MRSA by SERS on a chip
- Published: Feb 25, 2013
- Author: Steve Down
- Channels: Raman
Methicillin-resistant Staphylococcus aureus (MRSA) can be distinguished from methicillin-sensitive S. aureus (MSSA) by SERS using a lab-on-a chip, say US and Chinese scientists. The system can even identify and measure the amount of MRSA in mixtures with MSSA.
In a system designed by Michael Konkel and colleagues from Washington State University and Tianjin University of Science and Technology, the bacteria are fed into the microchannels to form droplets of a suspension with mineral oil before being mixed with a silver nanocolloid suspension and sodium chloride solution. The droplets are illuminated with a 532-nm laser for SERS within the microchannel and spectra are collected, as described in Analytical Chemistry.
Although the spectra from MRSA and MSSA are similar, there are sufficient differences to distinguish between them. In a rapid analysis, 17,400 SERS spectra were obtained from 21 MSSA and 37 MRSA isolates from infected humans within 3.5 hours and a differentiation index of 3.43-4.06 was established. The system was also used to distinguish between MRSA isolates that were part of a clinical outbreak and those that were not.