Urinary tract infections in renal transplant recipients at a quaternary care centre in Australia

BACKGROUND: Urinary tract infections (UTI) are the most common of infections after renal transplantation. The consequences of UTIs in this population are serious, with increased morbidity and hospitalisation rates as well as acute allograft dysfunction. UTIs may impair overall graft and patient survival. We aimed to identify the prevalence and risk factors for post-transplant UTIs and assess UTIs’ effect on renal function during a UTI episode and if they result in declining allograft function at 2 years post-transplant. Additionally, the causative organism, the class of antibacterial drug employed for each UTI episode and utilisation rates of trimethoprim/sulfamethoxazole (TMP/SMX) prophylaxis were also quantified. METHODS: This was a retrospective study of 72 renal transplant patients over a 5-year period who were managed at the Royal Brisbane and Women’s Hospital. Patient charts, pathology records and dispensing histories were reviewed as part of this study and all UTIs from 2 years post transplantation were captured. RESULTS: Of these patients, 20 (27.8%) had at least one UTI. Older age (p = 0.015), female gender (p < 0.001), hyperglycaemia (p = 0.037) and acute rejection episodes (p = 0.046) were risk factors for developing a UTI on unadjusted analysis. Female gender (OR 4.93) and age (OR 1.03) were statistically significant risk factors for a UTI on adjusted analysis. On average, there was a 14.4% (SEM 5.20) increase in serum creatinine during a UTI episode, which was statistically significant (p = 0.027), and a 9.1% (SEM 6.23) reduction in serum creatinine after the UTI episode trending toward statistical significance. (p = 0.076). Common organisms (Escherichia coli and Klebsiella pneumoniae) accounted for 82% of UTI episodes with 70% of UTI cases requiring only a single course of antibiotic treatment. Furthermore, the antibiotic class used was either a penicillin (49%) or cephalosporin (36%) in the majority of UTIs. The use of TMP/SMX prophylaxis for Pneumocystis carinii pneumonia prophylaxis did not influence the rate of UTI, with > 90% of the cohort using this treatment. CONCLUSIONS: There was no significant change in serum creatinine and estimated glomerular filtrate rate from baseline to 2 years post-transplant between those with and without a UTI.