Research Article

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

Ismail A. Radwan, Wafaa K. Mahdy, Esraa Hegazy, Hala S. H. Salam
Bacteriology, Mycology, and Immunology Department, Faculty of Veterinary Medicine Beni-SuefUniversity,Beni-Suef 62551, Egypt.

JVMR. 2017; 24(2): 303-310

Abstract

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 animals.

Keywords

Vancomycin, Staphylococcus aureus, Animal milk

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