COMPREHENSIVE ASSESSMENT OF STAPHYLOCOCCUS AUREUS CONTAMINATION IN RAW MILK: OCCURRENCE, ANTIBIOTIC RESISTANCE MECHANISMS, ENTEROTOXIN GENE MARKERS AND PUBLIC HEALTH RISKS

Staphylococcus aureus has evolved as one of the most outstanding foodborne pathogens. As a member of the ESKAPE group, it can "escape" the antimicrobial effects of biocidal agents, posing a global public health threat. Hence, the current research was designed to investigate the presence of Staph. aureus isolated from raw milk samples and evaluated their antibiotic resistance and enterotoxin genes. Fifty raw milk samples were randomly purchased from dairy farms, small holders, dairy shops and street vendors located in Cairo, Giza and Qalyubia governorates, Egypt to highlight the contamination at farm level and after distribution. Staph. aureus isolates were identified using biochemical and molecular methods. Antibiotic resistance was determined against 10 antibiotics, using the phenotypic disc diffusion assay and genotypically. Furthermore, 2 staphylococcal enterotoxin genes (SEA and SEC) were screened. The obtained results indicated that the mean counts of Staph. aureus was 1.9±0.2, 2.2±0.3, 1.6±0.3 and 2.9±0.2 log10 cfu/ml, among the raw milk samples from dairy farms, small holders, dairy shops and street vendors, respectively. Additionally, Multi-drug resistance (MDR) was exhibited in 50% of the isolates, and 78.95% were methicillin-resistant Staph. aureus (MRSA). Moreover, high resistance to penicillin (62.5%), cefoxitin (59.38%) and tetracycline (56.25%) was observed. A percentage of 28.13% of Staph. aureus strains were having enterotoxin genes, out of them 21.9% and 6.25% harbored SEA and SEC genes, respectively. Concurrently, the obtained findings advocate for the implementation of surveillance programs to ensure effective preventive measures starting at the farm level.