ABSTRACT
A novel screening procedure led to isolation of the structurally unique, bacterially produced, monocyclic β-lactam antibiotics, typically, nocardicin A in 1976 and sulfazecin in 1981. The in vitro and in vivo antibacterial activities of carumonam were compared with those of aztreonam and ceftazidime Both carumonam and aztreonam were less potent than ceftazidime against Gram-positive bacteria. Carumonam was highly active against Gram-negative bacteria, including members of the Enterobacteriaceae family, Pseudomonas aeruginosa and Haemophilus influenzae. Carumonam was more stable to cephalosporinases, but was slightly less stable than ceftazidime to some penicillinases. Carumonam was not active against Staphylococcus aureus, like aztreonam, but carumonam was weakly active against Streptococcus pneumoniae. A. Imada et al. reported a synthetic sulfazecin derivative, carumonam. The excellent activity of carumonam against Gram-negative bacteria is related to its high affinity for their PBP-3. The PBPs of Staphylococcus aureus showed little affinity to carumonam.
