Presence of Staphylococcus aureus, staphylococcal enterotoxins and antimicrobial resistance in traditionally produced raw milk cheeses

Abstract

The objectives of this study was to investigate the presence of Staphylococcus aureus, distribution of classical staphylococcal enterotoxin (SE) SEA to SEE, relevant gene/s and antimicrobial resistance pattern of S. aureus isolated from traditionally produced raw milk cheeses. A total of 106 fresh white cheese samples were examined. The 25 (23.6 %) of 106 cheese samples were found to be contaminated with coagulase positive staphylococci (CPS). From 52 isolates identified as S. aureus, one or more SEs was detected in 38.4 % of the isolates by ELISA whereas one or more se genes were detected in 50 % of the isolates by RT PCR. SEE (75 %) and see gene (61.5 %) were detected most frequently, whereas SED and sed gene were not detected in any isolates. Overall, 63.5 % of isolates were resistant to antimicrobial agents with 59.6 %, 13.5 %, 5.8 %, 5.8 % and 3.8 % of the isolates were resistant to penicillin, erythromycin, tetracycline, cefoxitin and kanamycin, respectively. The results of this study have revealed that cheeses made from raw milk were highly contaminated with S. aureus, therefore, creates a risk for public health due to the presence of enterotoxins as well as resistant strains against antimicrobial agents.