Detection of Staphylococcus aureus in milk by PCR

The aim of this study was to compare the detection of Staphylococcus aureus (S. aureus) in raw milk samples by polymerase chain reaction (PCR) with detection by cultural methods. A total of 100 milk samples were collected from individual cattle in industrial dairy herds in Urmia, Iran. DNA was extracted from all samples directly. PCR amplifications were performed with a pair of primers specific for the coa gene of S. aureus. In order to isolate S. aureus by cultural methods, bacteriological examinations were done on all samples. Of the 100 milk samples tested, 14% were positive on the basis of the cultural results while 21% of the samples were positive using amplification of the coa gene. There were no culture positive samples that were negative using PCR. PCR amplification of the coa gene could be used as a powerful tool for the identification of S. aureus in milk samples.