The occurrence of Aeromonas species in farmed fishes at Kafr El-Sheikh Governorate

The objective of this study was to examine the occurrence of Aeromonas species in farmed fish, specifically Oreochromis niloticus, Common carp, and Mugil cephalus, obtained from Kafr El-Sheikh Governorate. The incidence of Aeromonas spp. in examined fish (30 samples of each) was 36.7% in O. niloticus, 23.3% in Common carp and 20% in M. cephalus. Serotyping of positive samples revealed multiple strains with varying distribution rates. Evaluation of fish quality contaminated with pathogenic A. hydrophila revealed that acceptable samples constitute 83.3% of O. niloticus, 90% of Common carp and 93.3% of M. cephalus, while rejection rates were 16.7%, 10%, and 6.7%, respectively. Antimicrobial susceptibility of A. hydrophila isolates exhibited greater susceptibility to gentamicin, imipenem and amikacin, but showed resistance to streptomycin, erythromycin, cloxacillin, cefotaxime, nalidixic acid and cephalothin. A laboratory experiment was conducted to assess the antibacterial activity of lemon oil against Aeromonas hydrophila and to evaluate its effect on the sensory properties of fish fillets. Results demonstrated that lemon oil treatment, particularly at the 1.5% concentration, significantly improved the shelf life and sensory criteria of fish fillets compared to the control one.