Comparison of cefazedone with cefazolin and cephalothin in treatment of experimental infections in mice.

The chemotherapeutic efficacy of (6R,7R)-7-(2-[3,5-dichloro-4-oxo-1(4H)-pyridyl]-acetamido)-3-([(5-methyl-1,3,4-thiadiazol-2-yl)-thio)-8-oxo-5-thia-1-azabicyclo[4,2,0]oct-2-ene-2-carboxylic acid (cefazedone, Refosporen) was assayed in comparison to cefazolin and cephalothin in experimental bacterial murine infections with 6 gram-positive and 8 gram-negative strains of the genera Staphylococcus, Streptococcus, Pneumococcus, Escherichia, Klebsiella, Proteus, Pasteurella and Salmonella. In 5 out of 14 strains (Staphylococci, Streptococci, E. coli, Klebsiella) cefazedone was markedly superior to cefazolin, whereas both compounds were of similar activity against the remaining 9 isolates. As compared to cephalothin, cefazedone exhibited highly superior effectiveness in all organisms tested.