A 19 year old college student presents at the ER having had a fever and cough for 5 days. As she is there, she starts looking very ill. She is sweating and her coloring has become very pale and bluish. Her breathing is very rapid and her heart rate is accelerated. Despite aggressive treatment with fluids and i. v. antibiotics, she dies 5 hours after hospitalization. Catalase-positive, gram-positive cocci are isolated from her blood. What organism was most likely the cause of her symptoms