Phenotypic and Genotypic Virulence Factors and Antimicrobial Resistance of Motile Aeromonas spp. from Fish and Ground Beef

Motile Aeromonas spp. were isolated from 49 (44.1%) of 111 meat samples (74 fish and 37 ground beef). In this study, 31 (27.9%) isolates were identified as Aeromonas caviae, nine (8.1%) as A.hydrophila and nine (8.1%) as A.veronii biovar sobria. We detected the phenotypic and genotypic virulence factors. All strains showed lipase activity, 95.9% showed proteinase activity, 95.9% showed DNase activity, 93.9% produced siderophores, 85.7% showed lecithinase activity, 53.1% showed hemolysin activity and 30.6% produced slime. Furthermore, cytotoxic (act, aerA and hlyA) and cytotonic enterotoxin (alt and ast) genes were found in 21 (42.9%) strains. The strains carried at least one enterotoxin gene. Only one strain (A.hydrophila) carried all five genes. The act gene was the most frequently observed gene among all strains (22.4%). In an antimicrobial susceptibility test, 100% of strains were resistant to ampicillin followed by vancomycin (91.8%). Multidrug resistance to at least three or more agents was observed in 66.7% of A.hydrophila, 61.3% of A.caviae and 33.3% of A.veronii biovar sobria strains. Practical ApplicationsAeromonas spp. are ubiquitous aquatic organisms and are commonly isolated from food and water. They have emerged as an important human pathogen because of diarrhea related to foodborne outbreaks. Furthermore, these opportunistic bacteria have been associated with various human infections, such as peritonitis, endocarditis, septicemia and urinary tract infections. These bacteria are also predominantly pathogenic to aquatic animals, especially fish. This study indicates that the presence of motile Aeromonas spp. with virulence potential in meat may be a threat to public health. Thus, the potential health risk due to the consumption of inadequately cooked fish and ground beef harboring motile Aeromonas species should not be underestimated.