A polyphasic taxonomic study of Chryseobacterium strains isolated from dairy sources

A polyphasic taxonomic study, employing protein electrophoresis (SDS-PAGE), gas chromatographic analysis of cellular fatty acids (FAME), mol% G+C dete rmination and DNA-DNA hybridisations, was undertaken on 103 dairy isolates shown to belong to Chryseobacterium. Reference strains of the Chryseobacter ium species, CDC group IIb and Embedobacter brevis were included. SDS-PAGE. analysis yielded good differentiation between the investigated species. Ab out half of the strains could be clustered into nine major groups while the other half occupied a separate position. With FAME analysis no clear diffe rentiation of the Chryseobacterium species (except C. meningosepticum) anal SDS-PAGE groups could be achieved. FAME analysis, however, gave good diffe rentiation between the Chryseobacterium and Empedobacter strains. The mol% G+C of the isolates tested, ranged between 36.4 and 39.0. The combination o f SDS-PAGE and DNA-DNA hybridization identified a large group of dairy isol ates as C. indologenes, one isolate as C. gleum and two new genotypic group s, comprising five and 15 dairy isolates respectively, emerged from the pol yphasic study. Another large part of strains have a separate or uncertain p osition in Chryseobacterium and remained classified as Chryseobacterium spe cies CDC group IIb.