Explosing nuc and mecA Genes in Staphylococcus aureus Isolates from Dairy Cow Milk through Molecular Characterization
F Rachmawati1*, T Ariyanti1, SM Noor1, Y Anastasia1, PM Widiyanti1, H Handayani S Purba2, W Suwito3, A Indrawati4, Suhaemi1, S Mulyati1, Sukatma1, Sumirah1 and A Mulyadi1

1 Research Center for Veterinary Science, Research Organization for Health, National Research and Innovation Agency (BRIN), Bogor, Indonesia
*E-mail: fahera.76[at]gmail.com
2 Research Center for Genetic Engineering, Research Organization for Life Sciences and Environment, National Research and Innovation Agency (BRIN), Bogor, Indonesia
3 Research Center for Food Technology and Processing, Research Organization for Agriculture and Food, National Research and Innovation Agency (BRIN), Yogyakarta, Indonesia
4 IPB University, Bogor, Indonesia

Abstract

Staphylococcus aureus is a significant causative agent of food-borne diseases, capable of adapting to various food environments and producing enterotoxins that lead to food poisoning. The emergence of methicillin-resistant S. aureus (MRSA) poses an increased threat to public health due to its resistance to &#946--lactam antibiotics, commonly used to treat Staphylococcal infections. The prevalence of Livestock-associated MRSA (LA-MRSA) remains high in various regions worldwide, with new virulence and resistance factors posing growing concerns for human health. This study aimed to detect nuc and mecA genes in S. aureus isolates from dairy cow milk. Five S. aureus isolates from the PRV collection, previously identified phenotypically using Baird-Parker Medium (BPM), were analyzed. Molecular confirmation of S. aureus was performed using PCR to detect 23S rRNA and nuc genes, while the mecA gene was targeted for MRSA identification. Results showed that all five isolates were positive for both 23S rRNA and nuc genes, confirming their identity as S. aureus. However, the mecA gene was not detected in any of the isolates, indicating the absence of MRSA among the tested samples. This study demonstrates the successful molecular identification of S. aureus in dairy cow milk samples through the detection of 23S rRNA and nuc genes. The absence of the mecA gene suggests that these particular isolates are not methicillin-resistant. Further research with larger sample sizes is recommended to better understand the prevalence of MRSA in dairy environments and its potential impact on public health.

Keywords: Staphylococcus aureus, MRSA, dairy cow milk, nuc gene, mecA gene, food safety

Topic: Food Security and Food Processing