Staphylococcus lugdunensis Endocarditis Complicated by Embolism in an 18-Year-Old Woman with Mitral Valve Prolapse

Staphylococcus lugdunensis is a coagulase-negative staphylococcus (CNS). It is a major cause of prosthetic valve endocarditis; mitral valve prolapse (MVP) has emerged as a prominent predisposing structural cardiac abnormality. We describe a case of Staphylococcus lugdunensis endocarditis in an 18-year-old woman with preexisting mitral valve prolapse complaining of fever, a one-month history of continuous-remittent fever ( 38.6°C). The transthoracic echocardiogram revealed large vegetation on the anterior mitral valve leaflet flopping from the atrial side to the ventricular side. Five sets of blood cultures were positive for coagulase-negative staphylococci. During hospitalization, after two weeks of antibiotic therapy, the patient complained of sudden pain in her right leg associated with numbness. Lower limb arterial Doppler ultrasound showed an arterial thrombosis of right common iliac artery. Transfemoral iliac embolectomy was promptly performed and on septic embolus S. lugdunensis with the same antibiotic sensitivity and the same MIC values was again isolated. Our patient underwent cardiac surgery: triangular resection of the A2 with removal of infected tissue including vegetation. Our case is an example of infective endocarditis by S. lugdunensis on native mitral valve in a young woman of 18 with anamnesis valve prolapse. 1. Introduction Staphylococcus lugdunensis is a coagulase-negative staphylococcus (CNS). It is a major cause of prosthetic valve endocarditis, particularly during the initial years after valve surgery, an important cause of nosocomial infective endocarditis (IE) and the cause of 3 to 8 percent of native valve endocarditis, usually in the setting of prior valve abnormalities; among these, mitral valve prolapse (MVP) has emerged as a prominent predisposing structural cardiac abnormality [1]. S. lugdunensis, which was first described in 1988 [2], was distinguished from other coagulase-negative staphylococcal species via DNA relatedness studies based on 11 clinical strains. Like other CNS, S. lugdunensis in humans ranges from a harmless skin commensal to a life-threatening pathogen (as with infective endocarditis) but it is considered unique among CNS because of its propensity for causing aggressive native valve infective endocarditis (IE) often fatal and usually community acquired [3]. We describe a case of Staphylococcus lugdunensis endocarditis in an 18-year-old woman with preexisting mitral valve prolapse in order to emphasize the aggressiveness, as documented in the literature yet available, of this staphylococcus which takes on