🫁🤒Community‑Acquired Pneumonia in a Young Adult

Scenario
A 45‑year‑old man with no significant past medical history presents with a 3‑day history of fever (38.5 °C), productive cough, pleuritic chest pain, and mild dyspnea. He is haemodynamically stable (BP 125/80, HR 95, RR 20, SpO₂ 94% on room air). Laboratory tests show WBC 12 × 10⁹/L. Chest X‑ray demonstrates a right lower‑lobe consolidation. His CURB‑65 score is 1 (age < 65 but BUN normal), indicating inpatient—or close outpatient—management.

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Question:

Which empiric antibiotic regimen is most appropriate for this patient?

A) IV ceftriaxone + IV azithromycin
B) IV ampicillin–sulbactam + IV azithromycin
C) IV levofloxacin monotherapy
D) IV ceftaroline + IV azithromycin

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✅ Correct Answer: A) IV ceftriaxone + IV azithromycin

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💡 Key Teaching Points

1. Most common CAP pathogens:

   • Streptococcus pneumoniae (25–40%)

   • Haemophilus influenzae (10–20%)

   • Moraxella catarrhalis (~5–10%)

   • Atypicals (Mycoplasma, Chlamydophila, Legionella) (~10–20%)

2. Empiric non‑ICU inpatient regimen:

   • β‑lactam (ceftriaxone, cefotaxime, or ampicillin–sulbactam) + macrolide for dual coverage.

   • Respiratory fluoroquinolone monotherapy (e.g., levofloxacin) is an alternative if β‑lactams are contraindicated.

3. Why CTX + Azithro wins:

   • Targets both typical and atypical organisms with well‑studied synergy.

   • IV route ensures therapeutic levels in pneumonia.

   • Lower cost and toxicity compared with ceftaroline combinations.

4. When to consider others:

   • Amp‑sulb + Azithro: if concern for anaerobes or local practice uses ampicillin–sulbactam.

   • Levofloxacin: in true β‑lactam allergy, or when oral step‑down is anticipated early.

   • Ceftaroline: when MRSA risk is high or initial therapy fails—but not routine for CAP.