title: Identification of Highly Pathogenic Microorganisms by Matrix-Assisted Laser Desorption Ionization-Time of Flight Mass Spectrometry: Results of an Interlaboratory Ring Trial.
abstract: In the case of a release of highly pathogenic bacteria (HPB), there is an urgent need for rapid, accurate, and reliable diagnostics. MALDI-TOF mass spectrometry is a rapid, accurate, and relatively inexpensive technique that is becoming increasingly important in microbiological diagnostics to complement classical microbiology, PCR, and genotyping of HPB. In the present study, the results of a joint exercise with 11 partner institutions from nine European countries are presented. In this exercise, 10 distinct microbial samples, among them five HPB, Bacillus anthracis, Brucella canis, Burkholderia mallei, Burkholderia pseudomallei, and Yersinia pestis, were characterized under blinded conditions. Microbial strains were inactivated by high-dose gamma irradiation before shipment. Preparatory investigations ensured that this type of inactivation induced only subtle spectral changes with negligible influence on the quality of the diagnosis. Furthermore, pilot tests on nonpathogenic strains were systematically conducted to ensure the suitability of sample preparation and to optimize and standardize the workflow for microbial identification. The analysis of the microbial mass spectra was carried out by the individual laboratories on the basis of spectral libraries available on site. All mass spectra were also tested against an in-house HPB library at the Robert Koch Institute (RKI). The averaged identification accuracy was 77% in the first case and improved to >93% when the spectral diagnoses were obtained on the basis of the RKI library. The compilation of complete and comprehensive databases with spectra from a broad strain collection is therefore considered of paramount importance for accurate microbial identification.
authors.affiliation: Robert Koch Institute, Proteomics and Spectroscopy (ZBS 6), Berlin, Germany.
authors.forename: Peter
authors.initials: P
authors.lastname: Lasch
authors.affiliation: Public Health Agency of Sweden, Solna, Sweden.
authors.forename: Tara
authors.initials: T
authors.lastname: Wahab
authors.affiliation: Austrian Agency for Health and Food Safety, Vienna, Austria.
authors.forename: Sandra
authors.initials: S
authors.lastname: Weil
authors.affiliation: National Center for Epidemiology, Department of Bacteriology, Budapest, Hungary.
authors.forename: Bernadett
authors.initials: B
authors.lastname: Pályi
authors.affiliation: Friedrich-Loeffler-Institut, Institute of Bacterial Infections and Zoonoses, Jena, Germany.
authors.forename: Herbert
authors.initials: H
authors.lastname: Tomaso
authors.affiliation: Bundeswehr Institute of Microbiology, Munich, Germany.
authors.forename: Sabine
authors.initials: S
authors.lastname: Zange
authors.affiliation: Norwegian Institute of Public Health, Oslo, Norway.
authors.forename: Beathe
authors.initials: B
authors.lastname: Kiland Granerud
authors.affiliation: National Institute for Nuclear, Chemical and Biological Protection, Milin, Czech Republic.
authors.forename: Michal
authors.initials: M
authors.lastname: Drevinek
authors.affiliation: National Veterinary Institute, Technical University of Denmark, Frederiksberg, Denmark.
authors.forename: Branko
authors.initials: B
authors.lastname: Kokotovic
authors.affiliation: Spiez Laboratory, Federal Office for Civil Protection, Spiez, Switzerland.
authors.forename: Matthias
authors.initials: M
authors.lastname: Wittwer
authors.affiliation: Mabritec AG, Riehen, Switzerland.
authors.forename: Valentin
authors.initials: V
authors.lastname: Pflüger
authors.affiliation: Microbiology Laboratory and Infectious Diseases Biorepository, L. Spallanzani National Institute for Infectious Diseases, Rome, Italy.
authors.forename: Antonino
authors.initials: A
authors.lastname: Di Caro
authors.affiliation: Robert Koch Institute, Proteomics and Spectroscopy (ZBS 6), Berlin, Germany.
authors.forename: Maren
authors.initials: M
authors.lastname: Stämmler
authors.affiliation: Robert Koch Institute, Highly Pathogenic Microorganisms (ZBS 2), Berlin, Germany.
authors.forename: Roland
authors.initials: R
authors.lastname: Grunow
authors.affiliation: Robert Koch Institute, Highly Pathogenic Microorganisms (ZBS 2), Berlin, Germany JacobD@rki.de.
authors.forename: Daniela
authors.initials: D
authors.lastname: Jacob
mesh_terms: D001419:Bacteria / Q000737:chemistry* / Q000145:classification*; D001431:Bacteriological Techniques / Q000379:methods*; D005060:Europe; D007391:International Cooperation; D059021:Laboratory Proficiency Testing; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization / Q000379:methods*