Staphylococcus aureus: Difference between revisions
From IDWiki
Staphylococcus aureus
m (Aidan moved page Staphylococcus Staphylococcus Staphylococcus aureus to Staphylococcus aureus without leaving a redirect) |
No edit summary |
||
| Line 1: | Line 1: | ||
| ⚫ | |||
| ⚫ | |||
| − | |||
| ⚫ | |||
* Facultative anaerobic, Gram-positive coccus |
* Facultative anaerobic, Gram-positive coccus |
||
| Line 7: | Line 5: | ||
* Colony morphology: large, round, golden yellow colonies, often hemolytic on blood agar |
* Colony morphology: large, round, golden yellow colonies, often hemolytic on blood agar |
||
| − | + | = Pathophysiology = |
|
| − | + | == Virulence factors == |
|
* Surface proteins for fibrinogen and other substances (used for binding to host endothelial cells) |
* Surface proteins for fibrinogen and other substances (used for binding to host endothelial cells) |
||
| Line 16: | Line 14: | ||
* Superantigens that bind to MHC molecules and T-cell receptors, leading to release of huge amounts of cytokines |
* Superantigens that bind to MHC molecules and T-cell receptors, leading to release of huge amounts of cytokines |
||
| − | + | = Clinical Presentation = |
|
| − | + | == Skin and soft tissue infections == |
|
* Boils and carbuncles |
* Boils and carbuncles |
||
| − | + | == Scalded-skin syndrome == |
|
* Aka Ritter disease |
* Aka Ritter disease |
||
* Sunburn-like, bullous rash that can lead to skin loss (most common in kids with Staph infections of the nasopharynx or skin) |
* Sunburn-like, bullous rash that can lead to skin loss (most common in kids with Staph infections of the nasopharynx or skin) |
||
| − | + | == Bacteremia == |
|
* See [''Staphylococcus aureus'' bacteremia](Staphylococcus aureus bacteremia.md) |
* See [''Staphylococcus aureus'' bacteremia](Staphylococcus aureus bacteremia.md) |
||
| − | + | == Infective endocarditis == |
|
* Usually more acute presentation |
* Usually more acute presentation |
||
* High mortality |
* High mortality |
||
| − | + | == Myriad other infections == |
|
* Osteomyelitis |
* Osteomyelitis |
||
| Line 45: | Line 43: | ||
* Pneumonia, especially ventilator-associated or influenza-related |
* Pneumonia, especially ventilator-associated or influenza-related |
||
| − | + | == Superantigen-related syndromes == |
|
* Food poisoning |
* Food poisoning |
||
* Staphylococcal toxic-shock syndrome |
* Staphylococcal toxic-shock syndrome |
||
| − | + | = Management = |
|
| − | + | == Methicillin-susceptible ''Staphylococcus aureus'' (MSSA) == |
|
* First-line: cloxacillin, then cefazolin or cephalexin |
* First-line: cloxacillin, then cefazolin or cephalexin |
||
* Others: clindamycin, fluoroquinolones, Septra, doxyxycline, erythromycin |
* Others: clindamycin, fluoroquinolones, Septra, doxyxycline, erythromycin |
||
| − | + | == Methicillin-resistant ''Staphylococcus aureus'' (MRSA) == |
|
* First-line: vancomycin |
* First-line: vancomycin |
||
* Others: linezolid (if lungs) and daptomycin (if blood), but also consider Septra, ciprofloxacin, doxycycline, and clindamycin |
* Others: linezolid (if lungs) and daptomycin (if blood), but also consider Septra, ciprofloxacin, doxycycline, and clindamycin |
||
| + | |||
| ⚫ | |||
| + | [[Category:Gram-positive cocci]] |
||
Revision as of 19:30, 14 August 2019
Microbiology
- Facultative anaerobic, Gram-positive coccus
- Microscopy: groups or clusters ("cluster of grapes")
- Colony morphology: large, round, golden yellow colonies, often hemolytic on blood agar
Pathophysiology
Virulence factors
- Surface proteins for fibrinogen and other substances (used for binding to host endothelial cells)
- Membrane-damaging (hemolytic) toxins
- Exfoliative toxins (A and B) which disrupt the junction between epidermal cells
- Superantigens that bind to MHC molecules and T-cell receptors, leading to release of huge amounts of cytokines
Clinical Presentation
Skin and soft tissue infections
- Boils and carbuncles
Scalded-skin syndrome
- Aka Ritter disease
- Sunburn-like, bullous rash that can lead to skin loss (most common in kids with Staph infections of the nasopharynx or skin)
Bacteremia
- See [Staphylococcus aureus bacteremia](Staphylococcus aureus bacteremia.md)
Infective endocarditis
- Usually more acute presentation
- High mortality
Myriad other infections
- Osteomyelitis
- Native and prosthetic joint infections
- Pyomyositis
- Deep organ abscesses
- Surgical site infections
- Pneumonia, especially ventilator-associated or influenza-related
- Food poisoning
- Staphylococcal toxic-shock syndrome
Management
Methicillin-susceptible Staphylococcus aureus (MSSA)
- First-line: cloxacillin, then cefazolin or cephalexin
- Others: clindamycin, fluoroquinolones, Septra, doxyxycline, erythromycin
Methicillin-resistant Staphylococcus aureus (MRSA)
- First-line: vancomycin
- Others: linezolid (if lungs) and daptomycin (if blood), but also consider Septra, ciprofloxacin, doxycycline, and clindamycin
