Virulence characterization of Escherichia coli sequence type 131 clone isolated from hospital-acquired and community-acquired urinary tract infections, Egypt

Abstract

The recently emerged E. coli ST131 clone is now a predominant cause of UTIs. There is a need to understand the virulence characteristics of this clone to limit its dissemination. We aimed to detect the presence of ST131 clones among E. coli strains isolated from UTI infections and compare the virulence carriage capacity between ST131 and non-ST131 strains. A total of 89 (63.5%) E. coli strains isolated from 140 patients with UTI were investigated for six different virulence genes using PCR-based assays. Overall, 65 of 89 (73%) E. coli isolates belonged to the ST131 clone. Of these, 61 isolates (93.8%) were of the O25-ST131 clone, and only 4 isolates (6.2%) were of the O16-ST131 clone. From 24 catheterized patients, 20 (83.3%) were positive for the ST131 clone. Regarding the adhesin virulence genes, the fimH gene was detected in all studied isolates. Then, papEF, sfa(sfa/foc), and papA genes were found in 59.6%, 53.9%, and 30.3% of isolates, respectively. However, the iroN and hylA genes were found in 52.8% and 16.9%, respectively. E. coli ST131 isolates exhibited a higher prevalence among hospital-acquired UTIs than community-acquired UTIs, raising concern that this emerging clone has become a threat to nosocomial infections. The high virulence potential among E. coli ST131 isolates suggests that the virulence characterizations of this clone are in a continuous step-up evolution. More importantly, increased carriage of adhesin genes among ST131 isolates was demonstrated and can be targeted to develop new management strategies for UTI infections.