In-vitro activity of antibiotics against Legionella pneumophila isolates from water systems.

The activity of five antibiotics was tested against 82 isolates of Legionella pneumophila obtained from water systems in nine European countries. All isolates were susceptible to clarithromycin (MICs 0. 03-0.5 mg/L), erythromycin (MICs 0.125-2.0 mg/L), ciprofloxacin (MICs 0.06-0.25 mg/L), pefloxacin (MICs 0.06-0.5 mg/L) and rifampicin (MICs < or = 0.007-0.015 mg/L). It seems that antibiotics used for legionellosis continue to exhibit good activity against L. pneumophila isolates from environmental sources in European countries.