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

A review of cefixime, a new orally absorbed iminomethoxy aminothiazolyl cephalosporin, highlights its potent antibacterial activity and broad therapeutic potential. Cefixime demonstrates inhibitory effects against approximately 90% of key pathogens, including Streptococcus pneumoniae, Streptococcus pyogenes, Branhamella catarrhalis, Haemophilus influenzae, Escherichia coli, Klebsiella pneumoniae, Proteus mirabilis, and Neisseria gonorrhoeae at concentrations ≤0.25 μg/ml.

Against other Enterobacteriaceae, cefixime achieves 90% inhibition at concentrations <1 μg/ml, though certain strains of Enterobacter spp., Citrobacter freundii, and Morganella morganii show resistance. Notably, cefixime lacks activity against enterococci, Listeria, Pseudomonas aeruginosa, Acinetobacter, Bacteroides spp., and staphylococci.

Compared with other oral cephalosporins such as cephalexin, cephradine, cefadroxil, and cefaclor, cefixime exhibits superior in vitro activity against most bacteria, excluding staphylococci. Its stability against most plasmid and chromosomal beta-lactamases, and retained efficacy in serum, blood, and urine, further enhance its clinical value.

Experts note cefixime’s excellent in vitro performance against common respiratory and urinary tract pathogens positions it as a promising addition to oral antibacterial therapy.