Method for unspecific enrichment of bacterial cells
The present invention relates to a method for unspecific enrichment of bacterial cells by means of cationic or anionic polymers and magnetic carriers.
1. A method for separating bacteria from a sample comprising:
a) preparing a mixture comprising the bacteria-containing sample and a cationic polymer at an acidic pH and in the absence of magnetic particles, whereby a polymer network comprising the bacteria is formed;
b) adding to the mixture a magnetic carrier comprising a magnetic pigment or a magnetic polystyrene-bead; and
c) separating the polymer network comprising the magnetic carrier and the bacterial cells embedded in the polymer network by precipitation from the mixture.
2. The method of claim 1 , wherein the cationic polymer is chitosan or polylysine.
3. The method of claim 2 , wherein cationic polymer is chitosan, whose concentration is from 0.05 to 100 μg/ml culture.
4. The method of claim 2 , wherein the cationic polymer is polylysine, whose concentration is from 12.5 to 150 μg/ml culture.
5. The method of claim 1 , wherein the magnetic carrier is a magnetic pigment or a magnetic polystyrene-bead with a NH 2 —, COOH— or OH-surface.
6. The method of claim 1 , wherein the sample is incubated with the cationic polymer at room temperature.
7. The method of claim 1 , wherein the pH is at or below 4.
8. The method of claim 1 , wherein the pH is at or below 3.
9. The method of claim 1 , wherein the bacteria are gram-positive.
10. The method of claim 1 , wherein the bacteria are gram-negative.
11. The method of claim 1 , further comprising separating the bacteria from the polymer network following step c).
12. A method for separating bacteria from a sample comprising:
a) preparing a mixture comprising the bacteria-containing sample and chitosan or polylysine at a pH at or below 4 and in the absence of magnetic particles, whereby a polymer network comprising the bacteria is formed;
b) adding to the mixture a magnetic pigment or a magnetic polystyrene-bead; and
c) separating the polymer network comprising the magnetic pigment or a magnetic polystyrene-bead and the bacteria by precipitation from the mixture.
13. The method of claim 12 , further comprising separating the bacteria from the polymer network following step c).