Morphology & Culture Characteristics of Streptococcus pyogenes
   

MORPHOLOGY AND CULTURE CHARACTERISTICS OF STREPTOCOCCUS PYOGENES

MORPHOLOGY OF STREPTOCOCCUS PYOGENES

Shape – Streptococcus pyogenes is a Round shape (coccus) bacterium

Size – The size of Streptococcus pyogenes is about 0.5 µm – 1 µm (diameter)

Arrangement Of CellsS. pyogenes is arranged in Chains

MotilityS. pyogenes is a Non-motile bacterium.

FlagellaStreptococcus pyogenes is a Non-flagellated bacterium

SporesS. pyogenes is a Non-sporing Bacterium

Capsule – present in Some Species of Streptococcus

Gram Staining Reaction – Gram +ve bacterium



CULTURE REQUIREMENTS OF STREPTOCOCCUS PYOGENES

Special requirementsStreptococcus pyogenes requires enriched media for the growth and readily grows in a media containing Blood, Serum or Sugars, commonly Blood Agar medium is used for the cultivation of Streptococcus pyogenes.

 Optimum temperatureS. pyogenes grows best at 37°C

⇒ Optimum pH – 7.4-7.6

⇒ Oxygen requirementsStreptococcus pyogenes is an Aerobic and Facultative anaerobic bacterium i.e. can tolerate high levels of oxygen as well as readily grows in an environment with the low level of oxygen too. Presence of 5-10% CO2 promotes the growth and hemolysis in the medium.

⇒ There are various culture media used for the cultivation of Streptococcus pyogenes in the laboratory and most commonly the Blood Agar and PNF medium is used, the media are as follows –

  • Nutrient Agar medium
  • Sheep Blood Agar medium
  • Crystal Violet Blood Agar medium (selective medium)
  • PNF medium is also a selective culture medium for the isolation of Streptococcus pyogenes
  • The liquid medium (Nutrient Broth medium, TSB medium, Peptone water etc.)

⇒ The PNF medium which is the Selective medium for Streptococcus pyogenes can be prepared by incorporating Polymixin B Sulfate, Neomycin sulfate and Fusidic Acid in the Horse Blood Agar medium for the growth of Streptococcus pyogenes.

Check out the Morphology & Cultural Characteristics of Staphylococcus aureus

CULTURAL CHARACTERISTICS OF STREPTOCOCCUS PYOGENES

Cultural CharacteristicsNAM (Nutrient Agar MediumBlood Agar Medium (BAM)Crystal Violet Blood Agar (CVBA) mediumPNF medium
Hemolysis-----β - Hemolysisβ - Hemolysisβ - Hemolysis
ShapeCircular (Pin point)Circular (Pin point)Circular (Pin point)Circular (Pin point)
Size0.5-1 mm0.5-1 mm0.5-1 mm0.5-1 mm
ElevationLow Convex - convexLow ConvexLow ConvexLow Convex
SurfaceMatt (in Virulent strains) ; Glossy (In Non-Virulent Strains) ; mucoid (in case of Capsule production)Matt (in Virulent strains) ; Glossy (In Non-Virulent Strains) ; mucoid (in case of Capsule production)Matt (in Virulent strains) ; Glossy (In Non-Virulent Strains) ; mucoid (in case of Capsule production)Matt (in Virulent strains) ; Glossy (In Non-Virulent Strains) ; mucoid (in case of Capsule production)
ColorLight yellowLight golden yellow, surrounded by clear zone (beta hemolysis).YellowGolden yellow, surrounded by clear zone (beta hemolysis).
StructureSemi-Transparent  - OpaqueSemi-TransparentSemi-Transparent  - OpaqueSemi-Transparent  - Opaque
streptococcus pyogenes on columbia horse blood agar medium - streptococcus on blood agar medium
STREPTOCOCCUS PYOGENES ON COLOMBIA HORSE BLOOD AGAR MEDIUM

In liquid culture media like peptone water and Nutrient broth or Glucose broth, the growth of the bacterium occurs as a granular turbidity with a powdery deposits which is due to the heavy bacterial chains that settle down and appears as a powdery deposit which is further analyzed for the morphology (under the microscope), gram reaction, biochemical tests, and Streptococcus pyogenes specific tests.



SAHIL BATRA

Hi, I'm the Founder and Developer of Paramedics World, a blog truly devoted to Paramedics. I am a Medical Lab Tech, a Web Developer and Bibliophiliac. My greatest hobby is to teach and motivate other peoples to do whatever they wanna do in life.

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