Related to penicillins, imipenem, meropenem and ertapenem are the most broadly active antibacterials known. For this reason they tend to be used for situations where resistance to other classes of antibiotics necessitates their use.

Recent increases in ESBLs especially in ICU has increased the use of carbapenems. They are very expensive. Unfortunately problem organisms such as MRSA and VRE are usually not susceptible to carbapenems and resistance amongst nosocomial Gram-negatives is rising.