Abstract
In vitro and in vivo antibacterial activity of cefteram pivoxil was studied using 37 clinical isolates of cephem-resistant Escherichia coli (cefaclor; MIC>12.5μg/mL) and compared to those of other oral antibacterial agents. MIC90 of cefteram (the active form of cefteram pivoxil) against cephem-resistant E.coli (37 strains) was 3.13μg/mL and less than those of cefiditoren (6.25μg/mL), cefpodoxime (25μg/mL), cefdinir (25μg/mL), cefixime (50μg/mL), amoxicillin (>100μg/mL), and cefaclor (>100μg/mL) and comparable to that of norfloxacin (3.13μg/mL). MIC90s of tested drugs against 25 strains of cephem-susceptible E. coli were as follows: cefditoren (0.2μg/mL), cefixime (0.39μg/mL), cefteram (0.78μg/mL), cefpodoxime (3.13μg/mL), cefdinir (3.13μg/mL), cefaclor (3.13μg/mL), and amoxicillin (3.13μg/mL). The difference between MIC90s against cephem-resistant and susceptible E. coli was lowest for cefteram. No cephem-resistant strains showed hydrolytic activity against the cephems tested except for cefaclor. The therapeutic effect of cefteram pivoxil against an experimental mouse urinary tract infection caused by cephem-resistant E.coli TK-776 was superior to that of cefdinir, cefditoren, cefixime, and cefaclor, reflecting its in vitro activity.
