[Legionella and Legionellosis].

Diagnosed and reported Legionella pneumonias are slightly increasing during recent years. This might at least partially be due to more frequently used diagnostic tests.In severe pneumonia, nucleic acid amplification based methods should supplement the L. pneumophila serogroup-1 urinary antigen test because of their improved spectrum and sensitivity.Recent in vitro data suggest enhanced efficacy of levofloxacin when compared to macrolides. This complements recent clinical cohort data. Thus levofloxacin (750-1000 mg/d) is regarded the treatment of choice for confirmed legionellosis. Second line options are azithromycin or moxifloxacin. Treatment duration of 7 days should be sufficient in most cases.Development of resistance is rare and no routine resistance testing is necessary.