Continuous antibiotic prophylaxis prevents recurrent UTIs in patients who self-catheterise

Adults who practise CISC and experience repeated UTIs are likely to benefit from antibiotic prophylaxis, a study published in The Lancet Infectious Diseases has shown, although this approach could increase antimicrobial resistance.

In a randomised, open-label, superiority trial, Holly Fisher and colleagues enrolled 404 community-dwelling users of CISC who had recurrent UTIs. The researchers randomly allocated participants to receive either antibiotic prophylaxis once daily (prophylaxis group, n=203) or no prophylaxis (control group, n=201) for 12 months.

The primary analysis included 181 adults allocated to the prophylaxis group and 180 adults in the control group; the remaining 43 participants were missing follow-up data before 6 months.

The analysis showed that the incidence of symptomatic antibiotic-treated UTIs over 12 months (primary endpoint) was halved by the use of antibiotics, with 1.3 cases per person-year (95% CI 1.1–1.6) in the prophylaxis group and 2.6 cases per person-year (95% CI 2.3–2.9) in the control group. The incidence rate ratio was 0.52 (0.44–0.61; p<0.0001), indicating a 48% reduction in UTI frequency with antibiotic prophylaxis.

Antibiotic resistance

Antibiotic prophylaxis was well tolerated: there were 22 minor adverse events in the prophylaxis group related to antibiotic prophylaxis during the study, predominantly gastrointestinal disturbance (6 participants), skin rash (6 participants), and candidal infection (4 participants). However, resistance against the antibiotics used for UTI treatment was more frequent in urinary isolates from the prophylaxis group than in those from the control group at 9–12 months of trial participation (nitrofurantoin 24% vs 9%, p=0.038; trimethoprim 67% vs 33%, p=0.0003; and co-trimoxazole 53% vs 24%, p=0.002).

Importantly, the authors assessed episodes of symptomatic UTIs rather than merely bacteriuria (which is not a clinically meaningful endpoint). However, caution is required in interpreting the results as the study was not placebo-controlled and the primary outcome was determined on the basis of patient-reported outcomes.

'The long-term implications of this intervention are uncertain, but increased pathogen resistance might make it more difficult to treat established infections in individuals, and increased resistance of bacteria that colonise urine and contribute to the faecal microbiome are a public health concern,' said the authors.

'The severity of individual patient distress from repeated UTIs and local threats from antimicrobial resistance should simultaneously be considered when appraising and implementing this evidence of benefit of treatment.'

Repeated symptomatic urinary tract infections (UTIs) affect 25% of people who use clean intermittent self-catheterisation (CISC) to empty their bladder.