[Antibacterial effect of cefixime].

Cefixime (CFM) is a new hemi-synthetic orally active cephalosporin which exhibits a particular affinity for PBPs 3, 1a, 1bs. Its penetration through the Gram negative bacilli outer membrane is similar to that of third generation cephalosporins. The MICs were assessed by the agar dilution method against 2,489 bacterial strains collected in 10 hospitals. Against Enterobacteriaceae, MICs50 and 90 are respectively (mg/l): naturally non beta-lactamase-producing species: E. coli and Shigella: 0.25-0.5, Salmonella: 0.06 - 0.25, P. mirabilis: 0.008 - 0.0.32; chromosomal penicillinase producing species: Klebsiella: 0.06 - 2; chromosomal cephalosporinase producing species: E. cloacae and C. freundii: 1 - greater than 128, S. marcescens: 0.25 - 16, Proteus indole: + 0.06 - 4, P. stuartii: 0.032 - 0.5. CFM activity is not altered in strains producing an acquired penicillinase. On the other hand, CFM appears to be inactive against cephalosporinase hyperproducing mutants and its activity is variably decreased against expanded spectrum beta-lactamase producing strains. CFM is inactive against P. aeruginosa (MIC50 and 90: 64 - 128) and against A. baumannii (16 - 128). Haemophilus and gonococci, beta-lactamase producing or not, as well as meningococci, are highly susceptible to CFM (MIC 0.008 - 0.12). B. catarrhalis is usually inhibited by 0.03 to 0.5. CFM is moderately active against meticillin-sensitive staphylococci (MIC50 and 90: 1-64), and inactive against meticillin-resistant strains. Enterococci are usually resistant, whereas streptococci and pneumococci are inhibited by low concentrations: 0.08 to 1. CFM is a bactericidal antibiotic, as shown by MBC and killing curves determination. These antibacterial properties relate CFM to the third generation cephalosporins and position the compound in an excellent place among the orally active cephalosporins.