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S. lugdunensis PJI — SCE Infectious Diseases MCQ

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ModerateBone & Joint InfectionS. lugdunensis PJISCE Infectious Diseases

A 65-year-old woman develops a wound infection after total knee replacement. Deep tissue cultures grow Staphylococcus lugdunensis. The surgeon asks about the significance of this organism. What key message should be communicated?

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

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Correct answer: B — S. lugdunensis is a coagulase-negative staphylococcus that causes aggressive infections resembling S. aureus — it should NEVER be dismissed as a contaminant; treat as you would S. aureus PJI

S. lugdunensis deserves special attention among CoNS because it causes aggressive, destructive infections more closely resembling S. aureus than typical CoNS. In the context of PJI, S. lugdunensis should be treated with the same urgency and duration as S. aureus PJI. It is usually methicillin-susceptible (unlike most CoNS) — Flucloxacillin is first-line. Key principle: any S. lugdunensis isolated from a clinical specimen (blood culture, deep tissue, synovial fluid) should be assumed pathogenic until proven otherwise.

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