Cephalosporins, carbapenems, and monobactams.

Nonpenicillin beta-lactams exhibit a variable spectrum of antimicrobial activity, have a wide range of clinical uses and a favorable safety profile. Cefepime's twice-daily dosage and increased activity against Enterobacteriaceae may offer some advantages over older cephalosporins. The carbapenems offer a broad antimicrobial spectrum, and meropenem has an improved safety profile compared with imipenem. Aztreonam is a useful alternative for patients with aerobic gram-negative infections who are allergic to penicillin. The emergence of resistant organisms, however, is an increasing problem with the frequent use of these antibiotics.