[Infection in lung transplantation]

Lung transplantation is now considered an established therapeutic option for patients with severe respiratory failure. Nevertheless, complications are frequent and can lead to intermediate- or long-term graft dysfunction and decreased survival. According to the registry of the International Society for Heart and Lung Transplantation, survival rates in these patients at one, two, and five years are 74%, 65%, and 47%, respectively. The main obstacle to long-term success of lung transplantation, however, is chronic rejection, which is characterized histologically as bronchiolitis obliterans and occurs in up to two-thirds of patients. One of the most important risk factors for the development of bronchiolitis obliterans, in addition to the number of previous acute rejection episodes and the incidence of persistent rejection, is cytomegalovirus infection and disease. Moreover, recent evidence has indicated a role for respiratory viruses as risk factors for the development of chronic rejection in lung transplant recipients. Infectious complications are a frequent cause of morbidity and mortality in these patients and are the cause of death in nearly half of them. Bacterial infection is the most frequent infectious complication in lung transplant patients. Among the total of infections, 35%-66% are bacterial and 50%-85% of patients present at least one episode. CMV is the second most frequent cause of infectious complications following lung transplantation. Despite the use of various preventive strategies, the risk of developing CMV disease in lung transplant recipients is over 5% during the first year. This is the only type of solid organ transplant in which the etiology of fungal infection is characteristically Aspergillus spp., in contrast to others in which infection by Candida spp. is most common. The incidence of invasive aspergillosis is about 4%.