Monobactams

Monobactams are parenteral beta-lactam bactericidal antibiotics.

AztreonamAztreonam is currently the only available monobactam. Aztreonam has activity similar to that of ceftazidime againsthas activity similar to that of ceftazidime against

• Enterobacterales that do not produce AmpC beta-lactamase, extended-spectrum beta-lactamase (ESBL), or Klebsiella pneumoniae carbapenemase (KPC)

• Pseudomonas aeruginosa

Aztreonam is not active against anaerobes. Gram-positive bacteria are resistant to aztreonam (in contrast to cephalosporins). Aztreonam acts synergistically with aminoglycosides.

Aztreonam shares structural similarities with few other beta-lactams, making cross-hypersensitivity unlikely, except with Aztreonam shares structural similarities with few other beta-lactams, making cross-hypersensitivity unlikely, except withceftazidime and cefiderocol, which have similar R1 side chains. Thus, and cefiderocol, which have similar R1 side chains. Thus,aztreonam is used mainly for severe aerobic gram-negative bacillary infections (including meningitis) in patients who have a serious beta-lactam allergy but who nevertheless require beta-lactam therapy. Aztreonam is also not labile to metallo-beta-lactamases and can therefore be useful for some infections in which resistance to other beta-lactam antibiotics is mediated by that enzyme.

Other antibiotics are added to cover any suspected gram-positive species or anaerobes.

The dose of aztreonam is reduced in renal failure.