Occurrence and molecular surveillance of pathogenesis risk-associated factors in Staphylococcus aureus recovered from raw sheep's milk cheese

Abstract

The aims of our study were to ascertain the presence of different accessory gene regulator (agr) groups, to monitor the occurrence of 12 biofilm- and 5 enterotoxin- related genes and moreover to explore the biofilm-forming ability and antibiotic susceptibility in Staphylococcus aureus isolated from raw sheep’s cheese.From 92 samples of raw sheep’s cheeses, 32% (29 cheeses) harboured Staphylococcus aureus; among those 89.6% were biofilm producers, 55% had enterotoxigenic potential and 17.2% were phenotypically resistant to oxacillin. Five oxacillin resistant isolates were positive for blaZ and were classified into 5 different spa types (t179, t216, t1773, t12029, t13487). In the present study, 79% of Staphylococcus aureus isolates were agrI or agrII-positive. Four biofilm-associated genes (clfA, cna, bbp and fnbpA) were detected only in agr-positive strains.