The in vitro antimicrobial activity of desacetylcefotaxime compared to other related beta-lactams

Like all other cephalosporins that contain an acetyl side chain in the 3' position, cefotaxime (CTX) is partially desacetylated in vivo. Desacetylcefotaxime (des-CTX) possesses a broad antimicrobial spectrum and high beta-lactamase stability. With the exception of Pseudomonas aeruginosa, Morganella morganii, Bacteroides fragilis, and Staphylococcus aureus, most strains of other species tested usually had mean MICs of des-CTX lower than 1 microgram/ml. Its activity is generally lower than that of the parent compound. It was only against some strains of P. cepacia that des-CTX surpassed the activity of CTX. The activity of des-CTX markedly exceeds the activity of many therapeutically used cephalosporins. This is especially true for Haemophilus influenzae, Neisseria meningitidis, most species of Enterobacteriaceae, and streptococci other than Streptococcus faecalis.