Comparative in-vitro activity and mode of action of ceftriaxone (Ro 13-9904), a new highly potent cephalosporin

Publisher Website
Google Scholar
Abstract
The new parenteral cephalosporin, ceftriaxone (Ro 13-9904), was shown to be highly potent against a wide range of Gram-negative and Gram-positive clinical bacterial isolates. Geometric mean MIC values for all Gram-negative organisms, with the exception of Pseudomonas, were ≤ 0.8 mg/l. Activity against Proteus mirabilis was especially marked. With the exception of its activity against Staphylococcus aureus, ceftriaxone was invariably as active and usually more active than the related cephalosporin, cefotaxime. All other cephalosporins tested were less potent than ceftriaxone. An examination of cephalexin-resistant strains demonstrated exceptional susceptibility to ceftriaxone suggesting marked resistance to cephalosporinases. Ceftriaxone gave rise to filamentation of Escherichia coli and Ps. aeruginosa at sub-inhibitory concentrations and an increasingly marked bacteriolytic response at higher levels. In contrast, ceftriaxone was bactericidal to Staph. aureus at a maximal rate at all effective concentrations.