MALDI-TOF mass spectrometry and high-consequence bacteria: safety and stability of biothreat bacterial sample testing in clinical diagnostic laboratories Tracz, Dobryan M. and Tober, Ashley D. and Antonation, Kym S. and Corbett, Cindi R.,, 67, 341-346 (2018), doi = https://doi.org/10.1099/jmm.0.000695, publicationName = Microbiology Society, issn = 0022-2615, abstract= We considered the application of MALDI-TOF mass spectrometry for BSL-3 bacterial diagnostics, with a focus on the biosafety of live-culture direct-colony testing and the stability of stored extracts. Biosafety level 2 (BSL-2) bacterial species were used as surrogates for BSL-3 high-consequence pathogens in all live-culture MALDI-TOF experiments. Viable BSL-2 bacteria were isolated from MALDI-TOF mass spectrometry target plates after ‘direct-colony’ and ‘on-plate’ extraction testing, suggesting that the matrix chemicals alone cannot be considered sufficient to inactivate bacterial culture and spores in all samples. Sampling of the instrument interior after direct-colony analysis did not recover viable organisms, suggesting that any potential risks to the laboratory technician are associated with preparation of the MALDI-TOF target plate before or after testing. Secondly, a long-term stability study (3 years) of stored MALDI-TOF extracts showed that match scores can decrease below the threshold for reliable species identification (<1.7), which has implications for proficiency test panel item storage and distribution., language=, type=