A 74-year-old woman, who has been followed for the past 25 years for chronic obstructive pulmonary disease (COPD) comes to the emergency department complaining of 48 hours of temperatures to 38.6 C (101.4 F) and worsening shortness of breath. She has a chronic productive cough, which has become more copious. On physical examination, she has rhonchi and increased fremitus in the posterior mid-lung field. A Gram's stain reveals many epithelial cells and multiple gram-positive and gram-negative organisms; no neutrophils are seen.
Which of the following is the most likely organism causing the symptoms?