Epidemiology of pneumonia in kidney transplantation

Pneumonia remains an important cause of morbidity among solid organ transplant recipients.

We prospectively evaluated all renal transplant patients at our center from July 2003 to December 2008 who had pneumonia that required hospitalization. We gathered data regarding underlying diseases as well as pretransplant, transplant, and posttransplant characteristics. Pneumonia defined according to the Centers for Disease Control and Prevention criteria was classified depending on its origin as community acquired or nosocomial. In all patients, microbiologic samples of respiratory secretions and blood were collected at the physician's discretion. The indication to perform a fiberoptic bronchoscopy was the presence of multiple, bilateral, or diffuse pulmonary infiltrates or the absence of a clinical or radiologic response after 3 days of antimicrobial therapy.

Among 610 kidney transplant recipients, we diagnosed 60 episodes of pneumonia in 54 patients (8.8%), of which 23 had a nosocomial origin (38%) and 37 community acquired (62%). Bacterial infection was the most frequent etiology (44%), followed by fungal in 4 (7%) and viral in 2 (3.5%). The most commonly isolated microorganism in nosocomial pneumonia was Pseudomonas aeruginosa (26%, among which 50% was multidrug resistant). In 34% there was no microbiologic isolation. The most common pathogen among community-acquired pneumonias was Strepococcus pneumoniae (11%). In 54% of cases there was no microbiologic confirmation of disease. The overall accuracy of bronchoalveolar lavage was 72%. A total of 21 patients with pneumonia (35%) were admitted to the intensive care unit; of these, 14 had a nosocomial origin (60%) and 9 (15%) died due to the infection (8 [88%] of whom had nosocomial pneumonia; P=.001).

Our data confirmed that nosocomial pulmonary infections are associated with considerable morbidity and mortality in renal transplant recipients. The performance of invasive procedures is useful for the diagnosis of pneumonia.