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15 Cards in this Set
- Front
- Back
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Name some common resident flora of dry and exposed areas of skin.
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Staph epidermidis
Corynebacterium species Anaerobic gram + cocci Propionibacterium species (smell of axilla) |
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What are the two most pathogenic transient colonizers of skin?
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Staph aureus
Strep pyogenes |
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Three most predisposing factors for bacterial entry through skin?
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1. Excessive moisture- allows skin to macerate
2. Trauma- minor cuts, to majory breaches (GSW) 3. Compromise to blood supply |
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Where is the clinical manifestation of impetigo?
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Confined to the epidermal layer
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Where is the clinical manifestation of erysipelas?
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Dermal lymphatic tissue
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Where is the clinical manifestation of cellulitis?
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Involvement of subcutaneous tissue
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What is an abscess?
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walled-off infected sites containing necrotic tissue and large amounts of bactera, and white blood cells. The wall is typicall made up of fibrin from stimulated fibroblasts.
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Name three types of abscesses and their description.
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Folliculitis- superficial infection of the hair follicle
Furuncles (boil)- enlargement of follicular abscess Carbuncles- cluster of furuncles to form large, multifocal infection. |
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What are some general clinical presentations for skin infections?
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Abscess, necrosis, exanthem (rash)
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Describe Staph aureus.
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Gram positive cocci, catalase positive, coagulase positive, facultative anaerobe, invasive, extracellular
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Staph aureus has many colonization techniques that it uses. Name some of the them.
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S. aureus is very capable of adhering to many different cell surface proteins. It has many MSCRAMMs (like S. pyogenes) that are able to bind to fibronectin, fibrinogen, elastin, and collagen.
-clumping factor: allows binding to 3 different points on fibrinogen. -S. aureus is also able to produce slime; extremely virulent biofilm that can set on foreign objects in the body. -it is able to induce non-phagocytic cells to uptake the organism |
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What are the most common spread mechanisms for S. aureus?
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Nose to hand contact
Sometimes it is spread through respiratory droplets (in pneumonia cases) |
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What is the key localized lesion seen in S. aureus?
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abscess
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What locus if knocked out in the S. aureus gene causes a loss of virulence?
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agr
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What is the leading cause of bacteremia?
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Invasive S. aureus infection
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