Prevalence and Characterization of PVL-Positive Isolated from Raw Cow's Milk.

The present study aimed to investigate the prevalence, antibiotic susceptibility profiles, and some toxin genes of Panton-Valentine leukocidin (PVL)-positive () 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 , which was identified in 41.1% (288/700) of the samples. Among the isolates, 113 PVL-positive were identified and subjected for further analysis. The PVL-positive were investigated for the existence of toxin-related genes, including hemolysin (), toxic shock syndrome toxin-1 (), and enterotoxins (, , , , , , and ). Genotypic resistance of PVL-positive strains was performed for the detection of and genes. Among the PVL-positive , , , and were detected in 44.2, 6.2%, and 0.9%, respectively, while the and genes were identified in 54.9% and 0.9%, respectively. The and genes were successfully identified in 84.9 (96/113) and 32.7% (37/113) of the total evaluated isolates, respectively. PVL-positive 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 (MRSA) and 38.2% of methicillin-sensitive (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.