In vitro activity of a new broad spectrum, beta-lactamase-stable oral cephalosporin, cefixime.

Cefixime is a new orally absorbed iminomethoxy, aminothiazolyl cephalosporin. It inhibits the majority, 90%, of Streptococcus pneumoniae, Streptococcus pyogenes, Branhamella catarrhalis, Haemophilus influenzae, Escherichia coli, Klebsiella pneumoniae, Proteus mirabilis and Neisseria gonorrhoeae at concentrations less than or equal to 0.25 micrograms/ml. It inhibits 90% of the other members of the Enterobacteriaceae at concentrations less than 1 microgram/ml, with the exception of some strains of Enterobacter spp., Citrobacter freundii and Morganella morganii, Cefixime does not inhibit enterococci, Listeria, Pseudomonas aeruginosa, Acinetobacter, Bacteroides spp. or staphylococci. In general, cefixime has in vitro activity superior to cephalexin, cephradine, cefadroxil and cefaclor against all bacteria with the exception of staphylococci. Cefixime is not destroyed by most of the common plasmid and chromosomal beta-lactamases and its activity is not reduced by serum, blood or urine. Cefixime overall has excellent in vitro activity against the commonly encountered respiratory and urinary tract pathogens.