Isolation and identification of Aeromonas hydrophila Isolated from tilapia (Oreochromis niloticus)

Abstract

Tilapia (Oreochrornis niloticus) is one of the most abundant cultured species in Malaysia. In fact, it is also listed as major farmed fish species in global aquaculture production. However, the intensification of fish farming has been accompanied by outbreak of many infectious diseases. Motile Aeromonad Septicaemia (MAS) caused by Aeromonas hydrophila nas been reported as the most common bacteria disease that affects aquaculture industry. This study was conducted to isolate and identify A. hydrophila from a farm-raised tilapia in Terengganu, Malaysia. Thirteen isolates that successfully isolated from intestine of tilapia fry were identified using conventional method including morphological tests, biochemical tests and physiological tests. Result revealed that l 00% of presumptive isolates were A. hydrophila and all isolates were capable to produce a or p hemolysis in blood agar. The phenotypic relationships among isolates were investigated using numerical taxonomy. Dice coefficient (So) was used to compute the similarity between isolates. Finally, dendrogram was constructed using data clustering method performed by Unweighted Pair Group Method with Arithmetic Mean