Serum sensitivity ofBurkholderia(Pseudomonas)cepaciaisolates 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.