Prevalence of Hemolytic and Enterotoxigenic Aeromonas Spp. in Healthy and Diseased Freshwater Food Fishes as Assessed by Multiplex PCR

Abstract

A total of 103 representative colonies from 53 healthy and diseased food fish samples were tested for the incidence of Aeromonas spp. Of which 57% of colonies were positive for Aeromonas spp. by the multiplex PCR (MPCR). On an average, the prevalence was found to be 66% with highest incidence in diseased fishes (76%). About 48% of healthy fish samples were observed to contain Aeromonas. The biomoleculoar identification revealed that the selected virulent hemolytic and enterotoxigenic genes appeared in four different patterns viz. alt; act//hlyA/aer; alt and act//hlyA/aer; ast, alt and act//hlyA/aer, among the MPCR positive isolates of Aeromonas spp. The overall prevalence of the toxin genes alt, act/hlyA/aer and ast among the MPCR positive Aeromonas isolates was found to be 89.8%, 72.9% and 20%, respectively. The biochemical confirmation of the MPCR positive Aeromonas isolates revealed different species in the tested samples belonging to A. hydrophila, A. sobria, A. caviae, A. jandaei, A. veronii, A. schubertii and A. trota and the dominant species was found to be A. hydrophila (48%).

A novel detection method for the pathogenic Aeromonas hydrophila expressing aerA gene and/or hlyA gene based on dualplex RAA and CRISPR/Cas12a

“…Enzyme-linked immunosorbent assay (ELISA; Swain et al, 2003), dot blotting (Longyant et al, 2010), and serotyping (Nielsen et al, 2001) have low diagnostic sensitivity. Over the past decade, a large number of assays based on PCR technology have been developed to detect A. hydrophila by targeting virulence gene (Wang et al, 2003;Hussain et al, 2014). However, these methods require professional personnel and specialized equipment and are not suitable for on-site application or resource-constrained areas.…”