A taxonomic study of some gram-negative yellow-pigmented rods

Numerical taxonomy proved useful in delineating 28 strains conforming to the redefined genus Flavobacteriurn from a collection of 86 clinical and non-clinical isolates. However an additional 3 reference strains (F. aquatile NCIB 8694, F. meningosepticum NCTC 10016 and Group IIF NCTC 10798) failed to cluster with the majority of Flavobacterium strains and their unrelatedness to the redefined genus requires investigation. Further 5iochemi cal characterisation resulted in the identification of strains corresponding to species descriptions of F. balustinum (CDC Group IIb), \F. breve\" and F. odoratum. Fifteen strains could not be classified into species and may be regarded as evidence for the absence of discrete species in the genus. A close relationship between the redefined genus and gliding Bacteria was indicated by the clustering together of gliding strains and Flavobacterium strains. The-clustering of gliding strains with F. aquatile NCIB 8694 confirmed the phenetic similarity between F. aquatile and gliding bacteria and the lack of similarity between F. aquatile and the majority of Flavobacterium isolates. Electron microscopic observations showed that F. aquatile NCIB 8694 and F·. meningosepticum NCTC 10016 are aflagellate and that F. aquatile NCIB 8694 possesses extracellular appendages similar to those reported on gliding bacteria."