A 62-year-old man with a prosthetic aortic valve develops fevers and malaise. His valve was replaced 5 years ago because of aortic stenosis from a bicuspid valve. He has a systolic ejection murmur but no other abnormalities on examination. Blood cultures are most likely to grow which of the following?
High-Yield Explanation
S. epidermidis is still the most frequent early and late cause of endocarditis in patients with prosthetic heart valves. The other organisms are seen less frequently in late prosthetic valve endocarditis.