OCCURRENCE OF MULTIPLE GENOMOVARS OF BURKHOLDERIA-CEPACIA IN CYSTIC-FIBROSIS PATIENTS AND PROPOSAL OF BURKHOLDERIA MULTIVORANS SP. NOV

We performed an integrated genotypic and phenotypic analysis of 128 st rains of the genera Burkholderia, Ralstonia, and Pseudomonas in order to study the taxonomic structure of Burkholderia cepacia and its relat ionships with other Burkholderia species. Our data show that presumed B. cepacia strains isolated from cystic fibrosis patients belong to at least five distinct genomic species, one of which was identified as B urkholderia vietnamiensis. This group of five phenotypically similar s pecies is referred to as the B. cepacia complex. The name Burkholderia multivorans is proposed for one of these genomic species, which was f ormerly referred to as B. cepacia genomovar II; the remaining B. cepac ia groups are referred to as genomovars I, III, and IV, pending additi onal differential phenotypic tests. The role and pathogenic potential of each of these taxa, particularly in view of the potentially fatal i nfections in cystic fibrosis patients, need further evaluation, The da ta presented also demonstrate that Pseudomonas glathei and Pseudomonas pyrrocinia should be reclassified as Burkholderia in species.