Cefetamet

Cefetamet (Ro 15-8074) is a cephalosporin antibiotic and the active metabolite of Cefetamet pivoxil (HY-B1894A). Cefetamet binds to bacterial penicillin-binding protein (PBP) (IC₅₀ for PBP3 in Escherichia coli W3110 is 2.5 μg/mL). Cefetamet has significant activity against Gram-negative bacteria such as Enterobacteriaceae, Neisseria species, and Haemophilus influenzae, as well as Gram-positive bacteria such as Streptococcus. Cefetamet kills and lyses Treponema pallidum. Cefetamet can be used in the research of respiratory tract, urinary tract, ear, nose and throat infections, and syphilis^{[1][2][3][4][5]}. IC50 & Target:IC₅₀: 2.5 μg/mL (PBP3 in Escherichia coli W3110^[3] In Vitro:Cefetamet exhibits high in vitro activity against most members of the Enterobacteriaceae, Haemophilus influenzae, Neisseria spp., and Streptococcus pneumoniae (MIC₉₀ ≤ 2 μg/mL)^[2].
Cefetamet shows high in vitro activity against Enterobacteriaceae, Neisseria spp., Vibrio spp., Haemophilus influenzae and streptococci other than enterococci^[3].
Cefetamet exhibits poor affinity for the PBPs of Staphylococcus aureus, with IC₅₀s of 90, >100, 52 and >100 μg/mL for PBP 1 to 4^[3].
Cefetamet (0.05-0.1 μg/mL; 24 h) kills and lyses Treponema pallidum in vitro^[4].
In Vivo:Cefetamet (1-30 mg/kg; i.m.; once) cures experimental syphilis in rabbits, with the best effect when administered before clinical manifestations^[4].