Frequency risk factors and complications of urinary tract infections following renal transplantation: A single-center experience

Objective: Urinary tract infections (UTIs) that develop after renal transplantation are significant complications that adversely affect graft survival and patient morbidity. The aim of this study is to evaluate the incidence, risk factors, causative microorganisms, and effects on graft survival of UTIs in kidney transplant recipients followed at Van Yüzüncü Yıl University Faculty of Medicine Hospital. Material and Methods: A total of 285 renal transplant recipients who presented to our hospital between November 1, 2023 and October 31, 2024, were retrospectively included in the study. Demographic data, primary renal diseases, donor types, accompanying comorbidities, immunosuppressive treatment regimens and the development of UTIs were analyzed. The presence and types of UTIs, causative microorganisms, and antibiotic resistance profiles were also evaluated.. Results: Urinary tract infection (UTI) developed in 8.4% (n=24) of the 285 patients. Female gender was identified as a significant risk factor for UTI development (p=0.001). Age, primary renal disease, donor type, presence of comorbidities, and immunosuppressive regimens were not significantly associated with UTI. Of all UTI cases, 83.3% were classified as lower urinary tract infections. The most frequently isolated pathogens were Escherichia coli (50%), Klebsiella pneumoniae (25%), and Enterococcus faecalis (20.8%). Extended-spectrum β-lactamase (ESBL) production was common among Gram-negative bacteria. Tacrolimus and cyclosporine levels were significantly higher in patients who developed UTI (p<0.001). No significant early deterioration in serum creatinine levels was observed in patients with UTI. The rate of recurrent UTI was 29.1%, and there was no significant association between recurrent UTI and renal function. A history of pre-transplant UTI was associated with an approximately twofold increased risk of post-transplant UTI (OR: 2.16), though this was not statistically significant (p=0.108). Urinary leukocyte count demonstrated high diagnostic performance for UTI detection (AUC=0.984, p<0.001). Conclusion: The development of urinary tract infections (UTIs) in renal transplant recipients is particularly associated with female gender and immunosuppressive drug levels. Gram-negative bacteria are the most common causative agents, and the presence of ESBL-producing isolates complicates treatment approaches. A history of pre-transplant UTI may increase the risk of post-transplant infection. Although no significant early impairment in renal function was observed following UTI, long-term follow-up remains essential. These findings may contribute to the development of infection control strategies and the establishment of individualized treatment plans in transplant centers