title: Optical fingerprinting in bacterial epidemiology: Raman spectroscopy as a real-time typing method.
abstract: Hospital-acquired infections (HAI) increase morbidity and mortality and constitute a high financial burden on health care systems. An effective weapon against HAI is early detection of potential outbreaks and sources of contamination. Such monitoring requires microbial typing with sufficient reproducibility and discriminatory power. Here, a microbial-typing method is presented, based on Raman spectroscopy. This technique provides strain-specific optical fingerprints in a few minutes instead of several hours to days, as is the case with genotyping methods. Although the method is generally applicable, we used 118 Staphylococcus aureus isolates to illustrate that the discriminatory power matches that of established genotyping techniques (numerical index of diversity [D]=0.989) and that concordance with the gold standard (pulsed-field gel electrophoresis) is high (95%). The Raman clustering of isolates was reproducible to the strain level for five independent cultures, despite the various culture times from 18 h to 24 h. Furthermore, this technique was able to classify stored (-80 degrees C) and recent isolates of a methicillin-resistant Staphylococcus aureus-colonized individual during surveillance studies and did so days earlier than established genotyping techniques did. Its high throughput and ease of use make it suitable for use in routine diagnostic laboratory settings. This will set the stage for continuous, automated, real-time epidemiological monitoring of bacterial infections in a hospital, which can then be followed by timely corrective action by infection prevention teams.
authors.affiliation: Department of Medical Microbiology and Infectious Diseases, Erasmus Medical Center, Rotterdam, The Netherlands.
authors.forename: Diana F M
authors.initials: DF
authors.lastname: Willemse-Erix
authors.forename: Maarten J
authors.initials: MJ
authors.lastname: Scholtes-Timmerman
authors.forename: Jan-Willem
authors.initials: JW
authors.lastname: Jachtenberg
authors.forename: Willem B
authors.initials: WB
authors.lastname: van Leeuwen
authors.forename: Deborah
authors.initials: D
authors.lastname: Horst-Kreft
authors.forename: Tom C
authors.initials: TC
authors.lastname: Bakker Schut
authors.forename: Ruud H
authors.initials: RH
authors.lastname: Deurenberg
authors.forename: Gerwin J
authors.initials: GJ
authors.lastname: Puppels
authors.forename: Alex
authors.initials: A
authors.lastname: van Belkum
authors.forename: Margreet C
authors.initials: MC
authors.lastname: Vos
authors.forename: Kees
authors.initials: K
authors.lastname: Maquelin
mesh_terms: D015373:Bacterial Typing Techniques / Q000379:methods*; D016172:DNA Fingerprinting; D016521:Electrophoresis, Gel, Pulsed-Field; D006801:Humans; D055624:Methicillin-Resistant Staphylococcus aureus / Q000737:chemistry / Q000145:classification; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013059:Spectrum Analysis, Raman / Q000379:methods*; D013211:Staphylococcus aureus / Q000737:chemistry* / Q000145:classification*; D013997:Time Factors