MONOBACTAM

Aztreonam: Beta lactam antibiotic in which the other ring is missing
Antibacterial spectrum: gram negative enteric bacilli, H.influenzae, Pseudomonas
It does not inhibit gram positive cocci or anaerobes (spectrum resembling aminoglycoside)
Resistant to gram negative beta lactamases
Lack of cross sensitivity with other beta lactam antibiotic is important feature
So aztreonam can be used in pts allergic to Pn or cephalosporin
ADR: Rashes & rise in serum transaminase
Use : Hospital acquired infections originating from biliary, gastrointestinal & urinary tracts