SCREENING OF HAEMOLYTIC AEROMONAS SP. ISOLATED FROM MARINE FISH SAMPLES

Aeromonas species are facultatively anaerobic Gram negative bacterium that belongs to the family Aeromonadaceae. In the present study, 350 marine fish gut samples were collected and analyzed among which 200 samples showed the presence of Aeromonas. Starch ampicillin agar was used for Aeromonas isolation, and the colonies were identified phenotypicaly and genotypicaly through biochemical characterization and rnpB amplification respectively. Conventional biochemical identification is time consuming and may lead to misidentification of Aeromonas isolates, so molecular based identification-rnpB gene was used for the identification of Aeromonas isolates. Further haemolytic activity of the Aeromonas isolates were performed on 5% blood agar plates in which some revealed 44% of ? haemolysis and over 8.4% showed ? haemolytic activity but some isolates did not have any haemolytic activity i.e., 47% showed ? haemolysis. The presence of hyl gene which is responsible for haemolytic activity was also confirmed using PCR and 51.5% of the isolates were positive for hyl gene (550 bp). Thus the Aeromonas sp. is considered as an emerging pathogen and identified as a high-risk carrier.