Development and validation of a loop mediated isothermal amplification (LAMP) assay for the detection of Staphylococcus aureus in bovine mastitis milk samples

•A new real-time fluorogenic LAMP assay for detection of Staphylococcus aureus was developed.•The LOD calculation was included the matrix milk in addition to pure culture.•The used method is simple and fast.

Staphylococcus (S.) aureus is one of the most important animal pathogens causing bovine mastitis. Also, it is a major human pathogen that may produce a variety of toxins which cause staphylococcal food poisoning. In the present study a LAMP assay based on gene nuc to identify S. aureus was developed and validated. The specificity of the LAMP assay was confirmed by using 70 S. aureus isolates and 21 non-S. aureus strains. The optimal temperature-time combination to amplify gene nuc successfully was 65 °C and 30 min. The analytical sensitivity of the developed LAMP assay was 0.26 pg of S. aureus DNA per reaction. The limit of detection evaluated with milk spiked with S. aureus was 9 × 102 CFU mL−1. The final results of this assay were available within less than 2 h. The present study showed that the LAMP assay based on gene nuc appeared to be rapid and simple, and could also be used to identify S. aureus isolates from mastitis milk of dairy cows.