Flavobacterium johnsoniae

Flavobacterium johnsoniae is a Gram-negative, non-motile, rod-shaped bacterium that thrives in various habitats. This organism is classified as an aerobe, requiring oxygen for growth. It possesses flagella, which are typically associated with mobility; however, F. johnsoniae does not exhibit movement. The optimal growth temperature for F. johnsoniae is around 20°C, indicating its mesophilic nature, as it can grow within a temperature range suitable for moderate warmth. This bacterium is characterized by having a single replicon and two membranes, which is typical of Gram-negative bacteria. F. johnsoniae is known to have a free-living biotic relationship, meaning it does not rely on a host organism for survival. However, it has been observed in association with various fish species, including catfish and other freshwater fish like Pangasianodon hypophthalmus, Lates calcarifer, Trichopodus pectoralis, and members of the Ictaluridae family. The ecological role of Flavobacterium johnsoniae may be significant in aquatic environments, particularly in relation to its interaction with fish hosts. Its presence in these ecosystems could suggest a role in nutrient cycling or as a contributor to the microbial community structure surrounding freshwater fish species. Understanding its distribution and interactions can provide insights into the dynamics of microbial life in aquatic habitats.