What are the antibiotic choices for Community-Acquired Pneumonia (CAP)?

From the Guidelines

For community-acquired pneumonia (CAP), the recommended antibiotic regimen is a beta-lactam plus a macrolide or a respiratory fluoroquinolone, with the specific choice depending on the treatment setting and patient risk factors, as outlined in the 2019 American Thoracic Society and Infectious Diseases Society of America guidelines 1.

Treatment Settings and Regimens

The treatment setting and patient risk factors play a crucial role in determining the appropriate antibiotic regimen for CAP.

• For outpatient treatment of healthy individuals without risk factors, amoxicillin 1g three times daily for 5 days is a reasonable option.
• For patients with comorbidities or recent antibiotic use, consider azithromycin 500mg on day 1, then 250mg daily for 4 more days, or doxycycline 100mg twice daily for 5 days.
• For hospitalized non-ICU patients, combination therapy with a beta-lactam (such as ampicillin-sulbactam 3g IV every 6 hours, ceftriaxone 1-2g IV daily, or cefotaxime 1-2g IV every 8 hours) plus a macrolide (such as azithromycin 500mg IV daily) is recommended for 5-7 days 1.
• For ICU patients, use a beta-lactam plus either azithromycin or a respiratory fluoroquinolone like levofloxacin 750mg IV daily.

Pathogen Coverage and Treatment Duration

These regimens target the most common CAP pathogens, including Streptococcus pneumoniae, Haemophilus influenzae, and atypical organisms like Mycoplasma pneumoniae.

• Treatment duration should typically be 5 days for most patients, extending to 7 days for more severe cases.
• Reassess after 48-72 hours to consider de-escalation to targeted therapy based on culture results when available 1.

Considerations for Specific Patient Populations

Certain patient populations, such as those with recent hospitalization or prior respiratory isolation, may require additional considerations when selecting an antibiotic regimen.

• For patients with recent hospitalization, consider adding coverage for MRSA and obtaining cultures/nasal PCR to allow de-escalation or confirmation of need for continued therapy 1.
• For patients with prior respiratory isolation, consider adding coverage for P. aeruginosa and obtaining cultures to allow de-escalation or confirmation of need for continued therapy 1.

From the FDA Drug Label

Levofloxacin tablets are indicated for the treatment of community-acquired pneumonia due to methicillin-susceptible Staphylococcus aureus, Streptococcus pneumoniae (including multi-drug-resistant Streptococcus pneumoniae [MDRSP]), Haemophilus influenzae, Haemophilus parainfluenzae, Klebsiella pneumoniae, Moraxella catarrhalis, Chlamydophila pneumoniae, Legionella pneumophila, or Mycoplasma pneumoniae [see Dosage and Administration (2.1) and Clinical Studies (14.2)]. MDRSP isolates are isolates resistant to two or more of the following antibacterials: penicillin (MIC ≥ 2 mcg/mL), 2nd generation cephalosporins, e.g., cefuroxime, macrolides, tetracyclines and trimethoprim/sulfamethoxazole. Clinical success rates (cure plus improvement) in the clinically evaluable population were 90.9% in the levofloxacin 750 mg group and 91.1% in the levofloxacin 500 mg group.

Antibiotics choice for CAP:

• Levofloxacin is indicated for the treatment of community-acquired pneumonia (CAP) due to various pathogens, including methicillin-susceptible Staphylococcus aureus, Streptococcus pneumoniae, Haemophilus influenzae, and others.
• The clinical success rates for levofloxacin in CAP are high, ranging from 90.9% to 91.1% in clinically evaluable populations.
• MDRSP isolates can be treated with levofloxacin, with a clinical success rate of 95% in microbiologically evaluable patients.
• The choice of antibiotic for CAP should be based on the suspected or confirmed pathogen, as well as local epidemiology and susceptibility patterns 2, 2.
• Key points to consider when choosing an antibiotic for CAP include:
  • The severity of the infection
  • The presence of underlying medical conditions
  • The potential for resistance to certain antibiotics
  • The need for adjunctive therapy in certain cases.

From the Research

Antibiotics Choice for Community-Acquired Pneumonia (CAP)

• The choice of antibiotics for CAP depends on various factors, including the severity of the disease, patient's age, and presence of comorbidities 3, 4, 5, 6.
• A study published in 2008 found that azithromycin 1g once daily for 3 days was at least as effective as amoxicillin-clavulanate 875/125 mg twice daily for 7 days in the treatment of adult patients with CAP 3.
• Another study published in 2023 suggested that short treatment duration for CAP, such as 3-5 days, may be sufficient for some patients, and clinical criteria can be used to discontinue antibiotic treatment 4.
• A randomized trial published in 2018 found that monotherapy with oral Levofloxacin was as effective as treatment with Ceftriaxone plus Azithromycin combination in patients with CAP who required hospitalization 5.
• A study published in 2024 compared the safety of different antibiotic regimens for the treatment of outpatient CAP among otherwise healthy adults and found that broad-spectrum antibiotics were associated with increased risk of adverse drug events (ADEs) compared to narrow-spectrum regimens 6.
• It is worth noting that one of the provided studies is not relevant to the topic of antibiotics choice for CAP, as it discusses the evaluation of immunity in chickens against fowlpox 7.