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Rapid method for distinction of gram-negative from gram-positive bacteria


A rapid method for distinction between gram-negative and grampositive bacteria by means of a 3% solution of potassium hydroxide is tested on 71 gram-positive and 55 gram-negative bacterial strains. The method proved reliable with one exception only, a Bacillus macerans strain. That strain was definately gram-negative on staining. Other Bacillus strains were proved gram-positive by the test, even those being gram-negative on staining.

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Gregersen, T. Rapid method for distinction of gram-negative from gram-positive bacteria. European J. Appl. Microbiol. Biotechnol. 5, 123–127 (1978).

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  • Potassium
  • Hydroxide
  • Bacillus
  • Bacterial Strain
  • Potassium Hydroxide