In Situ Strain-Level Detection and Identification of Vibrio parahaemolyticus Using Surface-Enhanced Raman Spectroscopy

Abstract

The outer membrane of a bacterium is composed of chemical and biological components that carry specific molecular information related to strains, growth stages, expressions to stimulation, and maybe even geographic differences. In this work, we demonstrate that the biochemical information embedded in the outer membrane can be used for rapid detection and identification of pathogenic bacteria using surface-enhanced Raman spectroscopy (SERS). We used seven different strains of the marine pathogen Vibrio parahaemolyticus as a model system. The strains represent four genetically distinct clades isolated from clinical and environmental sources in Washington, U.S.A. The unique quasi-3D (Q3D) plasmonic nanostructure arrays, optimized using finite-difference time-domain (FDTD) calculations, were used as SERS-active substrates for sensitive and reproducible detection of these bacteria. SERS barcodes were generated on the basis of SERS spectra and were used to successfully detect individual strains in both blind samples and mixtures. The sensing and detection methods developed in this work could have broad applications in the areas of environmental monitoring, biomedical diagnostics, and homeland security.

Prospects for plasmonic hot spots in single molecule SERS towards the chemical imaging of live cells

“…152 Biochemical information can be also collected from pathogenic bacteria by in situ SERS measurements. 153 SERS barcodes can be constructed from seven different strains of the marine pathogen Vibrio parahaemolyticus in their natural state and can be used as a successful model system. This approach is promising for the genetic identification of the strain-level differences in SERS spectra.…”

The application of Raman spectroscopy for the detection and identification of microorganisms

“…A more complex, quasi‐3D plasmonic nanostructure array served to identify different Vibrio parahaemolyticus strains using the SERS spectral characteristics of the biochemical information embedded in the outer membrane. This barcode‐like information enabled the detection and quantification of whole bacteria in mixtures of two isolates . The first attempts to transfer the SERS technology for the selective identification of bacteria pathogen in body fluids have already been presented (Section on Identification of Pathogens from Spiked Body Fluids and Real‐world Patient's Samples).…”

Optical Biosensing of Bacteria and Bacterial Communities

“…To fully exploit the spectral information, to the point that minor differences from acquired Raman spectra or images can be used to assign bacterial species with confidence, sophisticated statistical analyses are usually required. With the help of these chemometric tools, Raman spectroscopy and its derivatives have the capacity to be both selective and specific, as evidenced by the fact that bacteria have been differentiated at the strain level from pure culture [14, 55], tap water samples [29], and clinical samples [13, 25, 54] using Raman techniques.…”

“…In the same study, these three different species of Gram-negative bacteria were differentiated from each other with the help of principle component analysis (PCA) [15]. More recently seven different strains of Vibrio parahaemolyticus were differentiated with a LOD of 10 5 CFU mL −1 [14]. Moreover, SERS has been coupled with microfluidics and confocal microscopy to rapidly differentiate between methicillin-resistant S. aureus and methicillin-sensitive S. aureus from clinical isolates [13].…”