Beta-Lactam Antibiotics

Abstract

CephalosporinsCephalosporins have been grouped into "generations" on the basis of their spectrum of activity against gram-negative rods (Table 4). Since the pharmacologic characteristics of first- and second-generation cephalosporins have previously been reviewed,^{197 198 199 200 201 202} only selected aspects of the most important agents will be mentioned here.First- and Second-Generation CephalosporinsFirst-generation cephalosporins, such as the parenteral drugs cephalothin (Keflin, Seffin) and cefazolin (Ancef, Kefzol) and the oral agent cephalexin (Keflex), are the most active of all cephalosporins against staphylococci and nonenterococcal streptococci.¹⁹⁷ Methicillin-resistant staphylococci and penicillin-resistant pneumococci are usually resistant to these agents.²⁰³ Even in instances in which in vitro susceptibility . . .