Recent developments in antimicrobial therapy with beta-lactam antibiotics.

There are three new penicillin and three new cephalosporin compounds available in the United States. All have been developed via biochemical manipulation of the beta-lactam ring and its adjacent chemical groups. The antibacterial spectrum of activity has been greatly expanded. Each of the six new agents has a unique antimicrobial profile which mandates independent evaluation. Therapeutic use of these drugs, particularly in treatment of gram-negative meningitis, has yielded success rates not previously witnessed. Application of these antibiotics as prophylactic agents for surgical procedures remains controversial. Guidelines are offered to distinguish one agent from another based on antimicrobial, pharmacokinetic and toxicologic properties.