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44 Cards in this Set

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List the clinically relevant strains of Staphylococcus. x2
Staphylococcus Aureus

Staphylococcus Epidermidis
Basic features of Staphylococcus species. x2
Gram positive

Catalase positive
Why is Staphylococcus so effective at utilizing the carrier state on fomites or the skin of people?
Can survive a long time on dry surfaces.
Why is Staphylococcus effective in food poisoning?
Can survive in high salt concentration
What is an inherent feature of Staph. Aureus that can be used in the lab to distinguish Staph. Aureus from other Staph. strains?
Coagulase positive
List two basic lesions you might get from Staph. Aureus.
Pyogenic Exudate

Abscesses
Describe the pyogenic exudate of Staph. Aureus.
Pus filled with dead phagocytic cells and dead bacterial cells.
Describe the abscesses of Staph. Aureus.

- Benefit for bacteria?
- Benefit for host?
"Stand off" between bacteria and phagocytes, where the phagocytes are surrounding the bacteria.

Bacteria are protected from being phagocytized

Host can have localized containment.
What does it mean that an abscess can be a seeding point for Staph. Aureus?

Thus, what should happen to abscesses?
Bacteria will clump together without worry of phagocytosis due to the fibrin.

Then it will escape the abscess using staphylokinase.

Thus, important to drain.
What separates the bacteria and the phagocytes in an abscess?

What does the bacteria use to escape this crazy love-nest we call an abscess?
Fibrin

Staphylokinase b/c it lyses fibrin clots.
List the pyogenic skin infections that you can get with Staphylococcus Aureus.
Impetigo

Folliculitis

Furuncles (boils)

Caruncles

Cellulitis
Impetigo:

- progression
Small red papules
-> Vesicles filled with clear/yellow fluid
-> Blisters filled with pus
-> Eruption leads to crusty yummies on skin
Folliculitis:

- define
- can become what?
Infection of hair follicle

Furuncle
What is a Stye?
Folliculitis located at base of eyelid.
Furuncles:

- define
- can become what?
Extension of folliculitis.
Large, painful, and raised nodules with underlying necrotic tissue.

Caruncles
Caruncles:

- define
- systemic symptoms x2
Coalesced furuncles that extends to deeper tissue

Fevers and chills via bacteremia
Define cellulitis
Inflammation of subcutaneous tissue.
Wound infection due to Staph. Aureus:

- usually occurs after what?
- symptoms x3
- can lead to what?
- treatment
Surgery

Edema
Pain
Accumulation of Puss material

Bacteremia

Reopen wound and remove purulent material or FB

If uncleared, than do Antibiotic therapy.
Staphylococcus Aureus Pneumonia:

- types (w/ description) x3
- treatment for all of 'em
- when do you NOT use this treatment
1. Hematogenous
(occurs w/ pts w/ bacteremia)
2. Aspiration
(after aspiration of oral secretions)
3. Necrotizing
(community-acquired that can lead to septic shock)

IV Penicillinase resistant PCN
(oxacillan)

DON'T USE FOR MRSA
Staph. Aureus induced osteomyelitis:

- occur commonly in where
- treatment
- prognosis
Vertebral involvement

Surgery + Antimicrobial therapy

Very Good!!!!!!
Bacteremia associated with Staphylococcus Aureus can lead to what? x2
Endocarditis

Sepsis
Bacteremia induced endocarditis:

- can affect?
- mortality rate
- visible sign
Otherwise healthy heart valves

50%

Septic embolism
How does Staph. Aureus cause septic embolism?
Caused by occlusion of capillaries with the growth of it's colonies
Staph. Aureus induced Septic Arthritis:

- describe
- common in what group
Painful, erythematous joint with purulent material

Patients receiving intra-articular injections
Ritter's Disease:

- AKA
- common in?
- symptoms x2
Staphylococcus Scalded Skin Syndrome (SSSS)

Neonates and young children

1. Large blisters with CLEAR fluid
2. Desquamation of epithelium
Bullous Impetigo:

- Symptoms
- Common in?
- what is unique about it that separates it from SSSS
Localized form of SSSS
(blisters with desquamation)

Adults

Culture positive blisters
Staphylococcal Toxic Shock Syndrome (TSS):

- etiology
- common in?
- disease restricted to?
- symptoms x5
Dissemination of TSST-1 toxin

14 - 25 y.o. females

Those that don't have antibodies to TSST-1 toxins

1. Fever
2. Hypotension
3. Multi-organ involvement
4. Diffuse rash
5. Desquamation
T/F - Staphylococcal food poisoning is an infection by staphylococcal toxins.
False.

It is an INTOXICATION, not an infection.
Staphylococcal food poisoning:

- etiology
- onset
- symptoms x4
- treatment
Staphylococcal Enterotoxin A

4 hours after ingestion

Nausea
Vomiting
Diarrhea
Abdominal pain

Relieve the abdominal symptoms
(IV fluid replacement)
T/F - Staphylococcal food poisoning can be avoided by microwaving the contaminated food.
False

b/c toxins involved, not bacteria
T/F - Fever is usually a sign for Staphylococcal food poisoning.
False.

No fever
Methicillan Resistant Staph. Aureus (MRSA):

- carries what gene
- resistant to what Ab
- how
- treatment x2
mecA gene

PCN

has penicillinase

1. Vancomysin
2. Topical mupirocin
(for clearing nasal carriers)
What do you use for MSSA?
Oxacillan
List the virulence factors for Staph. Aureus. x9
Peptidoglycan
Capsular polysaccharides

Panton-Valentine Leukocidin
Protein A
Cytotoxin
Exfoliative toxin

MSCRAMM's/Adhesions
Enterotoxins (superantigen)
TSST-1 (superantigen)
What does protein A do?
Binds to Fc portion of IgG
What does the Panton-Valentine Leukocidin do?
Lyses Neutrophils
Which toxins are responsible for SSSS? x2
Exfoliative Toxin A (ETA)
Exfoliative Toxin B (ETB)
Which toxins are responsible for food poisoning?
Enterotoxins (8)
What does MSCRAMMs/Adhesions do?
Allows binding to host cell.
Which one(s) of the Staph. Aureus virulent factors can act as superantigens?
Enterotoxins

TSST - 1
Which toxins are responsible for TSS?
TSST - 1 toxin
How difficult is it to control Staph. aureus?
Very hard to control
What is the major mode of transmission for Staph. aureus?
Hands of healthcare workers
What are preventative ways to control Staph. aureus? x4
1. Wash hands/Hand antisepsis

2. Wound antisepsis

3. Isolate MRSA patients

4. Nasal carriage elimination