Treatment of Community-Acquired Pneumonia
For community-acquired pneumonia (CAP), the recommended first-line treatment is a beta-lactam (such as amoxicillin or ceftriaxone) combined with a macrolide (preferably azithromycin) to cover both typical and atypical pathogens. 1
Treatment Based on Setting and Severity
Outpatient Treatment
Mild CAP without comorbidities:
Mild CAP with comorbidities:
Inpatient Treatment (Non-ICU)
- Ceftriaxone (1-2 g/day) PLUS azithromycin 1, 4
- Alternative: Respiratory fluoroquinolone (levofloxacin) monotherapy 1, 3
ICU Treatment
- Ceftriaxone PLUS either a macrolide or respiratory fluoroquinolone 1
- For suspected Pseudomonas: Antipseudomonal β-lactam (piperacillin-tazobactam, cefepime, imipenem, or meropenem) PLUS either ciprofloxacin/levofloxacin or an aminoglycoside plus azithromycin 1
- For suspected MRSA: Add vancomycin or linezolid to standard therapy 1
Pathogen-Specific Treatment
- Streptococcus pneumoniae: Beta-lactams (amoxicillin, cefotaxime, ceftriaxone) 1
- Mycoplasma pneumoniae: Macrolide (azithromycin preferred) 1
- Legionella spp.: Levofloxacin (preferred), moxifloxacin, or macrolide ± rifampicin 1
- Chlamydophila pneumoniae: Doxycycline, macrolide, levofloxacin, or moxifloxacin 1
- Pseudomonas: Antipseudomonal β-lactam plus either ciprofloxacin/levofloxacin or an aminoglycoside plus azithromycin 1
Treatment Duration
- Standard uncomplicated CAP: Minimum of 5 days, with extension guided by clinical stability 1
- CAP caused by MRSA or Pseudomonas aeruginosa: 7 days 1
- Clinical stability criteria for stopping antibiotics:
- Resolution of vital sign abnormalities
- Ability to eat
- Normal mentation
- Patient afebrile for 48-72 hours 1
Supportive Care
- Oxygen therapy: Maintain SaO₂ >92% in uncomplicated cases 1
- For COPD patients: Guided by arterial blood gas measurements to avoid CO₂ retention 1
- Monitoring: Regular assessment of vital signs, mental status, and oxygen saturation at least twice daily 1
- IV to oral switch criteria:
- Hemodynamically stable
- Clinically improving
- Able to ingest medications
- Normally functioning gastrointestinal tract 1
Common Pitfalls to Avoid
- Inadequate initial coverage: Ensure coverage for both typical and atypical pathogens
- Delayed switch from IV to oral therapy: Switch when patient meets criteria to reduce hospital stay
- Inappropriate duration: Treat for minimum 5 days and until clinically stable
- Failure to recognize treatment failure: Fever should resolve within 2-3 days; persistent fever beyond 3 days, worsening respiratory symptoms, or progression of pulmonary infiltrates indicate treatment failure 1
- Overuse of broad-spectrum antibiotics: Use narrow-spectrum antibiotics when a pathogen is identified 1
Special Considerations
- COVID-19 and influenza testing: Should be performed when these viruses are common in the community 4
- De-escalation: Consider after 48-72 hours if no evidence of bacterial superinfection and clinical response is adequate 1
- Corticosteroids: May reduce 28-day mortality when administered within 24 hours of severe CAP development 4
Remember that early appropriate antibiotic therapy is critical for reducing morbidity and mortality in CAP, and treatment should be initiated promptly after diagnosis.