A Bacteriophage-Based Electrochemical Biosensor for Detection of Methicillin-Resistant Staphylococcus aureus

Bacterial pathogens are important targets for detection and early diagnostics of infection in healthcare. Methicillin-resistant Staphylococcus aureus (MRSA) is a bacterium that can cause severe complications such as pneumonia and septicemia from surgical site infections. In this work, a carbon nanotube (CNT)-based impedimetric biosensor using SATA-8505, a bacteriophage, as a recognition element was developed for the detection of MRSA USA300, a common strain of MRSA found in surgical infections. The biosensor allows for fast and selective detection of viable MRSA cells by measuring impedance changes on the electrode surface as a result of bacterial capture by the phage-functionalized CNT electrode. The immobilization of the bacteriophage was achieved by inducing an electric-field and using a charge-directed orientation strategy, and activity of the immobilized phage was confirmed by an infectivity study using disk diffusion methods. The biosensing platform showed high selectivity and sensitivity toward MRSA USA300 with a limit of detection of 1.23 × 10 ² CFU/ml in aqueous solution and 1.29 × 10 ² CFU/ml in blood plasma. The biosensing platform could potentially be integrated into a lab-on-a-chip platform for point of care use and for other pathogens such as Pseudomonas aeruginosa , Klebsiella and Listeria monocytogenes.