Flagellin gene profiling of Helicobacter pylori infecting symptomatic and asymptomatic individuals

Abstract Diversity within and around the flagellin (fla) A gene of Helicobacter pylori was studied by polymerase chain reaction/restriction fragment length polymorphism (PCR/RFLP) analysis and genomic Southern blot hybridization profiling. Four distinct pattern types were identified by Dde l restriction analysis of the 1.5-kb fla A amplicon of 55 strains. Most strains (73%) had the same fla A RFLP type, but subtypic variation was evident in some strains. No consistent associations were observed for selected strain subsets between the Dde l fla A profiles and phenotype (motility and cytotoxicity), urease gene profile or patient symptomatology. A subset of seven (F-1 profile) and four (F-2 profile) strains with identical Hin dlll digest patterns provided further evidence that the fla A gene was relatively highly conserved within H. pylori . By contrast, the fla A gene blot hybridization profiles were more diverse and consistent with greater variation at restriction sites in adjacent regions of the genome. We conclude that analyses of polymorphisms within the fla A gene provide limited discrimination between strains of H. pylori . The fla A genomic blot profiles offer greater potential for molecular typing purposes, although no associations with other pathogenicity factors or disease symptoms could be deduced.