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Rapid Identification of Intact Whole Bacteria Based on Spectral Patterns Using Matrix Assisted Laser Desorption Ionization Time-of-Flight Mass Spectrometry (MALDI-TOF MS).


1) To evaluate the potential use of matrix assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS) as a method for the rapid identification of whole bacteria, either by comparison with archived reference spectra or by co-analysis with cultures of known bacteria. 2) To establish a standard set of conditions for the acquisition of MALDI/TOF mass spectra from bacteria suitable for use in bacterial identification. 3) To obtain some measure of the distribution of signals (ions at specific masses) obtained using standard MALDI/TOF MS conditions based on the analysis of a variety of related and unrelated bacteria. 4) To use standard (pattern recognition) as well as newer (artificial intelligence andprincipal components analysis) mass spectral recognition techniques to evaluate whether or not the standardized mass spectra obtained from bacteria are sufficiently distinct to allow identification of specific bacteria or to select related bacteria from a group. 5) To evaluate the use of mass spectral recognition techniques for the identification of bacteria from mixtures based on MALDI/TOF MS analysis of the mixture. 6) To determine the minimum number of bacteria necessary for obtaining standard mass spectra. 7) To evaluate the effects on the reproducibility of spectra obtained from whole bacteria under different conditions of sample handling, storage, and cell growth.

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FY 2000 Accomplishments: 1) Demonstrated gene-specific, marker detection (acid resistance) across bacterial strains and characterization of bacteria from natural substrates without prior enrichment. 2) This work has resulted in three invited reviews and two manuscripts this year. 3) An invited collaboration to the CFSAN for development of methods of Vibrio sub-speciation on MALDI TOF mass spectrometers.

Lay, Jackson
DHHS/FDA - National Center for Toxicological Research
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