Bacterial Urinary Tract Infection After Solid Organ Transplantation in the RESITRA Cohort

Background: Urinary tract infection (UTI) is the most common infection in renal transplant patients, but it is necessary to determine the risk factors for bacterial UTI in recipients of other solid organ transplants (SOTs), as well as changes in etiology, clinical presentation, and prognosis.

Methods: In total, 4388 SOT recipients were monitored in 16 transplant centers belonging to the Spanish Network for Research on Infection in Transplantation (RESITRA). The frequency and characteristics of bacterial UTI in transplant patients were obtained prospectively from the cohort (September 2003 to February 2005).

Results: A total of 192 patients (4.4%) presented 249 episodes of bacterial UTI (0.23 episodes per 1000 transplantation days); 156 patients were kidney or kidney-pancreas transplant recipients, and 36 patients were liver, heart, and lung transplant recipients. The highest frequency was observed in renal transplants (7.3%). High frequency of cystitis versus pyelonephritis without related mortality was observed in both groups. The most frequent etiology was Escherichia coli (57.8%), with 25.7% producing extended-spectrum β-lactamase (ESBL). In all transplants but renal, most cases occurred in the first month after transplantation. Cases were uniformly distributed during the first 6 months after transplantation in renal recipients. Age (odds ratio [OR] per decade 1.1, 95% confidence interval [CI] 1.02-1.17), female gender (OR 1.74, 95% CI 1.42-2.13), and the need for immediate post-transplant dialysis (OR 1.63, 95% CI 1.29-2.05) were independent variables associated with bacterial UTI in renal and kidney-pancreas recipients. The independent risk factors identified in non-renal transplants were age (OR per decade 1.79, 95% CI 1.09-3.48), female gender (OR 1.7, 95% CI 1.43-2.49), and diabetes (OR 1.02, 95% CI 1.001-1.040).

Conclusions: UTI was frequent in renal transplants, but also not unusual in non-renal transplants. Because E. coli continues to be the most frequent etiology, the emergence of ESBL-producing strains has been identified as a new problem. In both populations, most cases were cystitis without related mortality. Although the first month after transplantation was a risk period in all transplants, cases were uniformly distributed during the first 6 months in renal transplants. Age and female gender were identified as risk factors for UTI in both populations. Other particular risk factors were the need for immediate post-transplant dialysis in renal transplants and diabetes in non-renal transplants.