Review of the in-vitro spectrum and characteristics of cefmetazole (CS-1170).

The in-vitro antimicrobial qualities of cefmetazole are summarized from a review of over 30 publications. Cefmetazole, a 7 alpha-methoxy cephalosporin, is shown to have an antimicrobial spectrum closely resembling cefoxitin's. However, cefmetazole is approximately two- to eight-fold more active than cefoxitin against commonly isolated species such as Escherichia coli, Klebsiella spp., Proteus mirabilis, Staphylococcus aureus, pyogenic streptococci, pneumococci, and Haemophilus influenzae. Cefmetazole is also active against anaerobic pathogens, Neisseria spp., Citrobacter diversus, indole-positive Proteus spp. and Branhamella catarrhalis. Cefmetazole is bactericidal against aerobic and anaerobic pathogens. Its MICs and MBCs are minimally influenced by high inoculum concentrations. beta-Lactamases failed to hydrolyze cefmetazole significantly and cefmetazole is considered the most stable of the cephamycin drugs. Some Bacteroides strains produce beta-lactamases that are uniquely inhibited by cefmetazole. In-vitro tests with cefmetazole have been evaluated and interpretive criteria established for NCCLS methods: susceptible greater than or equal to 18 mm (less than or equal to 8.0 mg/l) and resistant less than or equal to 14 mm (greater than or equal to 32 mg/l). The consistent cross-resistance and -susceptibility observed between cefmetazole and cefoxitin requires the testing of only one of these agents routinely. Quality control guidelines for cefmetazole disc diffusion (30 micrograms disc) and dilution tests are summarized in this review.