A novel Polymerase Spiral Reaction assay for the rapid detection of penicillin-resistant Staphylococcus aureus genes

Abstract

     In this study, a visual method was developed to detect and identify penicillin-resistant Staphylococcus aureus (PRSA) based on the polymerase spiral reaction (PSR). This method can be performed under isothermal conditions using Bst DNA polymerase and two-pair primers specifically designed to target the blaZ gene, which encodes penicillin-resistance in S. aureus. Investigation of reaction conditions showed that at the temperature of  65 °C and the concentration of primer pairs F2/R2 = 0.1 µM and F1-Nr/R1-N = 1.6 µM, the reaction gave optimal PSR result within only 50 minutes. The detection limit of PSR in genomic DNA and bacterial cells were 10 pg/μL and 5 CFU/mL, respectively, which were more sensitive than with standard PCR. In addition, this method was shown to be highly specific, as non-PRSA bacteria negligibly interfered with PRSA detection. These results indicated that a novel, effortless and reliable PSR assay developed in this study has potential application in the screening for penicillin-resistant of S. aureus in hospitals and communities.