What is the antibiotic treatment for Community-Acquired Pneumonia (CAP)?

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Last updated: February 15, 2025View editorial policy

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From the Guidelines

Antibiotic treatment for Community-Acquired Pneumonia (CAP) should be based on effective treatment of the most commonly reported bacterial pathogens, including Haemophilus influenzae, Streptococcus pneumoniae, and Moraxella catarrhalis, and may include an aminopenicillin with clavulanic acid, a macrolide, or a tetracycline.

Key Considerations

  • The choice of antibiotic should be guided by the patient's clinical presentation, severity of illness, and presence of coexisting illnesses or risk factors for drug-resistant pathogens 1.
  • For healthy adults, antibiotic options may include amoxicillin, doxycycline, or a macrolide, while patients with comorbidities may require a β-lactam with a macrolide or a respiratory fluoroquinolone 1.
  • The duration of antibiotic therapy should be at least 5 days, with extension of therapy guided by validated measures of clinical stability, such as resolution of vital sign abnormalities, ability to eat, and normal mentation 1.
  • Current evidence supports the use of shorter-duration antibiotics in the treatment of CAP, with a minimum of 5 days of antibiotics recommended by the 2019 Infectious Diseases Society of America (IDSA)/American Thoracic Society (ATS) guideline 1.

Specific Antibiotic Options

  • Aminopenicillins with clavulanic acid, such as amoxicillin-clavulanate, may be used as first-line therapy for outpatient CAP, especially in patients with no modifying factors 1.
  • Macrolides, such as azithromycin or clarithromycin, may be used as alternative therapy for patients with penicillin allergy or as part of combination therapy for patients with comorbidities 1.
  • Respiratory fluoroquinolones, such as levofloxacin or moxifloxacin, may be used as alternative therapy for patients with comorbidities or risk factors for drug-resistant pathogens, but should be used judiciously to minimize the risk of resistance 1.

From the Research

Antibiotic Treatment for Community-Acquired Pneumonia (CAP)

The antibiotic treatment for CAP typically involves empirical therapy that covers both typical and atypical pathogens.

  • The beta-lactams have historically been considered standard therapy for the treatment of CAP, but rising resistance rates are a primary concern facing physicians 2.
  • Current guidelines recommend either combination therapy with a beta-lactam and a macrolide or an antipneumococcal fluoroquinolone alone for patients with comorbidities or recent antibiotic therapy 2.
  • Fluoroquinolones, such as moxifloxacin, gatifloxacin, and levofloxacin, have been shown to be effective in the treatment of CAP due to S pneumoniae, with clinical success rates of > 90% 2.
  • Combination therapy, including a beta-lactam and a macrolide, has been associated with better outcomes and lower mortality in severe CAP, especially in patients requiring intensive care unit (ICU) admission 3, 4.
  • The use of azithromycin, telithromycin, and fluoroquinolones in short-course regimens has been shown to be efficacious, safe, and tolerable in patients with CAP 2.
  • New antibiotics, such as delafloxacin, omadacycline, lefamulin, solithromycin, nemonoxacin, and ceftaroline, have been approved or are in development for the treatment of CAP, offering enhanced empiric treatment of antibiotic-resistant bacterial pathogens 5.

Specific Treatment Recommendations

  • For outpatients with comorbidities and previous antibiotic therapy, nursing home patients with CAP, hospitalized patients with severe CAP, bacteremic pneumococcal CAP, presence of shock, and necessity of mechanical ventilation, combination antibiotic therapy is recommended 4.
  • Macrolides have shown different properties other than antimicrobial activity, such as anti-inflammatory properties, and are often used in combination therapy for CAP 4.
  • Narrow-spectrum agents are often as effective as broad-spectrum agents and result in less collateral damage, and national and local antibiotic guidance should promote choices of agents for narrow-spectrum prescribing even for severe CAP where appropriate 6.

References

Guideline

Guideline Directed Topic Overview

Dr.Oracle Medical Advisory Board & Editors, 2025

Research

New antibiotics for community-acquired pneumonia.

Current opinion in infectious diseases, 2019

Research

Antibiotics for community-acquired pneumonia.

The Journal of antimicrobial chemotherapy, 2009

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

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