USMLE Step 1 - Question 32

A 56 year old female with a history of mitral valve prolapse has been experiencing fevers and joint pains for 3 weeks. She recently underwent a tooth extraction. Physical examination reveals a III/VI holosystolic murmur at the cardiac apex which was not present on prior examinations. Her erythrocyte sedimentation rate is markedly elevated. A painful nodule on the pad of her left index finger has developed. Which of the following is the most likely culprit? 

A. Staphalococcus aureus

B. Pseudomonas auriginosa

C. Streptococcus viridins

D. Candida albicans