Identification of pathogens in body fluids
Identification of infectious pathogens, particularly viruses, bacteria and other microorganisms is effected with a method whereby pathogens of acute infections can be identified, without first culturing them in external nutrient media, by mass spectrometric measurement of their protein profiles obtained from pathogens directly precipitated from body fluid into pellets by centrifuging. With this method, pathogens which cause acute infections can be identified in less than one hour.
1. A method for the mass spectrometric identification of pathogens in a blood sample, the method comprising the steps of:
(a) destroying blood particles in the blood sample;
(b) precipitating by centrifuging the pathogens without further multiplication from the blood sample directly into a pellet;
(c) subjecting the pathogens to a mass spectrometric analysis of their proteins; and
(d) identifying the pathogens by comparison of protein mass spectra with reference protein mass spectra.
2. The method according to claim 1 , wherein in step (c) the pathogens in the pellet are smeared directly onto mass spectrometric sample support plates and sprinkled with matrix solution for ionization of their proteins by matrix-assisted laser desorption.
3. The method according to claim 1 , wherein in step (c) the proteins are extracted from the pathogens using an extraction fluid while the pellet with the pathogens rests in a centrifuge tube, and the fluid is subjected to mass spectrometric measurement.
4. The method according to claim 3 , wherein the extraction fluid is subjected to mass spectrometric analysis using electrospray ionization.
5. The method according to claim 3 , wherein the extraction fluid is subjected to mass spectrometric analysis using ionization by matrix-assisted laser desorption.
6. The method according to claim 5 , wherein the extraction fluid is applied to a mass spectrometric sample support plate onto which a layer of matrix crystals has already been deposited.
7. The method according to claim 5 , wherein a matrix substance solution is added to the extraction fluid before this is applied to the sample support plate.
8. The method according to claim 1 , wherein, for extraction of the proteins, the pathogens of the pellets are decomposed by chemical, physico-chemical or physical means.
9. The method according to claim 8 , wherein the extraction fluid is subjected to mass spectrometric analysis using electrospray ionization.
10. The method according to claim 8 , wherein the extraction fluid is subjected to mass spectrometric analysis using ionization by matrix-assisted laser desorption.
11. A method for the mass spectrometric identification of pathogens in a blood sample, the method comprising the steps of:
(a) precipitating by centrifuging the pathogens without further multiplication from the blood sample together with blood particles into a pellet;
(b) destroying the blood particles in the pellet;
(c) subjecting the pathogens to a mass spectrometric analysis of their proteins; and
(d) identifying the pathogens by comparison of protein mass spectra with reference protein mass spectra.
12. The method according to claim 11 , wherein the blood particles which are present in the pellet are destroyed by osmosis.
13. The method according to claim 12 , wherein distilled water is used for destroying the blood particles in the pellet by osmosis.
14. The method according to claim 11 , wherein a further centrifuging after step (b) deposits a pellet containing enriched pathogens.