アジスロマイシン と セフトリアキソン併用
The newer macrolides (especially azithromycin) and the respiratory tract quinolones (especially levofloxacin) are effective for Legionella infection. In four studies that included a total of nearly 600 patients with Legionnaires' disease, outcomes were similar in patients who received quinolones (levofloxacin, ofloxacin, ciprofloxacin) compared with those who received macrolides (erythromycin, clarithromycin). However, more rapid defervescence, fewer complications, and/or shorter hospital stay were seen with the quinolones.
Suspected or proven Legionella pneumonia should be treated in most patients with levofloxacin (750 mg once daily) or azithromycin (1 gram on day 1, followed by 500 mg once daily). Patients from long-term care facilities, those with nosocomial infection, and those who have received transplants should be treated with a fluoroquinolone to provide better coverage of other gram-negative bacilli and, in the case of transplant recipients and HIV patients, to avoid interactions between macrolides and immunosuppressive drugs.
We recommend parenteral treatment initially for all patients with suspected Legionella pneumonia, given gastrointestinal dysfunction in some patients. A switch to oral therapy can be made after the patient defervesces.
The total duration of therapy for Legionella pneumonia is 7 to 10 days. A longer course of antibiotics of 21 days might be considered for immunosuppressed patients who are severely ill upon presentation.
Combination antibiotic therapy of a quinolone plus azithromycin might be considered for severely ill patients with extrapulmonary legionellosis. We also use rifampin as part of combination therapy with quinolones in selected patients, but drug interactions can be problematic.
Legionnaires' disease is not transmitted from person to person; thus, isolation for hospitalized patients is unnecessary. Since the source of the organism is the hospital drinking water, prevention of nosocomial legionellosis is possible by routine culturing of the hospital drinking water. Monochloramine disinfection of municipal water supplies is associated with decreased risk of Legionella infection in the community.
Quinolones versus macrolides
There are no randomized, controlled trials comparing fluoroquinolones and macrolides. In four studies that included a total of nearly 600 patients with Legionnaires' disease, outcomes were similar in patients who received quinolones (levofloxacin, ofloxacin, ciprofloxacin) compared with those who received macrolides (erythromycin, clarithromycin) . However, more rapid defervescence, fewer complications, and/or shorter hospital stay were seen with the quinolones. In a retrospective cohort analysis of adults hospitalized with Legionella pneumonia, the use of azithromycin alone or a quinolone alone was associated with a similar mortality rate (6.3 and 6.5 percent, respectively) and length of stay.
Monotherapy versus combination therapy
Anecdotal cases and selected laboratory studies have suggested possible benefit with combination therapy of a quinolone plus azithromycin or a quinolone plus rifampin. However, observational studies of antibiotic therapies for Legionnaires' disease have not validated this approach.
Oral versus parenteral and duration of therapy
Although oral therapy has proven effective in cases of Legionnaires' disease, we recommend that antibiotics be given parenterally initially to remove the possibility of incomplete gastrointestinal absorption, given the prominent gastrointestinal manifestations in some patients. When an objective clinical response can be documented (eg, defervescence), treatment can be concluded with oral agents.
Levofloxacin (500 mg once daily for 10 to 14 days or 750 mg once daily for five days) was effective in treating both mild to moderate and severe Legionella infection documented in 71 patients in 6 trials of community-acquired pneumonia. When levofloxacin is used, we prefer to give 750 mg once daily for 7 to 10 days. When azithromycin is used, we favor an initial dose of 1 gram on day 1, followed by 500 mg daily, with a total duration of therapy of 7 to 10 days.
For immunosuppressed patients who are severely ill upon presentation, a 21-day course of levofloxacin (750 mg once daily) is often recommended.
Clin Infect Dis. 2005;40(6):800.
Antimicrobial chemotherapy for Legionnaires disease: levofloxacin versus macrolides.
- Our findings strongly suggest that monotherapy with levofloxacin is a safe and effective treatment for legionnaires disease, including in patients with severe disease. In these patients, levofloxacin appears to be more effective than clarithromycin.
Clin Infect Dis. 2005;40(6):794.
Clinical outcomes for hospitalized patients with Legionella pneumonia in the antigenuria era: the influence of levofloxacin therapy.
Fluoroquinolones vs macrolides in the treatment of Legionnaires disease.
Arch Intern Med. 2000;160(9):1294.
Azithromycin vs cefuroxime plus erythromycin for empirical treatment of community-acquired pneumonia in hospitalized patients: a prospective, randomized, multicenter trial.
Antimicrob Agents Chemother. 1997;41(9):1965.
A multicenter, randomized study comparing the efficacy and safety of intravenous and/or oral levofloxacin versus ceftriaxone and/or cefuroxime axetil in treatment of adults with community-acquired pneumonia.