Rapid and duplex detection of MRSA using SERS-based molecular beacons

The presence of the mecA gene and penicillin-binding protein 2a (PBP2a) plays an important role in the antibiotic resistance of methicillin-resistant S. aureus (MRSA). We have developed a method for duplex detection of transmembrane PBP2a expression and the mecA gene using the plasmonic decay properties of Surface-enhanced Raman scattering (SERS) and the unique properties of beacon molecules. The duplex SERS-based test was more specific, sensitive, and rapid than polymerase chain reaction for genetic materials or ELISA for PBP2a expression, and it has a limit of detection that can detect as little as 27 PBP2a-expressed S. aureus and 8.5 pM of mecA. The efficacy of the duplexing test was demonstrated by the observed receiver operating characteristics (ROC) with its area under the curve (AUC) of 0.92 for MRSA-spiked samples. Additionally, the sensor can be developed and integrated with a portable Raman system for on-site detections.