Can You Use Phage Cocktails to Control for Vibrio parahaemolyticus in Aquaculture?

Aquaculture is a huge industry in the modern world and provides huge economic boosts to coastal areas. However, aquaculture is riddled with problems that are needed to be overcome. One of these is the stopping bacterial infections from decimating the organisms being grown and harvested. Currently this is achieved by antibiotic, however the more antibiotics are used, the more likely the targeted species will develop a resistance to the antibiotic. Furthermore, antibiotic are not species specific usually and this can cause further problems in ecosystems.  This problem has led to a re-emergence of the push for phage therapy. This also has the problem that bacteria may develop a resistance to the species specific phage, leading to an inability to control infections of commercially important species.  One possible solution is to have phage cocktails, a mixture of multiple phages. It is thought that a development of resistance for multiple phages will be less likely to occur. Therefore, the article investigates the efficiency of 3 V.parahaemolyticus phages (VP-1, VP-2 & VP-3) cocktails to control V.parahaemolyticus in aquaculture.

It was found that phage cocktails could be a way to increase the efficiency of the control of V.parahaemolyticus  in aquaculture systems compared to adding just one phage to the system. However, it was also found that the phages within the cocktail should be selected carefully. An example is VP-3 (which was found to have the highest and fastest rate of bacterial inactivation out of the 3 phages) which had a similar efficiency of inactivation as a cocktail of VP1 & VP-2. Also, a cocktail of VP-1, VP-2 & VP-3 were shown to have no significant difference in efficiency compared to both VP-2 alone and VP-3 alone. Whereas a cocktail of VP-2 & VP-3 was shown to have a better efficiency than VP-3 alone. This is suggested by the authors to be due to VP-1 and VP-3 having the same receptor which they use to attach and infect the host cell.  This needs to be researched to confirm, however may provide important information in what phages should go into a phage cocktail, phages which use different receptors. There are other criteria which are highlighted in the article which may affect the efficiency of a phages cocktails: 1) host range; 2) latent period; 3 )burst size and 4) survival in the environment. These would have to be researched for each phage within the phage cocktail before considering the phag