A method of identifying a microorganism by mass spectrometry, comprising: ▪ acquiring at least one mass spectrum of said microorganism; ▪ for each acquired mass spectrum: ∘ detecting peaks of the spectrum in a predetermined mass range; ∘ generating a list of peaks identifying at most one peak in each interval of a predetermined subdivision of the range of mass-to-charge ratios, the width of the intervals of the subdivision increasing along with the mass-to-charge ratio according to relations: L b = exp b − β α × exp 1 α − 1 α = b min − b max + 1 ln m min − ln m max β = b max + 1 × ln m min − b min × ln m max ln m min − ln m max where the subdivision intervals are referenced with integers greater than 1, from integer b min, for the lowest mass-to-charge ratios in the range, to integer b max, for the higher mass-to-charge ratios in the range, L(b) is the width of the interval referenced with integer- b, m min is a lower bound of the range of mass-to-charge ratios, and m max is an upper bound of the range of mass-to-charge ratios; and ▪ analyzing the list(s) of peaks obtained according to a knowledge base of previously-identified microorganisms and/or types of microorganisms, method wherein there are from 900 to 1,500 intervals. ▪ acquiring at least one mass spectrum of said microorganism; ▪ for each acquired mass spectrum: ∘ detecting peaks of the spectrum in a predetermined mass range; ∘ generating a list of peaks identifying at most one peak in each interval of a predetermined subdivision of the range of mass-to-charge ratios, the width of the intervals of the subdivision increasing along with the mass-to-charge ratio according to relations: L b = exp b − β α × exp 1 α − 1 α = b min − b max + 1 ln m min − ln m max β = b max + 1 × ln m min − b min × ln m max ln m min − ln m max where the subdivision intervals are referenced with integers greater than 1, from integer b min, for the lowest mass-to-charge ratios in the range, to integer b max, for the higher mass-to-charge ratios in the range, L(b) is the width of the interval referenced with integer- b, m min is a lower bound of the range of mass-to-charge ratios, and m max is an upper bound of the range of mass-to-charge ratios; and ∘ detecting peaks of the spectrum in a predetermined mass range; ∘ generating a list of peaks identifying at most one peak in each interval of a predetermined subdivision of the range of mass-to-charge ratios, the width of the intervals of the subdivision increasing along with the mass-to-charge ratio according to relations: L b = exp b − β α × exp 1 α − 1 α = b min − b max + 1 ln m min − ln m max β = b max + 1 × ln m min − b min × ln m max ln m min − ln m max where the subdivision intervals are referenced with integers greater than 1, from integer b min, for the lowest mass-to-charge ratios in the range, to integer b max, for the higher mass-to-charge ratios in the range, L(b) is the width of the interval referenced with integer- b, m min is a lower bound of the range of mass-to-charge ratios, and m max is an upper bound of the range of mass-to-charge ratios; and ▪ analyzing the list(s) of peaks obtained according to a knowledge base of previously-identified microorganisms and/or types of microorganisms,