An Outbreak of Mediastinitis Among Heart Transplant Recipients Apparently Related to a Change in the United Network for Organ Sharing Guidelines

Objective:To describe an outbreak of mediastinitis in heart transplant recipients.Design:Retrospective and contemporaneous cohort study.Setting:Urban tertiary-care university hospital with a large cardiac transplantation program.Patients:Heart transplant recipients.Interventions:Modifications of donor harvest technique; procedures aimed at decreasing skin and mucosal bacterial colonization; strict aseptic technique in the intensive care unit; and aggressive policing of established infection control practices.Results:In April 1999, mediastinitis rates among heart transplant recipients increased abruptly from a baseline of 6 cases per 100 procedures to sequential quarterly rates of 22, 31, and 50 cases per 100 procedures, whereas infection rates in other cardiac operations were unchanged. Bacteria causing these infections were multidrug-resistant "nosocomial" organisms. The epidemic occurred 2 months after a change in the United Network for Organ Sharing organ allocation algorithm. This change resulted in an increase in the duration of preoperative hospitalization from a median of 52 to 79 days (P= .008) and may have promoted prolonged hospitalization of patients with high illness severity. Aggressive multidisciplinary interventions were temporally associated with a return to preoperative mediastinitis rates without changing length of hospitalization prior to transplantation.Conclusions:Changes in organ allocation for transplant that prolong waiting time in the hospital and alter illness acuity may lead to increased rates of postoperative infection. Measures to limit bacterial colonization may be a helpful countervailing strategy.