ANTIMICROBIAL PHENOTYPES OF GEOGRAPHICALLY MATCHED Staphylococcus aureus ISOLATED FROM BUFFALO’S MILK AND CLINICAL HUMAN CASES IN EGYPT: POTENTIAL ZOONOTIC RISKS

Global emergence of antibiotic-resistant food-borne pathogens is a major public health problem. This study aimed to determine the potential zoonotic risk of Staphylococcus aureus in buffalo's milk in Egypt. A total of 102 raw buffalo’s milk samples and 51 human nasal swabs were collected at Kafrelsheikh city, Egypt. All samples were examined for occurrence of S. aureus . Detected isolates were characterised based on DNase activity, mecA gene acquisition, and antibiotic resistance patterns. S. aureus was detected in 33.3% of buffalo's milk samples and29.4% of human nasal swabs. Multiple drug-resistant S.aureus (MDRSA) represented 88.2% and 90% of buffalo and human S. aureus isolates, respectively. Buffalo and human S. aureus isolates showed highest resistance rate for erythromycin (100%), and lowest resistance rate for gentamicin (22.2%). Interestingly, there was no significant difference in resistance patterns between methicillin-resistant S. aureus (MRSA) and methicillin-sensitive S. aureus (MSSA) ( P< 0.46 - 0.97). One-third of the detected S. aureus phenotypes (5/15, 33.3%) were identical between buffalo and human isolates. Moreover, there was no significant difference in antibiotic resistance patterns between buffalo and human isolates ( P< 0.1 - 0.97).This study highlights the potential public health risk of MDRSA transmission via buffalo's milk. Key words: buffalo’s milk, S. aureus , DNase , mecA , antibiogram, zoonotic risk