In vitro activity of U-76,252 (CS-807), a new oral cephalosporin.

U-76,252 is the prodrug of U-76,253. MICs of U-76,253 were 0.015 to 0.06 microgram/ml for greater than or equal to 90% of the strains of Streptococcus spp., Haemophilus influenzae, and Proteus mirabilis; 0.25 to 1 microgram/ml for Branhamella catarrhalis, Escherichia coli, Klebsiella spp., and Citrobacter diversus; 1 to 8 micrograms/ml for Staphylococcus spp.; and 2 to greater than 16 micrograms/ml for other members of the family Enterobacteriaceae and Aeromonas hydrophila; for 72% of the latter group, MICs were less than or equal to 4 micrograms/ml. MICs for Pseudomonas aeruginosa and Enterococcus faecalis were greater than 16 micrograms/ml.