Pyogenic Bacteria - Staph and Strep

Question 1

Clinical syndromes associated with Staph and Strep

Answer 1

Skin infections/eruptions
Wound infections
URI (sinusitis/pharyngitis)
Pneumonia (debilitated patients)
Food poisoning/TSS
Septicemia/disseminated infections

Question 2

What kind of inflammatory response does staph and strep illicit?

Answer 2

suppurative response - accounts for a majority of suppurative infections and abscess formation

Question 3

The role of what type of immune response is very important with staph and strep?

Answer 3

role of phagocytosis/opsonization very important

Question 4

Diseases that interfere with what immune function are characterized by increased infections with pyogenic bacteria?

Answer 4

neutrophil function

Question 5

General forms of disease from staph

Answer 5

1. abscess formation (particularly skin); cellulitis
2. bacteremia (sepsis): endocarditis, kidneys, bones, joints
3. toxin-mediated disease: food poisoning, TSS

Question 6

Staph virulence factor important in abscess formation

Answer 6

coagulase positive versus coagulase negative

Question 7

Staph virulence factors

Answer 7

coagulase
toxins (enterotoxins, cytolytic, TSST-1, superantigen)
penicillinase
fibronectin and vitronectin
protein A

Question 8

Pseudomonas causes what in CF patients

Answer 8

bronchiectasis

Question 9

Primary mode of protection against staph organisms in humans?

Answer 9

non-immune mediated phagocytosis

Question 10

major cause of infection in burns and surgical wounds

Answer 10

staph

Question 11

2nd most common cause of nosocomial infections

Answer 11

staph

Question 12

TSST-1 acts as a superantigen to stimulate

Answer 12

large amounts of IL-1, IL-2, and tumor necrosis factor

Question 13

TSS results in

Answer 13

systemic inflammation similar to gram-negative sepsis

Question 14

TSS patients present with

Answer 14

fever, diffuse macular rash, low blood pressure (shock); exfoliation after 10-14 days

Question 15

Bronchopneumonia is most commonly found in which types of patients?

Answer 15

mostly hospitalized, debilitated patients

Question 16

Protein A

Answer 16

binds to the Fc portion of immunoglobulins

Question 17

fibronectin and vitronetin

Answer 17

bind to host cells

Question 18

penicillinase

Answer 18

plasmid-mediated antibiotic resistance

Question 19

how are strep infections grouped

Answer 19

by Lancefield antigens

Question 20

how are strep infections typed

Answer 20

according to their ability to hemolyse blood agar

Question 21

Strep infections of breaks in skin, wound infections

Answer 21

cellulitis, impetigo, erysipelas

Question 22

Strep infections of the URT

Answer 22

strep throat, sinusitis, otitis media

Question 23

Post-streptococcal hypersensitivity disease

Answer 23

rheumatic fever
immune complex glomerulonephritis
erythema nodosum (vasculitis)

Question 24

Lancefield antigens (subtypes)

Answer 24

Group A
Group B
Group D
alpha-hemolytic/viridans

Question 25

Group A strep

Answer 25

beta hemolytic | pharyngitis/post streptococcal disease

Question 26

Group B strep

Answer 26

perinatal sepsis/newborns | UTIs

Question 27

Group D strep

Answer 27

anaerobic S. faecalis (enterococcus) | endocartitis, UTI

Question 28

alpha-hemolytic/viridans

Answer 28

subacute bacterial endocarditis | access to blood stream from mouth colonization by dental work

Question 29

Streptococcus mutans

Answer 29

major cause of dental caries

Question 30

Streptococcus virulence factors

Answer 30

cell wall polysaccharides/capsules (M proteins) streptokinase, streptolysin O,S erythrogenic toxin

Question 31

M proteins

Answer 31

prevent phagocytosis

Question 32

streptokinase, streptolysin O,S

Answer 32

help to lyse ECM along tissue plains

Question 33

what causes rheumatic fever?

Answer 33

host antibodies to group A strep antigens that cross-react with host tissues

Question 34

what causes acute poststreptococcal glomerulonephritis?

Answer 34

deposition of immune complexes in the kidney following group A infections

Question 35

group A infections

Answer 35

Strep throat, impetigo, skin infections with GAHS

Question 36

acute pharyngitis/upper respiratory infections with Strep

Answer 36

redness, edema, pain fever chills characterized by extreme inflammation and a suppurative exudate on tonsils punctate abscesses in tonsillar crypts peritonsillar, retropharyngeal abscess formation

Question 37

scarlet fever

Answer 37

febrile exanthematous disorder erythrogenic toxin produced by bacteria; violaceous red rash on trunk, strawberry tongue desquamation of skin

Question 38

post-streptococcal sequelae

Answer 38

post-streptococcal glomerulonephritis | rheumatic fever

Question 39

acute rheumatic fever

Answer 39

antibodies to M proteins cross-react with tissues | fever, joint disease, myocardial and valvular disease

Question 40

chronic rheumatic heart disease

Answer 40

long-standing damage to mitral and aortic valves

Question 41

Strep skin infections

Answer 41

``` cellulitis, pyoderma impetigo erysipelas necrotizing fasciitis subacute bacterial endocarditis puerperal sepsis ```

Question 42

Strep cellulitis/pyoderma

Answer 42

extensive spreading redness, swelling, pain | less localized than staph infections

Question 43

impetigo

Answer 43

contagious, skin infection in kids may also be due to staph can lead to post-streptococcal glomerulonephritis

Question 44

erysipelas (groups A/C)

Answer 44

middle-aged persons, warm climate, erythematous cutaneous involvement without suppuration

Question 45

GABHS necrotizing fasciitis

Answer 45

uncommon deep-seated soft tissue infection gangrene pre-existing immunodeficiency subcutaneous strep infection with necrosis that is overtaken by anaerobes (gas formation) mortality 50-70%

Question 46

subacute bacterial endcarditis

Answer 46

associated with S. viridans; transient bacteremia following dental work left sided valvular endocarditis prophylactic Abx for dental worm

Question 47

puerperal sepsis (perinatal)

Answer 47

Group B; overwhelming sepsis in newborns

Question 48

Pathologic features of strep infections

Answer 48

skin - suppurative inflammation with cellulitis (small abscess formation) strep throat

Question 49

Pathologic features of strep skin infections

Answer 49

diffuse interstitial neutrophilic infiltrates with minimal destruction of host tissues characteristic redness and pain erythrogenic/pyrogenic toxins cause fever, rash less likely to cause discreet abscesses (like staph)

Question 50

Pathologic features of strep throat

Answer 50

erythematous, painful (erythrogenic toxins) | collections of pus (crypts, peritonsillar abscess)

Question 51

Diagnosis of strep throat

Answer 51

rapid strep test - Group A streptococcal carbohydrate antigen confirmatory culture - catalase negative; antibiotic specificity

Question 52

Diagnosis of rheumatic fever

Answer 52

anti-streptolysin O Ab titers

Question 53

Impetigo can be caused by

Answer 53

Staph or Strep

Question 54

Erysipelas caused by

Answer 54

Strep

Question 55

Paronychia caused by

Answer 55

Staph

Question 56

Scalded skin syndrome/Ritter disease caused by

Answer 56

Staph

Question 57

TSS caused by

Answer 57

S. aureus and Strep pyogenes

Question 58

Cellulitis caused by

Answer 58

Staph and Strep

Question 59

Necrotizing fasciitis caused by

Answer 59

Strep pyogenes and anaerobes

Question 60

Food poisoning caused by

Answer 60

Staph aureus