Vancomycin resistance among methicillin-resistant Staphylococcus aureus isolates from animal milk

Document Type : Original Article


1 Bacteriology, Mycology, and Immunology Department, Faculty of Veterinary Medicine BeniSuefUniversity,Beni-Suef 62551, Egypt

2 Microbiology and Immunology Department, Faculty of Medicine, El-MiniaUniversity, El Minia 61519, Egypt


Staphylococcus aureus(S. aureus) is a major cause of mastitis in dairy animals
and a serious pathogen affecting human health. The current study was
designed to investigate the extent of S.aureus in milk samples collected from
dairy animals as well as human clinical samples,beside determination of its
antimicrobial susceptibility pattern. Also, the prevalence of both mecA and
vanA genes among some selected methicillin-resistant isolates was
investigated. Out of 120 milk samples obtained from different animals (cows,
buffaloes, sheep, and goats), 81 (67.5%) samples reacted positive for S.
aureus, whereas 67 (74%) out of 90 human samples were found positive for S.
aureus. Disk diffusion susceptibility testing revealed that S.aureus isolates of
humans were more resistant than thoseof animals against all tested
antimicrobials except for clindamycin. A high rate of multi-drug resistance
(MDR) and mecA gene was recorded in S. aureusof both animals and humans.
Surprisingly,vanAgene, which is responsible for vancomycin resistance was
detected only in S. aureus isolated from animal milk. To the best of
ourknowledge, it is the first record of vanA gene in S. aureus recovered from


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