Resumo

Background: Staphylococcal food poisoning is considered to be caused mainly by Staphylococcus aureus, a worldwide leading foodborne pathogen due to a wide range of toxin-mediated virulence factors. Coagulase negative staphylococci (CoNS) have been frequently found in caprine milk and dairy products, and have been reported as the major mastitis-causing agent in goats. However, there is a lack of studies about the characterization of enterotoxins and enterotoxin-encoding genes in CoNS from animal-derived foods. Thus, the aim of this study was to evaluate the presence of enterotoxin-encoding genes in CoNS contaminating goat milk and cheese processing plants. Methods: CoNS (n=45) previously cultured from caprine milk, cheese and swabs taken from the surface of utensils and equipments of a cheese processing plant in Paraiba State, Brazil were analyzed by uniplex-PCR for detection of the classic (sea, seb, sec, sed) and novel (see, seg, seh and sei, sei) enterotoxin-encoding genes. Besides, PCR was also used to detect mecA encoding resistance against methicillin. Positive controls used in the reactions included S. aureus ATCC 13565 (sea), S. aureus ATCC 14458 (seb), S. aureus ATCC 19095 (sec, seh and sei), S. aureus ATCC 23235 (sed and seg), and S. aureus ATCC 27664 (see). Results and Discussion: Enterotoxin-encoding genes were found in 8 (17.8%) isolates. Amongst the enterotoxin-encoding genes patterns detected, it was observed sea (n=2), seb (n=1), sec (n=1), sea+seb+sec (n=1), seg (n=2), sec+seg (n=1). The genes sed, seh and sei were not detected. Three isolates were positive for mecA gene, from which two of them also harbored seg. The results of the present study demonstrate that CoNS found in caprine dairy products can harbor enterotoxin-encoding genes. Therefore, the role of CoNS as foodborne pathogens must be further investigated, especially for the goat dairy industry.