Seven cases of surgical native valve endocarditis caused by coagulase-negative staphylococci: An underappreciated disease.

Background: Native valve endocarditis caused by coagulase-negative staphylococci is uncommon and the diagnosis is infrequently considered. The disease, however, appears to be increasing in frequency and can pursue an aggressive clinical course. We report the clinical features of 7 cases of coagulase-negative staphylococcal native valve endocarditis (CNS-NVE) seen at 1 institution with a large cardiovascular referral base over a 10-month period. All cases required valve replacement surgery.

Methods: Clinical history, echocardiograms, and microbiologic and histopathologic data were reviewed for 7 patients with surgical CNS-NVE.

Results: Four patients had intravenous central catheters, and 1 had recent surgery, whereas the remaining 2 had no identifiable risk factors. Presentations ranged from subacute (4 cases) to acute with complications (3 cases). Complications included congestive heart failure, stroke, and heart block. Echocardiography demonstrated valvular lesions in all 7 cases. Valve pathologic study demonstrated gram-positive cocci in all 7 cases; blood cultures grew coagulase-negative staphylococci in 6 cases and valve cultures grew Staphylococcus epidermidis in 5 cases.

Conclusions: Coagulase-negative staphylococci, including S epidermidis, can cause severe native valve endocarditis requiring valve replacement. The increasing use of intravascular access devices in the community may herald an increase in the incidence of CNS-NVE. A high index of diagnostic suspicion in the appropriate clinical setting is critical for optimal management.