Extraction system and method for extracting microorganisms contained in a sample

A method for identifying and/or characterizing microorganisms contained in a sample, the method comprising:

• providing an extraction system comprising:
• a support bar comprising a sample well, a reagent well containing a selective lysis buffer, at least one washing well containing a washing reagent, and at least one protection and retention housing,
• a pipetting element removably mounted on the support bar and extending at least partially into the at least one protection and retention housing, and
• a filtering and transfer device removably mounted on the support bar and extending at least partially into the at least one protection and retention housing, said filtering and transfer device comprising:
• a hollow body having an elongated shape and comprising a proximal end portion and a distal end portion, and
• a filtering element fixed to the distal end portion of the hollow body,
• introducing a predetermined amount of a sample containing microorganisms in the sample well,
• withdrawing a predetermined amount of the selective lysis buffer contained in the reagent well by the pipetting element,
• placing the withdrawn selective lysis buffer in the sample well by the pipetting element,
• lysing cells and/or particles that are not micro-organic contained in the sample and/or lysing predetermined microorganisms contained in the sample so as to supply a lysed sample,
• at least partially immersing the filtering and transfer device in the lysed sample contained in the sample well,
• filtering at least part of the lysed sample through the filtering element under aspiration,
• capturing and accumulating microorganisms in the filtering element,
• at least partially immersing the filtering and transfer device in the washing reagent contained in the at least one washing well,
• washing the filtering element and the captured and accumulated microorganisms in the washing reagent contained in the at least one washing well,
• transferring, by the filtering and transfer device, the washed microorganisms onto an analysis support or into a receiver, the transferring including depositing, by the filtering and transfer device, at least one part of the washed microorganisms onto one or more predetermined spots of a MALDI-TOF MS analysis plate, and
• analyzing the transferred microorganisms so as to identify and/or characterize the transferred microorganisms, the analyzing including performing a mass spectrometry analysis of the MALDI-TOF type on the microorganisms deposited on the MALDI-TOF MS plate,
• wherein the filtering element has a cylindrical shape with a diameter adapted to the diameter of a spot of the MALDI-TOF MS analysis plate, and has a flat or hemispherical distal portion that protrudes from the distal end portion of the hollow body.