Researchers at the University of Strathclyde (Glasgow, Scotland) have developed a surface-enhanced Raman scattering (SERS)-based test that could help speed meningitis diagnosis, leading to better outcomes for patients.
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Several types of bacteria cause meningitis and each is sensitive to different antibiotics. Karen Faulds, BSc, Ph.D., and PhD student Kirsten Gracie of the Centre for Molecular Nanometrology at Strathclyde, with partners at the University of Manchester in England, used SERS (a spectroscopic imaging technique) to identify which bacteria were present in a single sample, with a view to analyzing cerebral spinal fluid from patients suspected to have meningitis.
Faulds, a Reader in Strathclyde’s Department of Pure and Applied Chemistry, led the study. "Meningitis is a hugely virulent and, in some forms, potentially highly dangerous infection," she explains. "The type of antibiotic used to treat it depends on the strain of meningitis, so it is essential to identify this as quickly as possible."
"The great advantage of the SERS technique is that it gives sharp, recognizable signals, like fingerprinting, so we can more easily discriminate what analytes—or chemical substances—are present in a mixture," Faulds adds.
A series of DNA probes, containing dyes detectable by SERS, made it possible to single out the different pathogens, including Haemophilus influenzae, Streptococcus pneumoniae, and Neisseria meningitidisis. The faster the type of bacteria can be identified by DNA analysis, the faster patients can receive the most effective antibiotic for their condition. It also reduces the need for broadband antibiotics, overuse of which is increasing bacterial resistance.
Combining the SERS technique with chemometrics (data-driven extraction of information from chemical systems) means the amount of bacteria in a sample can be measured while simultaneously identifying the bacteria. The chemometrics work was carried out in collaboration with Prof. Roy Goodacre at the University of Manchester.
The researchers believe the new test would be particularly useful where co-infection of multiple species is common and identifying the dominant pathogen present would allow targeted treatment.
Full details of the work have been published in the journal Chemical Science; for more information, please visit http://pubs.rsc.org/en/content/articlelanding/2014/sc/c3sc52875h.
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