Screening and Identification of Vibrio cholerae Bacteriophages VC3 and Its Role in the Inhibition and Removal of Biofilms in Seafood.

As biological control agents, bacteriophages can both inhibit the pathogenic bacteria and remove the bacterial biofilms from the seafood. Vibrio cholerae is the pathogen of cholera and the severe infection could lead watery diarrhea and even death. The double-layer agar plate method was used to isolate and screen the V. cholerae bacteriophages from the samples of aquaculture water and sewage. Purified bacteriophages were examined through genome sequencing, as well as morphological and biological characterizations. Among the isolated bacteriophages, bacteriophage VC3 was found to be a long-tailed bacteriophage. Whole-genome sequencing showed that the full length of VC3 genome was 27,645 bp. It was a circular dsDNA, with 40.37% G + C content. The optimal multiplicity of infection was 1, the incubation period was 20 min, the burst period was 40 min, and the lysis volume was 73 PFU/cell. Bacteriophage VC3 exhibited good activity under low temperatures and neutral pH conditions. Bacteriophage VC3 could effectively inhibit and eliminate the biofilm of V. cholerae. In addition, bacteriophage VC3 significantly inhibited V. cholerae in fish fillets and shrimp meat. At the same time, it also showed lytic activity against 9 pathogenic bacteria, indicating that it has the potential to inhibit a variety of pathogenic bacteria.