MOLECULAR CHARACTERIZATION OF Aeromonas hydrophila ISOLATED FROM Pangasius hypophthalmus (Sauvage, 1878) IN PAHANG RIVER, MALAYSIA.

Nur-Nazifah M.*, Siti-Zahrah A., Syamil M.,Sofiyah A.
Kulliyyah of Science, International Islamic University Malaysia,
Bandar Indera Mahkota, 25200 Kuantan
Pahang, Malaysia
nurnazifah@iium.edu.my

Pahang, Malaysia are very famous of its Pangasius spp (Patin) aquaculture activity. Pangasius spp. has excellent potential for inland aquaculture system with its fast growing ability and good market value in European markets (Singh and Lakra, 2012).Pangasius spp. is one of the largest and most important inland fisheries in the world which mainly contribute as a food source. The production of Pangasius spp. in Malaysia showed tenfold increased from 1,625.21 tonnes in 2000 to 10,891.51 tonnes in 2011. However, Pangasius culture has been reported to face disease problem causing almost 30% mortalities especially in Sungai Pahang and Sungai Kuantan due to multiple infections of bacteria and virus. The reported bacterial disease was Motile Aeromonas Septicemia (MAS) while virus is channel catfish virus (CCV). Thus, the aim of this study is to understand Aeromonas hydrophila that had cause MAS infection in Pangasius hypophthalmus at Pahang River.

Bacteria were collected from liver, kidney and spleen of Pangasius hypophthalmus cultured in Pahang River Malaysia. Isolated bacteria were cultured onto Brain Heart Infusion (BHI) Agar and identified using Gram staining, biochemical tests and API systems. Aeromonas spp. isolates were then subjected to conventional Polymerase Chain Reaction (PCR) using 16s rRNA gene and ITS gene. The amplified genes were sent for DNA sequencing and the results were tested with BLASTn to search for any sequence similarity with other bacteria in the Genebank. Construction of phylogenetic tree was carried out using MEGA 6 software.

From the DNA sequencing method, isolates obtained were confirmed as Aeromonas hydrophila. Neighbor-joining method of phylogenetic tree constructed also reveals that the genetic variation of the isolates is similar with Aeromonas hydrophila from China and India. Thus, this information will facilitate to trigger a better prevention and treatment against MAS.