A 70-year-old man with COPD and type 2 DM is admitted for community-acquired pneumonia (CAP). PSI/PORT score puts him in Class IV. Blood cultures and sputum are sent. Urine Legionella antigen and Streptococcus pneumoniae antigen tests are negative. Procalcitonin is 4.8 ng/mL. The MOST appropriate empirical antibiotic regimen for hospitalised non-ICU CAP per IDSA/ATS 2019 guidelines is:
- A Amoxicillin-clavulanate orally only
- B Vancomycin plus piperacillin-tazobactam for all hospitalised patients
- C Ceftriaxone alone for non-ICU CAP to avoid macrolide resistance
- D Beta-lactam (ampicillin-sulbactam or ceftriaxone) PLUS a macrolide (azithromycin); OR a respiratory fluoroquinolone (levofloxacin/moxifloxacin) monotherapy ✓
Explanation
IDSA/ATS 2019 CAP guidelines recommend for non-ICU hospitalised patients (moderate severity): (1) combination therapy with a beta-lactam (ceftriaxone 1–2 g daily, or ampicillin-sulbactam) PLUS a macrolide (azithromycin or clarithromycin), OR (2) respiratory fluoroquinolone monotherapy (levofloxacin 750 mg/day or moxifloxacin 400 mg/day). These regimens provide coverage for both typical (S. pneumoniae, H. influenzae) and atypical pathogens (Legionella, Mycoplasma, Chlamydia). Negative Legionella urinary antigen does not exclude atypical coverage need. Anti-MRSA/Pseudomonal coverage (vancomycin + piperacillin-tazobactam) is only for ICU patients with specific risk factors.
Reference: Harrison's Principles of Internal Medicine, 21st ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.