Tailored UTI Prevention Strategies Proposed

SAN FRANCISCO—Prevention strategies for recurrent urinary tract infections (rUTIs) should be based on patients' individual characteristics, and should include consideration of non-antibiotic approaches, according to Dutch researchers

Vaginal application of estrogens can be recommend for postmenopausal women with at least three UTIs per year, according to Suzanne Geerlings, MD, of the Academic Medical Center in Amsterdam. The disappearance of vaginal lactobacilli in postmenopausal women increases the likelihood of colonization with Enterobacteriaceae, which is associated with the occurrence of UTIs. In addition, she said, in an earlier study performed by other investigators, oral administration of Lactobacillus rhamnosus GR-1 and Lactobacillus reuteri RC-14 has been shown to restore the vaginal lactobacilli flora and to reduce colonization by potentially pathogenic bacteria.

At the 52nd Interscience Conference on Antimicrobial Agents and Chemotherapy, Dr. Geerlings presented the findings of two UTI prevention trials conducted in The Netherlands. One trial included 252 postmenopausal women with rUTIs. In this trial, 127 women received trimethoprim-sulfamethoxazole (TMP/SMX) 480 mg once daily and 125 received capsules of lactobacilli (L. rhamnosus GR-1 and L. reuteri RC-14) twice daily as prophylaxis for 12 months.

The mean cumulative number of symptomatic UTIs after 12 months was 2.9 for TMP/SMX recipients and 3.3 for the lactobacilli recipients. The percentage of patients with at least one symptomatic UTI at 12 months and the median time to first recurrence also favored TMP/SMX.  The researchers concluded that TMP/SMX was more effective for preventing rUTIs. Development of antibiotic resistance among the normal bacterial flora was considerably less in the women receiving lactobacilli, so the researchers concluded that lactobacilli may be an acceptable alternative for UTI prevention, especially in women who are against taking antibiotics.

In the other study, 221 premenopausal women with rUTIs were randomized to receive 12-months of prophylaxis with TMP/SMX 480 mg once-daily (110 subjects) or cranberry capsules 500 mg twice-daily (111 subjects). Cranberries contain fructose and proanthocyanidins, which can inhibit adherence of Escherichia coli to the uroepithelial cell receptors, Dr. Geerlings said.

After 12 months, the mean number and the proportion of patients with at least one symptomatic UTI were higher in the cranberry than in the TMP/SMX group (4.0 or 78% vs. 1.8 or 71%). The median times to the first symptomatic UTI were four months for the cranberry group and eight months for the TMP/SMX group.  Within four weeks, however, the researchers observed increased resistance rates for trimethoprim, TMP/SMX, amoxicillin, and ciprofloxacin among E. coli isolates of the normal flora.

After discontinuing TMP/SMX, resistance reached baseline levels after three months. As expected, antibiotic resistance did not increase in subjects taking cranberries. Both the cranberry preparation and TMP/SMX were equally well tolerated. The researchers concluded that TMP/SMX regimen was more effective than the cranberry regimen for preventing rUTIs. They cautioned that the greater efficacy of TMP/SMX should be weighed against the increased likelihood of antibiotic resistance.

Although cranberries were not as effective as TMP/SMX, Dr. Geerlings pointed out that a previous meta-analysis showed that in women with rUTIs, cranberry products reduced the incidence of recurrences at 12 months by 35% compared with placebo or control interventions.

For women who want to take cranberry capsules for UTI prevention, Dr. Geerlings said, physicians should tell them that cranberry preparations are only effective in one-third of the patients and only in the premenopausal women.

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