Prevalence of Pathogenicity Island Markers among Commensal, Avian Pathogenic, and Uropathogenic Escherichia coli Strains.

Abstract

Virulence genes are often present on pathogenicity islands (PAIs) and serve as markers for specific pathogenic types of Escherichia coli. We studied the prevalence of PAIs associated with diarrheagenic (DEC PAI markers) and uropathogenic (UPEC PAI markers) E. coli among strains isolates from various sources, considering their phylogenetic group affiliation and pathogenic potential. DEC PAI markers were detected in 41.7% of fecal E. coli (FEC), 46.4% of avian pathogenic E. coli (APEC), and 84.6% of UPEC. UPEC more frequently contained PAIs carrying the siderophore biosynthesis gene clusters in comparison with FEC or APEC. UPEC PAI markers were equally prevalent in ExPEC groups (APEC and UPEC); however, PAIs exhibited greater diversity in uropathogenic strains. A positive correlation was found between the prevalence of the PAI genes and phylogenetic group B2, as well as the number of virulence genes present.