Clinical spectrum of gram-positive infections in lung transplantation

Gram-positive (GP) organisms are among the most common cause of infections in early postsurgical and immunocompromised populations. Patients recovering from lung transplantation (LT) are particularly susceptible owing to the physiologic stress imposed by surgery and induction with intense immunosuppression. Sites, types, and timing of GP infections following LT are not well documented. This report describes the clinical spectrum of GP infections and their effects on surgical airway complications (SAC) and bronchiolitis obliterans syndrome (BOS) following LT.

Data were collected from 202 patients undergoing 208 LT procedures at a single institution between November 1990 and November 2005. Data were retrospectively analyzed according to timing, location, and causative pathogen.

In the median follow-up period of 2.7 years (range, 0-13.6 years), 137 GP infections were confirmed in 72 patients. Sites of infection included respiratory tract (42%), blood (27%), skin, wound and catheter (21%), and other (10%). GP pathogens identified were Staphylococcus species (77%), Enterococcus species (12%), Streptococcus species (6%), Pneumococcus (4%), and Eubacterium lentum (1%). The likelihood of SAC and BOS was increased in lung allograft recipients with GP pneumonia as compared with those without (hazard ratio 2.1; 95% confidence interval=1.5-3.1).

GP organisms were responsible for infections in 40% of lung allograft recipients and most commonly isolated from the respiratory tract and blood stream. Staphylococcal species were most frequently identified, 42% of which were methicillin-resistant Staphylococcus aureus (MRSA). Given the strong association of respiratory tract infections with the development of SAC and BOS, empiric antimicrobial strategies after LT should include agents directed against GP organisms, especially MRSA.