Cefotaxime and desacetylcefotaxime: an example of advantageous antimicrobial metabolism.

Although the antibacterial activity of desacetylcefotaxime (des-CTX), the principal metabolite of cefotaxime (CTX), is eightfold lower than cefotaxime, the metabolite inhibits many B-lactamase-producing Enterobacteriaceae and unusual Pseudomonas species resistant to agents such as cefamandole, cefoxitin, and cefoperazone. des-CTX is more stable than CTX to attack by beta-lactamases of some species such as Bacteroides fragilis, Proteus vulgaris, and the k-1 enzyme of Enterobacter-Klebsiella. des-CTX acts synergistically with CTX against many Enterobacteriaceae and Streptococcus faecalis. The antibacterial activity of the combination of CTX/des-CTX indicates that the drug can be administered every 8-12 hr and provides excellent, broad-spectrum antimicrobial activity.