Flavobacterium

Flavobacterium is a genus of Gram-negative, non-spore-forming, rod-shaped bacteria in the phylum Bacteroidota (formerly Bacteroidetes), class Flavobacteriia, order Flavobacteriales, and family Flavobacteriaceae. Members are widespread in the environment, especially in soil, freshwater, and marine habitats, where they participate in organic-matter degradation and form biofilms on plant and other surfaces. Most colonies appear yellow to orange due to flexirubin-type pigments, a characteristic feature of many species. They are typically chemoorganotrophic and primarily aerobic or facultatively aerobic, and most are non-fermentative. Many Flavobacterium species exhibit gliding motility on solid surfaces, aiding surface colonization.

Ecology and significance: Flavobacterium species are important players in aquatic ecosystems and soil microbiomes. Some species are notable fish pathogens, such as Flavobacterium columnare, which causes columnaris disease, and Flavobacterium psychrophilum, associated with bacterial coldwater disease in salmonids. In humans and other animals, several species can act as opportunistic pathogens, particularly in immunocompromised individuals, though such infections are relatively uncommon compared with other bacteria.

Taxonomy and evolution: The genus contains numerous species, and taxonomic classification within Flavobacterium has undergone revisions as molecular methods have advanced. Some species formerly placed in Flavobacterium have been reclassified into other genera (for example Elizabethkingia and Chryseobacterium), reflecting ongoing refinement of bacterial taxonomy. Research on Flavobacterium continues to illuminate mechanisms of gliding motility, pigment production, and environmental adaptation.