A new bacteriophage, VHML, isolated from a toxin-producing strain of Vibrio harveyi in tropical Australia

Some strains of Vibrio harveyi are known to be pathogenic for fish and many invertebrates including crustaceans. Despite their importance, their modes of virulence have yet to be fully elucidated. Here, we present a previousl y unreported bacteriophage extracted from a toxin-producing strain of V. ha rveyi isolated from moribund prawn larvae in tropical Australia. Classifica tion into the family Myoviridae was based upon morphological characteristic s (an icosahedral head, a neck/collar region and a sheathed rigid tail) and nucleic acid characteristics (double-stranded linear DNA). We have termed the bacteriophage VHML (Vibrio Harveyi Myovirus Like). VHML is a temperate bacteriophage that has a narrow host range and shows an apparent preference for V. harveyi above other vibrios (63 Vibrio isolates tested) and other g enera (10 other genera were tested). The conventional methods for phage con centration and extraction of nucleic acids from phage particles were not ef ficient and the alternative methods that were used are discussed.