Pneumonia in Solid Organ Recipients: Spectrum of Pathogens in 217 Episodes

Background: Lower respiratory tract infection (LRTI) remains a leading cause of morbidity and mortality after solid organ transplantation (SOT). Patients and methods: We performed a retrospective analysis of 217 episodes of LRTI in 143 SOT patients from a single center. Results: There were 94 men and 49 women (85% Caucasian) of median age of 51 (range 17-79) years, including 50 renal, 86 liver, 6 pancreas, and 1 lung recipient. Forty patients experienced multiple episodes of LRTI. Median APACHE II score was 17 (range 5-40), median temperature was 38°C (range 35.3°C-40.2°C), and median white blood cell count was 12000 (range 100-106,000). Pneumonia developed at a median of 11 (range 2-191) days after the last surgical intervention. Of the 217 LRTIs, 163 were nosocomial infections (60 ventilator-associated). Overall crude mortality of 21% was increased in patients with multiple episodes of LRTI (25%) and after liver transplantation (33%). In 40 cases, treatment was initiated without identification of a specific pathogen. Overall, 202 microorganisms were found (41 mixed infections): Staphylococcus aureus (n = 32) of which 81% were MRSA; Escherichia coli (n = 9); Klebsiella spp (n = 7); Enterobacter spp (n = 11); Serratia spp (n = 12); Pseudomonas aeruginosa (n = 15); Stenotrophomonas maltophila (n = 15); Acinetobacter spp (n = 9); fungi (n = 18), and viruses (n = 17). Conclusion: LRTI remains one of the most common, dangerous infections in transplant recipients with higher mortality than in other populations. MRSA is a particular problem. As a significant number of SOT patients develop multiple episodes of LRTI, a thorough reevaluation of the current guidelines for the treatment of pneumonia is urgently needed.