Gram's stain

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Gram's stain

Etymology: Hans C.J. Gram

the method of staining microorganisms using a violet stain, followed by an iodine solution; decolorizing with an alcohol or acetone solution; and counterstaining with safranin. The retention of either the violet color of the stain or the pink color of the counterstain serves as a primary means of identifying and classifying bacteria. Also called Gram's method. See also gram-negative, gram-positive.

Gram's stain

a stain taken up by the Gram-positive bacteria that differentiates these from bacteria which fail to take up the stain (Gram-negative types). The initial stain is crystal violet/iodine complex, and Gram-negative bacteria are decolorized with alcohol whilst Gram-positive bacteria retain a blue/purple colour.

Gram's stain

A stain used in microbiology to classify bacteria and help identify the species to which they belong. This identification aids in determining treatment.

Mentioned in: Aminoglycosides, Diphtheria

Gram's stain

a staining procedure in which bacteria are stained with crystal violet, treated with strong iodine solution, decolorized with ethanol or ethanol-acetone and counterstained with a contrasting dye, usually safranin. The iodine alters the structure of the cell wall in gram-positive bacteria so that the crystal violet is locked within the cell. Organisms that retain the crystal violet stain are deep purple in color and are classed as gram-positive and those losing the crystal violet stain are classified as gram-negative and are red in color.

References in periodicals archive ?

When a significant inflammatory response is present, organisms harvested for culture may already be so damaged that visualization via Gram's stain is impaired or even impossible.

A reliable Gram's stain result begins with a properly made smear.

QC slides for Gram's stain can be made using stock strains of Staphylococcus spp.

No procedure in microbiology is more familiar to the lab professional than Gram's stain.

When all goes well, our beloved Gram's stain supplies crucial information leading to correct identification of isolates and provides rapid results to physicians waiting to treat seriously ill patients.

Failure of Gram's stain to detect Propionibacterium acnes in specimens from clinically significant infections.

Gram's stain: The key to microbiology

In this study, a third of the clinically healthy birds sampled had gram-negative bacteria present on Gram's stain cytology, culture, or both.

Although it appears that Gram's stain results were more likely to identify specific groups of bacteria compared with microbiologic culture, the 95% CI suggests that there is no difference between the 2 techniques in this study.

Fecal cultures are often used either in combination with fecal Gram's stain cytology or as a second tier diagnostic test to further evaluate potential pathogens identified on cytologic examination.

Results of Gram's stain cytology and bacterial culture of cloacal swab samples of healthy Hispanolian Amazon parrots (N=21).

The purpose of this investigation was to measure the level of agreement between results of fecal and cloacal Gram's stains and fecal aerobic bacterial culture to determine the clinical value of these diagnostic tests in clinically healthy psittacine birds.

The microscope slides were heat fixed and stained by standard methodology for Gram's stains, except that only brief contact (3 seconds) with the decolorization solution was used to avoid excessive decolorizing.

Measuring the level of agreement between cloacal gram's stains and bacterial cultures in Hispaniolan Amazon parrots (Amazona ventralis)