A 68-year-old man with fever, productive cough, and a single lobar consolidation on chest radiograph. What is first-line outpatient therapy if he has no comorbidities?

• A. Amoxicillin or doxycycline
• B. Amoxicillin-clavulanate
• C. Macrolide monotherapy
• D. Levofloxacin

Answer: (A)

Outpatient management of community‑acquired pneumonia in adults without comorbidity focuses on regimens that reliably cover Streptococcus pneumoniae (the most common cause) and also address atypical pathogens, with a preference for simplicity and safety. The two simplest first‑line options are high‑dose amoxicillin or doxycycline. Amoxicillin provides strong, reliable pneumococcal coverage, and using a higher dose helps overcome possible resistance. Doxycycline adds activity against atypical organisms like Mycoplasma and Chlamydophila. Either choice targets the typical and atypical pathogens likely in an otherwise healthy patient, making them appropriate first-line outpatient therapy.

Alternatives like amoxicillin‑clavulanate are more for patients with comorbidities or higher risk of beta‑lactamase–producing organisms; macrolide monotherapy is less favored in many settings due to rising pneumococcal macrolide resistance; and levofloxacin is a broader agent reserved for patients with comorbidities, recent antibiotic use, or contraindications to first-line options, given its greater risk of adverse effects.