The present study aimed to investigate the prevalence, antibiotic susceptibility profiles, and some toxin genes of Panton-Valentine leukocidin (PVL)-positive Staphylococcus aureus (S. aureus) in unpasteurized raw cow’s milk collected from… Click to show full abstract
The present study aimed to investigate the prevalence, antibiotic susceptibility profiles, and some toxin genes of Panton-Valentine leukocidin (PVL)-positive Staphylococcus aureus (S. aureus) in unpasteurized raw cow’s milk collected from retail outlets located at Mansoura, Dakahliya governorate, Egypt. In that context, a total of 700 raw cow’s milk samples were investigated for the presence of S. aureus, which was identified in 41.1% (288/700) of the samples. Among the S. aureus isolates, 113 PVL-positive S. aureus were identified and subjected for further analysis. The PVL-positive S. aureus were investigated for the existence of toxin-related genes, including hemolysin (hla), toxic shock syndrome toxin-1 (tst), and enterotoxins (sea, seb, sec, see, seg, sei, and selj). Genotypic resistance of PVL-positive strains was performed for the detection of blaZ and mecA genes. Among the PVL-positive S. aureus, sea, seb, and sec were detected in 44.2, 6.2%, and 0.9%, respectively, while the hla and tst genes were identified in 54.9% and 0.9%, respectively. The blaZ and mecA genes were successfully identified in 84.9 (96/113) and 32.7% (37/113) of the total evaluated S. aureus isolates, respectively. PVL-positive S. aureus displayed a high level of resistance to penicillin, ampicillin, and trimethoprim-sulfamethoxazole. Multidrug resistance (resistant to ≥3 antimicrobial classes) was displayed by all methicillin-resistant S. aureus (MRSA) and 38.2% of methicillin-sensitive S. aureus (MSSA) isolates. The obtained findings are raising the alarm of virulent PVL-positive MRSA clones in retail milk in Egypt, suggesting the requirement for limiting the use of β-lactam drugs in food-producing animals and the importance of implementing strong hygiene procedures in dairy farms and processing plants.
               
Click one of the above tabs to view related content.