Neomycin-polymyxin or gentamicin bladder instillations decrease symptomatic urinary tract infections in neurogenic bladder patients on clean intermittent catheterization

Introduction Recurrent urinary tract infections (UTIs) are common in patients with neurogenic bladder (NGB) performing clean intermittent catheterization (CIC) treated with or without oral antibiotic prophylaxis. Objective The authors aim to determine if daily neomycin-polymyxin or gentamicin bladder instillations reduce the rate of symptomatic UTIs, the need for oral antibiotic prophylaxis, emergency department (ED) visits for UTI, and inpatient hospitalizations for UTI in patients with NGB on CIC. The authors also aim to investigate resistance patterns in urine microorganisms in patients treated with antibiotic bladder instillations. Study design The authors retrospectively reviewed the records of all-age patients cared for in the pediatric urology clinic with NGB on CIC having symptomatic UTIs and on daily intravesical instillations of neomycin-polymyxin or gentamicin between 2013 and 2017. Symptomatic UTIs were defined as a positive urine culture with greater than 10,000 colony forming units/mL associated with one or more of the following patient complaints: cloudy/foul-smelling urine, fevers, chills, increase in bladder spasms, pain, urinary leakage, or physician decision for antibiotic treatment. Multidrug-resistant organisms were resistant to two or more classes of antibiotics. Results Fifty-two patients with a median age of 14.5 years and 192 distinct urine cultures were identified. 90.4% and 9.6% of patients received neomycin-polymyxin and gentamicin instillations, respectively. After initiation of intravesical antibiotics, the rate of symptomatic UTIs was reduced by 58% (incidence rate ratio [IRR]: 0.42, 95% confidence interval [CI]: 0.31-0.56; P < 0.001), the rate of ED visits was reduced by 54% (IRR: 0.46, 95% CI: 0.30-0.71; P < 0.001), and the rate of inpatient hospitalizations for UTI was reduced by 39% (IRR: 0.61, 95% CI: 0.37-0.98; P = 0.043). Fewer patients received oral antibiotic prophylaxis after initiation of antibiotic instillations (odds ratio: 0.12, 95% CI: 0.02-0.067; P = 0.016). There was a trend toward a decrease in multidrug resistance and no change in gentamicin resistance in urine microorganisms. Discussion This study describes a feasible alternative treatment for patients with NGB on CIC who have persistent UTIs despite oral antibiotic prophylaxis, and for some patients, it may suggest a possibility of discontinuing oral prophylaxis. Limitations include a retrospective design with a small cohort of patients and varying dosages of neomycin-polymyxin. Conclusions Antibiotic bladder instillations appear to decrease frequency of symptomatic UTIs, ED visits for UTI, inpatient hospitalizations for UTI, and the need for oral antibiotic prophylaxis in patients with NGB on CIC. There was no increase in multidrug resistance or gentamicin resistance in UTI organisms with use of intravesical antibiotic instillation.