Recurrent UTIs are common among patients on IC. These create significant patient morbidity and healthcare burden. In desperation, many physicians prescribe prophylactic oral or intravesical antibiotics. This practice is common among our Gillette clinic patients. However, the benefit is unclear and the risks are not insignificant. As such, practice variation is significant. In order to better define the evidence for or against gentamicin bladder irrigation and thus inform clinical practice both locally at our Gillette urology clinic and for practitioners at large we will pursue the following specific aims:

1. Compare rates of symptomatic urinary tract infection and asymptomatic bacteriuria among a population of Gillette patients on IC with and without gentamicin bladder instillation.
2. Compare antibiotic resistance rates among a population of Gillette patients on IC with and without gentamicin bladder instillation.

In the Gillette Lifetime Urology clinic, gentamicin bladder instillation (GBI) for UTI prophylaxis is common practice among our neurogenic bladder patients in IC. However, as previously shown, the evidence supporting this practice is mixed. Potential risks of this practice include wasted costs, wasted materials, wasted time and growing antibiotic resistance. Potential benefits include reduced use of systemic antibiotics, a reduction in symptomatic UTIs and fewer hospitalizations for febrile UTIs. We seek to define the evidence for or against this practice by completing a double-blind randomized controlled trial of GBI vs. NS instillation. Such a trial would benefit our Gillette patients and the community of patients on IC worldwide.

Recurrent UTIs are common among patients on IC. These create significant patient morbidity and healthcare burden. In desperation, many physicians prescribe prophylactic oral or intravesical antibiotics. This practice is common among our Gillette clinic patients. However, the benefit is unclear and the risks are not insignificant. As such, practice variation is significant. In order to better define the evidence for or against gentamicin bladder irrigation and thus inform clinical practice both locally at our Gillette urology clinic and for practitioners at large we will pursue the following specific aims:

1. Compare rates of symptomatic urinary tract infection and asymptomatic bacteriuria among a population of Gillette patients on IC with and without gentamicin bladder instillation.
2. Compare antibiotic resistance rates among a population of Gillette patients on IC with and without gentamicin bladder instillation.

Inclusion Criteria:

1. Patients (>=16 years of age) with any diagnosis on IC of the bladder.
2. Patients may catheterize either thru the urethra or a stoma (e.g. Mitrofanoff).
3. A history of recurrent symptomatic UTI's (at least 3 per year).
4. Patient must be able to travel to Gillette's Lifetime clinic for quarterly urine cultures
5. Patient must have an "informed other" that can supplement any missing study information (incident UTI, treatment information, etc.)

Exclusion Criteria:

1. Patients currently on oral or intravesical antibiotic prophylaxis refusing to or not able to discontinue prophylaxis.
2. Patients colonized with gentamicin-resistant bacteria on baseline urine culture or a gentamicin allergy.