Escherichia coli virulence factors and serotypes in acute bacterial prostatitis.

BACKGROUND: Escherichia coli is the most frequent pathogen in both acute bacterial prostatitis and acute uncomplicated urinary infections. To assess the virulence profiles of E. coli in acute prostatitis, the serotypes and virulence factor (VF) genotypes were determined.

METHODS: We studied 107 E. coli isolates from cases of acute bacterial prostatitis, 76 isolates from acute pyelonephritis, 194 isolates from acute Cystitis and 80 fecal isolates from healthy people. All pyelonephritis and cystitis isolates were from women. Seven urovirulence determinants were analyzed by DNA colony hybridization, including the genes for type 1 fimbria (pil), P fimbria (pap), S fimbria (sfa), afimbrial adhesin AFA-I (afaI), alpha-hemolysin (hly), cytotoxic necrotizing factor 1 (cnf1) and aerobactin (aer). O:H:K serotypes were also determined.

RESULTS: With the exception of pil and afaI, all VFs were significantly more often associated with prostatitis, pyelonephritis and cystitis isolates than with the fecal isolates. The prevalence of sfa, hly and cnf1 was higher in prostatitis isolates than in pyelonephritis and cystitis isolates, and the pap+sfa+hly+cnf1+ genotype was dominant among prostatitis isolates (48.8%). Nine O serotype (O1, O2, O4, O6, O16, O18, O22, O25 and O75) accounted for 79.4%, 73.7% and 78.4% of the prostatitis, pyelonephritis and cystitis strains, respectively. There was an apparent correlation between serotype and genotype in uropathogenic E. coli.

CONCLUSION: The predominance of O serotypes in female urinary tract infections and a high percentage of multiple VFs among the prostatitis isolates suggested that VFs play important roles in the pathogenesis of acute bacterial prostatitis.