To counter the inherent minor variations

found between measurements of the MS spectra, the MS profiles in the reference library constructed here consist of the mean of 24 MS spectra. The fact that the identification of genetically highly related species appeared to be feasible demonstrates that even minor genetic differences are translated to specific proteomic differences. Conclusions Discrepancies between classical taxonomy BMS907351 and the genetic relatedness of species and biovars complicate the development of detection and identification assays. Despite these difficulties, the accurate identification of Brucella species was achieved with MALDI-TOF-MS by constructing a Brucella reference library based on genetic relationships according to MLVA data. We conclude that MALDI-TOF-MS can be developed into a fast and reliable identification method for

genetically highly related species when potential taxonomic and genetic inconsistencies are considered during the generation of the reference library. Acknowledgements We wish to thank K. Walravens for providing strains and D. van der Kleij for her comments and critical reading of the manuscript. This work was financially supported by the Dutch Ministry of Defense, grant number V1036. This work was part of the European Defence Agency (EDA) project B0060 involving biodefence institutions from Italy and The Netherlands. Electronic supplementary material GF120918 manufacturer Additional file 1: Table S1. Strains used during the study MAPK inhibitor with additional information. (XLS 98 KB) References 1. Brenner DJ, Krieg NR, Staley JT, Corbel MJ, Banai M: Bergey’s Manual of Systemic Bacteriology. In Volume 2 part C. 2nd edition. Edited by: Corbel SB-3CT MJ, Banai M. New York: Springer Science; 2005:370–386. 2. Franz DR, Jahrling PB, Friedlander AM, McClain DJ, Hoover DL, Bryne WR, Pavlin JA, Christopher GW, Eitzen EM Jr: Clinical recognition and management of patients exposed to biological warfare agents. JAMA 1997, 278:399–411.PubMedCrossRef 3. Yagupsky P, Baron EJ: Laboratory exposures to brucellae and implications for bioterrorism. Emerg Infect Dis 2005, 11:1180–1185.PubMedCrossRef 4. Yingst SL, Huzella LM, Chuvala L,

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