Abstract
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.