Distribution of virulence factors in Escherichia coli isolated from urine of cystitis patients.

The distribution of 7 urovirulence factors, such as type 1 pilus (pil), pilus associated with pyelonephritis (pap), S fimbriae (sfa), afimbrial adhesin I (afaI), hemolysin (hly), aerobactin (aer) and cytotoxic necrotizing factor 1 (cnf1) was examined by a DNA colony hybridization test among 194 Escherichia coli strains isolated from the urine of cystitis patients and in 80 strains isolated from the stool specimens of healthy adults. All virulence factors examined, except pil, were significantly more frequently detected among the cystitis isolates than among the fecal isolates. When individual virulence factors were analyzed against the others, an association was discernible which was not apparent when all 7 virulence factors were considered collectively. There was an apparent correlation between the genotypes and serotypes of the E. coli strains from the cystitis patients. From the data presented, it was proposed that genetic detection of virulence factors would be useful for rapid diagnosis of cystitis, especially in patients without severe pyuria or bacteriuria.