Carbapenems are a class of beta-lactam antibiotic that are active against many aerobic and anaerobic gram-positive and gram-negative organisms. Thienamycin was the first carbapenem to be discovered in 1976. Carbapenems are notable for their ability to inhibit beta-lactamase enzymes (also called penicillinase) - a type of enzyme that greatly reduces the activity of antibiotics such as penicillins and cephamycins. Of all the beta-lactam antibiotics, carbapenems possess the broadest spectrum of activity and the greatest potency against bacteria. Because of this, they are often reserved for more severe infections or used as "last-line" agents.
Carbapenems inhibit bacterial cell wall synthesis by binding to the penicillin-binding proteins and interfering with cell wall formation.