Infective endocarditis (IE) can be caused by bacterial or fungal infections invading the endocardial surface of the heart, such as its valves and chambers.
Staphylococcus
and
Streptococcus
species are mainly responsible for IE.
Streptococcus equinus
(
S. equinus
) has been rarely noted to cause IE. We present a case of a 69-year-old white male with a past medical history of severe aortic regurgitation, who during an elective aortic heart valve replacement surgery was noted to have multiple plaque-like vegetations at the base of the mitral valve that were positive for
S. equinus
. To date, there are only four cases of
S. equinus
endocarditis reported worldwide, with a high possibility of our case being the first reported in North America.