To better understand the etiology of recurrent urinary tract infection (UTI), the authors followed a cohort of 285 female college students with first UTI for 6 months or until second UTI. A first UTI due to Escherichia coli was followed by a second UTI three times more often than was a non-E. coli first UTI (24 vs. 8%; p = 0.02). In a logistic regression analysis limited to the 224 women from the University of Michigan Health Service and the University of Texas at Austin Health Service from September 1992 to December 1994, with a first UTI due to E. coli, vaginal intercourse increased the risk of a second UTI with both a different (odds ratio (OR) = 1.60, 95% confidence interval (CI): 1.19, 2.15) and the same (OR = 1.37, 95% CI: 0.91, 2.07) uropathogen, as did using a diaphragm, cervical cap, and/or spermicide (same uropathogen: OR = 1.53, 95% CI: 0.95, 2.47; different uropathogen: OR = 1.77, 95% CI: 1.22, 2.58). Condom use decreased the risk of a second UTI caused by a different uropathogen (OR = 0.68, 95% CI: 0.48, 0.99) but had no effect on a second UTI caused by the same E. coli (OR = 0.99; 95% CI: 0.66, 1.50). Type or duration of treatment was not associated with a second UTI. Although the risk of second UTI is strongly influenced by sexual behavior, women with a first UTI caused by E. coli are more likely than are those with a non-E. coli first UTI to have a second UTI within 6 months.

Escherichia coli causes most urinary tract infections (UTIs) in ambulatory populations. Several bacterial virulence factors occur more frequently among urinary E. coli isolates than among fecal isolates, but none have been reported to predict risk of second UTIs. DNA hybridization 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 UTI within 6 months of a negative test-of-cure. Three virulence factors were associated with a significantly lower risk of second UTI: cytotoxic necrotizing factor (relative risk [RR] = 0.0; 95% confidence interval [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 associated with a 2-fold increased risk of second UTI (RR, 2.30; 95% CI, 1.23, 4.29). Half of all paired first and second UTI isolates from the same subject were apparently the same.

The frequency of nine potential Escherichia coli urinary tract infection (UTI) virulence factors was investigated among 216 isolates from 208 women 18-40 years old with first-time UTI. Factors were afimbrial adhesions I-IV and F1845 pili (drb), aerobactin (aer), group II capsules (kpsMT), cytotoxic necrotizing factor 1 (cnf1), alpha-hemolysin (hly), outer membrane protease T (ompT), Pap and Prs pili (prf), S fimbriae (sfa), and type 1 pili (fim). Women were enrolled at two sites. Pairwise comparisons found 14 statistically significant associations between virulence genes after correcting for multiple comparisons. This is the first report of five associations: aer and drb, kpsMT and ompT, ompT and cnf1, ompT and sfa, and prf and ompT. As ompT is not closely linked genetically to kpsMT, cnf1, prf, or sfa, ompT may be functionally linked with one or more of these other virulence factors.

We describe the prevalence of colonization with group B Streptococcus species in a random sample of otherwise healthy male and nonpregnant female college students. Colonization with group B Streptococcus species occurs at a high frequency among healthy students, and there was a suggestion that it is associated with having engaged in sexual activity, tampon use, milk consumption, and hand washing done < or =4 times per day. However, larger studies are needed to verify these findings.

A total of 868 isolates was screened from seven different collections of organisms from previous studies ± pyelonephritis in children aged 1±24 months; ®rst, second and recurring urinary tract infection (UTI) in women aged 18±39 years; UTI in women aged 40±65 years and peri-urethral and faecal isolates from women aged 18±39 years ± for the presence of 10 potential Escherichia coli UTI virulence genes. Previously reported differences between the frequency of these genes in UTI compared with faecal isolates were con®rmed and extended. A single virulence signature (strains containing aer, kpsMT, ompT, ®m and papG AD ) occurred in 29% of the pyelonephritic isolates, but in no more than 11% of the other collections. Peri-urethral isolates were found to have frequencies of these 10 genes that differed from those found for both UTI and faecal isolates.