Distribution and genetic association of putative uropathogenic virulence factors iroN, iha, kpsMT, ompT and usp in Escherichia coli isolated from urinary tract infections in Japan.

OBJECTIVE

Many virulence factors (VFs) have been reported in uropathogenic Escherichia coli. Recently we found a putative uropathogenic island including a gene encoding uropathogenic specific protein (USP). We have described the association between usp and other VFs reported previously. In the current study we examined epidemiological associations among 5 putative uropathogenic VFs.

METHODS

In 427 E. coli strains, including 194, 76 and 107 isolates from patients with cystitis, pyelonephritis and prostatitis, respectively, and 50 isolates from the stool of healthy adults, we detected catecholate siderophore receptor (iroN), iron regulated gene A homologue adhesin (iha), group II capsule (kpsMT) and outer membrane protease T (ompT) by polymerase chain reaction assays. We analyzed their distribution and genetic association.

RESULTS

Relative prevalence ratios of iroN, iha, kpsMT, ompT and usp were 2.0 to 4.3 times more frequently in urinary tract infection isolates than in fecal isolates. Isolates from prostatitis were frequently associated with iroN, ompT and usp, whereas isolates from pyelonephritis frequently harbored usp. Together with iroN and iha we noted S-/F-fimbriae and iucD aerobactin (OR 95.9 and 187.2), while usp showed a close association with kpsMT and ompT (OR 38.3 and 38.4, respectively).

CONCLUSIONS

Of the putative uropathogenic VFs examined iroN, iha, kpsMT, ompT and usp were frequently associated with urinary tract infection. Especially iroN and usp were most frequently associated with prostatitis. Some VFs were closely associated with a specific anatomical site of infection. Strong associations among several VFs might indicate not only well-known genetic linkages, but also unknown functional linkages among these VFs.