Design: Retrospective multi-practice audit
Population: 256 adults on prophylaxis for recurrent UTI in 18 English practices
Primary outcome: Guideline regimen, review within 6 months, change after resistant isolate
Effect: 73.6% guideline regimen; 58.1% reviewed; 22.9% changed after resistance

This retrospective audit covered 18 general practices in Leicestershire and all adults prescribed antibiotic prophylaxis for recurrent urinary tract infection between November 2021 and January 2024: 256 patients, 74% women, mean age 67. It was published in Family Practice in July.

Median duration of prophylaxis was 2.2 years. Regimens matched guidelines in 73.6%, with frequent deviations in dose, formulation and duration. Only 58.1% were reviewed within six months of starting. A quarter (24.7%) grew a resistant urine isolate, which was associated with breakthrough infection, yet only 22.9% of those had their prophylaxis changed. Guideline adherence was lower in more deprived areas.

The finding is less about any single prescription than about the missing system: no review date, no rule for acting on a resistant culture. Both are simple to fix, and both matter for antimicrobial resistance.

Set a review date of six months when starting prophylaxis.
Change the drug when a culture shows resistance to it.
Use guideline doses, typically nitrofurantoin 50–100 mg or trimethoprim 100 mg at night.
Consider non-antibiotic options and a trial off at review.
Audit your own list; this was 18 ordinary practices.

Why it matters

Resistant isolates were driving breakthrough infections that nobody acted on.

The statistics, in plain English

This is an audit against standards, not a trial, so it measures practice rather than testing a fix. The association between resistance and breakthrough infection is observational. The sample of 256 in one English region may not generalise, but the gaps are common ones.