A Randomized Clinical Trial of Standard versus Expanded Cultures to Diagnose Urinary Tract Infections in Women

We compared urinary tract infection (UTI) symptom resolution rates at 7-10 days in symptomatic women randomized to treatment based on standard urine culture (SUC) versus expanded quantitative urine culture (EQUC) results.

Women ≥18 years old who responded "yes" to "do you feel you have a UTI?" agreed to urethral catheterization and followup. Symptoms were assessed using the validated UTI Symptom Assessment (UTISA) questionnaire. Culture method was randomized 2:1 (SUC:EQUC); antibiotics were prescribed to women with positive cultures. The primary outcome, UTI symptom resolution, was determined 7-10 days following enrollment on all participants regardless of treatment.

Demographic data were similar between groups. Of the SUC and EQUC groups 63% and 74% had positive cultures (p=0.10), respectively. Of participants with positive cultures 97% received antibiotics. Primary outcome data were provided by 215 of 225 participants (SUC 143 [95%], EQUC 72 [97%]). At the primary outcome assessment, 64% and 69% in the SUC and EQUC groups, respectively, reported UTI symptom resolution (p=0.46); UTISA scores improved from baseline in the EQUC arm compared to the SUC arm (p=0.04). In the subset of women predominated by non-Escherichia coli (76), there was a trend toward more symptom resolution in the EQUC arm (21%, p=0.08).

Symptom resolution was similar for the overall population (E. coli and non-E. coli) of women treated for UTI symptoms based on SUC or EQUC. Although the sample size limits conclusions regarding the utility of EQUC in women with non-E. coli uropathogens, the detected trend indicates that this understudied clinical subset warrants further study.