Characterization and genomic analysis of the vibrio phage R01 lytic to Vibrio parahaemolyticus

Abstract

Vibrio parahaemolyticus is a significant zoonotic pathogen that is capable of causing infections in marine animals and contaminating seafood. In this study, we characterized a bacteriophage, vibrio phage R01, which exhibited lytic activity against V. parahaemolyticus VP-ABTNL, a strain known to cause skin ulceration in the juvenile sea cucumber. Morphological analysis revealed that vibrio phage R01 belongs to the Siphoviridae family of the Caudovirales order. A one-step growth curve analysis showed that the latent period and burst period of R01 were approximately 20 min, with a burst size of 316 PFU (plaque-forming unit) per infected cell. The stability determination assay showed that the lytic activity of phage R01 was optimal at 4–28 °C and a pH of 7.0, while it ceased at temperatures higher than 60 °C. The inhibition ability of the vibrio phage R01 against the VP-ABTNL was tested in vitro using the phage with three MOI (multiplicity of infection) values of 1, 10 and 100. All treated cultures exhibited a significant (P < 0.05) inhibition of VP-ABTNL growth compared to the untreated culture. Notably, the phage treated culture with a MOI of 100 displayed a consistently inhibition capability, comparable to the antibiotic-treated group (P > 0.05). Subsequently, the whole genome of the vibrio phage R01 was sequenced and analyzed. The genome of phage R01 consists of 75,514 bp with a G+C content of 49.42%. Twenty-four of the 75 putative proteins encoded by this phage have known functions, and no rRNA and tRNA genes were identified. Phylogenetic analysis based on DNA polymerase and terminase large subunit revealed that phage R01 is a new species within the genus of Mardecavirus. These findings indicate that the vibrio phage R01 may serve as a viable alternative agent for preventing V. parahaemolyticus infections.