A total of 120 samples of mullet fish were collected from three different sources; marine water (Port Said), fresh water (Kafr ElZayate) and farms (Kafr Elshiekh) (40 samples from each). The samples were examined for the presence of E.coli and Salmonella. Thirty-seven E.coli isolates (21 from gills, and 16 from muscles) and fifty-six Salmonella isolates (31 from gills, and 25 from muscles) were identified by culture, biochemical analysis and PCR. The isolates were studied for their antimicrobial susceptibility using 12 Antibiotics that are mainly used in the veterinary field. E.coli isolates were highly sensitive to Amikacin (100%) and ciprofloxacin (97.3%) while resistant to Streptomycin and Doxycycline. Salmonella isolates were sensitive to ciprofloxacin (100%) and resistant to Nalidexic acid and Streptomycin. High multiple antibiotic resistance (MAR) index was detected in E. coli and Salmonella isolates from fresh water fish. By using PCR, the aadA2 gene responsible for resistance to Streptomycin was detected in the examined isolates.
Key words: E. coli, Salmonella, mullet fish, Antimicrobial Resistance
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