Method for Developing and Applying Databases for Idenfication of Microorganisms by MALDI-TOF Mass Spectrometry

摘要

A method for organism identification using MALDI TOF mass spectrometry includes generating a searchable database. A mass spectrum is acquired from a sample. Peak detection of the acquired mass spectrum is performed, binned, and a vector is generated. Dot products are computed between the generated vector of peak detected mass spectrum and averaged binned spectrum for each isolate. A relative probability that acquired mass spectrum matches a spectrum from each isolate in the searchable database is computed. A logarithmic score for matching the acquired mass spectrum with the mass spectrum is computed from each isolate. The logarithmic score for matching the acquired mass spectrum is compared with the mass spectrum from each isolate to a predetermined minimum passing score. A list of isolates is generated with greater than the predetermined minimum score. The probability rank and logarithmic score are then reported for each isolate with a minimum passing score.

主权项

1. A method for generating a searchable database for organism identification using Matrix Assisted Laser Desorption Ionization Time-Of-Flight (MALDI TOF) mass spectrometry, the method comprising:
a) acquiring a plurality of mass spectra data from samples of isolates of well-characterized organisms using MALDI TOF mass spectrometry; b) performing peak detection of the acquired mass spectra data to generate peak detected spectral data of the isolates for the well-characterized organisms; c) averaging the acquired mass spectra data; d) performing peak detection of the averaged mass spectra data to generate peak detected averaged spectral data of the isolates for the well-characterized organisms; e) binning the acquired mass spectra data and generating a plurality of vectors, where n is a number of bins used to determine the binned mass spectrum; f) computing an average binned spectrum of the isolates for the well-characterized organisms; g) computing dot products between the binned acquired mass spectra data and the averaged binned spectrum of the isolates for the well-characterized organisms; h) computing an average and a standard deviation of the dot products between the binned acquired mass spectra data and the averaged binned spectrum of the isolates for the well-characterized organisms; and i) creating a searchable database of the averaged mass spectra data, peak detected average mass spectra, average and standard deviation of the dot products between the binned acquired mass spectra data and the averaged binned spectrum of the isolates for the well-characterized organisms.