Northwestern University Feinberg School of Medicine
Introduction: Patients with neurogenic lower urinary tract dysfunction (NLUTD) may experience recurrent urinary tract infections (UTIs) refractory to traditional preventative measures given their bladder management needs. In smaller scale pediatric studies, intravesical gentamicin instillation has been described as a prophylactic measure to prevent UTIs in patients with NLUTD who catheterize. We describe a robust cohort of adult patients with NLUTD utilizing intravesical gentamicin. The objectives of the study were to 1) Evaluate whether there was a reduction in UTI frequency after initiating gentamicin prophylaxis; 2) Determine if UTI-related hospitalizations decreased with gentamicin use; 3) Assess for increased gentamicin resistance with use of bladder instillations. Methods: A retrospective cohort study of adult NLUTD patients who have used prophylactic gentamicin instillations at an academic institution between 2007 and 2022 was conducted. All patients intermittently self-catheterized or had an indwelling catheter. Exclusion criteria included absence of at least one symptomatic UTI documented in the medical record prior to gentamicin initiation. The number of UTIs and UTI-related hospitalizations for each patient were abstracted. Urine culture data was reviewed for gentamicin resistance. UTIs were defined as presence of urologic symptoms associated with positive culture. Statistical significance was assessed using Wilcoxon signed-rank test. Results: Forty-three patients with NLUTD were reviewed. Median length of time using gentamicin instillations was 22.9 months (IQR 26.2), with 38 patients continuing to use the instillations at the time of analysis. Overall, there was a significant reduction in the average number of UTIs per year from after initiation of gentamicin from 3.7 [SD=2.7] before gentamicin to 1.6 [SD=2.2] while using gentamicin (p < 0.001). The average number of UTI-related inpatient admissions did not significantly change with gentamicin instillation prophylaxis (0.9/year prior to gentamicin initiation, 0.5/year on gentamicin; p=0.06). The proportion of cultured bacteria resistant to gentamicin did not significantly increase after initiation of the instillations (p=0.3). Conclusions: Gentamicin instillations significantly reduced the number of UTIs experienced by adult NLUTD patients who catheterize and did not increase bacterial resistance to gentamicin. Prospective studies in patients with NLUTD are needed to further define the ideal administrative protocol and patient characteristics for optimal therapeutic success. SOURCE OF Funding: None
