What is the Gram stain reaction of streptococcus?

What is the Gram stain reaction of streptococcus?

Streptococci are Gram-positive, nonmotile, nonsporeforming, catalase-negative cocci that occur in pairs or chains. Older cultures may lose their Gram-positive character. Most streptococci are facultative anaerobes, and some are obligate (strict) anaerobes. Most require enriched media (blood agar).

Is Streptococcus mitis gram-positive?

2.1 Streptococcus mitis. S. mitis cells are gram-positive and spherical or elliptical in shape (about 0.6–0.8 μm in diameter).

What stain is used for streptococcus?

The Gram-stained smear is the most accurate method of early diagnosis of streptococcal pharyngitis.

What can go wrong in Gram staining?

Several factors may affect the results of Gram staining: If the smear is too thick, proper decolorizing will not be possible. If the smear is overheated during heat fixing, the cell walls will rupture. Concentration and freshness of reagents may affect the quality of the stain.

Where is the streptococcus bacteria found?

Group A streptococci are bacteria commonly found in the throat and on the skin. The vast majority of GAS infections are relatively mild illnesses, such as strep throat and impetigo.

What does Streptococcus mitis look like?

Streptococcus mitis, previously known as Streptococcus mitior, is a mesophilic alpha-hemolytic species of Streptococcus that inhabits the human mouth. It is most commonly found in the throat, nasopharynx, and mouth. It is a Gram-positive coccus, facultative anaerobe and catalase negative.

What are the properties of Streptococcus mitis bacteria?

Certain strains of S. mitis have the ability to produce IgIA1 protease and bind salivary alpha-amylase, which are two properties that are determinants for streptococcus viridans, which are a large group of generally non-pathogenic, commensal, streptococcal bacteria.

What should I do if I have a culture of Streptococcus?

If the culture is an unidentified gram-positive coccus, an Enterococcus, viridans Streptococcus, or of unknown identity (basically includes all cultures other than pneumococci, ß-hemolytic streptococci, and nutritionally variant streptococci), inoculate the following media.

How big are the cocci of Streptococcus spp?

Streptococci are coccoid bacterial cells microscopically, and stain purple (Gram-positive) when Gram staining technique is applied. They are nonmotile and non-spore forming. These cocci measure between 0.5 and 2 μm in diameter. As cellular division of Streptococcus spp. occurs along a single axis or plane, these bacteria grow in pairs or chains.

Where does Streptococcus mitis colonize the oral cavity?

Streptococcus mitis are commensal bacteria that colonize hard surfaces in the oral cavity such as dental hard tissues as well as mucous membranes and are part of the oral flora.