Isolation and identification of bacteriophages infecting ayu Plecoglossus altivelis altivelis specific Flavobacterium psychrophilum.
ABSTRACT In order to investigate methods for controlling systemic bacterial coldwater disease (CWD), bacteriophages that infect Flavobacterium psychrophilum were isolated by the enrichment method from pond water collected from Japanese ayu farms. The five phages isolated were classified as members of Myoviridae (PFpW-3, PFpC-Y), Podoviridae (PFpW-6, PFpW-7), and Siphoviridae (PFpW-8) and had highly variable patterns of infectivity for different F. psychrophilum isolates (n=128). The stability tests of the phages in different waters, pHs and temperatures were assessed, and the results indicated that none of the phages were affected by ayu farm conditions. Among the phages, PFpW-3 had high infectivity for F. psychrophilum isolated from ayu and other fish and demonstrated sufficient survivability in the stability tests. Thus, PFpW-3 and its indicator strain N2-3 were inoculated into cytophaga broth at different doses of multiplicity of infection (MOI) and proved to be efficient for the reduction of bacterial growth. This study may be the basis for a further evaluation of phage therapy in the treatment of CWD in Japanese ayu farms.
Article: A Review of Flavobacterium Psychrophilum Biology, Clinical Signs, and Bacterial Cold Water Disease Prevention and Treatment[show abstract] [hide abstract]
ABSTRACT: Bacterial coldwater disease and other infections caused by Flavobacterium psychrophilum are a worldwide concern, particularly for freshwater salmonid hatcheries. F. psychrophilum infections can be difficult to control; antibiotic resistance is common and no effective vaccines are currently available. This review summarizes the biology and charac-teristics of this important pathogen, as well as the techniques required for isolation and identification. In addition, the epi-demiology, clinical signs, treatment, and possible preventative measures of bacterial coldwater disease are discussed.The Open Fish Science Journal 01/2011; 411:40-48.