The difference between two phylogenetic groups A and B2 of Uropathogenic E. coli strains in terms of distribution of virulence genes

Escherichia coli is the most abundant bacterium that causes urinary tract infections. The E. coli strains that cause urinary tract infections, known as "Uropathogenic E.coli (UPEC)", contain various virulence factors. According to previous studies, the strains belonging to the phylogenetic group B2 are the most important strains, whereas strains of group A are the least effective strains for causing urinary tract infections. In this study, 100 samples of E. coli isolated from patients with urinary tract infection were confirmed by standard biochemical methods. After extraction of genomic DNA, 72 strains (55 strains belonging to phylogenetic group B2 and 17 samples belonging to group A) were selected by Triplex-PCR method to determine the distribution of virulence genes. The frequency of virulence genes cnf1, irp2, iha and ompT were observed to be 38.88%, 29.16%, 91.66% and 77.77%, respectively. The frequency of these genes in phylogenetic group B2 was significantly higher than group A. Significant difference was observed in the distribution of cnf1 and irp2 genes in both phylogenetic groups B2 and A (P≤0.05). In terms of gene distribution pattern, 10 unique patterns (Ec1-Ec10) were observed for these two groups. The results of this study showed that strains B2 contain more virulent genes than strains A and may have an important role in the development of urinary tract infections.