A 54 yo otherwise healthy man reports a cough productive of green sputum, fever, chills, & egophony & increased tactile fremitus in the left lower lobe. A CBC shows WBC count of 20,000/mm3 with 15 bands. His CXR is shown below
What is the most likely pathogen causing his illness?
A. Streptococcus pneumoniae
B. Mycoplasma pneumoniae
C. Pseudomonas
D. Staphylococcus aureus