Morphological varieties and host ranges of Vibrio parahaemolyticus bacteriophages isolated from seawater.

Eighteen bacteriophages lytic for Vibrio parahaemolyticus were isolated from seawater, and their ultrastructure was examined by electron microscopy. Based on the phage morphology, they were classified in four groups. Group I phages consisted of a hexagonal head and a tail with a contractile sheath. All the phages of the other three groups had a relatively long, noncontractile tail, but there were differences in the head structure among these phages. The phages of groups II and III had a hexagonal head and an elongated polyhedral head, respectively. Group IV phages exhibited a unique hexagonal head with knoblike projections. There appeared to be no correlation between the O and K serotypes of V. parahaemolyticus strains and the host ranges of the phages. The phages had varying sensitivities to heat and organic solvents.