Pseudomonas aeruginosa: role in the pathogenesis of the CF lung lesion

Lung disease is the leading cause of morbidity and mortality in individuals with cystic fibrosis (CF), with P. aeruginosa the main pulmonary infectious agent. Although CF patients can become infected with other microorganisms (such as Burkholderia cepacia complex, Staphylococcus aureus, Haemophilus influenzae, and atypical mycobacteria), P. aeruginosa predominates, eventually infecting approximately 80% of patients. Once established, P. aeruginosa infection usually persists until death. The interaction between the CF host and this opportunistic pathogen is unique and most likely directly contributes to the classical end-stage pathology of CF lung disease. However, the extent to which this constitutes success by the pathogen or failure by the host, or both, is yet to be determined. Many important questions remain regarding host susceptibility, the role of both innate and adaptive immune defenses, bacterial infectivity and transmission, and pathogen virulence factors. Here, we discuss some recent advances toward understanding this complex interaction between host and pathogen and how the interplay influences the CF lung lesion.