A new cephem antibiotic, Ceftriaxone (CTRX) was compared with other cephems as to in vitro antibacterial activities. CTRX revealed an excellent, broad spectrum antibacterial activity against gram-positive and gram-negative bacteria, as well as an antibacterial efficacy, similarly to Cefotaxime which was used as a reference drug.
The MIC of CTRX against S. aureus isolated from otorrhoea was distributed at a range from 0.78 to 25 μg/ml, showing a peak at 3.13 μg/ml. P. mirabilis, E. coli and K. pneumoniae were inhibited by ≤0.2 to 0.39 μg/ml of CTRX. It's activity was similar to that of Cefotaxime, Cefotiam, Cefoperazone, Ceftizoxime, Cefotetan, Latamoxef, Cefmenoxime and superior to that of Cefazolin, Cephapirin, Ceftezole and Cephacetrile against various pathogenic gram-negative bacteria.
CTRX showed MICs of 3.13 to 12.5 μg/ml, its peak being 12.5 μg/ml against 60 strains of pathogenic P. aeruginosa.