Activity of macrolides against organisms responsible for respiratory infection with emphasis on Mycoplasma and Legionella.

The activity of roxithromycin against Legionella pneumophila in vitro was approximately the same as that of rokitamycin and superior to those of erythromycin and josamycin. In experimental pneumonia due to L. pneumophila none of the animals in the roxithromycin and rifampicin groups died by day 10 of the infection. The MIC ranges of roxithromycin, erythromycin and rokitamycin for Mycoplasma pneumoniae were 0.008-0.063, 0.004-0.008 and 0.016-greater than 125, respectively. In experimental pneumonia caused by M. pneumoniae, roxithromycin showed good activity similar to that of erythromycin.