UTIs are the most common infection after renal transplant (RTx) with an incidence of 6-86%. Post-RTx UTI has been associated with risk for graft loss and mortality, and RTx recipients are at risk for multidrug-resistant (MDR) UTI given immunosuppression (IS) and instrumentation. We sought to evaluate the incidence, timing, microbiology, and MDR risk of post-RTx UTI, as well as to characterize asymptomatic bacteriuria (ASB) practices at our center.
This was a retrospective cohort of subjects with ≥1 positive culture (≥105 CFU/mL) during the first year post-RTx that were transplanted from 9/1/2012 to 10/1/2016. Each bacteriuria episode was adjudicated as cystitis, pyelonephritis, or ASB (Fig. 1). Subjects without bacteriuria were excluded from primary analysis but used to calculate UTI incidence. The primary outcome was 1-year symptomatic UTI incidence. Secondary outcomes: incidence of cystitis, pyelonephritis, and ASB; time-to-first UTI; microbiologic trends; and presence of MDR risk factors.
Baseline characteristics: 52% male, median age 57 years, 65% stented, 34% antithymocyte globulin induction, 94% standard IS regimen (tacrolimus/mycophenolate/prednisone), 93% trimethoprim/sulfamethoxazole prophylaxis, and 21% receipt of IV antibiotics for ≥ 48 hours within 90 days of first positive culture (IV Abx); Of 527 RTx subjects, 100 had ≥ 1 positive culture. The 100 subjects had 234 cultures representing 359 isolates. Primary outcome: 12.1% symptomatic UTI incidence. Secondary outcomes (1-year incidences): 18.6% positive culture, 4.3% cystitis, 8.6% pyelonephritis, 11.9% ASB. Time to the first symptomatic UTI was a median of 50 days. A summary of microbiologic results can be found in Figure 2. ASB occurred 130 times and was treated 74.6% of the time (Fig. 3). Significant risk factors for MDR UTI included female gender (p=0.005), IV abx (p=0.001), and recurrent UTI (p=0.017).
Incidence of symptomatic UTI at our center was lower than previous reports. E. coli and E. faecalis were the most common urinary pathogens identified. MDR risk factors identified were biologically plausible and consistent with prior literature. ASB treatment occurred frequently and is an area to target stewardship interventions.
C. Kovacs, None
B. Stephany, None
M. Spinner, None