HACEK Endocarditis — SCE Infectious Diseases MCQ
Instant feedback + full explanation. One question, done properly.
Educational content. Not a substitute for clinical judgement or local policy.
Reveal the answer and explanation
Correct answer: E — IV Ceftriaxone 2 g daily for 6 weeks (prosthetic valve — 6 weeks minimum)
HACEK organisms (Haemophilus, Aggregatibacter, Cardiobacterium, Eikenella, Kingella) are fastidious Gram-negative bacteria that cause ~5% of endocarditis cases. They are slow-growing and may initially present as culture-negative endocarditis (require prolonged incubation). IV Ceftriaxone 2 g daily is the treatment of choice. Duration is 4 weeks for native valve and 6 weeks for prosthetic valve endocarditis. Ampicillin is an alternative if the organism is beta-lactamase negative. HACEK organisms are intrinsically resistant to Vancomycin.
Reference: ESC 2023 – Endocarditis guidelines; BSAC 2012 – Endocarditis