Hypothesis: Urinary tract infection (UTI) is a common infection in women. Up to 60% of women develop UTI once in their lifetime, 20-40% have at least one recurrence, of whom 20-25% have multiple recurrences. Recurrent UTI (rUTI) is defined as two episodes of symptomatic UTI proven with positive urine cultures in 6 months or 3 such episodes in 1 year. Management of rUTI involves treatment of acute episodes and long-term prophylaxis with local estrogen cream, cranberry extracts, D-mannose, & oral antibiotics. Cost, side effects, allergy, and resistance are major concerns with prolonged oral antibiotics. Intravesical antibiotics (IVA) have been used to locally target the microorganism and avoid systemic side effects. Aminoglycosides specially Gentamycin have been extensively studied for IVA, used for treatment & prophylaxis, has lowest systemic absorption thus preventing toxicity, and are highly effective against the most common pathogen of rUTI- E. Coli.
Aim: This study aims to assess the results and effectiveness of Intra-vesical antibiotics in uncomplicated recurrent urinary tract infections.

We present a case series of 8 patients who presented with symptomatic rUTI. All patients were given daily instillation of 80 mg of Gentamicin in 50 ml normal saline(NS) after a lavage with sterile water, with complete aseptic precautions, for 7 days. Mean dwell time was 127.5 ± 21.21 minutes. Aminoglycosides (Gentamicin/Amikacin) was used based on their culture report. Sociodemographic parameters noted were age, height, weight, BMI, parity, menopausal status, use of vaginal estrogen cream, and relevant medical or surgical history, specially prolapse or incontinence surgeries. Clinical parameters noted were the various lower urinary tract symptoms(LUTS), presence of any genitourinary anomalies, prolapse staging, any significant post-void residue on pelvic scan, number of instillations given, any adverse reaction to instillation, duration of time when antibiotics remained in the bladder, and number of UTIs at follow up, the number and type of organisms grown before and after treatment, and antibiotic resistance pattern.

Mean age of patients 59.9 years (range 47-72). 50%(4/8) patients were sexually active.62.5%(5/8) patients were postmenopausal & using vaginal Estrogen cream. Most common pathogen was E.Coli in 87.5%(7/8). Other organisms causing recurrence were Morganella morganii, Proteus mirabilis, Enterococcus faecalis, and Pseudomonas. Most common symptoms were Dysuria 75% (6/8), frequency 62.5% (5/8), Urgency 62.5% (5/8), and urge incontinence 50% (4/8). PVR (Median - IQR) was 20(7.5 - 55) ml. Findings at 1,2- and 6-month follow-up: negative culture in 87.5% (7/8), decreased bacterial load in 12.5% (1/8), asymptomatic 87.5% (7/8). Mean number of recurrences reduced from 2.88±0.99 to 0.125±0.35 at 6months. Median number of pathogens isolated, reduced from 1.5 to 0. Median reduction in antibiotic resistance was from 10 to 0. No adverse events associated with instillation occured. None of the patients developed resistance to Gentamycin. Patients showed statistically significant improvement in various symptom & QoL scores like ICIQ-LUTS - LF, ICIQ-BOTHER, UDI6, UIQ7, PGI-I, & ICIQ-SATISFACTION. PGI-I score was 2 in 75% (6/8).

Our treatment resulted in a significant decrease in the rate of UTIs. The results also showed a reduction in the number of isolated pathogens in urine cultures. Antibiotic sensitivity profiles demonstrated a trend toward decreased resistance rates. No development of Gentamicin resistance occurred. In our study, we followed the duration of the antibiotic therapy for once daily instillation for 7 days except in one case where the patient had two recurrences after instillation, and we extended the duration of her treatment. The benefits of shorter therapy were improved patient compliance, decreased potential adverse effects, as well as reduced patient discomfort & financial burden.

The successful outcome in our case series suggests that IVA can be used in uncomplicated rUTI with promising results. Larger studies are required to create a standard protocol for dosage and duration of treatments.