Integrative profiling of Helicobacter pylori clinical isolates: virulence genes, antimicrobial susceptibility and genetic diversity in gastric cancer risk stratification

Background . Helicobacter pylori infection is a major risk factor for gastric cancer (GC), especially in East Asia. However, the mechanisms through which bacterial strain heterogeneity contributes to GC risk remain poorly understood. This study aims to elucidate the roles of specific virulence factors, antibiotic resistance profiles and genetic variations in H. pylori in GC development. Methods. We integrated host clinical data with phenotypic and genomic analyses of 31 clinical H. pylori isolates. Genomic analysis was performed to determine phylogenetic lineage and virulence markers. Antibiotic susceptibility and biofilm-forming ability of the clinical isolates were also assessed, and a genome-wide association study (GWAS) was employed to identify genetic polymorphisms linked to GC risk. Results. Among the isolates, 93.5 % of isolates belonged to the East Asian lineage and carried high-risk virulence markers ( cagA EPIYA-ABD, vacA s1m1). However, multidrug resistance was observed in 64.5 % of isolates, with high resistance rates to metronidazole (71.0%) and levofloxacin (48.4%) exceeding global averages. Strong biofilm-forming strains were significantly associated with tetracycline resistance compared to weak biofilm-forming strains. Additionally, GWAS identified five SNPs significantly associated with GC risk, with variants in hemC , babB and C694_RS04850 being enriched in high-risk strains. Conclusions. This study demonstrates the critical impact of H. pylori strain diversity in GC development, emphasizing the necessity for region-specific surveillance and innovative therapeutic strategies.