Virulence Factors and Pathogenicity Islands in Uropathogenic Escherichia coli in Brazilian Children

Escherichia coli (E. coli) is a Gram-negative bacillus responsible for intestinal and extraintestinal infections, and the main cause of urinary tract infection. Its pathogenicity is mediated through virulence factors located in regions of the bacterial chromosome called pathogenicity islands, in addition to the production of extended-spectrum beta-lactamases (ESBL).

Aims: Investigate the frequency of virulence factors from E. coli isolated in the urine of children with suspected urinary tract infection in the community, investigate the types of ESBL and its frequency of virulence factors and perform the phylogenetic classification of the strains.

Study design: This is an observational, descriptive and cross-sectional study carried out through the analysis of positive urine cultures from children aged 0 to 12 years old.

Place and Duration of Study: The samples were collected in the city of Londrina, state of Paraná (Brazil) and processed from May 1, 2021, to September 9, 2022.

Methodology: 89 E. coli samples from urine cultures were included. The PCR method was used for genotypic identification of the main virulence factors of E. coli.

Results: The iutA iron acquisition system was the most prevalent virulence factor (77.5%). There was a statistical difference in the two groups ESBL or non-ESBL in relation to the fimH and hlyA. The ESBL most prevalent was CTX-M2. PAI IV536 was the most prevalent among all isolates (52.8%) and the only pathogenicity island with a significant result. The most prevalent phylogenetic classification group was B2 (41.6%).

Conclusions: E. coli strains have an arsenal of virulence factors that allow them to induce infection, with the statistical difference between the ESBL and non-ESBL groups. PAI IV536 was the most prevalent among all isolates, in the same way as phylogenetic group B2. The finding of CTX-M2 like the more prevalent type of ESBL agrees with other studies in the region.