Differentiation of microorganisms in a sample, comprises extracting single cultures of microorganisms, receiving mass spectra on the cultures, and analyzing and comparing spectral details with reference spectra by mathematical similarity

摘要

Differentiation of microorganisms in a sample comprises that single cultures are extracted from the sample by cultivation on selective species medium, and the method further comprises cluster analysis of the extracted culture from the sample by matrix assisted lasers desorption/ionization time of flight mass spectra (MALDI-TOF MS) with a range of 2000-20000 Dalton. Differentiation of microorganisms in a sample comprises that single cultures are extracted from the sample by cultivation on selective species medium, and the method further comprises cluster analysis of the extracted culture from the sample by matrix assisted lasers desorption/ionization time of flight mass spectra (MALDI-TOF MS) with a range of 2000-20000 Dalton. The culture and/or extracted culture are identical to the reference subspecies when the distance of the spectra is smaller than sigma 1. The culture has a new subspecies, when the distance from all reference spectra and the other extracted cultures from the sample is greater than sigma 2. The culture and/or extracted culture are closely related to a reference subspecies when the distance of the spectra is greater than sigma 1 and smaller than sigma 2. The mass spectra of the single culture are compared by a euclidean distance matrix with the reference spectra, where the spectrum is constructed from the overlay of six complete single spectra. The values sigma 1 and sigma 2 are extracted from the euclidean distance matrix of the reference spectra.