Cystic fibrosis and the pseudomonads

The microbiology of pulmonary disease in cystic fibrosis has altered over the past 10 years. The major pathogens in this disease are now Pseudomonas aeruginosa and, increasingly, Pseudomonas cepacia. P. aeruginosa respiratory infection in these patients is rarely eradicated and this is often the only pathogen found at post-mortem. The most important points in the pathogenesis of this infection are probably the protective role of the bacterial mucoid exopolysaccharide and the interaction of various other bacterial factors with the immune system of the body. P. cepacia has recently emerged as the common isolate from the lungs of cystic fibrosis patients. The actual role of this organism in the progression of lung disease is poorly understood. There has been some speculation about the role of cross-infection in the acquisition of both of these organisms. The treatment of these infections is problematical because of the altered antimicrobial pharmaco-kinetics within the cystic fibrotic lung and the resistant properties of the organisms involved. Approaches which have been suggested recently include immunological interventions and genetic therapy.