Comparing clinical manifestations, treatment strategies and outcomes of Staphylococcus lugdunensis bacteraemia versus Staphylococcus aureus bacteraemia – a retrospective cohort study

Background Staphylococcus lugdunensis is a coagulase‐negative Staphylococcus that has been increasingly recognised as a significant pathogen capable of causing invasive infections similar to Staphylococcus aureus . Data comparing the clinical manifestations and outcomes of S. lugdunensis bacteraemia to S. aureus bacteraemia remain limited. This article seeks to compare the two diseases in order to better understand the clinical course of S. lugdunensis bacteraemia. Aims This study aims to compare the clinical course, management strategies, outcomes and complications of S. lugdunensis and S. aureus bacteraemia in order to better characterise S. lugdunensis bacteraemia. Methods We conducted a retrospective cohort study of 57 patients with S. lugdunensis bacteraemia and 66 matched patients with S. aureus bacteraemia across a metropolitan health service in Melbourne, Australia, between 2012 and 2024. Patient demographics, clinical features, biochemical markers, management strategies and outcomes were compared. Results Baseline demographics and comorbidities were similar between the groups. S. lugdunensis was more frequently isolated in polymicrobial cultures compared to S. aureus (14/57 vs 2/66) and was more frequently viewed as a contaminant by treating clinicians (12/57 vs 1/66). S. aureus bacteraemia was associated with longer duration of bacteraemia, and more frequent osteoarticular and spinal epidural infections. However, rates of infective endocarditis were similar between the two groups (9/57 vs 15/66), and inpatient and 90‐day mortality outcomes were comparable. Conclusion Our findings support the idea that S. lugdunensis bacteraemia should be approached with similar clinical vigilance as S. aureus , given comparable mortality and potential for serious complications, namely infective endocarditis. Improved clinician awareness is needed to reduce misclassification of S. lugdunensis as contaminants to allow for timely diagnosis and management.