Gram's iodinemedical dictionary

<microbiology> A solution containing iodine and potassium iodide, used in Gram's stain.

(05 Mar 2000)

Gram's stainmedical dictionary

<microbiology, technique> A method for differential staining of bacteria; smears are fixed by flaming, stained in a solution of crystal violet, treated with iodine solution, rinsed, decolorised, and then counterstained with safranin O.

Gram-positive organisms stain purple black and Gram-negative organisms stain pink; useful in bacterial taxonomy and identification, and also in indicating fundamental differences in cell wall structure.

(05 Mar 2000)

<procedure>

<microbiology> A method of staining bacteria using a violet stain. The gram staining characteristics (denoted as positive or negative) can assist in the identification of the offending bacteria.

A heat fixed bacterial smear is stained with crystal violet (methyl violet), treated with 3% iodine/potassium iodide solution, washed with alcohol and counterstained. The method differentiates bacteria into two main classes, gram-positive and gram-negative. Certain bacteria, notably mycobacteria, that have walls with high lipid content show acid-fast staining the stain resists decolouration in strong acid.

(27 Sep 1997)

gram-positive rods, grampus, Gram's iodine, Gram's stain < Prev | Next > grana, granadilla, granatin, granatum

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