Veterinarija ir Zootechnika

This research aims to assess the existence rate, most dangerous virulence genes (aerolysin (aerA) and hemolysis (ahh1)), antibiotics sensitivity, and resistance pattern of Aeromonas hydrophila strains that were isolated from 100 raw marketed buffalo milk samples, which were gathered from Dakahlia governorate, Egypt. The culturally obtained Aeromonas spp. were evidenced in about 87% of the examined raw market milk samples while the biochemical investigation revealed that 72% of the inspected samples were polluted with Aeromonas species. On the other hand, A. hydrophila was detected in about 30% of the examined market milk samples. In addition, molecular detection of aerA and ahh1 virulence factors of 19 A. hydrophila isolates using multiplex PCR was carried out. Then, it was detected that 8 (42.1%) isolates had aerA gene, while 5 (26.3%) isolates possessed ahhl gene and 4 (21.1%) isolates had both aerA and ahh1 genes. Additionally, 2 (10.5%) isolates were negative for the two inspected genes. All A. hydrophila isolates (19) showed resistance against streptomycin antibiotic; the average multiple antibiotic resistance between A. hydrophila isolates was 0.431, and it reached 1 in one strain (positive for aerA gene) as this strain was resistant to all used antibiotics. In conclusion, this study reveals a high incidence of multiple antibiotic resistance (MAR) of A. hydrophila strains that were isolated from marketed milk samples in Dakahlia governorate. Moreover, it indicates the presence of virulence genes.