Lecture 13: Streptococcus species

Question 1

Streptococcus pneumoniae

Answer 1

• opportunist

- alpha hemolytic: incomplete hemolysis and isn’t fully able to degrade hemoglobin in blood cells

Question 2

Streptococcus progenies (group A strep)

Answer 2

• beta hemolytic: clearing of blood hemoglobin
• strep throat
• pyogenic: able to form pus
• can lyse white blood cells
• expressed a lot of virulence factors

Question 3

Strep throat (S. Pyogenes)

Answer 3

Sore red throat whitish pus fever enlarged lymph nodes

• Strep progenies have hyaluronic acid capsules that evade phagocytosis (looks disguised)
• Adheres to epithelial cells of oral, nasal, and skin
• Produces fibronectin (Fn) binding protein, protein f

Question 4

Impetigo (S. Pyogenes)

Answer 4

• streptokinase breaks down structural proteins holding tissues together
• hyaluronidase breaks down hyaluanic acid (glue of connective tissue)
• two types: non bullous or bullous
• through cuts or wounds

Question 5

Necrotizing fasciitis (S. Pyogenes)

Answer 5

• exotoxins such as exotoxins A Is super super antigen that cause toxic shock
• Exptoxin B is protease that destroys tissue
• hyaluronidase
• DNases, lipases
• Streptolysins
• streptokinase break blood clots

Question 6

Hyaluronidase

Answer 6

Enzyme that breaks up hyaluronic acid and breaks down the linkage between epithelial cells