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.