From the Guidelines
The first-line treatment for Legionella pneumonia is azithromycin or levofloxacin, as recommended by the most recent and highest quality study 1.
Key Points
- Azithromycin is typically dosed at 500 mg IV or orally on day 1, followed by 250 mg daily for a total of 5-10 days.
- Levofloxacin is given as 750 mg IV or orally once daily for 7-14 days.
- For severe infections, some experts recommend combination therapy with both agents.
- Treatment duration should be extended to 14-21 days in immunocompromised patients or those with severe disease.
- These antibiotics are preferred because they achieve high intracellular concentrations, which is essential since Legionella is an intracellular pathogen that multiplies within alveolar macrophages, as noted in 1 and 1.
Rationale
The preferred treatment for Legionella pneumonia is based on the ability of azithromycin and levofloxacin to penetrate cells and reach the bacteria, as well as their good lung tissue penetration, as discussed in 1 and 1.
Additional Considerations
- Clinical improvement typically occurs within 3-5 days of appropriate therapy.
- The duration of treatment may vary depending on the severity of the disease and the patient's response to therapy, as mentioned in 1.
From the FDA Drug Label
Azithromycin for Injection, USP is indicated for the treatment of patients with infections caused by susceptible strains of the designated microorganisms in the conditions listed below... Community-acquired pneumonia due to Chlamydia pneumoniae, Haemophilus influenzae, Legionella pneumophila, Moraxella catarrhalis, Mycoplasma pneumoniae, Staphylococcus aureus, or Streptococcus pneumoniae in patients who require initial intravenous therapy The first line treatment for Legionella infections is Azithromycin (IV), as it is indicated for the treatment of community-acquired pneumonia due to Legionella pneumophila 2.
From the Research
First-Line Treatment for Legionella
- The first-line treatment for Legionnaires' disease includes either a fluoroquinolone (levofloxacin or moxifloxacin) or a macrolide (azithromycin preferred) 3, 4, 5.
- Azithromycin or levofloxacin can be considered as first-line therapy for Legionnaires' disease 5.
- Other antibiotics including tetracyclines, tigecycline, other fluoroquinolones, and other macrolides (especially clarithromycin) are also effective 5.
- Macrolides and fluoroquinolones are the recommended treatment for Legionnaires' disease, with similar outcomes 6.
Treatment Options
- Azithromycin has been shown to be efficacious in animal models and in clinical studies of patients with Legionnaires' disease 7.
- Clarithromycin, azithromycin, and levofloxacin were all found to be efficacious for the treatment of Legionnaires' disease in a prospective, observational study 6.
- The clinical response of quinolones may be somewhat more favorable compared to macrolides, but the outcome is similar 5.
Recommendations
- Antibiotics directed against Legionella spp. should be included early as empirical therapy for severe community-acquired pneumonia 3.
- Inadequate or delayed antibiotic treatment in Legionella pneumonia has been associated with a worse prognosis 3.
- The preferred therapy for legionellosis in immunocompromised patients is quinolone/macrolide combinations, such as levofloxacin plus azithromycin 4.