Characterization of a novel Vibrio parahaemolyticus host-phage pair and antibacterial effect against the host

Vibrio parahaemolyticus is a widely recognized pathogen that has caused numerous outbreaks and is prevalent in the marine environment. In this study, we investigated the characteristics of the novel V. parahaemolyticus strain BTXS2 and its associated phage, VB_VpP_BT-1011, isolated from the Bohai Coast (Tianjin, China). Strain BTXS2 is a short coryneform bacterium with a terminal flagellum and is able to utilize and metabolize a wide variety of organic matter because of its unique carbon source utilization and enzyme activity. It grows well in medium between pH 5.0 and 9.0 and salinities of simulated freshwater, estuary water, and seawater (NaCl 0.5%-3%). Multiple antibiotic resistance genes and virulence genes that endanger human health were found in the BTXS2 genome. Phage VB_VpP_BT-1011, which infects BTXS2, is a 40,065-bp double-stranded DNA virus of the family Myoviridae with a latent time of 30 min and burst size of 24 PFU/cell. Like its host, the phage tolerates a broad range of environmental conditions (salinity, 0-3% NaCl; pH 5.0-9.0; temperature, 4-37°C). A host range test showed that the phage only infected and inhibited isolate BTXS2. In summary, we investigated a novel V. parahaemolyticus host-phage pair and the antibacterial effect of the phage on V. parahaemolyticus, providing insights into marine microbial ecology and risks.