Molecular Detection of Some Virulence Genes in Aeromonas Species Isolated from Fishes and Water of Manzala Lake

Abstract

In a view of increasing the role of Aeromonas spp. in fish and human diseases, the present wok was conducted to assay the presence of six virulence genes using PCR in Aeromonas species isolated fromfishes and water of Manzala Lake. A total of 200 fish samples comprising 100 Oreochromis niloticus fish, 100 Mugil cephalus fish and 50 water samples were collected from El Gamil region in Lake Manzala. A total number of 258 isolates belonging to Aeromonas spp. were recovered from fish and lake water samples and they were biochemically identified into 4 biotypes. PCR assay of 15 representatives, biochemically confirmed Aeromonas spp. isolates showed that they were genetically confirmed belonging to genus Aeromonas based on specific16S rRNA gene sequence. Virulence properties of the 15 representative strains showed that the majority of the examined strains carried one or more virulence genes. A significant 5 virulence gene have been found in the tested Aeromonas isolates. The frequencies distribution of these genes wasaero (100%), act (20%), ahcytoen (13.33%), lip (13.33%), alt (6.67%). Meanwhile, Haemolysin (hly) gene could not be detected in any of examined Aeromonas isolates.