In vitro comparison of activity of cefixime with activities of other orally administered antimicrobial agents
Cefixime, cefuroxime, cephalexin, cefaclor, penicillin, ampicillin, amoxicillin alone and combined with clavulanate, erythromycin, and trimethoprim/sulfamethoxazole were tested in vitro against nearly 1,100 clinical isolates of bacteria. Minimal inhibitory concentrations (MICs) of > 32 μg/mL were observed for all cephalosporins against > 90% (MIC90) of isolates of Citrobacter freundii, Enterobacter aerogenes, Enterobacter cloacae, Morganella morganii, Acinetobacter anitratus, and Pseudomonas sp. An MIC90 of ≤ 0.25 μg of Cefixime per mL was observed with nonenterococcal streptococci, Klebsiella sp, Proteus mirabilis, Proteus vulgaris, Providencia stuartii, Salmonella sp, and Shigella sp. The MIC90 values of cefuroxime and amoxicillin/clavulanate were, respectively, > 32 and 16 μg/mL for Klebsiella oxytoca, 4 and 32 μg/mL for Klebsiella pneumoniae, 2 and 1 μg/mL for P mirabilis, and > 32 μg/mL for P stuartii. The MIC90 values of Cefixime, cefuroxime, amoxicillin/clavulanate, and trimethoprim/sulfamethoxazole were, respectively, 0.12, 2,0.12, and ≤ 0.5 μg/mL for Branhamella catarrhalis and 0.25,4,8, and 4 μg/mL for Haemophilus influenzae. Overall, trimethoprim/sulfamethoxazole was the most active compound, followed by Cefixime.