Staphylococcus Aureus Bacteraemias

Question 1

Through what mechanisms can staph aureus cause disease?

Answer 1

Toxin-mediated and non-toxin-mediated mechanisms

Question 2

Who is most at risk of staph aureus infections?

Answer 2

Immuno-compromised patients such as HIV sufferers or insulin dependent diabetics

Question 3

What are the most common sites of staph A infection?

Answer 3

Nostrils (most common)
Broken skin
Axillae
Vagina 
Perineum 
Oropharynx

Question 4

How are staph aureus infections classified?

Answer 4

Hospital acquired

Community acquired

Question 5

What are the frequent sites of distant septic metastasis in staph aureus infections?

Answer 5

• Bones and joints (especially when prosthetic materials are present)
• Epidural space and intervertebral discs
• Native and prosthetic cardiac valves and cardiac devices
• Visceral abscesses in spleen, kidneys and lungs

Question 6

What investigations can be useful in staph aureus infections?

Answer 6

• Microscopy and culture of specimens
• Multiple blood cultures before starting antibiotic therapy
• Repeat blood cultures 48-72hrs after starting therapy
• Biopsy samples for bone infection
• Imaging- CT, x-ray, MRI, radionuclide imaging
• Transthoracic echocardiography

Question 7

What is the basis of management of staph A infections?

Answer 7

The basis of management for invasive staphylococcal infections is antibiotic therapy, identification and clearance of source and surgical intervention where appropriate

Question 8

What antibiotics can be used in staph A infections?

Answer 8

• Flucloxacillin (first line)
• Vancomycin
• Teicoplanin
• Linezolid
• Daptomycin