Culture-Independent\nMultiplexed Detection of Drug-Resistant\nBacteria Using Surface-Enhanced Raman Scattering

Abstract

The rapid and accurate detection\nof bacteria resistance to β-lactam\nantibiotics is critical to inform optimal treatment and prevent overprescription\nof potent antibiotics. Here, we present a fast, culture-independent\nmethod for the detection of extended-spectrum β-lactamases (ESBLs)\nusing surface-enhanced Raman scattering (SERS). The method uses Raman\nprobes that release sulfur-based Raman active molecules in the presence\nof β-lactamases. The released thiol molecules can be captured\nby gold nanoparticles, leading to amplified Raman signals. A broad-spectrum\ncephalosporin probe R1G and an ESBL-specific probe R3G are designed\nto enable duplex detection of bacteria expressing broad-spectrum β-lactamases\nor ESBLs with a detection limit of 10³ cfu/mL in 1 h incubation.\nCombined with a portable Raman microscope, our culturing-free SERS\nassay has reduced screening time to 1.5 h without compromising sensitivity\nand specificity.