He came in with two days of fever and confusion. Doctors found lesions on his skin and, on imaging, in his brain, the scattered debris of infected material traveling through his bloodstream. Blood cultures grew Streptococcus pyogenes, the bacterium most Americans know as the cause of strep throat.
The obvious suspicion was infective endocarditis, an infection of the heart valves. But the test that normally confirms it kept coming back clean. Echocardiography was repeated, and no vegetations, the clumps of bacteria and clotted material that cling to infected valves, were seen.
