Antimicrobial prophylactic treatment of recurrent UTI is limited by emerging resistance, antibiotic allergies and intolerances. Intravesical aminoglycoside instillations (IAI) have been shown to reduce recurrence rate, without a short-term decline in kidney function or hearing. Thus far, treatment satisfaction has not yet been assessed, while this may play an important role in treatment adherence and persistence. Moreover, there is no data on the long-term safety of IAI, e.g. regarding the development of (pre)malignant bladder lesions.

Inclusion Criteria:

• Age ≥ 18 years
• Currently receiving or having received (no minimal duration) continuous or post-coital IAI (gentamicin, tobramycin or amikacin) for recurrent UTI prophylaxis and treatment

Exclusion Criteria:

• Exclusively receiving IAI for 'on-demand' treatment of UTI and not prophylactic purposes
• Receiving IAI as suppressive therapy for chronic prostatitis
• Presence of a chronic indwelling catheter
• Patient has objected to the use of his/her data
• Inability to provide informed consent

The study population will include adult male and female patients receiving IAI for recurrent UTI at the infectious diseases outpatient clinic of the Leiden University Medical Centre. A proportion of study participants will have urological and/or neurological comorbidities and a history of other prophylactic treatments for recurrent UTI.