Effects of recurrent urinary tract infections on graft and patient outcomes after kidney transplantation

Background Urinary tract infections (UTIs) are common following kidney transplantation (KT); however, the influence of recurrent post-KT UTI (R-UTI) is not well-characterized. Methods We compared graft outcomes, patient outcomes and multidrug-resistance rates between patients with no UTI, nonrecurrent UTI (NR-UTI) (urine sample containing >10 5 bacterial colony-forming units/mL) and R-UTI (≥2 UTIs in any 6-month period or ≥3 UTIs in any 12-month period) post-KT in a retrospective cohort study (1999-2014) at Barnes-Jewish Hospital (St Louis, MO). All adult KT recipients were included and those experiencing mortality within 30 days of KT were excluded. Results Of 2469 recipients included, 1835 (74.3%) had no UTI, 465 (18.8%) had NR-UTI and 169 (6.8%) had R-UTI. R-UTI was associated with poorer graft survival compared with NR-UTI [hazard ratio (HR) 1.45; 95% confidence interval (CI) 1.23-1.83; P < 0.001) and no UTI (HR 2.11; 95% CI 2.02-3.80; P < 0.001). This relationship persisted after adjusting for confounding factors in Cox regression (HR 2.01; 95% CI 1.53-2.66; P < 0.001). There was no difference in patient survival between no UTI and NR-UTI (HR 1.21; 95% CI 0.91-1.63; P = 0.181); however, R-UTI was associated with poorer patient survival compared with nonrecurrent cases (HR 1.87; 95% CI 1.21-2.89; P = 0.005). R-UTI were more likely to be caused by multidrug-resistant Gram-negative organisms (risk ratio 1.49; 95% CI 1.31-1.70; P < 0.001). Conclusions R-UTIs were associated with poorer graft and patient outcomes, as well as increased multidrug-resistance compared with nonrecurrent cases.