Risk Factors for Perioperative Urinary Tract Infection After Living Donor Kidney Transplantation Characterized by High Prevalence of Desensitization Therapy: A Single-Center Analysis

<b>Background/Objectives</b>: Limited research exists on risk factors for urinary tract infections (UTIs) in kidney transplant recipients, particularly in high-risk groups such as ABO-incompatible or donor-specific antibody (DSA)-positive cases. Early UTIs, especially within the first month post-transplant, impact on acute rejection and long-term graft outcomes, highlighting the need for risk factor identification and management. <b>Methods</b>: Among 157 living donor kidney transplant cases performed at our institution between 2009 and 2024, 128 patients were included after excluding cases with >72 h of perioperative prophylactic antibiotics or urological complications. UTI was defined as the presence of pyuria and a positive urine culture, accompanied by clinical symptoms requiring antibiotic treatment, occurring within one month post-transplantation. <b>Results</b>: The median onset of UTI was postoperative day 8 (interquartile range, IQR: 6.8-9.3). No subsequent acute rejection episodes were observed. The median serum creatinine at 1 month postoperatively was 1.3 mg/dL (IQR: 1.1-1.7), and this was not significantly different from those who did not develop UTI. In univariate analysis, low or high BMI (<20 or >25), longer dialysis duration (>2.5 years), desensitization therapy (plasmapheresis + rituximab), elevated preoperative neutrophil-to-lymphocyte ratio (NLR) (≥3), and longer warm ischemic time (WIT) (≥7.8 min) were significantly associated with an increased infection risk of UTI (<i>p</i> = 0.010, 0.036, 0.028, 0.015, and 0.038, respectively). Multivariate analyses revealed that abnormal BMI, longer dialysis duration, desensitization therapy, and longer WIT were independent risk factors for UTI (<i>p</i> = 0.012, 0.031, 0.008, and 0.033, respectively). The incidence of UTI increased with the number of risk factors: 0% (0/16) for zero, 10% (5/48) for one, 31% (16/51) for two, 45% (5/11) for three, and 100% (2/2) for four risk factors. <b>Conclusions</b>: Desensitization therapy, BMI, dialysis duration, and WIT were identified as independent risk factors for perioperative UTI. In patients with risk factors, additional preventive strategies should be considered, with extended antibiotic prophylaxis being one potential option.