Rapid Detection of Bacteria from Blood with Surface-Enhanced Raman Spectroscopy

Traditional methods for identifying pathogens in bacteremic patients are slow (24–48+ h). This can lead to physicians making treatment decisions based on an incomplete diagnosis and potentially increasing the patient’s mortality risk. To decrease time to diagnosis, we have developed a novel technology that can recover viable bacteria directly from whole blood and identify them in less than 7 h. Our technology combines a sample preparation process with surface-enhanced Raman spectroscopy (SERS). The sample preparation process enriches viable microorganisms from 10 mL of whole blood into a 200 μL aliquot. After a short incubation period, SERS is used to identify the microorganisms. We further demonstrated that SERS can be used as a broad detection method, as it identified a model set of 17 clinical blood culture isolates and microbial reference strains with 100% identification agreement. By applying the integrated technology of sample preparation and SERS to spiked whole blood samples, we were able to correctly identify both Staphylococcus aureus and Escherichia coli 97% of the time with 97% specificity and 88% sensitivity.