ABSTRACT
I. Overview Infectious complications are the leading cause of morbidity and mortality at all time points following lung transplantation and are the cause of death in at least 50% of lung transplant recipients. Bacterial infections are responsible for the majority of the infectious complications following lung transplantation, with most of these infections occurring in the immediate post-transplant period (two weeks). Upwards of 80% of all infections in lung transplant recipients occur in the lung, mediastinum, and pleural space (1,2). Although infections are a considerable hazard in the lung transplant recipient, chronic rejection characterized histologically by obliterative bronchiolitis remains the major impediment to successful long-term outcomes in lung transplantation. Obliterative bronchiolitis afflicts two-thirds of patients and is the major predisposing factor for cumulative increased infectious risk following lung transplantation. The combined process of increasing immunosuppression to manage obliterative bronchiolitis coupled with markedly impaired lung function and mucus clearance dramatically raises the predisposition to infections in these patients. Infectious complications are the most common cause of death in patients who develop obliterative bronchiolitis. Furthermore, evidence exists that bacterial infections may play a role in the establishment of obliterative bronchiolitis by amplification or persistence of an inflammatory immune response to foreign antigens and providing another form of non-alloimmune lung injury (3,4). In fact, pilot studies of long-term antimicrobial antibiotic therapy have shown preliminary evidence of a positive influence on outcome of obliterative bronchiolitis (5).
