Characterization of Aeromonas hydrophila from hemorrhagic diseased freshwater fishes in Anhui Province, China.

Aeromonas hydrophila currently has the status of a foodborne pathogen causing zoonotic diseases spreading from animals to humans. Sixty of typically hemorrhagic diseased freshwater fishes were collected from twelve aquafarms in Anhui Province. Twenty of A. hydrophila isolates were isolated and characterized by RAPD-PCR, antibiotics susceptibility testing and determination of virulence factors. RAPD-PCR fingerprinting revealed the complex diversity and genetic polymorphism (I-XIV RAPD types) with D of 0.958 on 90% patterns similarity and eight resistance patterns were observed by antibiotics susceptibility testing with D of 0.747. Furthermore, the virulence genes were present in 85% (aer), 40% (epr), 75% (ast), 35% (ahyB), 35% (act) and 80% (alt) of the strains, respectively. The result indicated that the same characterization (I RAPD type, resistance pattern and virulence factors) was found in A. hydrophila isolates from A aquafram, showing their close genetic relationship or origins.