Staphylococcus aureus is classified as a Gram-positive bacterium. This means that it retains the crystal violet stain during the Gram staining process, indicating that it has a thick layer of peptidoglycan in its cell wall.

May 17, 2020 · The purple color is not a natural phenomenon but the result of a Gram-stain that colors the thick peptidoglycan membrane of any gram-positive bacteria purple. The natural color of a colony of S. aureus is yellow; in fact, the word aureus means golden.

Mar 4, 2024 · 1. Gram Staining. Staphylococcus aureus, as a Gram-positive bacterium, exhibits a violet/purple color under the microscope after Gram staining. 2. Morphological Characteristics Under the Microscope. Staphylococcus aureus is characterized by its spherical or cocci morphology under microscopic examination.

Oct 23, 2024 · Staphylococci grow readily on most bacteriologic media under aerobic or microaerophilic conditions. Colonies on solid media are round, smooth, raised, and glistening. S. aureus usually forms gray to deep golden yellow colonies.

Mar 16, 2022 · Color: Typically, bacteria that are gram-positive appear purple to blue, and bacteria that are Gram-negative appear pink to red. Shape : The most common shapes include round ( cocci ) or rod-shaped ( bacilli ).

Jan 22, 2025 · Figure \(\PageIndex{4}\): In this specimen, the gram-positive bacterium Staphylococcus aureus retains crystal violet dye even after the decolorizing agent is added. Gram-negative Escherichia coli , the most common Gram stain quality-control bacterium, is decolorized, and is only visible after the addition of the pink counterstain safranin.

Gram-positive cells stain purple/violet. Gram-negative cells stain pink. The acid fast stain uses the following dyes: basic fuchsin and methylene blue. The acid fast stain is used to distinguish acid fast bacteria (reveals the cell wall structure of certain types of bacteria beyond Gram-positive and Gram-negative).

Nov 9, 2016 · A bacteria that retains the color of the crystal violet stain in the Gram stain. These cells have a cell wall containing a thick layer of peptidoglycan, which interacts with the stain, resulting in a purple/violet appearance under a microscope.

Mar 27, 2024 · Staphylococcus aureus is a Gram-positive bacterium (stain purple by the Gram stain) which are cocci-shaped and are usually arranged in groups that are classified as “grape-like.” On media, these microorganisms may grow up to 10% salt. The colonies can be yellow or golden (aureus refers to yellow or golden).

Gram Stain of Staphylococcus aureus Note gram-positive (purple) cocci in clusters. Staphylococcus aureus is shared under a CC BY license and was authored, remixed, and/or curated by LibreTexts.