Effect of lysozyme addition on the activity of phages against Vibrio parahaemolyticus

•The combination of lysozyme and phage show better activity than phage alone.•The use of phages with lysozyme is a useful strategy to reduce pathogenic bacteria.•Namely when less effective phages are available.

Phage therapy gained increased attention as an alternative to antibiotics in order to control bacterial diseases and prevent the spreading of multidrug-resistant bacteria in aquaculture. In this study, the addition of a lytic enzyme (lysozyme) during phage therapy was evaluated for the first time to control Vibrio infection. Three phages of Vibrio parahaemolyticus (VP-1, VP-2 and VP-3) were used. The results indicate that the combination of lysozyme and phage showed better activity in comparison to the activity of the phage alone. VP-1 and VP-2 phages in the presence of lysozyme were more effective in reducing bacterial concentration (reductions of 4.0 log) than the VP-3 phage (which was the most efficient against Vibrio). The application of phages along with lysozyme can be a very useful strategy to eliminate or reduce fish pathogenic bacteria in aquaculture, namely when less effective phages are available.