[Comparative effect of apalcillin and other beta-lactam antibiotics against the Bacteroides fragilis group].

The in vitro activity of apalcillin was compared with those of mezlocillin, piperacillin, cefoxitin, cefotaxime and cefotetan against 50 strains of Bacteroides fragilis group. The minimal concentrations were determined by a microdilution method in Wilkins-Chalgren medium and subculturing on agar. On the basis of MICs and MBCs range, the activity of apalcillin was similar to that of other beta-lactam antibiotics; cefoxitin was slightly more active. The mode MICs were as follow: apalcillin = 16 micrograms/ml, mezlocillin = 8 micrograms/ml, piperacillin = 2 micrograms/ml, cefoxitin = 8 micrograms/ml, cefotaxime = 8 and 32 micrograms/ml, cefotetan = 4 micrograms/ml. All the strains of B. thetaiotaomicron and B. vulgatus were susceptible to the six beta lactam compounds. The MBCs and MICs were similar. Apalcillin had the greatest bactericidal activity.