What is the first-line treatment for Legionella pneumonia?

Legionella pneumonia is a type of atypical pneumonia caused by the bacterium Legionella pneumophila. The first-line treatment for this infection is typically a macrolide antibiotic, with azithromycin being a common choice. Macrolides are effective against Legionella because they can penetrate human cells, where Legionella often resides, and they inhibit protein synthesis in the bacteria.

Given that Legionella does not respond well to beta-lactam antibiotics (like penicillin) due to its unique cell wall structure, and since tetracyclines (while potentially effective) are not the preferred first-line agents, azithromycin stands out as the most reliable and effective treatment option.

Ciprofloxacin, a fluoroquinolone, could also be effective against Legionella and might be used in certain cases, especially when a patient has other contraindications to macrolides or has a complicated presentation; however, it is considered secondary to azithromycin as initial treatment.

In summary, azithromycin is recommended due to its effectiveness, safety profile, and ability to target the intracellular nature of the organism, securing its status as the first-line therapy for Legionella pneumonia.