Antagonistic activity of Marine Streptomyces sp. on Fish pathogenic Vibrio species isolated from Aquatic Environment

Vibriosis is a bacterial disease of humans and animals, caused by Gram negative bacteria Vibrio sp. such as Vibrio cholerae, V. parahaemolyticus, V. harveyiand V. vulnificans. Vibriosis resulted in a significant economic loss for the aquaculture industry as it resulted in the death of fishes and shrimps mainly reared for human consumption. The project considers a biological control for vibriosis. The aim of the study was to determine the vibriocidal activity of actinobacteria strains isolated from marine sediments. Vibrio isolated on Thioglycolate Citrate Bile Salt Sucrose agar media (TCBS) from the water of aquaculture farm from Walajapet 13.00°N79.314°E Vellore, Tamil Nadu, India. Four different isolates were obtained (VS1, VS2, VS3 and VS4). Actinobacteria was isolated on Starch Casein Agar media (SCA) from the marine sediment samples. Five actinobacteria isolates (A1, A2, A3, A4 and A5) were obtained. The Vibriocidal activity of the actinobacteria isolates was performed by Agar Well diffusion method on Mueller Hinton Agar medium. Actinobacterial isolates A1, A4 and A5 showed vibriocidal activity on Vibrio cultures VS1, VS2 and VS3. A1 was found as the most potent isolate. An inhibition zone of 20mm was observed against VS1. The potential strain was identified as Streptomyces sp.