Title : A Unique Case of Infective Endocarditis: Staphylococcus lugdunensis Infective Endocarditis Presenting as Embolic Occipital Stroke Due to Posterior Mitral Leaflet Perforation
Abstract:
Statement of the Problem: Staphylococcus lugdunensis is an uncommon coagulase-negative staphylococcus with virulence comparable to Staphylococcus aureus. Although rare, it can cause aggressive native valve infective endocarditis, characterised by rapid valvular destruction, systemic embolisation, and a high requirement for early surgical intervention. Because it is often regarded as a contaminant in blood cultures, delayed diagnosis may result in severe complications. This case highlights the importance of recognising S. lugdunensis bacteraemia as clinically significant and the role of early echocardiographic assessment in preventing adverse outcomes.
Methodology & Clinical Presentation: A 56-year-old woman with a history of migraine, hypothyroidism, and hormone replacement therapy presented with confusion, slurred speech, weakness, pyrexia, dysuria, and urinary frequency. Initial investigations demonstrated elevated inflammatory markers, and she was treated for presumed heatstroke with a possible urinary tract infection before being discharged on pivmecillinam. Blood cultures subsequently grew S. lugdunensis but were interpreted as contaminants, and targeted antimicrobial therapy was not initiated. One month later, she re-presented with persistent constitutional symptoms and neurological deficits. MRI of the brain demonstrated a subacute right occipital infarction consistent with an embolic stroke. Repeat blood cultures again isolated S. lugdunensis. Clinical examination revealed a pansystolic murmur, and transoesophageal echocardiography demonstrated posterior mitral leaflet perforation with severe eccentric mitral regurgitation, confirming destructive native mitral valve infective endocarditis. The patient completed six weeks of intravenous flucloxacillin and was accepted for mitral valve surgery.
Findings: Repeated isolation of S. lugdunensis represented true bacteraemia rather than contamination. Delayed recognition resulted in embolic cerebral infarction and severe mitral valve destruction requiring surgical intervention. Transoesophageal echocardiography was pivotal in establishing the diagnosis and guiding definitive management.
Conclusion & Significance: Staphylococcus lugdunensis bacteraemia should never be dismissed as contamination, particularly in patients with persistent fever, positive blood cultures, or embolic neurological events. Early transoesophageal echocardiography and prompt targeted antimicrobial therapy are essential for identifying destructive infective endocarditis, facilitating timely surgical referral, reducing embolic complications, limiting valvular destruction, and improving clinical outcomes
