BACKGROUND: The efficacy of prophylactic intravesical antibiotic instillation to decrease urinary tract infections (UTI) in patients with neurogenic bladder who perform clean intermittent catheterization (CIC) has previously been demonstrated in observational studies of small sample sizes. We adopted intravesical antibiotic instillation in 2013 and aim to evaluate our extended 10-year experience. We hypothesize that intravesical instillations decrease annual symptomatic UTIs and associated emergency department (ED) visits.
METHODS: Patients of any age with neurogenic bladder performing CIC who were initiated on daily intravesical antibiotic instillations were retrospectively identified from 2013 to 2023 (IRB#24-000420). Intravesical antibiotics include neomycin-polymixin, gentamicin and tobramycin. Patients without a minimum of 6 months pre-instillation and 6 months post-instillation data for analysis were excluded. Our primary outcomes were annual symptomatic UTIs and annual ED visits related to symptomatic UTIs. Symptomatic UTIs were defined as culture positivity in the setting of patient complaints, including fevers, chills, increase in bladder spasms, pain, leakage that resolve following antibiotic treatment. Descriptive analyses were compared with the McNemar’s and Wilcoxon rank-sum tests.
RESULTS: Among the 92 patients who met inclusion criteria, the initial antibiotic instillation was neomycin-polymyxin in 77% and gentamicin in 23%. 9 patients (10%) were switched to tobramycin during the study period due to unavailability of either neomycin-polymyxin or gentamicin. Median age at time of instillation initiation was 13 years (IQR 7-19 years) and patients were 54% female. 67 patients (73%) identified as Hispanic or Latinx. Median follow-up time per patient was 18 months (IQR 10-52 months). Common etiologies of neurogenic bladder included spina bifida in 36 patients (39%) and cerebral palsy/developmental delay in 15 patients (16%). The most prevalent comorbidities were vesicoureteral reflux (17%), seizures (20%), and hydrocephalus (16%). 60% of patients (n=55) had a prior lower urinary tract reconstruction, among which the Mitrofanoff (74%) and bladder augmentation (67%) were most frequently performed. The annual incidence of UTIs decreased significantly from 3 per year (IQR 1.5-6) pre- to 1.5 per year (IQR, 0-2.5) post-initiation of bladder instillations (P<0.001). Frequency of ED visits for UTIs also decreased significantly after initiation of antibiotic instillation (P=0.03).
CONCLUSIONS: Intravesical antibiotic instillations decrease symptomatic UTI episodes and ED visits for UTIs in patients with neurogenic bladder on CIC. Our study represents one of the largest pediatric cohorts within the literature on prophylactic antibiotic bladder instillations.
