Cefodizime possesses a broad antibacterial spectrum including staphylococci, streptococci and Enterobacteriaceae. Neisseria gonorrhoeae and Haemophilus influenzae are also highly susceptible to cefodizime. Because of its beta-lactamase stability cefodizime is active against bacterial strains producing especially plasmid-coded enzymes. The MICs of cefodizime are slightly higher than those of cefotaxime, but with most Gram-negative bacteria they are lower than those of cefazolin, cefotiam and piperacillin. The in vitro activity of cefodizime is not dependent on inoculum size, or on the pH and composition of the test medium. Cefodizime did not induce in vitro resistance of Staphylococcus aureus or Escherichia coli. Because of its binding properties to PBPs 1A/B and 3, cefodizime leads to filamentation of Gram-negative rods and, at only slightly higher concentrations, to bacteriolysis.