skip to main content

S. aureus Bacteraemia — SCE Infectious Diseases MCQ

Instant feedback + full explanation. One question, done properly.

ModerateHealthcare-Associated InfectionsS. aureus BacteraemiaSCE Infectious Diseases

A 45-year-old man on the ID ward has Staphylococcus aureus bacteraemia. Blood cultures on day 3 are still positive. TOE is performed and is negative for vegetations. Repeat blood cultures on day 5 are negative. No removable focus is identified. What is the minimum recommended duration of antibiotic therapy from the date of first negative blood culture?

Educational content. Not a substitute for clinical judgement or local policy.

Reveal the answer and explanation

Correct answer: E — 14 days

Uncomplicated S. aureus bacteraemia (SAB) is defined as: no endocarditis on TOE, no prosthetic material, blood cultures clearing within 72 hours (though this case took 3–5 days), no evidence of metastatic infection. For uncomplicated SAB, minimum 14 days of IV antibiotics from the first negative blood culture is recommended. If any complicating features are present (persistent bacteraemia >72 hours — which this borderline case may represent — or metastatic infection), 4–6 weeks is required. This patient's clearance between day 3 and 5 is borderline and warrants careful clinical judgement.

Reference: BSAC 2023 – S. aureus bacteraemia guidelines; NICE NG104 – S. aureus bacteraemia