Virulence factors of uropathogenic Escherichia coli of urinary tract infections and asymptomatic bacteriuria in children.

BACKGROUND/PURPOSE: The clinical aspects of virulence genes of uropathogenic Escherichia coli (UPEC) are not fully understood. This study compared the presence of virulence genes in UPEC isolated from urinary tract infections (UTIs) and asymptomatic bacteriuria (ABU) in children.

METHODS

The study included children with UTI (n = 15) or ABU (n = 49) treated at Chung-Ang University Yongsan Hospital between 2010 and 2011. The strains were acquired from each urine sample collected, and 18 major virulence genes were detected by polymerase chain reaction. Antimicrobial susceptibility of all UPEC isolates was determined.

RESULTS

Sixty-four E. coli strains were isolated from the urine samples. The most commonly identified virulence gene in both groups was fimH (100.0% in the UTI group and 95.9% in the ABU group). The UTI isolates showed a higher prevalence of papEF and fyuA, and a lower prevalence of feoB than ABU isolates (p < 0.01 for all). The profile of virulence gene, fimH(+)kpsMTII(+)feoB(+) also showed a significant difference between the two groups (p < 0.01). Isolates from ABU were more resistant to most antimicrobials tested. The presence of papEF, feoB, and fyuA also correlated with the antimicrobial susceptibility of UPEC.

CONCLUSION

The virulence gene repertoire was different in the UPEC of UTI and ABU. The papEF, feoB, and fyuA genes showed meaningful differences between the two groups and may have an important role in the pathogenesis of overt UTI.