Distribution and Evolution of cagA, cagE, and vacA Genes among Helicobacter pylori Isolates in Bulgaria

Abstract

Helicobacter pylori is a species with a highly plastic genome encoding numerous virulence factors, such as the pathogenicity island (cagPAI) and vacuolating cytotoxin A (VacA). cagPAI consists of more than 26 genes, with cagA and especially cagE being essential predictors of cagPAI intactness. vacA gene has numerous allelic variations, among which s1m1i1 is the most virulent. The aim of our study was to assess cagA/cagE gene frequency and } allele status among clinical H. pylori isolates from Bulgaria for the period 2017–2024 and to compare the data with that from our previous study (2004–2010). In the current study, the rates of cagA, cagE, and the combination cagA(+)/cagE(+) were significantly lower compared to the previous study, as were the rates of the combinations vacA s1m1i1 and cagA+/cagE+/s1m1i1. In conclusion, H. pylori evolution showed a statistically significant decrease in the prevalence of cagA+/cagE+/vacA s1m1i1 virulence genotype over 14 years, observed in the groups of total patients, as well as in the subgroups of adults and non-ulcer patients.