Staphylococcus aureus, a food pathogen: virulence factors and antibiotic resistance

Staphylococcus aureus is an extraordinarily versatile pathogen responsible for staphylococcal food poisoning, hospital and community infections, as well as toxic shock syndrome. S. aureus is considered the most effective food-borne bacterial pathogen that has ever evolved. The S. aureus metagenome contains 10s of genes encoding staphylococcal enterotoxins, which are responsible for the clinical symptoms associated with staphylococcal food poisoning. S. aureus may be present in food products, being a potential vehicle for transmission. Antibiotics are widely used not only in humans but also in animal husbandry and other agricultural activities. The occurrence of multiresistant strains in food(s) has been increasing; contaminated food is considered an important vehicle for antimicrobial resistance. Methicillin-resistant S. aureus (MRSA) was first recognized in animal infections in 1972 in milk from mastitic cows in Belgium. Animal-associated MRSA infections in humans were first reported during 2003-05 in the Netherlands. Presently, it was reported that livestock-associated MRSA CC398 in pork identifies a potential pathway from farms to the wider population through retail pork. MRSA commonly carry enterotoxin genes but there has been only one report of food intoxication due to MRSA. Antibiotic resistance associated to enterotoxins genes made S. aureus an evolving threat.