A 49-year-old man presents to the emergency department with complaints of weakness, fatigue, and intermittent fever that has recurred for several weeks. He underwent cardiac valvular prosthesis implantation one month ago. Physical examination reveals red splinter-like streaks under the fingernails and petechiae on the chest. Blood cultures grew Gram-positive cocci in clusters, which are catalase-positive. Which of the following is the most likely diagnosis? A) Infective endocarditis caused by Staphylococcus aureus B) Prosthetic valve endocarditis caused by Staphylococcus epidermidis C) Subacute bacterial endocarditis caused by Streptococcus viridans D) Infective endocarditis caused by Enterococcus faecalis E) Toxic shock syndrome caused by Staphylococcus aureus
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The patient is a 49-year-old man who recently underwent cardiac valvular prosthesis implantation and presents with weakness, fatigue, intermittent fever, and physical findings of red splinter-like streaks under the fingernails and petechiae on the chest. These Show more…
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A 57-year-old man arrives at the emergency room complaining of weakness, fatigue, and intermittent fever that has recurred for several weeks. The patient had a cardiac valvular prosthesis implanted 5 years earlier. Physical examination reveals petechiae (pinpoint; nonraised, purplish red spots caused by intradermal hemorrhage) on the chest and stomach. Blood cultures grew catalase-positive, coagulase-negative cocci. The gram-positive organisms failed to ferment mannitol, and their growth was inhibited by novobiocin. What is the most likely infectious agent? A. Staphylococcus aureus B. Staphylococcus epidermidis C. Staphylococcus saprophyticus D. Streptococcus pneumoniae E. Streptococcus agalactiae
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