What is the Gram stain of Streptococcus pyogenes?

Streptococcus pyogenes (Group A streptococcus) is a Gram-positive, nonmotile, nonsporeforming coccus that occurs in chains or in pairs of cells. Individual cells are round-to-ovoid cocci, 0.6-1.0 micrometer in diameter (Figure 1).

What does Streptococcus look like on a Gram stain?

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.

What does Streptococcus pyogenes look like?

They display a white-greyish color and have a diameter of > 0.5 mm, and are surrounded by a zone of β-hemolysis that is often two to four times as large as the colony diameter. Microscopically, S. pyogenes appears as Gram-positive cocci, arranged in chains (Figure 1).

What color is Streptococcus?

The viridans streptococci are a large group of commensal bacteria that are either alpha-hemolytic, producing a green coloration on blood agar plates (hence the name “viridans”, from Latin vĭrĭdis, green), or nonhemolytic.

Is Streptococcus pyogenes a Heterotroph or Autotroph?

“Lunch Time!” Streptococcus mutans is a heterotrophic organism. This means that Streptococcus mutans cannot synthesize reduced organic compounds from inorganic sources and that it must obtain them by eating other organisms (Freeman).

What stains are used in gram staining?

Reagents:

Crystal violet (primary stain)
Iodine solution/Gram’s Iodine (mordant that fixes crystal violet to cell wall)
Decolorizer (e.g. ethanol)
Safranin (secondary stain)
Water (preferably in a squirt bottle)

What is Gram stain of Streptococcus pneumoniae?

Bacteriology. Streptococcus pneumoniae cells are Gram-positive, lancet-shaped cocci (elongated cocci with a slightly pointed outer curvature). Usually, they are seen as pairs of cocci (diplococci), but they may also occur singly and in short chains. When cultured on blood agar, they are alpha hemolytic.

What color is the Gram stain for Streptococcus pneumoniae?

Streptococcus pneumoniae bacteria are gram-positive cocci arranged in chains and pairs (diplococci) on microscopic examination. A green, α-hemolytic, zone surrounds S. pneumoniae colonies on blood-agar plates.