Virulence properties of Aeromonas spp. from modified-atmosphere- and vacuum-packed milk fish (Chanos chanos Forsskal, 1775)

Abstract

The study was undertaken to determine the pathogenic potential of Aeromonas spp.; Aeromonas hydrophila (18 isolates), Aeromonas veronii biovar sobria (15 isolates), and Aeromonas veronii biovar veronii (28 isolates) isolated from milk fish packed under modified atmosphere and vacuum and stored at 0–2 °C. The isolates were identified by biochemical methods and checked for the presence of 11 virulence genes; ahh1, aerA, act, ast, alt, asaI ahpA, ahpB, gcat, lip, and DNase. All the virulence genes were present in 39 % of the A. hydrophila isolates. Virulence-associated phenotypes were present in most of the isolates. The antibiotic resistance patterns of the Aeromonas spp. from fish revealed that all the isolates were resistance to ampicillin and penicillin. In addition, resistance of the isolates to cephalothin (86.7 %), carbenicillin (62.2 %), and erythromycin (40 %) was also observed. To our knowledge, this is the first report of isolation and characterisation of pathogenic Aeromonas spp. from modified atmosphere packed fish in India. The results of this study add to our knowledge of the ecology of this organism in packed fish, and may in the future help prevent infections in humans