- Design
- Pilot multicentre double-blind randomised placebo-controlled trial
- Population
- 50 women with recurrent uncomplicated urinary tract infections
- Primary outcome
- At least one microbiological recurrence over 26 weeks
- Effect
- 16.7% vs 42.3%; RR 0.39 (95% CI 0.14 to 1.14); p = 0.089
A pilot double-blind randomised trial in Archivio Italiano di Urologia e Andrologia (published 28 September) gave the probiotic Escherichia coli Nissle 1917 or placebo to 50 women with recurrent uncomplicated urinary tract infections, followed for 26 weeks.
At least one microbiological recurrence occurred in 16.7% (4 of 24) with the probiotic and 42.3% (11 of 26) with placebo, a relative risk of 0.39 (95% CI 0.14 to 1.14), which was not statistically significant. Positive cultures at 12 weeks were less frequent with the probiotic, and side effects were mild and mostly gastrointestinal.
Non-antibiotic prevention for recurrent UTI is a real need given antimicrobial resistance. This trial is too small to be conclusive, and recruitment fell short during the pandemic. It supports a larger trial, not routine use.
- Do not prescribe E. coli Nissle for recurrent UTI on the basis of this pilot alone.
- Continue established prevention options for recurrent UTI, such as increased fluid intake, vaginal oestrogen in postmenopausal women, and antibiotic prophylaxis where indicated.
- Confirm recurrent UTI with urine culture before starting any preventive strategy.
- Discuss the limits of current probiotic evidence with patients who ask.
Why it matters
Non-antibiotic prevention is needed, and this is an early signal worth a proper trial.
Don't overread it
The primary result was not statistically significant, and the trial enrolled only 50 women.
The statistics, in plain English
A relative risk of 0.39 suggests a large reduction, but the interval (0.14 to 1.14) includes no effect and even slight harm, so chance cannot be excluded.
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