Prevalence, antimicrobial resistance, virulence gene distribution and SCCmec typing of methicillin-resistant Staphylococcus aureus isolated from raw milk and dairy products

Najmeh Vahed  Dehkordi; Ebrahim  Rahimi; Noosha Zia  Jahromi

doi:10.18502/ijm.v16i5.16793

Najmeh Vahed Dehkordi Department of Food Hygiene, Faculty of Veterinary Medicine, Shahrekord Branch, Islamic Azad University, Shahrekord, Iran
Ebrahim Rahimi Research Center of Nutrition and Organic Products, Shahrekord Branch, Islamic Azad University, Shahrekord, Iran
Noosha Zia Jahromi Department of Biology, Faculty of Basic Science, Shahrekord Branch, Islamic Azad University, Shahrekord, Iran

DOI: https://doi.org/10.18502/ijm.v16i5.16793

Keywords: Methicillin-resistant Staphylococcus aureus; Drug resistance; Pathogenicity; Dairy products; Milk

Abstract

Background and Objectives: Researchers have focused on Staphylococcus aureus because it is transmitted through food, such as milk and dairy products, and causes human diseases. Prevalence, antimicrobial resistance, presence, and distribution of methicillin-resistant S. aureus (MRSA) virulence genes isolated from raw milk and dairy products were evaluated.

Materials and Methods: 300 samples of dairy products were collected from Shahrekord, Iran. S. aureus was identified using biochemical tests and screened for sensitivity to 13 antibiotics to identify resistance genes. In addition, SCCmec typing was performed.

Results: Out of 300, S. aureus was found in 82 samples. Raw milk had the highest contamination with S. aureus (60 of 82), followed by cheese (15 of 82), and butter (7 of 82). At least one resistance gene was present in every isolate of S. aureus. Virulence factors and enterotoxin-coding genes, such as sea, seb, sec, and sed were highly distributed.

Conclusion: The results of this study revealed the presence of toxin-producing MRSA strains in raw milk and dairy products. MRSA in dairy farms is an important risk factor for the spread of staphylococcal infections; therefore, further studies are needed to find strategies for controlling the presence of S. aureus, especially MRSA, in dairy products.