Analysis of antibiotic resistance and cagPAI variability in Helicobacter pylori strains from Malaysian patients.

Antibiotic resistance and virulence factor of Helicobacter pylori pose formidable challenge towards eradication of this pathogen. Heterogeneity of H. pylori cagPAI is essential in the emergence of antibiotic resistance. The objective of this study was to investigate the correlation between antibiotic resistance and cagPAI variability among H. pylori strains in multiethnic Malaysian patients. H. pylori antibiotic susceptibility profile to six antibiotic classes was determined using E-test and the presence of each cagPAI gene was determined using polymerase chain reaction (PCR). The highest resistance was observed against metronidazole (58.6%, 34/58), followed by clarithromycin (36.2%, 21/58), and levofloxacin (25.9%, 15/58); all strains were susceptible to amoxicillin, tetracycline and rifampicin. Clarithromycin-resistance in H. pylori was significantly higher among elderly patients (> 50 years old) (P = 0.040). Isolates harboring complete cagT4SS genes exhibited significantly higher resistance to antibiotic treatments, primarily towards a single antibiotic (P = 0.043). Resistance to a single antibiotic was significantly higher in East Asian strains (P = 0.027), of which majority of the infected patients were Chinese. Among the resistant isolates, 20.9% (9/43) exhibited multi-drug resistance (MDR), demonstrating resistance to metronidazole, clarithromycin, and levofloxacin concurrently. Female patients were notably at higher risk of being infected with MDR-H. pylori (P = 0.022) than males. Our findings offer insights into the association between variability of cagPAI and antibiotic resistance in H. pylori, of which further research is warranted to elucidate the mechanisms underlying cagPAI heterogeneity and antibiotic resistance in H. pylori for effective therapeutic strategies.