[Diagnosis and treatment of legionella pneumonia]

Legionellosis is a relatively rare condition but nevertheless is associated more frequently than many other pathogens with a severe course. Therefore, establishing a diagnosis of Legionellosis remains a challenge. The most significant progress in the diagnosis of Legionellosis is antigen-testing in urine by a rapid immunochromatographic test (ICT). This is an easy to handle bedside test which provides a result within 15 minutes. Sensitivity and specificity reach 80 % and 100 %, respectively. However, the exact place of this test within algorithms of clinical decision making still remains unsettled. Macrolides, doxycycline, fluoroquinolones and ketolides, and possibly also streptogramins are drugs with definitely or most probably sufficient activity against Legionella spp. and, therefore, are appropriate candidates within empirical initial antimicrobial treatment regimen of community-acquired pneumonia. Macrolides and fluoroquinolones should be the drugs of choice for the treatment of established Legionellosis. Oral macrolides should be prefered in patients with mild to moderate pneumonia; within the macrolides, azithromycin has the most favourable profile of activity. Alternatively, ciprofloxacin, levofloxacin and moxifloxacin may be selected. In severe Legionellosis as well as independently of severity in nosocomial legionellosis and immunosuppressed patients, intravenous fluoroquinolones are first choice drugs. Alternatively, azithromycin may be used. Whether a combination treatment including azithromycin or fluoroquinolones with rifampin or azithromycin with fluoroquinolone exert superior activity remains currently unknown.