Staph Aureus Bacteraemias Flashcards
What are the features of staph aureus?
- Most virulent of staph species
- Causes disease through toxin and non toxin mediated mechanism
- Part of normal human flora
- Gram positive coci
- Form grape like clusters on gram stain
Which groups have a much higher chance of being colonised by S. aureus?
Insulin dependent diabetics, HIV positive patients, those undergoing haemodialysis and those with skin damage
Why is s. aureus colonisation important?
Those colonised are at greater risk of subsequent infection
How are S. aureus blood stream infections classified?
- Healthcare or community acquired
- Absence or presence of identified associated sites of infection (primary or secondary)
Which infections can be caused by staph. aureus?
- Skin and soft tissue infections
- Deep seated abscesses, necrotising fasciitis and pyomyositis
- Osteomyelitis, septic arthritis and discitis
- Infective endocarditis
- Pneumonia and empyema
- Wound, vascular line and catheter infections
Name the frequent sites of distant metastases of S. aureus bacteraemia?
- Bones and joints (especially those with prosthetics)
- Epidural space and intervertebral disc
- Native and prosthetic cardiac valves and cardiac devices
- Visceral abscesses in spleen, kidneys and lungs
What investigations can be done for staph aureus bacteraemias?
- Microscopy and culture of specimens
- Multiple blood cultures before and after commencing antibiotic therapy
- Biopsy samples (bone infections)
- XR, CT, MRI, radionuclide imaging
- Transthoracic ECHO or TOE
What is the management of invasive staph infections?
- Antibiotic therapy
- Source identification and clearance
- Appropriate surgical intervention
Which antibiotics can be used to treat staph infections?
Fluclox, vancomycin, teicoplanin, linezolid and daptomycin
Why is vancomycin not the ideal drug to use for staph infections?
Poor tissue penetration, slow bactericidal activity, inconvenient admin and side effects
