- Design
- Pilot multicentre, double-blind, placebo-controlled randomised trial
- Population
- 50 women with recurrent uncomplicated UTI
- Primary outcome
- At least one microbiological recurrence over 26 weeks
- Effect
- 16.7% v 42.3%, RR 0.39 (0.14–1.14), p = 0.089
A pilot, double-blind, placebo-controlled trial in the Archivio Italiano di Urologia e Andrologia (28 September) randomised 50 women with recurrent uncomplicated UTI to Escherichia coli Nissle 1917, a probiotic strain, or placebo, and followed them for 26 weeks.
At least one culture-proven recurrence occurred in 4 of 24 women on the probiotic and 11 of 26 on placebo (16.7% v 42.3%; RR 0.39, 95% CI 0.14 to 1.14). The difference was not statistically significant. Positive cultures at 12 weeks were also less common (8.3% v 23.1%), and one quality-of-life domain improved. Side effects were mild and gastrointestinal.
The signal is worth a proper trial — non-antibiotic prevention is exactly what women with recurrent UTI and their GPs want. But a 50-woman pilot that missed significance is not a basis for prescribing. Established options remain the ones to discuss.
- E. coli Nissle 1917 is not yet an evidence-based option for recurrent UTI prevention.
- Discuss established measures first: hydration, post-coital voiding and vaginal oestrogen after menopause.
- Where prophylaxis is needed, weigh antibiotic and non-antibiotic options with the patient.
- Watch for adequately powered trials before recommending this probiotic.
Why it matters
Patients ask about probiotics for recurrent UTI, and this is the evidence behind the question.
Don't overread it
A pilot of 50 women with a non-significant primary result does not show the probiotic works.
The statistics, in plain English
A relative risk of 0.39 would mean 61% fewer recurrences, but with only 50 women the interval runs from 0.14 to 1.14 — including no effect. A pilot trial is designed to test feasibility, not to prove benefit.
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