Antagonistic activity of extra cellular product and component bacteria of Pseudomonas sp. against Aeromonas hydrophila from tilapia aquaculture in East Borneo

This research aims to evaluate the antibacterial activity of 103 protein fractions obtained from the extra cellular product (ECP) and four different fractions from the cellular component (whole cell product, heat-killed whole cell product, intra-cellular product and crude extra cellular product) of Pseudomonas sp. against Aeromonas hydrophila pathogen on tilapia fish. Antibacterial activities were measured by the zone of inhibition in a sensitivity test against A. hydrophila. Intra-cellular product, whole cell product, and heat-killed whole cell product of Pseudomonas sp. exhibited inhibition zone of 10 mm and crude of fraction ECP showed inhibition zone of 11 mm. All protein fractions of ECP displayed potential activity against A. hydrophila in Nila tilapia. 73.8% protein fractions had resistant inhibition and 20.4% possessed intermediate inhibition. 5.8% fractions caused sensitive inhibition. Our results showed that protein fractions of ECP were found to be the most effective to inhibit A. hydrophila growth.