A patient, suspected to have bacterial endocarditis, had two sets of blood cultures drawn. All four bottles are positive with gram-positive cocci in pairs and chains. On sheep blood agar, the gray, transparent, alpha-hemolytic colonies are catalase negative, optochin resistant, ESC negative and PYR negative. Which of the following patient histories correlates with the presence of this organism?

Question

Quizplus · Accepted Answer

The organism described is most likely Streptococcus viridans, which is known for causing endocarditis, particularly in individuals with pre-existing heart conditions who undergo dental procedures. This is because S. viridans, part of the normal flora of the mouth, can enter the bloodstream during such procedures.

A Patient, Suspected to Have Bacterial Endocarditis, Had Two Sets