A Rare Case of Streptococcus alactolyticus Infective Endocarditis Complicated by Septic Emboli and Mycotic Left Middle Cerebral Artery Aneurysm.

To date, S. alactolyticus endocarditis complicated by middle cerebral artery aneurysm has not been reported. We describe the case of a 65-year-old female with a history of hypertrophic cardiomyopathy with left ventricular outflow tract obstruction presenting with confusion and a apical holosystolic murmur. Angiography of the brain identified new bilobed left middle cerebral artery aneurysm. Serial blood cultures grew S. alactolyticus, and aortic and mitral valve vegetation were discovered on transesophageal echocardiography. The patient was treated with antimicrobial therapy, mitral and aortic valve replacements, and microsurgical clipping of cerebral aneurysm. This case serves to highlight the pathogenicity of a sparsely described bacterium belonging to the heterogenous S. bovis complex.