title: Incidence and virulence characteristics ofAeromonasspp. in fish.
abstract: OBJECTIVE
  This study was conducted to evaluate the presence ofAeromonasspp. in raw and ready-to-eat (RTE) fish commonly consumed in Assiut city, Egypt, and to determine virulence factors due to they play a key role in their pathogenicity.
  
  
  METHODS
  A total of 125 samples of raw and RTE fish samples were taken from different fish markets and fish restaurants in Assiut Governorate and screened for the presence ofAeromonasspp. by enrichment on tryptic soy broth then incubated at 30°C for 24 h. Plating unto the sterile Petri dishes containingAeromonasagar base to whichAeromonasselective supplement was added. The plates were incubated at 37°C for 24 h. PresumptiveAeromonascolonies were biochemically confirmed and analyzed for pathogenicity by hemolysin production, protease, and lipase detection.
  
  
  RESULTS
  The results indicated that raw fish were contaminated withAeromonasspp. (40% in wild and 36% in cultured Nile tilapia). Regarding RTE,Aeromonasspp. could be isolated with the percentage of 16%, 28% and 20% in fried Bolti, grilled Bolti and fried Bayad, respectively. Out of 35 isolates obtained, 22 were categorized asAeromonas hydrophila, 12 were classified asAeromonas sobriaandAeromonas caviaewere found in only one isolate. The virulence factors ofAeromonasspp. were detected and the results showed that all isolates produced of hemolysin (91.4%), protease (77.1%), and lipase enzyme (17.1%).
  
  
  CONCLUSIONS
  This study indicates that the presence ofA. hydrophilawith virulence potential in fresh and RTE fish may be a major threat to public health.
authors.affiliation: Department of Food Hygiene (Meat Hygiene), Faculty of Veterinary Medicine, Assiut University, 71515 Assiut, Egypt.
authors.forename: Ashraf M
authors.initials: AM
authors.lastname: Abd-El-Malek
keywords: Aeromonas hydrophila; fish; hemolysin; lipase; protease enzyme; public health