Strep

Front 1

How does strep appear on gram stain (other than positive)?

Back 1

Lines up like a strip (whereas staph clusters together)

Front 2

Difference between alpha and beta hemolytic

Back 2

alpha: can only partially lyse RBCs, leaving a greenish discoloration of culture medium around colony

beta: completely lyse RBCs, leaving a clear zone of hemolysis around the colony.

Front 3

What is another term for gamma hemolytic?

Back 3

non-hemolytic (they don't actually lyse RBCs)

Front 4

Strep are classified based on antigenic characteristics of the ___________

Back 4

C carbohydrate, aka Lancefield antigen. Given letter names A, -S

Front 5

Streptococcus pyogenes also called

Back 5

Group A beta-hemolytic strep

Front 6

What diseases does streptococcus pyogenes cause?

Back 6

Direct invasion/toxin:
skin infections, strep throat, scarlet fever, toxic shock syndrome

Antibody-mediated:
rheumatic fever, post-streptococcal glomerulonephritis

Front 7

Components of strep pyogenes cell wall that are antigenic (2)

Back 7

1) C Carbohydrate/lancefield antigen
2) M protein: major virulence factor for group A strep. Inhibits activation of complement, but plasma cells secrete antibodies against it.

Front 8

Enzymes of group A strep contributing to pathogenicity

Back 8

1) Streptolysin O (oxygen labile - inactivated by oxygen): destroys blood cells. ASO antibodies to this develop

2) Streptolysis S (oxygen stable). Also causes beta-hemolysis

3) pyrogenic/erythrogenic exotoxin: found only in a few strains, but can cause scarlet fever

4) toxic shock syndrome toxin

Front 9

Streptokinase:

Back 9

activates proteolytic enzyme plasmin that breaks up fibrin blood clots

Front 10

Difference between streptolysin O and S

Back 10

1) Streptolysin O (oxygen labile - inactivated by oxygen): destroys blood cells. ASO antibodies to this develop

2) Streptolysis S (oxygen stable). Also causes beta-hemolysis. Non antigenic

Front 11

4 types of disease caused by group A strep (either local invasion and/or exotoxin release)

Back 11

1) Strep pharyngitis
2) Strep skin infections
3) Scarlet fever
4) Strep toxic shock syndrome

Front 12

2 delayed antibody mediated diseases caused by group A beta hemolytic strep

Back 12

1) Rheumatic fever
2) Acute post-strep Glomerulonephritis

Front 13

Streptococcal pharyngitis: signs and symptoms

Back 13

red swolen tonsils and pharynx, purulent exudate, high temp, swolen lymph nodes. Lasts 5 days. Give antibiotics (penicillin)

Front 14

Treatment of skin infections and why

Back 14

penicillinase resistant penicillin like dicloxacillin, which covers both group A beta-hemolytic strep and staph aureus

Front 15

strep infection of dermis only

Back 15

erysipelas (almost always caused by strep, not staph)

Front 16

pustule usually on extremity or face that breaks down after 4-6 days to form a crus

Back 16

pyoderma

Front 17

necrotizing fasciitis caused by what kind of strep?

Back 17

group A beta hemolytic strep (Strep pyogenes) with M proteins that block phagocytosis, allowing bacteria to move rapidly through the tissue. Strep enter through a break and then follow path along the fascia.

Front 18

form of necrotizing fasciitis involving male genital area and perineum, often caused by mixed organisms but can be caused by Strep pyogenes.

Back 18

fournier's gangrene

Front 19

scarlet fever: what is special about the strep that causes it?

Back 19

group A beta-hemolytic strep actually produce a toxin (pyrogenic/erythrogenic toxin) that produces fever and rash.

The toxin comes from a phage.

Front 20

How to treat severe strep pyogenes infections?

Back 20

high dose penicillin and clindamycin (Strep pyogenes remains sensitive to penicillin, and clindamycin inhibits bacterial ribosome and thus shuts down protein synthesis of pyrogenic toxin and M protein)

Front 21

When does rheumatic fever happen?

Back 21

After untreated beta-hemolytic group A strep pharyngitis (NOT skin infection)

Front 22

6 symptoms of rheumatic fever

Back 22

1) Fever
2) Myocarditis
3) Joint swelling (arthritis)
4) Chorea - begins 2-3 weeks after. Aka St Vitus' Dance
5) Subcutaneous nodules
6) Rash - erythema marginatum

10-20 years post infection - may develop permanent heart damage.

Front 23

rheumatic fever is __________ mediated

Back 23

antibody

Front 24

How to prevent further damage to the heart after rheumatic fever?

Back 24

prophylactic penicillin therapy to prevent future beta-hemolytic group A strep infections (that would elicit more of the antibodies that recognize heart proteins too)

Front 25

Symptoms of acute post-strep glomerulonephritis

Back 25

Antibody-mediated inflammatory disease of kidney glomeruli.

Retention of water (puffy face), dark urine (due to hematuria - blood in urine), high blood pressure

Front 26

acute post-strep glomerulonephritis : cause

Back 26

occurs after strep infection of pharynx OR skin by nephritogenic strains of beta-hemolytic group A strep.

Antigens from this induce antibody response. Resulting complexes travel to kidneys and get depositied in glomerular basement membrane, leading to local glomerular destruction in kidney.

Front 27

Group B Strep: significance

Back 27

Dangerous during pregnancy. Think B for Baby.

Cause neonatal meningitis, pneumonia, sepsis.

Front 28

3 most common pathogens associated with meningitis in infants <3 months of age

Back 28

1) E coli
2) Group B strep
3) Listeria monocytogenes

Front 29

What 2 bacteria can cause meningitis later in life when maternal antibodies wane and new fetal antibodies develop?

Back 29

1) neisseria meningitides
2) haemophilus influenzae

Front 30

Characteristics of viridans group strep

Back 30

indigenous to GI tract; alpha-hemolytic (appear green on blood agar).

Front 31

viridans group strep associated with what 3 main types of infections

Back 31

1) Dental infections (s mutans)
2) Endocarditis (from dental procedures)
3) Abscesses

Front 32

Subacute bacterial endocarditis (SBE) is caused by ______ while acute bacterial endocarditis is associated with ________

Back 32

viridans Strep or group D strep; Staph aureus

Front 33

What strep causes abscesses?

Back 33

Anginosus; Intermedius

InterMeDius and AnginoSus IMeDiately ASess for ABSCESS

(if you culture a strep intermedius in blood there may be an abscess hiding in an organ - order CT)

Front 34

What are the major Group D strep?

Back 34

Enterococci (enterococcus faecalis and faecium), Non-enterococci (strep bovis and equinus)

Front 35

Characteristics of Enterococcus (faecalis and faecium)

Back 35

Normal bowel flora that are group D strep. Alpha hemolytic.

Not too virulent but do prey on hospitalized, weak patients. Common cause of nosocomial infections.

Front 36

What is VRE?

Back 36

vancomycin resistant enterococci (group D strep). A chromosomal transposon DNA element called vanA that modifies the terminus of peptidoglycan cell wall to have LOW AFFINITY FOR VANCOMYCIN. Can be transferred to Staph aureus!!

Front 37

Characteristics of non-enterococci Group D strep (esp Strep Bovis)

Back 37

Lives in GI tract, similar to enterococcus.

Remarkable association between this and colon cancer.

BOVIS in BLOOD, look for cancer in BOWEL

Front 38

BOVIS in BLOOD, Better Beware, CANCER in the BOWEL: what does this mean

Back 38

If Strep bovis (group D strep) is in the blood stream (bacteremia), 50% of patients will have colon cancer.

Front 39

Strep pneumoniae: characteristics

Back 39

NO lancefield antigen (so no Group). Major virulence factor is polysac capsule, which makes it hard to phagocytose.

&alpha; hemolytic

Front 40

Major virulence factor of Strep pneumoniae

Back 40

A polysaccharide capsule that is antigenic and can be neutralized by antibodies

Front 41

What does Strep pneumoniae cause?

Back 41

bacterial pneumonia and meningitis in adults; otitis media in children.

Front 42

Pneumococcus is to Parents what group B strep is to Babies: what does this mean?

Back 42

Strep pneumoniae causes meningitis in adults while group B strep causes menigitis in children.

Front 43

what is the quellung reaction?

Back 43

lab test by which to ID encapsulated bacteria, therefore to ID pneumococcus. (Strep pneumoniae).

When S pneumoniae on a slide smear are mixed with a small amount of antiserum (serum with antibodies to capsular antigens) and methylene blue, the capsule will appear to swell, allowing for rapid ID of organism.

Front 44

What is optochin sensitivity?

Back 44

Way to differentiate between Strep pnemoniae and Viridans (both alpha-hemolytic).

If you try to grow on optochin disc, strep pneumoniae wil be inhibited, but strep viridans will continue to grow.

Front 45

Three main bacteria causing otitis media

Back 45

1) Strep pneumoniae (30%)
2) Haemophilus influenza (25%)
3) Moraxella catarrhalis (15-20%)

Front 46

All Streptococci are CATALASE (POSITIVE, NEGATIVE)

Back 46

NEGATIVE

Front 47

Which Strep is sensitive to bacitracin?

Back 47

Only S.pyogenes, Group A strep is sensitive

Front 48

What is the CAMP test?

Back 48

S. aureus hemolysin and Strep agalactiae (GBS) hemolysin act synergistically


The CAMP test is a test to identify Group B β-streptococci[1][2] based on their formation of a substance (CAMP factor[3]) that enlarges the area of hemolysis formed by β-hemolysin from Staphylococcus aureus. It is frequently used to identify Listeria spp.

Front 49

What is the esculin test?

Back 49

Liquid or solid media containing bile esculin turns black with Group D Strep (Enterococcus)

Test to ID Group D strep

Front 50

_______ lysed in presence of bile (Na deoxycholate) - AKA bile soluble

Back 50

Pneumococci (S. pneumoniae)

Front 51

Which strep's growth is inhibited by optochin?

Back 51

Strep pneumoniae

Front 52

What is the sodium hippurate test?

Back 52

To ID S. agalactiae. (group B) They hydrolyze hippurate while other strep don't

Front 53

Cause scarlet fever in children and toxic shock syndrome in adults

Back 53

pyrogenic exotoxins

Front 54

What if Strep does not have M factor?

Back 54

It will not be virulent.

Front 55

What is ASO titer looking for?

Back 55

Clinical indicator of past S. pyogenes infection. It's looking for Antibodies to oxygen labile toxin Streptolysin O

Front 56

Most common cause of cellulitis

Back 56

Group A strep

Front 57

Mortality is highest in (strep, staph) toxic shock syndrome

Back 57

Strep

Front 58

Puerperal fever: cause

Back 58

group A strep

Front 59

Puerperal fever: symptoms

Back 59

Postpartum endometritis

Front 60

S pneumoniae: prevention

Back 60

Polyvalent vaccines composed of 23 polysaccharide types for adults

• Polyvalent vaccine composed of 7 types conjugated to protein for children—available since 2000

Front 61

S agalactiae: what kind of strep

Back 61

Group B (life-threatening to infant)

Front 62

Antibiotic therapy for Group D Strep/Enterococcus

Back 62

combination therapy (beta-lactam plus aminoglycoside)
. They're resistant generally

Front 63

Strep is more associated with (community, hospital) infections while staph is more associated with (community, hospital)

Back 63

Community; hospital