Aeromonas salmonicida isolated from wild and farmed fish and invertebrates in Oman

Aeromonas salmonicida was isolated from red spot emperor, king soldier bream, white-spotted rabbit fish and tilapia, and an invertebrate (abalone) in Oman during December 2011–May 2012. The cytotoxic enterotoxin ast gene was found widely distributed among the isolates; aerolysin-like protein ( act ) and the flagellin structural gene lafA less so; and the nuclease gene ( nuc ) not at all. However, there was not any evidence of pathogenicity among the isolates when tested in laboratory-based experiments using rainbow trout and Nile tilapia. Therefore, the risk of the pathogen to fish in Oman is unclear.