IDENTIFICATION AND CLASSIFICATION OF FLAVOBACTERIUM SPECIES FROM CLINICAL SOURCES

Abstract

Clinical isolates of aerobic yellow-pigmented, Gram-negative bacteria allied to Flavobacterium are classified in five taxa of which F. meningosepticum, F. odoratum and Group IIb are of some importance as human pathogens. Antibiotic resistance is a feature of these bacteria and preliminary data suggest their resistance is chromo— somally determined and not plasmid mediated. The taxa can be separated from each other by various biochemical tests and by data on chromosomal DNA characteristics. The similarities within and between species of Flavobacterium can be conveniently illustrated by means of bivariate scatter diagrams, with GiC content and base pairing as the variables. It is evident from such diagrams that most clinical species of Flavobacterium and unnamed taxa are comprised of a 'core' of highly related strains (typical strains) with a number of 'outliers' (atypical strains). The classification of the latter strains is problematic since they are often indistinguishable from typical strains in conventional phenotypic tests. The food and environmental strains so far examined are often atypical when compared with the clinical isolates.