Antimicrobial resistance genes of Vibrio parahaemolyticus and Aeromonas hydrophila isolated from Nile tilapia and Mugil fish farms in Kafr-Elsheikh governorate, Egypt

The progressive expansion of aquaculture practices led to the development of bacterial disease outbreaks, otherwise the continuous and extensive use of antibiotics to overcome these diseases. Vibrio and Aeromonas species are responsible for the most severe losses affecting the aquaculture industry in Egypt. The objective of our study to investigate the antibiotic susceptibility of Vibrio parahemolyticus and Aeromonas hydrophila species isolated from Nile tilapia and Mugil fish farms in Kafr El-Sheikh province, Egypt, and molecular detection of antibiotic resistance genes. A total of 305 samples were gathered from apparently path-genomic lesions in different organs from 100 diseased fishes, 65 isolates of Vibrio species were isolated and V. parahemolyticus was isolated with an incidence of 55.4%. Out of 100 examined fish samples 72 Aeromonas species were isolated, A. hydrophila was isolated with an incidence of 99.3 %. Vibrio parahemolyticus showed high resistance for amoxicillin and colistin followed by cefotaxime and streptomycin. Meanwhile, Aeromonas hydrophila were highly resistant to amoxicillin and tetracycline followed by streptomycin, cefotaxime, and colistin. Five isolates of V. Parahemolyticus and A. hydrophila were screened using PCR for detection of 4 antibiotic resistance genes β-lactamase resistance gene (blaTEM); aminoglycosides (aadA1); tetracycline-resistant A tetA (A) and polymyxin resistance (mcr1) which were distinguished in all five V. parahaemolyticus and A. hydrophila isolates. The high detection of V. parahaemolyticus and A. hydrophila antibiotic resistance genes in our study could pose a potential risk to public health so, control methods should be taken to prevent the emergence of antibiotic resistance.