Epidemiology and risk factors for late infection in solid organ transplant recipients

Information concerning the risk factors and outcome of late infection (LI) after solid organ transplantation (SOT) still remains scarce.

We prospectively analyzed all patients undergoing SOT from July 2003 to March 2008, who survived the first 6 months after surgery and with a minimum 1-year follow-up. Risk factors associated with the development of bacterial and cytomegalovirus (CMV) LI and survival were identified.

Overall, 942 SOT recipients (491 kidney, 280 liver, 65 heart, and 106 double transplants) were included. During the study period 147 patients (15.6%) developed 276 episodes of LI (incidence rate, 0.43 per 1000 transplantation-days). Bacteria were the most prevalent etiology (88.0%). Primary sources of infection included urinary tract (36.9%), intra-abdominal (16.7%), and sepsis without source (13.4%). Independent risk factors for late bacterial infection were: age (hazard ratio [HR] [per year] 1.0; 95% confidence interval [CI]: 1.0-1,0), female gender (HR 1.7; 95%CI: 1.1-2.6), anti-hepatitis C virus (HCV) positive serostatus (HR 1.8; 95%CI: 1.1-3.0), chronic allograft dysfunction (HR 3.2; 95%CI: 1.7-6.1), early CMV disease (HR 2.2; 95%CI 1.2-4.1), and early bacterial infection (HR 2.5; 95%CI 1.6-3.8). The occurrence of chronic allograft dysfunction was an independent risk factor for late CMV disease (HR 6.5; 95%CI: 1.7-24.6), whereas immunosuppression based on mammalian target of rapamycin inhibitors protected against the development of late CMV disease (HR 0.3; 95%CI: 0.1-1.0). Cox model selected anti-HCV positive serostatus (adjusted HR [aHR] 2.67; 95%CI: 1.27-5.59), age (aHR [per year] 1.06; 95%CI: 1.02-1.10), and the occurrence of LI (aHR 9.12; 95%CI: 3.90-21.33) as independent factors for mortality.

LI did not constitute an uncommon complication in our cohort, and patients at risk may benefit from close clinical monitoring.