Pseudomonas cepacia: biology, mechanisms of virulence, epidemiology

Pseudomonas cepacia, originally described as a plant pathogen, has emerged as an important cause of infection in altered hosts, particularly in the hospital setting. This organism's ability to survive and proliferate in a variety of solutions, medications, and even disinfectants and antiseptics has resulted in numerous clusters of common-source nosocomial infections. Many patients exposed to P. cepacia are merely colonized, but serious infections, including surgical and burn wound infections, bacteremia, meningitis, pneumonia, peritonitis, and urinary tract infections, are not rare. The virulence properties of this pathogen remain poorly characterized. Recently, P. cepacia has been reported in some cystic fibrosis centers as an increasingly frequent pulmonary pathogen. This trend has caused considerable concern because of reports of occasional cases of fulminant necrotizing pneumonia and bacteremia. Conversely, many patients with CF who become colonized with this organism have no ill effects. The epidemiology of P. cepacia in the CF population is unclear, but some patients probably acquire the organism from colonized siblings with CF. Circumstantial evidence suggests that the organism may also be acquired in the hospital. Treatment of infections is exceedingly difficult, particularly in patients with CF, because P. cepacia is resistant to a broad range of antibiotics.