Introduction
Staphylococcus warneri (S. warneri ) is a type of coagulase-negative staphylococci (CoNS) and is part of the normal flora of the skin, especially the nares, head, legs, and arms1. S. warneri is present in about 50% of healthy adults and represents approximately 4.0% to 7.8% of all skin staphylococci in healthy adults2–9. S. warneriis not frequently recognized as a significant human pathogen but is occasionally isolated from immunocompromised patients or patients with medical devices, such as prosthetic heart valves, central venous catheter, and disk prosthesis1. S. warneri is rarely reported as a causative agent of infective endocarditis (IE)1. Here, we reported a rare case of native mitral valve IE caused by S. warneri in a 72-year-old Asian woman who had mitral valve regurgitation without valvular heart prosthesis. To analyze the demographic characteristics, predisposing factors, comorbidities, and outcomes of such cases, we reviewed previously reported cases of IE caused by S. warneri.