Serum sensitivity of Burkholderia (Pseudomonas) cepacia isolates from patients with cystic fibrosis.

Bacterial strains which are sensitive to the bactericidal activity of serum are generally considered to be less virulent than serum-resistant strains and are seldom associated with bacteraemia. Burkholderia (Pseudomonas) cepacia is an important pathogen in cystic fibrosis and is associated with rapid fatal pulmonary decline and bacteraemia in 20% of colonised patients. In this study 19 isolates of B. cepacia expressing either rough or smooth LPS were investigated to determine the degree of serum sensitivity. Strains expressing rough-LPS were serum-sensitive: these included a highly transmissible strain of B. cepacia isolated from approximately 50 cystic fibrosis patients attending various U.K. regional centres and associated with cases of bacteraemia.