Broad spectrum antibiotic, active against Gram-positive (Corynebacterium, Staphylococcus and especially Gram-negative bacteria, such as Aerobacter, Enterobacter, E. coli, Klebsiella, Proteus and Salmonella. Pseudomonas aeruginosa and Bacteroides spp are resistant. An efficacious blood level is very quickly obtained after intramuscular injection (within 30 minutes).