Risk and prognosis of bacteremia and fungemia among first-time kidney transplant recipients: a population-based cohort study.

Background: Bacterial infections are common complications in kidney transplant recipients (KTRs). Little is known about incidence rates of bacteremia and fungemia (BAF) in KTRs.

Methods: In this population-based cohort study, we used medical and administrative registries to identify episodes of BAF among KTRs in the Central Denmark and North Denmark Regions during 1995-2010. KTRs were followed from the date of their first transplantation to the earliest of BAF, graft loss, death, emigration or 31 December 2010. We calculated incidence rates of first BAF episode overall and stratified by time from transplantation. Potential risk factors were assessed using Cox regression analysis. The Kaplan-Meier analysis was used to estimate 30- and 90-day mortality.

Results: Among 612 KTRs, we identified 138 first episodes of bacteremia during 2397 person-years of follow-up (PYFU). The overall incidence rate (IR) was 5.8 BAF episodes per 100 PYFU (95% confidence interval [CI]: 4.9-6.8). The incidence rate declined from 84.0 per 100 PYFU (95% CI: 61.6-114.5) during post-transplant day 0-30 to 2.3 per 100 PYFU (95% CI: 1.7-3.0) from post-transplant day 365 and onwards. Hospital-onset BAF comprised 39% of the episodes of BAF. The most frequently isolated microorganisms were Escherichia coli and Klebsiella species causing 49 (35.5%) and 29 (21.0%) episodes of BAF, respectively. The 30-day mortality was 2.1% (95% CI: 0.7-6.6).

Conclusions: While the risk of BAF in KTRs was high, thirty-day mortality was low. After the first post-transplant year, the IR of bacteremia was substantially lower than in the immediate post-transplant period.