Detection and identification of Staphylococcus aureus in raw milk by hybridization to oligonucleotide microarray

Staphylococcus aureus causes foodborne diseases if consumed in contaminated milk products. Rapid detection and characterization of foodborne pathogen S. aureus is crucial for epidemiological investigations and food safety surveillance. It is still a challenge to detect and identify bacterial pathogens quickly and accurately according to the samples. In this study, we have amplified 16S rRNA of S. aureus by specific primers, designed oligonucleotide probes, detected the sensitivity and specificity of the microarray assay, and also identified S. aureus in the raw milk samples by hybridization. The S. aureus and 2 control pathogens (Streptococcus suis in pigs and Shigella) were used for specificity of the microarray assay. Based upon the hybridization results, universal probes for bacterial pathogens, S. aureus probe, Staphylococcus spp. probe, nucleic acid fixture positive controls and positive experimental control showed positive signals with targeted S. aureus. The samples were diluted from 10(1) to 10(6) cfu per ml for evaluating the sensitivity of the microarray assay. The levels were as high as 10(3) cfu per ml, all of the samples showed positive signals. This method for rapid and effective detection and identification of S. aureus in raw milk demonstrated high sensitivity and specificity.