Term
| 3 species of staph are responsible for the majority of staph infections. What are they? |
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Definition
| S. aureus, S. epidermis, and S. saprophyticus |
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Term
| What is one way to differentiate between S. aureus, S. epidermis, and S. saprophyticus? |
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Definition
| S. aureus is coagulase (+) and the others are coagulase (-) |
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Term
| True or False: S. aureus causes more frequent and more varied diseases than any other human pathogen |
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Definition
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Term
| True or false: Serious staph infections usually occur in compromised hosts. |
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Definition
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Term
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Definition
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Term
| Which species of Staph is a different color than others and what are the colors? |
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Definition
| S. aureus appears golden yellow, and other species appear white. |
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Term
| What are the metabolic conditions for S. aureus? |
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Definition
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Term
| How is the peptidoglycan of Staph unique? |
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Definition
| the peptidoglycan of staph is unique because it is susceptible to lysostaphin (which cleaves glycine-glycine linkages) which is useful for identification |
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Term
| Is S. aureus catalase positive or negative? |
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Definition
Under aerobic conditions, S. aureus is catalase (+)
**Helps to distinguish between strep because strep is catalase (-) |
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Term
| What is the optimum temperature range for growth of S. aureus? |
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Definition
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Term
| Extracellular enzymes of S. aureus: |
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Definition
1. coagulase - clots plasma
2. hyaluronidase |
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Term
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Definition
1. alpha toxin
2. enterotoxin
3. exfoliative toxins
4. toxic shock syndrome toxin-1 (TSST-1) |
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Term
| How does alpha toxin work? |
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Definition
| alpha toxins are membrane active toxin that causes lysis of RBCs |
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Term
| How do enterotoxins work? |
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Definition
| they are super-antigens that act on neural receptors in the upper G.I. tract |
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Term
| What illness do enterotoxins cause? |
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Definition
| cause food poisoning--vomiting and diarrhea 2-5 hours after ingestion |
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Term
| How have enterotoxins evolved to resisit host defense? |
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Definition
| They are resistant to gastric enzymes and and heating at 100 degrees C for 30 minutes |
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Term
| exfoliative toxins mechanism of action: |
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Definition
| causes lysis of the intracellular attachment between cells of the granular layer of the epidermis |
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Term
| What illness/syndrome is caused by exfoliative toxins? |
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Definition
| scalded-skin syndrome - usually in young children |
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Term
| Toxic shock syndrome toxin-1 (TSST-1) mode of action: |
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Definition
| super-antigen: direct toxic effects on endothelial cells resulting in capillary leakage and hypotension |
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Term
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Definition
| lethal hypotension, rash with multiple organ system involvement |
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Term
| Staph. aureus is commonly resistant to: |
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Definition
| penicillins and cephalosporins |
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Term
| Resistance for all staphylococci: |
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Definition
**relatively more resistant to adverse environmental conditions than most nonsporulating bacteria
***survive for weeks in dried pus and sputum
****Resistant to common disinfectants; i.e. phenols and mercuric chloride |
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Term
| What are the clinical manifestations of S. aureus? |
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Definition
1. skin infections
2. respiratory infections
3. metastatic infections
4. food poisoning
5. TSS |
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Term
| What forms of skin infections do you get from staph aureus? |
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Definition
| folliculitis, carbuncles, boils, impetigo (usually in children) |
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Term
| True or False: Staph Pneumonia is often seen as a complication of other bacterial or viral infections: |
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Definition
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Term
| What is a characteristic of Staph Bacteremia? |
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Definition
Metastatic abscesses--most frequently on the
1. skin,
2. subcutaneous tissue,
3. and lungs.
**predisposed by trauma and debilitating disease |
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Term
| Symptoms of food poisoning from S. aureus: |
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Definition
avg. 4 hours after ingestion
1. severe cramping
2. abdominal pain
3. nausea
4. vomiting
5. diarrhea |
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Term
| Symptoms of Toxic Shock (TSS): |
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Definition
1. pyrogenic
2. hypotensive following vascular coagulation
3. renal failure
4. acidosis
5. rash |
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Term
| In males, TSS from Staph is associated with what body part: |
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Definition
strong association with focal staph infections: skin
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Term
| In females, TSS is associated with what area of the body: |
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Definition
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Term
| Catheter and shunt infections occur with what form of Staph? |
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Definition
| saprophiticus and epidermis |
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Term
| which form of staph is estimated as the most common cause of bacteremia? |
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Definition
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Term
| Which form of staph is the most common contaminant of specimens? |
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Definition
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Term
| Sites of infection for S. epidermis: |
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Definition
1. bacteremia (IV lines and valves)
2. meningitis (shunts)
3. periotenitis (via dialysis catheter)
4. septic arthritis (prosthetic joint)
5. endocarditis (prosthetic heart valve)
6. UTI
7. Local infections from implants |
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Term
| S. saprophiticus is most commonly involved in infections where? |
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Definition
UTI
* in young sexually active women |
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Term
| Where is staph found in the body as normal flora? |
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Definition
1. nasopharynx
2. perineum
3. skin
4. mucous membrane
5. and gut |
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Term
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Definition
1. Gram stain
2. streak on blood agar
3. inoculate into broth medium
4. Latex agglutination |
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Term
| To find the epidemiology of staph, what tests do you do? |
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Definition
1. antibiograms/biotyping
2. bacteriophage typing
3. serotyping |
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Term
| What percentage of staph are sensitive to penicillin? |
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Definition
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Term
| What percentage of staph are resistant to Beta Lactamase resistant pennicilin? |
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Definition
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Term
| To treat penicillinase resistant penicillin (methicillin), what antibiotic do you give? |
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Definition
1. a first generation cephalosporin: cephalothin
2. vancomycin for MRSA |
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