PCR-Based Method for Rapid and Minimized Electrochemical Detection of mec A Gene of Methicillin-Resistant Staphylococcus aureus and Methicillin-Resistant Staphylococcus epidermis

Methicillin-resistant Staphylococcus aureus (MRSA) is one of the most important pathogens that cause nosocomial infections. However, microbiological culture techniques take a few days to yield results; therefore, a simple, cost-effective, and rapid detection system is required for screening for MRSA and related bacteria: Methicillin- resistant Staphylococcus epidermidis (MRSE) carriers during the hospital admissions process. In this study, we described the simplified method using by one-time use and screen-printed carbon electrodes, relied upon current quantification of Hoechst dyes which bound with DNA amplified via polymerase chain reaction (PCR) targeted for MRSA mecA gene. Amount of DNA-bound Hoechst molecules were measured by the hand-held potentiostat within two minutes. We found that the peak of a Hoechst-mediated current depended upon the number of MRSA cells, and successfully distinguished between carriers and a non-carrier based on nasal swabs from the patients. This method required only 10 µL for application, and the results could be obtained within total 60 min from sample collection when a minimum of 1 × 103 MRSA cells was present. These results suggested that this minimized technique has the potential to become a useful system of active surveillance for MRSA/MRSE carriers.