What is the recommended treatment for community-acquired pneumonia?

Treatment of Community-Acquired Pneumonia

For hospitalized adults with community-acquired pneumonia (CAP) without risk factors for resistant bacteria, treat with combination β-lactam/macrolide therapy (such as ceftriaxone plus azithromycin) for a minimum of 5 days, stopping when the patient has been afebrile for 48-72 hours and has achieved clinical stability. 1

Outpatient Treatment

Previously Healthy Patients Without Risk Factors for Drug-Resistant S. pneumoniae

• Macrolide monotherapy (azithromycin, clarithromycin, or erythromycin) 1
• Alternative: Doxycycline 1

Patients With Comorbidities or Risk Factors for Resistance

Risk factors include: chronic heart, lung, liver, or renal disease; diabetes mellitus; alcoholism; malignancies; asplenia; immunosuppression; or antibiotic use within the previous 3 months 1

Choose one of the following:

• Respiratory fluoroquinolone (moxifloxacin, gemifloxacin, or levofloxacin 750 mg) 1
• β-lactam plus macrolide combination:
  • Preferred β-lactams: High-dose amoxicillin (1 g three times daily) or amoxicillin-clavulanate (2 g twice daily) 1
  • Alternative β-lactams: ceftriaxone, cefpodoxime, or cefuroxime (500 mg twice daily) 1
  • Doxycycline may substitute for the macrolide 1

Special Consideration for High Macrolide Resistance

In regions with ≥25% high-level macrolide-resistant S. pneumoniae (MIC ≥16 mg/mL), use respiratory fluoroquinolone or β-lactam/macrolide combination even for previously healthy patients 1

Inpatient Non-ICU Treatment

Two equally effective options:

• Respiratory fluoroquinolone monotherapy 1
• β-lactam plus macrolide combination 1
  • Preferred β-lactams: cefotaxime, ceftriaxone, or ampicillin 1
  • Ertapenem for selected patients with risk factors for gram-negative pathogens (excluding Pseudomonas) 1
  • Doxycycline may substitute for the macrolide 1
  • For penicillin-allergic patients: respiratory fluoroquinolone 1

Recent evidence suggests ampicillin may be comparable to ceftriaxone with lower rates of Clostridioides difficile infection, though this requires confirmation in larger trials. 2

Inpatient ICU Treatment (Severe CAP)

Standard Severe CAP Without Risk Factors for Pseudomonas or MRSA

β-lactam (cefotaxime, ceftriaxone, or ampicillin-sulbactam) PLUS either:

• Azithromycin 1
• Respiratory fluoroquinolone 1

For penicillin-allergic patients: respiratory fluoroquinolone plus aztreonam 1

Risk Factors for Pseudomonas aeruginosa

Antipneumococcal, antipseudomonal β-lactam (piperacillin-tazobactam, cefepime, imipenem, or meropenem) PLUS one of the following:

• Ciprofloxacin or levofloxacin (750 mg dose) 1
• OR Aminoglycoside plus azithromycin 1
• OR Aminoglycoside plus antipneumococcal fluoroquinolone 1

For penicillin-allergic patients: substitute aztreonam for the β-lactam 1

Suspected Community-Acquired MRSA

Add vancomycin or linezolid to the above regimens 1

Duration of Antibiotic Therapy

Minimum 5 days of treatment, with discontinuation when the patient:

• Has been afebrile for 48-72 hours 1
• Has no more than 1 sign of clinical instability 1
• Has achieved clinical stability (normal vital signs including heart rate, respiratory rate, blood pressure, oxygen saturation, temperature; ability to eat; normal mentation) 1

For suspected or proven MRSA or P. aeruginosa: treat for 7 days 1

Longer durations required for:

• Complications such as empyema, lung abscess, meningitis, or endocarditis 1
• Initial therapy not active against the identified pathogen 1
• Failure to achieve clinical stability within 5 days (prompts reassessment for resistant pathogens or complications) 1

Recent evidence supports even shorter 3-day courses for patients achieving clinical stability by day 3, particularly in younger patients with fewer comorbidities, though the 2019 ATS/IDSA guidelines maintain 5 days as the minimum standard. 3, 4

Adjunctive Corticosteroid Therapy

For severe CAP with persistent septic shock despite adequate fluid resuscitation, consider systemic corticosteroids within 24 hours of admission. 1, 5 This may reduce 28-day mortality in the most critically ill patients. 5

Hypotensive, fluid-resuscitated patients should be screened for occult adrenal insufficiency. 1

Timing and Route Considerations

Time to First Dose

For patients admitted through the emergency department, administer the first antibiotic dose while still in the ED. 1

IV to Oral Switch

Switch from intravenous to oral therapy when patients are:

• Hemodynamically stable and improving clinically 1
• Able to ingest medications 1
• Have normally functioning gastrointestinal tract 1

Use the same agent or same drug class when switching. 1 Inpatient observation while receiving oral therapy is not necessary. 1

Viral Testing and Pathogen-Directed Therapy

Test all patients for COVID-19 and influenza when these viruses are circulating in the community, as positive results may affect treatment decisions (antiviral therapy) and infection prevention strategies. 5

Once a pathogen is identified through reliable microbiological methods, switch to pathogen-directed therapy. 1 However, microbiological testing identifies a pathogen in only 38% of hospitalized CAP patients. 5

Common Pitfalls to Avoid

Do not use the healthcare-associated pneumonia (HCAP) classification to guide empiric anti-MRSA or antipseudomonal therapy, as this has led to overuse of broad-spectrum antibiotics. 1 Instead, base decisions on specific risk factors for resistant organisms.

Failure to achieve clinical stability within 5 days (occurring in up to 15% of patients) should prompt systematic assessment for resistant pathogens, complications (empyema, abscess), or alternative diagnoses—not simply continuation of the same therapy. 1

Avoid prolonging antibiotics beyond clinical stability without specific indication, as most patients achieve stability within 48-72 hours and do not benefit from extended courses. 1, 3