Streptococci & Enterococci

Question 1

Streptococci

Answer 1

can affect anything from the throat to the heart

can be suppurative or non

Question 2

Hemolysis (2 kinds)

Answer 2

Beta=complete destruction, colonies are clear and distinct

Alpha=green, incomplete destruction

Question 3

How to test for Beta-hemolytic, group A?

Answer 3

bacitracin sensitivity

Question 4

What do M proteins signify?

Answer 4

The more there are, the more virulent it is

Question 5

Streptococcus Pyogenes: what group/type, suppurative complications and nonsuppurative complications (3)

Answer 5

Group A, beta-hemolytic
Suppurative complications: pharyngitis, cellulitis, impetigo & necrotizing fascitis
Nonsuppurative: acute rheumatic fever, post strep glomerulonephritis & TSS

Question 6

Acute Rheumatic Fever

Answer 6

due to group A, beta hemolytic streptococcus pyogenes
ages 6-20, targets the mitral valve
cross rxn/molecular mimicry
associated with encapsulated & M-protein coat with GAS strain

Question 7

Post Strep Glomerulonephritis

Answer 7

due to group A, beta-hemolytic streptococcus pyogenes. caused by nephrogenic strain that forms Ab-complexes that deposit in the tissues

Question 8

Streptococcal TSS

Answer 8

• due to group A, beta-hemolytic streptococcus pyogenes. skin/soft tissue infections w/ M proteins
• caused by pyogenic exotoxins=superantigens (bind T cells and MHC 2 for cytokine release)
• hypotension & sunburn rash

Question 9

Streptococcus Agalactiae

Answer 9

• group B, beta-hemolytic

- neonatal sepsis & soft tissue diabetics

Question 10

Enterococcus

Answer 10

in GI tract, relatively Ab resistant

-UTI, biliary tract infection

Question 11

Strep Viridans

Answer 11

alpha-hemolytic.

• optochin test sensitive for pneumococci alpha-hemo only
• colonize mouth (transiently)
• endocarditis & cavities–extremes due to receptors and molecular mimicry