Flavobacterium columnare

Flavobacterium columnare is a thin Gram-negative rod bacterium of the genus Flavobacterium. The name derives from the way in which the organism grows in rhizoid columnar formations.

Contents

• Flavobacterium columnare
• columnaris bacteria flavobacterium columnare
• References

The species was first described by Davis (1922), and the name was validated by Bernardet and Grimont (1989).

F. columnare can be identified in the laboratory by a five-step method that demonstrates:

1. the ability to grow on a medium containing neomycin and polymyxin B
2. production of yellow pigmented rhizoid (root-like in appearance) colonies
3. production of a gelatin-degrading enzyme
4. binding of Congo red dye to the colony
5. production of a chondroitin sulfate-degrading enzyme

The species has been known previously as Flexibacter columnaris, Bacillus columnaris, and Cytophaga columnaris.

F. columnare is one of the oldest known diseases among warm-water fish, and manifests itself as an infection commonly known as columnaris. Infections are the second leading cause of mortality in pond raised catfish in the southeastern United States.