ORIGINAL ARTICLE Occurrence, Virulence Factors, Antimicrobial Resistance, and Genotyping of Staphylococcus aureus Strains Isolated from Chicken Products and Humans Rasha M. El Bayomi, 1 Heba A. Ahmed, 2 Maysa A. I. Awadallah, 2 Rasha A. Mohsen, 3 Abeer E. Abd El-Ghafar, 3 and Mahmoud A. Abdelrahman 3 Abstract Staphylococcus aureus in food is a consequence of inadequate hygienic handling and processing, posing a potential risk to public health. The current study aimed to characterize virulence factors, as well as antimi- crobial resistance of Staphylococcus aureus and methicillin-resistant S. aureus (MRSA) isolated from retail chicken products and hand swabs from vendors in Egypt. In addition, genetic relatedness of the isolates from chicken and humans was evaluated by polymerase chain reaction–restriction fragment length polymorphism (PCR-RFLP) using protein A as a target. A total of 110 samples were collected from chicken products (n = 80) and vendors (n = 30). Overall, 30 (37.5%) chicken products samples were positive for S. aureus, whereas hand swabs from meat handlers revealed that 18 (60%) were positive. Ten MRSA strains were characterized by the presence of the mecA gene, comprising seven isolates from chicken and three from humans. Virulence- associated factors were evaluated by PCR, revealing that 31.3% of S. aureus isolates harbored the Panton– Valentine leukocidin (PVL) gene, whereas 10.4% were positive for the sea and sed genes each, and only two isolates were positive for c-hemolysin–associated gene. Genotyping using spa PCR-RFLP showed identical restriction banding patterns of MRSA isolates of human and chicken meat origin, indicating the genetic relatedness of the isolates. To the best of our knowledge, this is the first study to characterize PVL-positive MRSA from chicken products and to utilize spa-RFLP for evaluating the genetic relatedness between MRSA of human and chicken origin in Egypt. Key Words: S. aureus—MRSA—PVL—c-Hemolysin—Enterotoxins—spa-PCR-RFLP. Introduction T he poultry industry in Egypt has grown in the last years to keep up with the increased trend of consump- tion. Staphylococcus aureus is a widespread foodborne pathogen colonizing the nasal passages, skin, and intestinal tracts of different animals and humans (Hanson et al. 2011). The presence of S. aureus in food could be attributed to the contamination of raw meat during slaughtering, processing, and storage (Tassew et al. 2010, Hennekinne et al. 2012). Food poisoning due to S. aureus enterotoxins is ranked third worldwide; in addition, these toxins are heat stable, and as few as 20–100 ng of the toxin can produce illness (Asao et al. 2003, Schelin et al. 2011). Resistance to antibiotics is an increasing concern worldwide and is associated mainly with uncontrolled usage of antimi- crobials for treatment or as growth promoters in food animals (Barber et al. 2003). S. aureus resistant to penicillinase- resistant pencillins is referred to as methicillin-resistant S. aureus (MRSA). Resistance of methicillin is mediated by the mecA gene, which encodes penicillin-binding protein 2a, with a decreased binding affinity for b-lactams (Chambers 1997). Because of its multidrug resistance pattern, MRSA is considered a public health concern, especially for immuno- compromised patients (Pesavento et al. 2007, Kraushaar and Fetsch 2014). Panton–Valentine leukocidin (PVL) is one of the important exotoxins causing severe skin and soft tissue infections and necrotizing pneumonia (Kraushaar and Fetsch 1 Department of Food Control, Faculty of Veterinary Medicine, Zagazig University, Zagazig, Egypt. 2 Department of Zoonoses, Faculty of Veterinary Medicine, Zagazig University, Zagazig, Egypt. 3 Department of Microbiology, Animal Health Research Institute, Mansoura Branch, Mansoura, Egypt. VECTOR-BORNE AND ZOONOTIC DISEASES Volume X, Number X, 2016 ª Mary Ann Liebert, Inc. DOI: 10.1089/vbz.2015.1891 1