A 32-year-old man is brought to the emergency department because of a 2-day history of confusion and rapidly progressive dyspnea. He has had a fever and chills for the past five days. . He has smoked two packs of cigarettes daily for 15 years and drinks one to two beers daily. He has a history of intravenous heroin use. He appears pale, anxious, and in severe distress. His temperature is 39.3°C (102.7°F), respirations are 30/min, pulse is 59/min, and blood pressure is 80/50 mm Hg. Pulse oximetry on room air shows an oxygen saturation of 75%. Examination shows multiple linear hemorrhages underneath the nails. There are nontender maculae on both palms and soles. Fine rales are heard bilaterally on auscultation of the chest. Cardiac examination shows an S3; a grade 3/6 high-pitched decrescendo early diastolic murmur is heard along the left sternal border and right second intercostal space. Chest imaging reveals scattered bilateral peripheral lung opacities. HIV testing is negative. This patient's blood cultures are most likely to grow which of the following organisms?

Question

A 32-year-old man is brought to the emergency department because of a 2-day history of confusion and rapidly progressive dyspnea. He has had a fever and chills for the past five days. . He has smoked two packs of cigarettes daily for 15 years and drinks one to two beers daily. He has a history of intravenous heroin use. He appears pale, anxious, and in severe distress. His temperature is 39.3°C (102.7°F), respirations are 30/min, pulse is 59/min, and blood pressure is 80/50 mm Hg. Pulse oximetry on room air shows an oxygen saturation of 75%. Examination shows multiple linear hemorrhages underneath the nails. There are nontender maculae on both palms and soles. Fine rales are heard bilaterally on auscultation of the chest. Cardiac examination shows an S3; a grade 3/6 high-pitched decrescendo early diastolic murmur is heard along the left sternal border and right second intercostal space. Chest imaging reveals scattered bilateral peripheral lung opacities.  HIV testing is negative.  This patient's blood cultures are most likely to grow which of the following organisms?

Quizplus · Accepted Answer

Eductional Objective: Staphylococcus aureus causes acute bacterial endocarditis with rapid onset of symptoms, including shaking chills (rigors), high fever, dyspnea on exertion, and malaise.  In intravenous drug users, it can cause right-sided endocarditis with septic embolization into the lungs.

A 32-Year-Old Man Is Brought to the Emergency Department Because