gram-positive (redirected from Gram-positive bacterium)

gram-positive /gram-pos·i·tive/ (-poz´it-iv) retaining the stain or resisting decolorization by alcohol in Gram's method of staining, a primary characteristic of bacteria whose cell wall is composed of peptidoglycan and teichoic acid.

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gram-positive or Gram-positive

adj.

Of, relating to, or being a bacterium that retains the violet stain used in Gram's method.

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Gram-positive

Referring to a bacteria that takes on a purplish-black color when exposed to Gram's stain.

Mentioned in: Aminoglycosides

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gram-positive

Etymology: Hans C.J. Gram; L, positivus

retaining the violet color of the stain used in Gram's method of staining microorganisms. This property is a primary method of characterizing organisms in microbiology. Some of the most common kinds of gram-positive pathogenic bacteria are Bacillus anthracis, Clostridium species, Mycobacterium leprae, Mycobacterium tuberculosis, Staphylococcus aureus, Streptococcus pneumoniae, and Streptococcus pyogenes.

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gram-positive,

n retaining the violet color of the stain used in Gram's method of staining microorganisms. Staining property is a common method of classifying bacteria. See also Gram's stain.

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gram-positive

said of bacteria that resist decolorization by alcohol in Gram's method of staining (see gram's stain) and thus retain the crystal violet-iodine complex and appear purple; a characteristic of bacteria whose cell wall is composed of a thick layer of peptidoglycan and teichoic acid.