Stopping Recurrent UTIs in Postmenopausal Women

Paul G. Auwaerter, MD


June 19, 2012

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Hello. This is Paul Auwaerter for Medscape Infectious Diseases, speaking from the Division of Infectious Diseases at Johns Hopkins.

One of the most frequent requests for outpatient consultation is for recurrent urinary tract infections (UTIs) in postmenopausal women. I thought I would spend a few moments talking about some of the recent data, as well as some challenges in trying to help these women.

Low-dose antibiotics (nitrofurantoin or trimethoprim/sulfamethoxazole) remain the gold standard in prevention; however, many providers are loathe to prescribe them because of concerns about emergence of resistance, as well as the fact that much of the data showing efficacy are from older studies[1] that were done in times when there was less resistance with some of the key urinary pathogens.

That said, topical estrogens have been proven in at least 2 small randomized controlled trials[2] to reduce urinary tract infections by one third to three quarters, so I have been a strong advocate for having women consider the use of topical estrogen. Women who don't like topical application can use the estradiol vaginal ring, which can be replaced every 3 months.

Now, that is one possibility, and it is nice that we are not giving an antimicrobial agent. What has gotten more press lately, with more trials being conducted, is the use of probiotics. The theory is that probiotics reduce the number of pathogenic gram-negative organisms in fecal flora, and perhaps in vaginal flora as well, which would otherwise get past the urethral and mucosal barriers and into the bladder.

A recent trial by a Dutch group[3] examined the use of Lactobacillus taken twice daily vs regular dosing of trimethoprim/sulfamethoxazole for 1 year. This trial included 252 women with a history of about 7 UTIs, on average, per year by self-report. In both groups, reported UTIs were reduced -- 2.9 per year for the antibiotic group and 3.3 per year for the Lactobacillus group. The time to the first UTI was 6 months in those taking trimethoprim/sulfamethoxazole and 3 months in those taking Lactobacillus. However, not surprisingly, the women in the probiotic group had significantly less resistance (20%-40% rates of Escherichia coli resistance), but this increased to 80%-95% resistance rates in the women who took trimethoprim/sulfamethoxazole.

Although the study had limitations (they didn't have full enrollment, they didn't reach noninferiority measures, and the UTIs were self-reported), it is important in that the number of UTIs seemed to be reduced and, of course, the rates of resistance were lower.

Indeed, last year, a trial of Lactobacillus vaginal suppositories published in Clinical Infectious Diseases[4] showed a trend toward fewer UTIs, so it may just be that study numbers were low -- but of course, we don't have anything conclusive.

This affects much of the literature in this field. Cranberry extracts and cranberry juice have been studied for many years.[5,6] In fact, the Dutch group[5] also examined cranberry extract vs trimethoprim/sulfamethoxazole and found much less resistance in the cranberry group (not a surprise), but overall cranberry data are mixed, very heterogeneous, and hard to interpret.

So, how do I counsel patients? There are some interesting studies and trends but, of course, no robust data. I advocate trying 3 approaches to see whether they can yield some improvement. I strongly advocate for consideration of:

  • Low-dose estrogen (if there is no contraindication from the patient's gynecologist);

  • Cranberry extracts (which patients are often taking on their own anyway); and

  • Lactobacillus (generally by mouth, because vaginal suppository methods are not yet commercially available).

None of these 3 approaches has been well studied to see whether it has any impact, but at least in my experience, these approaches seem to result in fewer UTIs and allow me to avoid using long-term antibiotics or having to reduce the dose of antibiotics for a symptomatic UTI.

This is an area needing study, especially because increasing rates of resistance have made this a notorious problem for many women. I have a handful of women who have untreatable UTIs because of antibiotic resistance, so some of the non-antimicrobial measures probably will have to take precedence because we have so little to offer otherwise in terms of new drugs in the pipeline.

Thanks very much for listening, and good luck with your next set of patients.


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