Cephalosporins are semisynthetic b-lactam antibiotics that are structurally and pharmacologically related to penicillins, carbacephems (e.g., loracarbef), and cephamycins (e.g., cefotetan, cefoxitin). Cephalosporins generally are divided into 4 groups (“generations”) based on their spectra of activity. Cefaclor, cefadroxil, cefdinir, cefditoren pivoxil, cefpodoxime proxetil, cefprozil, ceftibuten, cefuroxime axetil, cephalexin, and cephradine also are used orally for the treatment of mild to moderate skin and skin structure infections caused by susceptible staphylococci or streptococci.