Detection of Enterotoxigenic Potential of <i>Staphylococcus Aureus</i> Isolates from Cheese Samples with Two Different Methods

Abstract

<jats:title>Abstract</jats:title> <jats:p>The primary objective of our study was to detect the occurrence of enterotoxigenic <jats:italic>Staphylococcus aureus</jats:italic> in diverse types of cheese (cow’s milk cheese and mixed milk cheese) samples from R.N. Macedonia. Cheese samples were analyzed for enumeration and isolation of the <jats:italic>S. aureus</jats:italic> strains according to ISO 6888-1. We detected the toxigenic potential of the strains by the use of the Enzyme Link Fluorescent Assay VIDAS system, and we confirmed the presence of the SEs (<jats:italic>sea, seb, sec, sed, see</jats:italic>) genes by multiplex PCR. The results showed that out of 270 samples of cheese, coagulase-positive staphylococci (CPS) were detected in 27 (10%), and coagulase-negative staphylococci in five samples (1.8%). Biochemically, all 27 CPS samples were confirmed to be <jats:italic>Staphylococcus aureus.</jats:italic> With VIDAS SET2 test we confirmed that 11 isolates are producers of one of the toxins limited by the test. With the conventional PCR we confirmed genes in only 7 isolates. Most common detected gene was <jats:italic>seb</jats:italic> n=3 (42.8%), followed by <jats:italic>sea</jats:italic> n=2 (28.6%), and <jats:italic>sec</jats:italic> n=2 (28.6%). Additionally, <jats:italic>sed</jats:italic> and <jats:italic>see</jats:italic> genes were not detected in any of the <jats:italic>S. aureus</jats:italic> isolates. Discrepancies between the two test methods for detection of enterotoxigenic potential are not uncommon. The presence of viable <jats:italic>Staphylococcus aureus</jats:italic> cells that have enterotoxin potency demonstrates the importance of appropriate hygiene practices in the diary process and also the maintenance of the products in order to obtain a safe final product for the consumers.</jats:p>