Activity of the cefotaxime (HR756) desacetyl metabolite compared with those of cefotaxime and other cephalosporins.

The desacetyl metabolite (DES) of cefotaxime (HR756) is formed in vivo to a significant extent. The in vitro activities of DES, the parent compound, and cefazolin, cefoxitin, and cefuroxime were compared against 70 bacterial isolates. DES was found to possess approximately 1/10th the activity of the parent compound against the common Enterobacteriaceae, but was somewhat more active than the other three compounds tested. DES had no useful activity against Pseudomonas aeruginosa and was less active than cefotaxime or cefoxitin against Staphylococcus aureus or Bacteroides fragilis. Because DES may accumulate in renal failure or be concentrated in the biliary tract, its antimicrobial activity may have considerable clinical significance.