A Comparison of Several Media Formulations for Optimal Isolation and Growth of Flavobacterium branchiophilum in both Aquacultural and Natural Settings

Abstract

Flavobacterium branchiophilum is part of the normal microbial flora found in streams and soils. In certain situations F. branchiophilum is also credited with causing bacterial gill disease in fish populations. The objective of this research was to determine if a media formulation exists for selectively isolating and cultivating this bacterium. The isolation and growth characteristics of three commonly occurring Flavobacterium species were examined with various formulations, with and without supplementation. In laboratory-controlled and environmental field experiments the cytophaga agar formulation, supplemented with vitamins and antibiotics, isolated and cultivated F. branchiophilum, inhibited the isolation of F. columnare and suppressed the growth of F. psychrophilum. This media formulation shows promise as a laboratory-based tool for use in studying the ecology of this bacterium, its pathogenic effects on native and farm-raised salmonids, and its impact on the ecology and water quality of local watersheds subjected to aquacultural practices.