Gentamicin May Not Reduce Post Kidney Transplant Urinary Tract Infection Risk

New research suggests intravesical gentamicin administered at the time of ureteroneocystostomy may not reduce the incidence of urinary tract infections (UTIs) following kidney transplantation.1

The findings indicate gentamicin may not be efficacious as infection prophylaxis against UTI-driving pathogens compared with no antibiotic irrigation, with investigators emphasizing clinicians should continue to individualize management based on patient-specific urine culture data.1

“UTIs remain a frequent complication following kidney transplantation, and strategies to mitigate the risk of post-transplant UTIs continue to be highly sought after,” wrote study investigator Andrew Santeusanio, PharmD, BCPS, director of PGY-2 Solid Organ Transplant Residency at Mount Sinai Hospital, and colleagues.1

Common urinary pathogens isolated after kidney transplantation include Escherichia coli, Enterococcus species, and Pseudomonas species. To reduce UTI risk, clinicians may perform intraoperative antibiotic bladder irrigation during ureteroneocystostomy using agents targeting these organisms.1,2,3

Gentamicin, a potent aminoglycoside antibiotic, is often used for infection prophylaxis. Prior studies have explored gentamicin bladder irrigation as a preventative strategy, though evidence regarding the efficacy of antibiotic bladder irrigation has remained conflicting.1,2,3

To further evaluate this practice, investigators conducted a single-center retrospective cohort study using records from the Internal Transplant Institute to identify adult patients who underwent first isolated kidney transplantation. Outcomes were compared between patients who received bladder irrigation with a single dose of gentamicin 80 mg/2 mL and a control group who did not receive antibiotic irrigation. Maintenance immunosuppression consisted of tacrolimus for 3 months, in combination with mycophenolate and tapering corticosteroids based on immunologic risk.1

The primary endpoint was the incidence of culture-confirmed UTI within 3 months of transplantation. Patients with a positive urine culture showing bacterial growth >10⁴ colony-forming units (CFUs) who received antibiotic treatment were considered to have met the primary endpoint. Key secondary endpoints included delayed allograft function, serum creatinine, culture-confirmed UTI >10⁵ CFUs, and acute rejection at 3 months.1

The analysis included 764 adult patients aged ≥18 years, including 358 in the control group and 406 in the gentamicin group. The mean age of transplant recipients was 53.6 years, with most patients being male and representing diverse racial backgrounds.1

Investigators reported no statistically significant differences between groups in induction or maintenance immunosuppression. However, significantly more patients in the control group required reoperation compared with the gentamicin group (4.2% vs 1.7%; P = .04).1

At 3 months, graft survival was 98.8% among patients receiving gentamicin (n = 401) and 99.2% among control patients (n = 355). Overall, 121 patients (15.8%) developed a UTI within 3 months of transplantation.1

For the primary endpoint, investigators observed an increased incidence of culture-confirmed UTI in the gentamicin group compared with the control group (18.2% vs 13.1%; P = .05). These differences were no longer statistically significant when analyses were restricted to organisms with >10⁵ CFUs (13.3% vs 10.1%; P = .16), organisms susceptible to gentamicin (16.7% vs 12.0%; P = .06), or infections occurring before ureteral stent removal (6.2% vs 3.1%; P = .06). Median time to first UTI was 28 days in the gentamicin group and 34 days in the control group, with freedom from UTI favoring the control group (P = .04).1

Analysis of secondary outcomes showed no significant differences between groups in delayed allograft function (23.4% vs 20.7%; P = .36), acute rejection (3.4% vs 3.3%; P = .94), serum creatinine at 3 months (mean [SD], 1.5 [0.8] vs 1.5 [0.7]; P = .54), or incidence of Clostridioides difficile infection (1.7% vs 1.1%; P = .48). However, the gentamicin group had a higher incidence of BK viremia >10,000 IU/mL compared with controls (5.9% vs 2.5%; P = .02).1

In multivariable analysis, investigators identified older age, female sex, treated acute rejection, longer dialysis vintage, and increased urinary catheter duration as independent risk factors for post-transplant UTIs.1

After adjustment, intravesical gentamicin was no longer statistically associated with increased UTI risk (P = .07). Factors that remained significantly associated with UTI risk included recipient age (relative risk [RR], 1.03 per decade), female sex (RR, 1.67), treated acute rejection (RR, 2.97), longer dialysis vintage (RR, 1.07 per year), and longer indwelling catheter duration (RR, 1.06 per day).1

Although the findings suggest no added benefit from gentamicin bladder irrigation, investigators emphasized the importance of individualized prophylactic strategies.1

“The choice of antibiotic prophylaxis should still be individualized based on culture data for patients with a history of UTIs or donors with a positive urine culture at the time of organ recovery,” investigators concluded.1

References

1. Dean S, Santeusanio A, Patel G, Wadhera V, Shapiro R. Efficacy of a Single Dose of Intravesical Aminoglycoside for the Prevention of Urinary Tract Infections in Kidney Transplant Recipients. Clinical Transplantation. 2026;40(1). doi:https://doi.org/10.1111/ctr.70449

2. Harmon C, Hassoun A. Antibiotic Bladder Irrigation in Preventing and Reducing Chronic Urinary Catheter-Related Urinary Tract Infections (UTI). Open Forum Infectious Diseases. 2017;4(suppl_1):S347-S347. doi:https://doi.org/10.1093/ofid/ofx163.833

3. Gravetz A, Tennak V, Khamis M, et al. Evaluation of Intraoperative Gentamicin Bladder Irrigation for Mitigation of Urinary Tract Infections After Kidney Transplantation: A Propensity Score–Matched Analysis of a Randomized Controlled Trial. Hod-Dvorai R, ed. Journal of Transplantation. 2025;2025(1). doi:https://doi.org/10.1155/joot/9377493

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