(Poster 47) Duration of Antibiotic Prophylaxis for Recurrent Urinary Tract Infection

Objectives: The American Urogynecologic Society recommends continuous antibiotic prophylaxis for prevention of recurrent urinary tract infection (rUTI) be initiated for 3 months with continuation for 6 months based on efficacy and side effects. This study compares the percentage of women experiencing symptomatic UTIs following cessation of antibiotic prophylaxis between those receiving 3 months antibiotic prophylaxis to those receiving longer prophylactic regimens.

Methods: This is a retrospective cohort study of non-pregnant women ages 18-89 prescribed continuous antibiotic prophylaxis for rUTI by any of five Urogynecologists at a single institution between 1/1/2020 and 8/1/2023. The primary outcome was the percentage of women experiencing symptomatic, culture-documented UTIs in the 3 months following discontinuation of antibiotic prophylaxis. Positive urine culture was defined as more than 1,000 colony forming units per milliliter of uropathogenic bacteria. Women were grouped based on duration of prophylaxis prescribed: 3 months, >3-6 months, >6 months. Secondary outcomes included rates of antibiotic resistance in uropathogens and the percentage of women with breakthrough UTIs during antibiotic prophylaxis.

Results: Of 985 women diagnosed with rUTIs during the study period, 53 (5.4%) were prescribed continuous antibiotic prophylaxis: 32 (60.4%) for 3 months, 13 (24.5%) for >3-6 months, and 8 (15%) for >6 months. Demographic and clinical characteristics are presented in Table 1. The majority had attempted one or more prior UTI prevention treatments and used vaginal estrogen during the study period; approximately 30% of patients had diabetes. Nitrofurantoin was the most prescribed prophylactic antibiotic followed by cephalexin and trimethoprim. Fifteen patients experienced 26 UTIs in the first three months following cessation of prophylaxis with no difference in the percentage across groups (Table 2). Escheriachia coli was the most frequently isolated uropathogen (n=19, 73.1%) followed by Klebsiella (n=4, 15.4%), then Enterococcus, Streptococcus viridans and Pseudomonas (each n=1, 3.8%). No causative uropathogens of UTIs following prophylaxis cessation were resistant to the previously prescribed prophylactic antibiotic. Overall, 14 patients experienced breakthrough UTIs during antibiotic suppression, with increasing frequency associated with increasing duration of prophylaxis. Post-hoc analysis demonstrated significant differences only between patients receiving 3 months versus >6 months prophylaxis (p=0.02).

Conclusions: The duration of antibiotic prophylaxis did not impact recurrence of UTI in the 3 months following cessation of antibiotic prophylaxis for rUTI, though conclusions are limited by this retrospective data. Of note, no causative uropathogens of post-cessation UTIs were resistant to the prophylactic antibiotic. Further prospective research is needed to define the optimal timeline for antibiotic prophylaxis and investigate longer term resistance patterns following continuous prophylactic antibiotic regimens.

Table 1 Legend: Data presented as n (%) unless otherwise noted
IQR, interquartile range; BMI, body mass index; UTI, urinary tract infection
*Women may endorse ≥ 1 prevention

Table 2 Legend: Data presented as n (%)
UTI, urinary tract infection; mo, months