Mortality associated with Acinetobacter baumannii infections experienced by lung transplant recipients

Lung transplantation (LTX) requires continual systemic immunosuppression, which can result in infections that may compromise recipient survival. A recent outbreak of Acinetobacter baumannii at our institution resulted in infections experienced in both LTX recipients and nontransplant patients. A retrospective review was conducted of patients who had A. baumannii recovered from blood, other normally sterile body fluids, and/or respiratory secretions and who had clinical follow-up extending to 1 year postinfection. A. baumannii was considered "multidrug-resistant" when its growth was not inhibited by minimum inhibitory concentrations of multiple antibiotics. Despite the resistance profile, patients were treated with a combination of antibiotics, which included tigecycline, colistimethate, and when susceptible, imipenem. Once infection was diagnosed, immunosuppression was reduced in all LTX recipients. Six LTX recipients became infected with A. baumannii and were contrasted to infections identified in 14 non-LTX, nonimmunosuppressed patients. A. baumannii was persistently recovered in 4 of 6 LTX recipients (66.7%) compared with only 1 of 14 (7.1%) non-LTX patients (χ(2) = 9.9, p = 0.005). LTX recipients received antibiotic therapy for an average of 76 ± 18.4 days compared with 16.0 ± 6.8 days for the non-LTX patients (p = 0.025, Mann-Whitney U test). All 4 of the 6 (66.7%) LTX recipients died as a consequence of their infection compared with 1 of 14 (7.1%) of the non-LTX patients (χ(2) = 9.9, p = 0.005). Despite receiving more antibiotic therapy, LTX recipients who were infected with multidrug-resistant A. baumannii were less likely to clear their infection and experienced greater mortality compared with non-LTX patients.