Question

A $41$-year-old man is evaluated in the hospital on the third day of his admission for community-acquired pneumonia. He initially presented with a two-day history of high fever, productive cough, and right-sided pleuritic chest pain. On admission, his temperature was $38.8^\circ\text{C}$ ($101.8^\circ\text{F}$), blood pressure was $118/74\text{ mm Hg}$, pulse was $110\text{/min}$, and respirations were $24\text{/min}$. Chest radiography showed a right lower lobe consolidation. He was subsequently started on empiric intravenous levofloxacin.

Today, the patient reports feeling significantly better. He has been afebrile for the past $24\text{ hours}$, and his cough has improved. Current vital signs are temperature $37.1^\circ\text{C}$ ($98.8^\circ\text{F}$), blood pressure $122/78\text{ mm Hg}$, pulse $82\text{/min}$, and respirations $16\text{/min}$. He is tolerating a regular diet.

Blood cultures drawn on admission are now positive for Streptococcus pneumoniae. Susceptibility testing of the isolate demonstrates the following:

Which of the following is the most appropriate next step in pharmacotherapy?