Urinary Tract Infection as a Sexually Transmitted Disease


Synopsis: The same strain of E. coli causing urinary tract infection in women was detected in the initial urine sample of one-fifth of their male sexual partners, suggesting sexual transmission of this uropathogen.

Source: Foxman B, et al. Transmission of uropathogens between sex partners. J Infect Dis 1997;175:989-992.

Foxman and colleagues tested the hypothesis that urinary tract pathogens may be transmitted between sex partners. Nineteen non-pregnant women age 18-40 years who had symptomatic urinary tract infections due to Escherichia coli were enrolled. Diabetics and subjects who had recently been catheterized or hospitalized were excluded. Vaginal and rectal cultures were also obtained from the women. Initial-stream urine was collected from their most recent male sex partner within four days; it was then cultured. None of the couples had engaged in anal intercourse, and all the men were circumcised.

E. coli was recovered from the urine of four (21%; 95% confidence interval, 3-38%) of the men, with densities ranging from 2000-10,000 cfu/mL. Two of the four men with positive cultures reported urinary urgency, while one of those with negative cultures reported painful urination and one complained of chills and back pain.

The E. coli obtained from each of the men was identical to that obtained from urine, vaginal, and/or rectal culture of their sex partner by "virulence profile" and by pulsed field gel electrophoresis.


The findings in this study are consistent with sexual transmission of E. coli causing urinary tract infection. The association between initiation of sexual activity or of an increase in sexual activity and the development of urinary tract infection in women has been previously described. Thus, it has been estimated that initiating sexual activity increases the risk of urinary tract infection 3.5-fold (Geiger AM, et al. Am J Public Health 1995; 85:1146-1148).

Furthermore, a multivariate analysis of college-aged women presenting to a student health service with acute urinary tract infection found that, among those who were sexually active, intercourse in the previous 48 hours or in the previous 3-7 days, as well as diaphragm use in the previous 48 hours and a prior urinary tract infection were significant risk factors (Strom BL, et al. Ann Intern Med 1987;107:816-823).

Hooton and colleagues have also reported that the method of contraception plays an important role in increasing the risk of urinary tract infection (Hooton TM, et al. JAMA 1991;265:64-69). They examined 104 women prior to sexual intercourse, the morning after, and 245 hours later, and found that the prevalence of E. coli bacteriuria increased only slightly in users of oral contraceptives, but increased markedly in both foam and condom users and diaphragm-spermicide users. Vaginal colonization with this organism was also more frequent in the latter groups.

While many clinicians have assumed that at least part of the increased risk associated with penetrative heterosexual intercourse is a mechanical one, related to facilitation of the entry of colonizing uropathogens into the urethra, the current study suggests that, at least in some couples, additional factors may be at work. In some women, urinary tract may indeed be considered a sexually transmitted disease.