Synopsis
Treat every credible Staphylococcus aureus bloodstream isolate as clinically important, document rapid culture clearance, control the source and distinguish genuinely uncomplicated disease from endocardial or metastatic infection.
- Treat every credible S aureus blood-culture episode as true bacteraemia until a complete assessment proves otherwise.
- Repeat peripheral blood cultures every 24 to 48 hours until documented clearance; the clearance date helps define duration.
- Examine skin, wounds, vascular access, heart, spine, joints, neurological system and every implanted prosthesis for source and spread.
- Remove infected or unnecessary intravascular catheters promptly and drain abscesses or wash out infected joints.
- Perform echocardiography; use TOE when clinical probability, persistent bacteraemia, prosthetic material or inadequate TTE makes occult endocarditis plausible.
- Use intravenous flucloxacillin for MSSA when safe and a monitored MRSA-active regimen when resistance or allergy requires it.
- Uncomplicated disease requires all criteria: rapid clearance, defervescence, controlled removable source, no implanted prosthesis, no endocarditis and no metastatic focus.
- Treat truly uncomplicated bacteraemia for at least 14 days of effective therapy from clearance; complicated infection generally needs four to six weeks or longer according to focus.
Key red flags
Staphylococcus aureus in a correctly collected blood culture is not dismissed as contamination.
Positive cultures beyond 48 to 72 hours of active treatment predict an uncontrolled source, endocarditis or metastatic infection.
New murmur, heart failure, conduction delay or embolic deficit requires urgent endocarditis evaluation.
Back pain, focal bone tenderness, hot joint or weakness may indicate vertebral osteomyelitis, epidural abscess or septic arthritis.
Any retained prosthetic valve, vascular graft, joint, cardiac device or intravascular catheter increases complicated-infection risk.
Hypotension, confusion, oliguria, mottling or rising lactate requires immediate sepsis escalation.
Fever, rigors, hypotension, confusion or organ dysfunction may accompany any source and requires immediate active intravenous treatment.
Tenderness, purulence, thrombosis or rigors during line use suggest catheter infection; an apparently clean site does not exclude intraluminal biofilm.
Murmur, embolus, heart failure, conduction change or persistent bacteraemia raises endocarditis probability, but none is required for diagnosis.
New focal back pain, radicular pain, weakness or sphincter disturbance may reflect vertebral infection or epidural abscess.
Investigation priorities
Document sterilisation, detect persistent bacteraemia and establish the clearance date.
Management branches
A laboratory reports S aureus from blood or Gram-positive cocci strongly suggest it in an unwell patient.
- Contact the treating team urgently, use ABCDE and ensure an active intravenous regimen is prescribed with allergy and renal status documented.
- Obtain repeat peripheral cultures before the next dose when feasible without delaying urgent therapy.
- Remove unnecessary or infected vascular catheters and drain readily accessible pus; send deep material for culture.
- Ask specifically about valves, all prostheses, back or joint pain, injection exposure, recent surgery and neurological symptoms.