Three Cases of Community-Acquired Pneumonia: Is It Bacterial, Viral, or Fungal?

Dallas J. Smith, PharmD, MAS; Kaitlin Benedict, MPH; Samantha Williams, MPH; Jeremy A. W. Gold, MD, MS; Mitsuru Toda, PhD, MS


September 18, 2023

Editorial Collaboration

Medscape &

Inappropriate and unnecessary antibiotics are common in primary care, urgent care, and emergency room settings. It can be difficult to distinguish whether community-acquired pneumonia (CAP) is due to a bacterial, viral, or fungal etiology. Clinicians should consider all three etiologies on CAP presentation to improve antimicrobial stewardship and patient outcomes.

Case #1

A 47-year-old man presents to his primary care provider in Rhode Island for evaluation of possible community-acquired pneumonia. His past medical history includes hypertension and occasional gastrointestinal reflux disease. He has a cough, fever, and mild shortness of breath but no other symptoms. His clinician sends him home with a prescription for doxycycline 100 mg twice daily for 5 days. Two weeks later, the patient returns to their primary care provider with worsening shortness of breath and no improvement. The primary care provider takes a more detailed history and notes that:

  • Patient's father died from cardiovascular disease at age 52 years

  • Patient recently returned from camping in northern Minnesota

  • Patient has been taking melatonin to help with insomnia