clarithromycin resistance of H. pylori by detecting two major point mutations (A2142G and A2143G) in the 23S rRNA gene. Further we assessed the histology of gastric mucosa of dyspeptic patients as a reasonably good predictor of cancer risk specially, in H. pylori positive patients. Methods & Materials: The study was a cross-sectional, descriptive study where 138 dyspeptic patients undergoing endoscopy examination were included. Ethical approval was granted from the ethical review committee, University of Sri Jayewardenepura (No-723). H. pylori infection was diagnosed by Polymerase chain reaction (PCR) amplification of the glmM gene of H. pylori. A2142G and A2143G point mutations associated with clarithromycin resistance were determined by PCR restriction fragment length polymorphism (RFLP). Histological features of the gastric mucosa were examined using H & E stain and gastritis was classified microscopically according to the updated Sydney system. Results: Seventeen percent (24/138) of the dyspeptic patients were positive for H. pylori by PCR. Of them 13 were males (54%) while 11 were females (46%). All H. pylori strains had a point mutation at A2142G, while A2143G mutation was not detected. Based on histological findings, 15 patients were diagnosed as H. pylori associated chronic active gastritis. Though mild to moderate infiltration of polymorphonuclear and mononuclear cells were observed in all H. pylori positive patients, gastric atrophy and metaplasia were not observed. Conclusion: This is the first report describing the presence of A2142G point mutation which is associated with clarithromycin resistance in a Sri Lankan population. It is therefore important to determine the eradication efficacy of H. pylori following clarithromycin treatment in Sri Lanka which can give an insight regarding the pheno-typical expression of the A2142G mutation. Further the proportion of H. pylori infections was found to be 17% in Sri Lanka.