Isolation, characterization, and preliminary application of three Vibrio phages in controlling Vibrio alginolyticus

Vibrio alginolyticus is a notable pathogen that can infect fish, shellfish, and other aquatic life. It is also a common pathogen of humans and aquatic animals. At present, the problem of antibiotic-resistant V. alginolyticus is becoming increasingly severe. The Vibrio phage can replace antibiotics in the treatment of Vibrio infection. Three phages, named XZ1, XZA, and XZB were isolated from the coastal waters of Qingdao. XZ1 and XZA were classified as Straboviridae and XZB was classified as Caudoviricetes. They were all stable in a wide pH (4.0–10.0) and temperature (20–60 °C) range, could withstand ultraviolet irradiation for 12 min, and survive a salinity of 25 g/L. There were no integrase or virulence factors in their genomes. In vitro, the phage cocktail preparation had a good inhibitory effect on the formation of V. alginolyticus biofilm. At room temperature, phages significantly reduced the number of V. alginolyticus on foodstuffs (yellow croaker) compared to the control group. This study lays a foundation for the prevention and control of V. alginolyticus infection using phages in the future.