MASS SPECTROMETRIC DETERMINATION OF MICROBIAL RESISTANCES

摘要

The invention relates to a mass spectrometric method for determining microbial resistances to antibiotics. The invention provides specific methods comprising cultivation in synthetic media, in which several amino acids, preferably only a single amino acid, are isotopically labeled by incorporating 13C, 15N, 18O or 34S. If several amino acids are isotopically labeled, they are labeled in such a way that they are each heavier than the corresponding unlabeled amino acids by the same integer mass difference Δm. This ensures that the mass shifts of the peaks always amount to an integer multiple of the mass difference Δm. The total mass difference can be kept relatively small by selecting suitable amino acids. A mass shift of the protein peaks in media with antibiotics indicates that the microbes are resistant. A second embodiment first produces isotopically labeled microbes, which are then tested for their resistance by cultivating them in normal media.

主权项

1. A method for the mass spectrometric determination of the resistance of microbes from a sample under investigation, the method comprising:
providing a synthetic growth medium which contains proteinogenic amino acids, wherein at least one of the amino acids is isotopically labeled, and wherein all of the isotopically labeled amino acids have the same integer mass difference Δm in relation to corresponding unlabeled amino acids; cultivating said microbes in a first culture using the synthetic growth medium with the addition of a predetermined antibiotic; cultivating said microbes in a second culture using the synthetic growth medium without the addition of said antibiotic; and acquiring mass spectra of the microbes from the first and second cultures and comparing them to each other.