cephamycins

Cephamycins are a class of broad-spectrum antibiotics derived from the fungus *Acremonium* (formerly *Cephalosporium*), specifically *Acremonium chrysogenum* and related species. They belong to the cephalosporin family but possess distinct structural and functional characteristics that differentiate them from other cephalosporins. Cephamycins are notable for their resistance to beta-lactamase enzymes, which are produced by many bacteria to confer antibiotic resistance, making them effective against a range of Gram-positive and Gram-negative pathogens.

The first cephamycin discovered was cefoxitin, introduced in the 1970s. Cephamycins contain a methoxy group at the C-7 position of the beta-lactam ring, which enhances their stability against beta-lactamases, particularly those produced by *Bacteroides* species. This property makes them particularly useful in treating infections caused by anaerobic bacteria, such as those found in the gastrointestinal tract and female reproductive system.

Cephamycins are typically administered intravenously or intramuscularly and are used to treat a variety of infections, including intra-abdominal infections, gynecological infections, and skin and soft tissue infections. They are often prescribed when other antibiotics, such as penicillins or first-generation cephalosporins, are ineffective due to bacterial resistance.

Common side effects of cephamycin use include diarrhea, nausea, and allergic reactions, though these are generally mild. More severe allergic reactions, such as anaphylaxis, can occur but are rare. Cephamycins are generally well-tolerated, but cross-reactivity with other beta-lactam antibiotics may occur in individuals with penicillin allergies.

Resistance to cephamycins can develop through various mechanisms, including the production of extended-spectrum beta-lactamases (ESBLs) or the alteration of penicillin-binding proteins in bacterial cells. As a result, their use is monitored to prevent the emergence of resistant bacterial strains. Cephamycins remain an important class of antibiotics in clinical practice, particularly in settings where anaerobic infections are prevalent.