Monobactam

Aztreonam
Drug class
Aztreonam. (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 identifiers
Use	Bacterial infection
ATC code	J01DF
External links
MeSH	D008997
Legal status
In Wikidata

Monobactams are bacterially-produced monocyclic β-lactam antibiotics. The β-lactam ring is not fused to another ring, in contrast to most other β-lactams.^[1]

Monobactams are narrow-spectrum antibiotics^[2] effective only against (strictly or facultatively^[3]) aerobic Gram-negative bacilli,^[4][5][3] exhibiting a high level of resistance to beta-lactamases of these organisms.^[3] Due to their narrow spectrum, monobactams can be used to treat infections by susceptible bacteria without disrupting the patient's microbiota.^[2] Monobactams are nevertheless seldom used.^[2]

^[6] Other monobactams include tigemonam,^[7] nocardicin A, and tabtoxin. An example of a monobactam that lacks antibiotic activity, but is used clinically for other purposes, is the cholesterol absorption inhibitor ezetimibe which is used to treat hypercholesterolemia^{[citation needed]}