Identification of Highly Pathogenic Microorganisms by Matrix- Assisted Laser Desorption Ionization–Time of Flight Mass

In the case of a release of highly pathogenic bacteria (HPB), there is an urgent need for rapid, accurate, and reliable diagnostics. MALDI-TOFmass spectrometry is a rapid, accurate, and relatively inexpensive technique that is becoming increasingly impor-tant 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 dis-tinct microbial samples, among them five HPB, Bacillus anthracis, Brucella canis, Burkholderia mallei, Burkholderia pseu-domallei, 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 spec-tral changes with negligible influence on the quality of the diagnosis. Furthermore, pilot tests on nonpathogenic strains wer