[The in vitro effects of josamycin on various strains of bacteria].
The minimal inhibitory concentration of josamycin was studied by the dilution plate method on the strains Staphylococcus aureus, plasmacoagulase negative staphylococci, Streptococcus pyogenes, Streptococcus agalactiae, and enterococci. The effect of josamycin was compared with that of erythromycin, penicillin, ampicillin, oxacillin, tetracycline, chloramphenicol, cotrimoxazol, and furantion. Of the series of 572 strains tested, josamycin was most effective in the strains Staphylococcus aureus, Streptococcus pyogenes, and Streptococcus agalactiae. All the strains tested were susceptible to josamycin, including the Staphylococcus aureus strains resistant to erythromycin. Of the plasmacoagulase negative staphylococci 2.6% resistant strains and 86.3% strains with decreased susceptibility were found. Of the enterococci 41.2% of the strains were resistant to josamycin. In these strains the most effective antibiotics were ampicillin and furantoin.