Clinical outcomes for hospitalized patients with Legionella pneumonia in the antigenuria era: the influence of levofloxacin therapy.

Background: Although the reduction in case-fatality rate recently observed among patients with Legionella pneumonia has been largely attributed to the progressive utilization of urine antigen testing, other factors, such as changes in empirical antibiotic therapy, may also have contributed. We have analyzed more-recent outcomes of Legionella pneumonia in an institution where urine antigen testing was reflexly performed in cases of community-acquired pneumonia without an etiological diagnosis.

Methods: From a prospective series of 1934 consecutive cases of community-acquired pneumonia in nonimmunocompromised adults, 139 cases of Legionella pneumophila pneumonia were selected for observational review. Legionella cases were analyzed for outcome with respect to antibiotic treatment, mortality, complications, length of stay, time to defervescence, and stability.

Results: The early case-fatality rate was 2.9% (4 of 139 patients), and the overall case-fatality rate was 5% (7 of 139 patients). One hundred twenty patients (86.3%) received an appropriate initial therapy, which included macrolides (i.e., erythromycin or clarithromycin) in 80 patients and levofloxacin in 40. Levofloxacin progressively replaced macrolides as the initial therapy during the study period. Compared with patients who received macrolides, patients who received levofloxacin had a faster time to defervescence (2.0 vs. 4.5 days; P<.001) and to clinical stability (3 vs. 5 days; P=.002). No differences were found regarding the development of complications (25% vs. 25%; P=.906) and case-fatality rate (2.5% vs. 5%; P=.518). The median length of hospital stay was 8 days in patients treated with levofloxacin and 10 days in those who received macrolides (P=.014).

Conclusions: Legionella pneumonia is still associated with significant complications in hospitalized patients, but recent mortality is substantially lower than that found in earlier series. Levofloxacin may produce a faster clinical response than older macrolides, allowing for shorter hospital stay.