Prevalence and characteristics of Aeromonas species isolated from processed channel catfish

From August 1994 to May 1995, 238 channel catfish fillets collected from th ree processing plants in the Mississippi Delta at four time periods were te sted for the presence of Aeromonas species. Identification of Aeromonas spp . was accomplished using an automated Vitek bioassay system with gram-negat ive and nonfermenter cards. Approximately 36.1% were positive for A. hydrop hila, 35.7% for A. sobria, and 10.9% for A. caviae. All three Aeromonas spp . were found in all three processing plants, and the incidence of A. hydrop hila contamination appeared to be higher in summer than other seasons. Eigh ty-six percent of the Aeromonas isolates were hemolytic on 5% sheep blood a gar plates. Most isolates were susceptible to chloramphenicol, neomycin, st reptomycin, and trimethoprim-sulfamethoxazole and resistant to ampicillin a nd bacitracin. Results suggest that Aeromonas spp. are prevalent in process ed channel catfish, and most isolates are hemolytic and resistant to ampici llin and bacitracin.