Gut feeling: Extent of virulence and antibiotic resistance genes inHelicobacter pyloriand campylobacteria

Abstract

BackgroundHelicobacter pylori, a member of campylobacteria, is the leading cause of chronic gastritis and gastric cancer. Virulence and antibiotic resistance ofH. pyloriare of great concern to public health. However, the relationship between virulence and antibiotic resistance genes inH. pyloriin relation to other campylobacteria remains unclear.Materials and MethodsBy using the virulence and comprehensive antibiotic resistance databases, we explored all available 354 complete genomes ofH. pyloriand compared it with 90 species of campylobacteria for virulence and antibiotic resistance genes/proteins.ResultsOn average,H. pylorihad 129 virulence genes, highest amongHelicobacter spp. and 71 antibiotic resistance genes, one of the lowest among campylobacteria. Just 2.6% of virulence genes were shared by all campylobacterial members, whereas 9.4% were unique toH. pylori.The cytotoxin-associated genes (cags) seemed to be exclusive toH. pylori. Majority of the isolates from Asia and South America werecag2-negative and many antibiotic resistance genes showed isolate-specific patterns of occurrence. Just 15 (8.8%) antibiotic resistance genes, but 103 (66%) virulence genes including 25 cags were proteomically identified inH. pylori.Arcobacterial members showed large variation in the number of antibiotic resistance genes and there was a positive relation with the genome size.ConclusionLarge repository of antibiotic resistance genes in campylobacteria and a unique set of virulence genes might have important implications in shaping the course of virulence and antibiotic resistance inH. pylori.