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 ago. Blood cultures grew ceain gram-positive cocci on which catalase and coagulase test were done. The gram-positive organisms failed to ferment mannitol, and their growth was inhibited by novobiocin. CATALASE TEST SLIDE COAGULASE TEST Lesions seen on skin What is the most likely infectious agent?