| CPC C12Q 1/18 (2013.01) [C12Q 1/34 (2013.01); G01N 33/6851 (2013.01); G01N 2333/986 (2013.01); G01N 2800/26 (2013.01); G01N 2800/44 (2013.01)] | 11 Claims |

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1. A method for the determination of a β-lactam resistance of microbes based on the production of β-lactamases by the microbes, the method comprising:
obtaining the microbes from a colony cultivated on a nutrient medium or from a blood culture;
combining the microbes with a β-lactam antibiotic covalently bonded to a 6-His tag in a solution, wherein β-lactamases of the microbes may cause hydrolytic breakdown of the β-lactam antibiotic;
extracting remaining 3-lactam antibiotic and/or its breakdown product from the solution via a reversible bond of the 6-His tag to an extracting partner;
partly applying the extracted remaining-lactam antibiotic and/or breakdown product to a mass spectrometric support; and
measuring an enzymatic breakdown of the β-lactam antibiotic by the β-lactamases of the microbes mass spectrometrically by acquiring a mass spectrum of the extracted remaining β-lactam antibiotic and/or breakdown product using a time of flight mass spectrometer with ionization by matrix-assisted laser desorption, wherein a matrix used is α-cyano-4-hydroxycinnamic acid.
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