A 52-year-old woman has had a chronic cough for the past 2 years, accompanied by a small amount of occasionally blood-streaked, whitish sputum On physical examination, her temperature is 37.9 C, pulse is 72/min, respirations are 22/min, and blood pressure is 125/80 mm Hg. Crackles are heard on auscultation over the upper lung fields. Heart sounds are faint, and there is a 15 mm Hg inspiratory decline in systolic arteria pressure. The chest radiograph shows prominent heart borders with a water bottle"configuration. Pericardiocentesis yields 200 mL of bloody fluid. Infection with which of the following organisms is most likely to produce these findings? A B C D E