9-10) Streps

What does strepto mean?

twisted sphere

-division on the same plane

streptococci produce ______________ (acidic / basic) environments

acid

-fermentation

-low oxygen

Streptococci have ____ protein capsule. What is the function?

Which strep does not have it?

M protein

-most capsules are carbohydrates but this is protein!

-strep pyogenes also has conventional polysaccharide capsule but not as important as M protein

-inhibits complement fixation and opsonization

-evade phagocytosis

**Strep pneumonia does not have central M protein

Are the following pyogenic or viridans? Alpha / beta / gamma?

-Strep mutans

-Strep sobrinus

-Strep pneumonia

-Strep pyogenes

Pyogenic -BETA

-S. Pyogenes aka G.A.S.

Viridans (green) -ALPHA

-S. mutans

-S. sobrinus

-S. pneumonia (Mitus group)

For early schemes in defining strep there were 2 schemes.

For hemolysis on blood agar what are the 3 categories?

Which category has further categorization through ______________ capsule serology?

-Alpha (normal cells)

-Beta (hemolytic properties)

-Gamma (no hemolytic)

Beta hemolytic types have lancefield capsule serology (A, B, C)

What respiratory infections can arise from Strep pyogenes?

Strep Throat

-which leads to scarlet fever when toxin (SpeA or Spec) from bacteria is released in blood

-Pneumonia (more fatal but less common than infection from Strep pneumonia)

What is Erysipelas? What bacteria is responsible for it?

Progressing follicle infection with very redding of skin

-Strep pyogenes

Protein G is found in _______________ (strep / staph)

Protein A is found in _______________ (strep / staph)

What is the function?

G: strep

A: staph

-non specifically binds to Fc of immunoglobins backwards

-interferes with opsonization

-antiphagocytic

What 2 exotoxins are associated with Strep pyogenes pathology?

1. cytolytic toxins

-streptolysin cause hemolysis on blood agar plates

2. pyrogenic exotoxins: toxic shock syndrome

What antibiotics should be given to treat strep pyogenes?

1. penicillin (not a lot of resistance)

2. clindamycin or erythromycin or azithromycin if allergic

What are the 2 main post infection sequelae of Strep pyogenes?

Rheumatic fever

-autoimmunity, damage to heart valve

Glomerulonephritis

-immune complex deposit in kidney, transient inflammation

What is the most common cause of meningitis in adults?

Streptococcus pneumoniae

-20-30% of pneumonia cases but can happen without getting pneumonia

What is the most frequent cause of otitis media in infants and children?

Streptococcus pneumoniae

What is the microscopic morphology that can definitively identify Strep pneumonia when accompanied with symptoms of meningitis or pneumonia?

Where can you take a sample from?

Gram positive diplococci

-"lancet shape"

-elderly people and babies

Sample from

-blood

-rust colored sputum

-CNS fluid

*NOT throat swab

What are the 3 main diseases that Strep pneumonia cause?

-pneumonia

-otitis media (but many other things cause it too)

-meningitis (but other things cause it too)

Is there a vaccine for the following?

-Strep pyogenes

-Strep pneumonia

-Strep pyogenes: no

-Strep pneumonia: yes

What are the 2 exotoxins of Strep pneumonia?

Pneumolysis

-works anaerobically only

-hemolytic kills phagocytes

IgA1 protease

-cuts slgA

The old vaccine for Strep pneumophila works well for adults but not children, why does the new one work better for children?

Which is the new vs old?

-PCV7

-PPV

Old vaccine (PPV)

-carbohydrate only

New vaccine (PCV7)

-conjugated to a protein! (children are not as good with antigen presentation but conjugation of protein helps)

*this conujation effect is also seen in Neisseria meningitidis vaccine