Staphylococcus aureus: Difference between revisions
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Staphylococcus aureus
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== Management == |
== Management == |
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| + | |||
| + | * Duration depends on clinical syndrome |
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=== Methicillin-susceptible ''Staphylococcus aureus'' (MSSA) === |
=== Methicillin-susceptible ''Staphylococcus aureus'' (MSSA) === |
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| − | * First-line: cloxacillin, then cefazolin or cephalexin |
+ | * First-line: [[cloxacillin]], then [[cefazolin]] or [[cephalexin]] (for oral) |
| − | * Others: clindamycin, fluoroquinolones, |
+ | * Others: [[clindamycin]], [[fluoroquinolones]], [[TMP-SMX]], [[doxyxycline]], [[erythromycin]] |
=== Methicillin-resistant ''Staphylococcus aureus'' (MRSA) === |
=== Methicillin-resistant ''Staphylococcus aureus'' (MRSA) === |
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| − | * First-line: vancomycin |
+ | * First-line: [[vancomycin]] |
| − | * Others: linezolid (if lungs) and daptomycin (if blood), but also consider |
+ | * Others: [[linezolid]] (if lungs) and [[daptomycin]] (if blood), but also consider [[TMP-SMX]], [[ciprofloxacin]], [[doxycycline]], and [[clindamycin]] |
{{DISPLAYTITLE:''Staphylococcus aureus''}} |
{{DISPLAYTITLE:''Staphylococcus aureus''}} |
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Revision as of 19:35, 4 September 2019
Microbiology
- Facultative anaerobic, Gram-positive coccus
- Catalase and coagulase positive
- 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, including Panton-Valentine leukocidin (PVL)
- Exfoliative toxins (A and B) which disrupt the junction between epidermal cells, causing scalded skin syndrome
- Superantigens that bind to MHC molecules and T-cell receptors, leading to release of huge amounts of cytokines
- Toxic shock syndrome toxin 1 (TSST-1) is implicated in TSS
- Exotoxins B and C cause TSS and also food poisoning
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
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
- Duration depends on clinical syndrome
Methicillin-susceptible Staphylococcus aureus (MSSA)
- First-line: cloxacillin, then cefazolin or cephalexin (for oral)
- Others: clindamycin, fluoroquinolones, TMP-SMX, doxyxycline, erythromycin
Methicillin-resistant Staphylococcus aureus (MRSA)
- First-line: vancomycin
- Others: linezolid (if lungs) and daptomycin (if blood), but also consider TMP-SMX, ciprofloxacin, doxycycline, and clindamycin
