Gentamicin bladder instillations decrease symptomatic urinary tract infections in neurogenic bladder patients on intermittent catheterization.

Introduction: This study aimed to determine if gentamicin bladder instillations reduce the rate of symptomatic urinary tract infection (UTI) in neurogenic bladder (NGB) patients on intermittent self-catheterization (ISC) who have recurrent UTIs. Secondary aims were to examine the effects of intravesical gentamicin on the organism resistance patterns.

Methods: We retrospectively reviewed our prospective NGB database. Inclusion criteria were NGB patients performing ISC exclusively for bladder drainage with clinical data available for six months before and six months after initiating prophylactic intravesical gentamicin instillations. Symptomatic UTIs were defined as symptoms consistent with UTI plus the need for antibiotic treatment.

Results: Twenty-two patients met inclusion criteria; etiology of NGB was 63.6% spinal cord injury, 13.6% multiple sclerosis. Median time since injury/diagnosis was 14 years and 6/22 (27.3%) had undergone urological reconstruction. Patients had fewer symptomatic UTI's (median 4 vs. 1 episodes; p<0.004) and underwent fewer courses of oral antibiotics after initiating gentamicin (median 3.5 vs. 1; p<0.01). Days of oral antibiotic therapy decreased from 15 before to five after gentamicin, but this did not reach significance. There were fewer telephone encounters for UTI concerns per patient (median 3 vs. 0; p=0.03). The proportion of multi-drug-resistant organisms in urine cultures decreased from 58.3% to 47.1% (p=0.04) and the rate of gentamicin resistance did not increase. Adverse events were mild and rare.

Conclusions: Gentamicin bladder instillations decrease symptomatic UTI episodes and reduce oral antibiotics in patients with NGB on ISC who were suffering from recurrent UTIs. Antibiotic resistance decreased while on gentamicin instillations.