Staph aureus: Presentation
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Bacteria - Gram Positive
- Staph aureus: Overview
- Staph aureus: Presentation
- Methicillin-Resistant Staph aureus (MRSA)
- Staph saprophyticus
- Strep pneumoniae: Overview
- Strep pneumoniae: Presentation
- Strep viridans
- Strep pyogenes: Overview
- Strep pyogenes: Presentation
- Strep agalactiae
- Strep bovis
- Enterococcus
- Bacillus anthracis
- Bacillus cereus
- Clostridium tetani
- Clostridium perfringens
- Clostridium botulinum
- Clostridium difficile
- Corynebacterium diphtheriae
- Listeria monocytogenes
- Nocardia
- Actinomyces
Staph Aureus Presentation
- Commonly colonizes the nares, ears, axilla, and groin
- Note: Staphylococcus aureus is a constituent of the normal skin flora
- Most common cause of nosocomial (hospital-related) infections, especially with intravascular devices or IV drug use (access via skin)
- Inflammatory disease
- Skin infections
- E.g. impetigo, cellulitis, skin abscesses
- Pneumonia
- causes superimposed bacterial pneumonia on viral infections
- Acute endocarditis
- Common in IV drug users
- Tricuspid valve is usually affected
- Patients may develop multiple septic emboli in lungs, which can cause pulmonary infarcts
- Septic arthritis
- Most common cause of septic arthritis
- More common in IV drug users
- Osteomyelitis
- Adhesion to collagen is the main virulence factor of Staphylococcus aureus in osteomyelitis.
- Most common cause of osteomyelitis overall
- Skin infections
- Toxin-mediated disease
- Toxic shock syndrome (TSST-1)
- TSST-1 is a superantigen that crosslinks MHC II and T-cell receptor, resulting in polyclonal T-cell activation
- fever, vomiting, rash, desquamation, shock, end-organ failure
- Toxic shock syndrome (TSS) is caused by Staphylococcus aureus. TSS presents with fever, vomiting desquamation, and hypotension.
- TSS results in ↑ AST, ↑ ALT, ↑ bilirubin.
- Associated with prolonged use of vaginal tampons or nasal packing
- Compare with Strep pyogenes TSS: toxic shock-like syndrome associated with painful skin infection
- Scalded skin syndrome (exfoliative toxin)
- Exfoliative toxin destroys keratinocyte attachments in the stratum granulosum
- Typically seen in newborns, children, adults with renal insufficiency
- Gastroenteritis/food poisoning (enterotoxin)
- Preformed enterotoxin
- Heat stable, not destroyed by cooking
- Short incubation period (2- 6 hr), followed by vomiting and abdominal cramps (more common) and diarrhea (rare)
- associated with consumption of certain precooked foods, dairy products, custard, and mayonnaise that sits at room temperature for an extended period of time (e.g. picnic, potluck)
- Preformed enterotoxin
- Toxic shock syndrome (TSST-1)