Characterization and complete genome sequence analysis of a newly isolatedphage against Vibrio parahaemolyticus from sick shrimp in Qingdao, China

Foodborne diseases have become a serious havoc, where antimicrobial resistance is throwing significant challenges on daily basis. With the increase of drug-resistant bacteria and food-borne infection associated with Vibrio parahaemolyticus, new and effective strategies were needed to control the emergence of vibriosis. Lytic bacteriophages come up as a promising way to resist the pathogenic population in various applications. In this study, a V. parahaemolyticus specific phage vB_VpS_PG28 was isolated from sewage in the seafood market. Results showed vB_VpS_PG28, is strictly a lytic bacteriophage and has a relatively large burst size of 103 plaque-forming units per infected cell. Comparative genomic and bioinformatic analyses proved that vB_VpS_PG28 is a new bacteriophage that had a homologous relation with Vibrio phages of family Siphoviridae, especially with phage VH2_2019, but transmission electron microscopy of vB_VpS_PG28 morphology characterized its morphology is similar to that of Myoviridae family. In silico analysis indicated that the vB_VpS_PG28 genome consists of 82712 bp (48.08% GC content) encoding 114 putative ORFs without tRNA, and any gene associated with resistance or virulence factors has not been found. The bacteriophage in the present study has shown significant outcomes in order to control bacterial growth under in vitro conditions. Thus, we are suggesting a beneficiary agent against foodborne pathogens. Further, to ensure the safe usage of phage oral toxicity testing is recommended.