Analysis of fliC variation among clinical isolates of Burkholderia cepacia

PCR and restriction fragment length polymorphism (RFLP) typing of flagellin genes (fliC) from 57 clinical isolates of Burkholderia cepacia indicated t hat only type II flagellins were present. Twenty-two isolates previously id entified as the epidemic UK cystic fibrosis strain were indistinguishable b y this method, as were 11 isolates from a pseudo-outbreak in Senegal. Other clinical isolates, including 19 from disparate sources in Malaysia, were s eparated into nine fliC RFLP groups, exhibiting a large degree of divergenc e. When isolates were indistinguishable by fliC genotyping, their similarit y was confirmed by whole genome macro-restriction analysis with pulsed-fiel d gel electrophoresis following XbaI digestion. The variation in fliC seque nces of B. cepacia was far greater than that with B. pseudomallei, supporti ng the view that 'B. cepacia', as currently defined, may comprise several d ifferent genomic species.