Cephamycins are a group of beta-lactam antibiotics. They are very similar to cephalosporins, and the cephamycins are sometimes classified as cephalosporins.
Like cephalosporins, cephamycins are based upon the cephem nucleus. Unlike most cephalosporins, cephamycins are a very efficient antibiotic against anaerobic microbes.
Cephamycins were originally produced by Streptomyces, but synthetic ones have been produced as well.
Cephamycins possess a methoxy group at the 7-alpha position.
In addition, cephamycins have been shown to be stable against extended-spectrum beta-lactamase (ESBL) producing organisms, although their use in clinical practice is lacking for this indication.