Cranberries vs Antibiotics to Prevent Urinary Tract Infections

JAMA Internal Medicine, 07/26/2011

Beerepoot MAJ et al. - In premenopausal women, trimethoprim-sulfamethoxazole (TMP-SMX), 480 mg once daily, is more effective than cranberry capsules, 500 mg twice daily, to prevent recurrent urinary tract infections (UTIs), at the expense of emerging antibiotic resistance.

Methods

  • In a double-blind, double-dummy noninferiority trial, 221 premenopausal women with recurrent UTIs were randomized to 12-month prophylaxis use of trimethoprim-sulfamethoxazole (TMP-SMX), 480 mg once daily, or cranberry capsules, 500 mg twice daily.
  • Primary end points were the mean number of symptomatic UTIs over 12 months, the proportion of patients with at least 1 symptomatic UTI, the median time to first UTI, and development of antibiotic resistance in indigenous Escherichia coli.

Results

  • After 12 months, the mean number of patients with at least 1 symptomatic UTI was higher in the cranberry than in the TMP-SMX group (4.0 vs 1.8; P = .02), and the proportion of patients with at least 1 symptomatic UTI was higher in the cranberry than in the TMP-SMX group (78.2% vs 71.1%).
  • Median time to the first symptomatic UTI was 4 months for the cranberry and 8 months for the TMP-SMX group.
  • After 1 month, in the cranberry group, 23.7% of fecal and 28.1% of asymptomatic bacteriuria E coli isolates were TMP-SMX resistant, whereas in the TMP-SMX group, 86.3% of fecal and 90.5% of asymptomatic bacteriuria E coli isolates were TMP-SMX resistant.
  • The authors found increased resistance rates for trimethoprim, amoxicillin, and ciprofloxacin in these E coli isolates after 1 month in the TMP-SMX group.
  • After discontinuation of TMP-SMX, resistance reached baseline levels after 3 months.
  • Antibiotic resistance did not increase in the cranberry group.
  • Cranberries and TMP-SMX were equally well tolerated.

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