ISOLATION, CHARACTERIZATION AND STABILITY OF LYTIC BACTERIOPHAGE (AhFM22) INFECTING AEROMONAS HYDROPHILA.

Fish farming contributes to aquaculture production for the domestic and international markets in India. Intensification of the aquaculture production systems has led to increased stress to fish. Thus, diseases occur more frequently across the entire region of India. One of the most common types is hemorrhagic septicemia caused by Aeromonas hydrophila. A. hydrophila is an opportunistic pathogenic bacterium causing diseases in human and fish. The emergence of multidrug-resistant A. hydrophila isolates has been increasing in recent years. In this study, we performed antibiotic susceptibility to A. hydrophila Ah34 strain. The MAR index of A. hydrophilaAh34 is 0.372 which infers the predominate use of antibiotics in aquatic environments. To develop an alternative bio-control measure for multi-drug resistant pathogenic Aeromonas hydrophila, which causes motile Aeromonas septicemia in fish, a novel virulent bacteriophage (AhFM22) was isolated from sewage water sample. The titer value of the purified phage AhFM22 was 1.29 x 107 PFU/mL. AhFM22 displayed latent period of 40 min with burst size of 670 PFU per infected cell. Since AhFM22 has a narrow host range, for effective phage therapy, different phages are needed for preparation of cocktails that are capable of killing the heterogeneous A. hydrophila strains. Further detailed in vivo studies are needed to confirm the protective efficacy of newly isolated AhFM22 against A. hydrophila infection. [ABSTRACT FROM AUTHOR]