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S. lugdunensis Endocarditis — SCE Infectious Diseases MCQ

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HardBone & Joint InfectionS. lugdunensis EndocarditisSCE Infectious Diseases

A 60-year-old man with a metallic aortic valve on Warfarin develops Staphylococcus lugdunensis native mitral valve endocarditis. TOE shows a 14 mm vegetation with severe mitral regurgitation. Blood cultures clear by day 3 of IV Flucloxacillin. What is unique about S. lugdunensis endocarditis?

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Correct answer: E — S. lugdunensis is a coagulase-negative staphylococcus that behaves like S. aureus — it causes aggressive, destructive native valve endocarditis with high rates of valve destruction and mortality

S. lugdunensis is unique among coagulase-negative staphylococci — despite being CoNS, it behaves clinically like S. aureus. It causes aggressive, destructive native valve endocarditis with high rates of paravalvular abscess, valve perforation, and embolic events. Mortality is 40–50% without surgery. It should NEVER be dismissed as a contaminant when isolated from blood cultures. It is usually methicillin-sensitive (unlike most CoNS). Early surgery should be strongly considered given the aggressive natural history. Treatment follows S. aureus endocarditis protocols.

Reference: ESC 2023 – Endocarditis; BSAC 2023 – S. lugdunensis