VIRULENCE CHARACTERISTICS OF ESCHERICHIA-COLI CAUSING FIRST URINARY-TRACT INFECTION PREDICT RISK OF 2ND INFECTION

Escherichia coli causes most urinary tract infections (UTIs) in ambula tory populations. Several bacterial virulence factors occur more frequ ently among urinary E. coli isolates than among fecal isolates, but no ne have been reported to predict risk of second UTIs. DNA hybridizatio n was used to characterize the bacterial virulence profiles of urinary E. coli isolates from 174 women with first UTI and compared for risk of second UTI. Of the women, 28 (16%) had a culture-confirmed second U TI within 6 months of a negative test-of-cure. Three virulence factors were associated with a significantly lower risk of second UTI: cytoto xic necrotizing factor (relative risk [RR] = 0.0; 95% confidence inter val [CI], 0.0, 0.42); hemolysin (RR, 0.10; 95% CI, 0.01, 0.69), and S fimbrial adhesin (RR, 0.25; 95% CI, 0.06, 1.00). Dr binding was associ ated with a 2-fold increased risk of second UTI (RR, 2.30; 95% CI, 1.2 3, 4.29). Half of all paired first and second UTI isolates from the sa me subject were apparently the same.