Isolation and characterization of bacteriaophages against virulent Aeromonas hydrophila [post]

2020 unpublished
Aeromonas hydrophila is an important water-borne pathogen that leads to a great economic loss in aquaculture. Along with the abuse of antibiotics, drug-resistant strains rise rapidly. In addition, the biofilms formed by this bacterium limited the antibacterial effect of antibiotics. Bacteriaophages have been attracted increasing attention as a potential alternative to antibiotics against bacterial infections. Results: Five phages against pathogenic A. hydrophila, named N21, W3, G65, Y71 and
more » ... 3, G65, Y71 and Y81, were isolated. Morphological analysis by transmission electron microscopy revealed that phages N21, W3 and G65 belong to the family Myoviridae, while Y71 and Y81 belong to the Podoviridae. These phages were found to have broad host spectra, although their burst sizes were varied per infected host cell at their optimal multiplicity of infection. They were sensitive to high temperature but had a wide adaptability to the pH. In addition, the phages G65 and Y81 showed considerable effect on growth and biofilm inhibition of A. hydrophila; and the phages G65, W3 and N21 were able to scavenge mature biofilm effectively. Phage treatments applied to the pathogenic A. hydrophila in mice model resulted in a significantly decreased bacterial loads in tissues. Conclusions: Five A. hydrophila phages were isolated with broad host ranges, low latent periods, and wide pH and thermal tolerance. And the phages exhibited varying abilities in controlling A. hydrophila infection. This work presents promising data supporting the future use of phage therapy. Background Aeromonas hydrophila is a Gram-negative, rod-shaped bacterium that is ubiquitous found in natural aquatic environments. The bacterium is predominantly pathogenic to poikilothermy animals, including fish, frogs, turtles, snakes and amphibians [1]. It is responsible for the large-scale outbreak of fish hemorrhagic septicemia, leading to severe economic losses to aquaculture industry worldwide [2]. The bacterium is also an important pathogen that infects humans and other mammals, causing gastroenteritis and various systemic infections. A.hydrophila is a very typical pathogen of humananimal-fish comorbidity [1]. In general, the prevention and treatment of diseases depends mainly on extensive application of novel virulent phage infecting the Aeromonas hydrophila isolated from rainbow trout (Oncorhynchus mykiss). Virus Res. 2019; 273:197764. 28. Chandrarathna H, Nikapitiya C, Dananjaya SHS, De Silva BCJ, Heo GJ, De Zoysa M, Lee J. Isolation and characterization of phage AHP-1 and its combined effect with chloramphenicol to control Aeromonas hydrophila.
doi:10.21203/rs.2.21272/v1 fatcat:aholbvv7zrepzhqyrvgwwc7bve