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.