What is the recommended antibiotic treatment for Legionella infection with elevated WBC count?

From the Guidelines

For Legionella infection with elevated WBC count, the recommended antibiotic treatment is a fluoroquinolone (such as levofloxacin 750 mg once daily for 7-14 days) or a macrolide (such as azithromycin 500 mg on day 1, then 250 mg daily for 4 more days). The choice of antibiotic is based on the severity of the infection and the patient's underlying health status.

• For severe infections or immunocompromised patients, combination therapy with a fluoroquinolone plus azithromycin or a fluoroquinolone plus rifampin (600 mg daily) may be used 1.
• Intravenous administration is preferred initially for hospitalized patients, with transition to oral therapy when clinically improved.
• Treatment duration should be extended to 14-21 days for immunocompromised patients or those with severe disease, as recommended by guidelines for the management of adult lower respiratory tract infections 1. The elevated WBC count indicates significant inflammatory response, supporting the need for prompt treatment.
• Fluoroquinolones and macrolides are effective because they achieve high intracellular concentrations, which is essential since Legionella is an intracellular pathogen that resides within alveolar macrophages 1. Adequate hydration and respiratory support should also be provided as part of comprehensive management.
• The preferred treatment for legionnaires’ disease for hospitalized patients is azithromycin or a fluoroquinolone (moxifloxacin, gatifloxacin, and levofloxacin; gemifloxacin is only available as an oral formulation) 1.
• Treatment should be initiated as rapidly as is feasible, as delay in therapy is associated with an increased mortality rate 1.

From the FDA Drug Label

1. 2 Community-Acquired Pneumonia: 7 to 14 Day Treatment Regimen Levofloxacin tablets are indicated for the treatment of community-acquired pneumonia due to ... Legionella pneumophila

The recommended antibiotic treatment for Legionella infection is levofloxacin.

• Levofloxacin is indicated for the treatment of community-acquired pneumonia due to Legionella pneumophila.
• Elevated WBC count is not a contraindication for the use of levofloxacin. 2

From the Research

Antibiotic Treatment for Legionella Infection with Elevated WBC Count

• The recommended antibiotic treatment for Legionella infection includes macrolides and fluoroquinolones 3, 4, 5.
• Azithromycin and levofloxacin are considered as first-line therapy for Legionella infection 4, 6.
• Other effective antibiotics include tetracyclines, tigecycline, and other macrolides such as clarithromycin 3, 4.
• The choice of antibiotic may depend on the severity of the infection and the patient's underlying health conditions 3, 4.
• Elevated WBC count is a common finding in Legionella infection, and antibiotic treatment should be initiated promptly to reduce the risk of complications and mortality 5, 7.

Comparison of Antibiotic Treatments

• A study comparing levofloxacin and azithromycin found no significant differences in outcomes, including time to defervescence, length of hospital stay, and mortality 7.
• Another study found that clarithromycin, azithromycin, and levofloxacin were all efficacious for the treatment of Legionnaires' disease, with no significant differences in fever duration, length of hospital stay, or mortality 5.
• Azithromycin has been shown to be safe and efficacious for the treatment of hospitalized patients with Legionnaires' disease 6.

Treatment Considerations

• The preferred therapy for legionellosis in immunocompromised patients is quinolone/macrolide combinations, such as levofloxacin plus azithromycin 3.
• Legionella cultures should be more widely available, especially in hospitals where the drinking water is colonized with Legionella 4.
• Routine use of Legionella testing, especially the Legionella urinary antigen test, is recommended for all patients with community-acquired pneumonia 4.