monobactam monobactam monobactams are monocyclic and bacterially-produced β-lactam antibiotics. the β-lactam ring is not fused to another ring, in contrast to most other β-lactams. monobactams are effective only against aerobic gram-negative bacteria (e.g., neisseria, pseudomonas). siderophore-conjugated monobactams show promise for the treatment of multi drug-resistant pathogens. aztreonamdrug classaztreonam. (the four-membered ring at the bottom is the β-lactam. there is a second thiazole ring, but it is not fused to the β-lactam ring.)class identifiersusebacterial infectionatc codej01df