In vitro and in vivo antibacterial activities of E1077, a novel parenteral cephalosporin

Abstract

E1077, a new injectable cephalosporin with a broad antibacterial spectrum and potent antibacterial activity, was evaluated for its in vitro and in vivo antibacterial activities in comparison with those of cefpirome, cefuzonam, ceftazidime, and cefotaxime. E1077 showed broad in vitro antibacterial activity against gram-positive and gram-negative bacteria. Against methicillin-susceptible Staphylococcus aureus, E1077 was as active as cefpirome; the MIC for 90% of strains tested (MIC90) was 1.0 microgram/ml. Against methicillin-resistant S. aureus, E1077 was less active (MIC90, 64 micrograms/ml). For Enterobacter cloacae and Pseudomonas aeruginosa, E1077 was fourfold more active than cefpirome, with MIC90s of 1.0 and 16 micrograms/ml, respectively. For Proteus vulgaris, the MIC90 of E1077 was 32 micrograms/ml, which was fourfold greater than that of cefpirome. Against other gram-negative strains tested, the in vitro activity of E1077 was comparable to that of cefpirome. The broad antibacterial spectrum of E1077 was reflected by its in vivo efficacy against experimental septicemia caused by gram-positive and gram-negative bacteria. Against S. aureus 90 and P. aeruginosa E7, E1077 had activity superior to those of the reference compounds; against most other bacterial strains, the efficacy of E1077 was similar to that of cefpirome. Levels of E1077 in plasma and tissue of mice were studied. At 15 min after a single subcutaneous administration, E1077 displayed high peak levels (mean, 31.8 +/- 3.1 micrograms/ml). These results indicate that the in vitro and in vivo efficacies of E1077 are similar to those of cefpirome except against P. aeruginosa and P. vulgaris.