CagA genotype and metronidazole resistant strain of Helicobacter pylori in functional dyspepsia in Thailand

Background and Aim: Many previous studies indicated relationship between H. pylori infection and functional dyspepsia (FD) but pathogenesis remains unclear. The aim of this study was to determine relationship between cagA genotype and metronidazole resistant strains of H. pylori in Thai FD patients. Methods: Total of 412 Thai FD patients who underwent gastroscopy at Thammasat University Hospital, Thailand between June 2008 and May 2010 were enrolled. Two antral gastric biopsies were obtained for CLO test, cultures and E-test for metronidazole. Cag A genotype was determined by PCR. FD patients were diagnosed by Rome III criteria and categorized as epigastric pain syndrome (EPS) and postprandial distress syndrome (PDS). Results: 133 FD patients (31%) were infected with H. pylori (56 male, 77 female). There were 37 patients with EPS and 96 patients with PDS. Cag A genotype was performed in 114 patients and CagA 1a was demonstrated in 24.6%. Cag A 1a was relatively higher prevalence in PDS than EPS without statistical significance (26% vs 22%; P > 0.05). E-test for metronidazole was performed in 100 patients (32 EPS and 68 PDS patients) and metronidazole resistant strains were found in 30%. Metronidazole resistant strains were significantly higher in PDS than EPS patients (38.2% vs 12.5%; P = 0.03). In EPS patients, presence of cagA 2a gene was significantly higher in metronidazole resistant than metronidazole sensitive strains (100% vs 74.1%; OR = 4.8, 95% CI = 1.2-26.8, P = 0.01). Conclusions: PDS was the predominant type of FD in Thailand. Metronidazole resistant strains and cagA 2a gene of H. pylori infection was commonly found in Thai FD patients. In EPS patients, cagA 2a gene might be related to metronidazole resistant strains of H. pylori infection in Thailand.