Unusually virulent coagulase-negative Staphylococcus lugdunensis is frequently associated with infective endocarditis: a Waikato series of patients.

Background: Staphylococcus lugdunensis, a species of coagulase-negative staphylococci is associated with a wide variety of infections ranging from mild skin and soft tissue infections to serious infections which include brain abscess, chronic osteomyelitis and infective endocarditis. The aim of this study was to review cases of S. lugdunensis bacteraemia isolated from a New Zealand tertiary institution and describe the clinical presentation, diagnosis and treatment of the patients.
Methods: All blood cultures reported positive for S. lugdunensis from the Microbiology Laboratory, Waikato Hospital, New Zealand between March 2006 to April 2011 were reviewed.
Results: A total of 11 cases of S. lugdunensis bacteraemia were identified during the 5-year period. Three (27%) cases were due to infective endocarditis with one delayed diagnosis due to the failure of recognize the coagulase-negative Staphylococcus. Transthoracic or transoesophageal echocardiography was performed in 6 (55%) of the patients. One patient with endocarditis required early surgery and the other two were managed successfully with intravenous antibiotics. There was no in hospital mortality in the patients with endocarditis. The remaining 8 cases included 1 (9%) necrotizing fasciitis, 1 (9%) immunocompromised nosocomial multiple organism sepsis, 1 (9%) deep tissue infection requiring 6 weeks of intravenous antibiotics, 2 (18.5%) superficial skin infection, 1 (9%) nosocomial post-pacemaker insertion infection and 2 (18.5%) had fever of unknown origin. All isolates were sensitive to Flucloxacillin and Vancomycin. Overall the survival rate of the acute presentation and treatment was 91% (10/11).
Conclusion: Three of our 11 patients (27%) with S. lugdunensis bacteraemia were diagnosed with infective endocarditis. Evaluation for endocarditis is therefore advised in patients who have positive blood culture for this organism.