A 29-year-old man comes to the physician for a 3-day history of fever and mildly productive cough. He has history of IV drug use. CD4 count is 180/μL. Current medications are zidovudine, efavirenz, and ritonavir. Physical examination shows dullness to percussion over the right lower lobe. Chest x-ray shows infiltrates and consolidation in the right lower lobe. He has no recent history of antibiotic use. The most appropriate empiric pharmacologic therapy for this patient’s acute presentation inhibits which of the following?
30S
50S
Dihydrofolate reductase and dihydropteroate synthase
DNA gyrase
D-Ala-D-Ala
