CYP2C19 Genotype, CagA Genotype and Antibiotic Resistant Strain of Helicobacter pylori Infection

Abstract

Background: H. pylori is a class I carcinogen and major cause of gastric cancer. Few previous studies reported<br />relationship between H. pylori infection, CYP2C19 genotype and functional dyspepsia (FD) subtype. The aim of this<br />study was to determine relationship between CYP2C19 genotype and FD subtype patients(host factor) with antibiotic<br />resistant strains of H. pylori infection and CagA genotype(bacterial factor). Methods: FD patients who were investigated<br />with gastroscopy at Thammasat University Hospital, Thailand during March 2017-November 2017 were enrolled. Two<br />antral gastric biopsies were obtained for rapid urease test, E-test and cultures. CagA genotypes (CagA1a and CagA2a)<br />were determined by PCR and CYP2C19 genotype was determined by PCR-RFLP. FD patients were categorized as<br />epigastric pain syndrome(EPS) and postprandial distress syndrome (PDS). Results: 93 FD patients with H. pylori<br />infection were enrolled (37 male, 56 female, mean age 54.5 years). There were 33 patients with EPS and 60 patients<br />with PDS. CYP2C19 genotype revealed 55.9% rapid metabolizer (RM), 40.9% intermediate metabolizer (IM) and<br />3.2% poor metabolizer (PM) genotypes. Antibiotics susceptibility tests demonstrated 62.8% resistant to metronidazole,<br />12.9% resistant to clarithromycin and 27.1% resistant to fluoroquinolone. CagA 1a and CagA 2a were demonstrated<br />in 6 patients(11.5%) and 46 patients(88.5%). CagA2a genotype was more prevalent in PDS than EPS patients<br />(94.3%vs.76.5%; P =0.08) without significance. In intermediate metabolizer (IM), CagA2a genotype was significant<br />higher in PDS than EPS(100% vs.25%; P=0.004). Conclusions: PDS, CYP2C19 RM genotype and CagA 2a gene of<br />H. pylori infection were the predominant type of FD in Thailand. Metronidazole remain the most common antibiotic<br />resistant strain of H. pylori infection in FD patients. PDS (host factor) was significantly related to CagA2a genotype<br />(bacterial factors) only in patients with intermediate metabolizer. Appropriate dose of proton pump inhibitor (PPI) and<br />correct regimens for H. pylori eradication in FD patients should be consider to improve clinical outcomes.