Heterogeneity of the populations of organotrophic microorganisms on the skin of diseased fish
The results of the molecular genetic studies have shown that bacteria belonging to the microbiota external coverings of fish are very diverse, and the composition and structure of bacterial populations depend on the aquatic environment and the fish species. The purpose of this study was an identification of organotrophic microorganisms isolated from the skin and scales of diseased fish from expositional aquaria. Microorganisms belonging to widespread in fresh water genera: Acinetobacter, Aeromonas, Pseudomonas, Flavobacterium, Janthinobacterium and Shewanella were cultured from the skin scraping. Original, autochthonous and opportunistic for fish species were identified among the isolated strains. Identification of the bacteria revealed a heterogeneous of populations of Aeromonas, Acinetobacter, Pseudomonas and Shewanella. Strains identified as pathogenic of fish and those could act as primary infectious agents have been determined among these microorganisms. They are Aeromonas sobria, A. salmonicida subsp. salmonicida, Acinetobacter johnsonii, Pseudomonas baetica and Shewanella putrefaciens. These species of organotrophic microorganisms are important for the microbiological monitoring the state of the environment under artificial management of fish.