Pathogens resistant to antimicrobial agents. Epidemiology, molecular mechanisms, and clinical management.

The emergence of resistance to antimicrobial agents continues to be a major problem among both nosocomial and community-acquired pathogens. Bacteria employ a variety of strategies to avoid the inhibitory effects of antibiotic agents, and have evolved highly efficient means for the dissemination of resistance traits. The result has been the emergence of multidrug-resistant pathogens such as penicillin-resistant pneumococci, vancomycin-resistant enterococci, methicillin-resistant staphylococci, as well as a variety of multiresistant gram-negative organisms. Control of antibiotic-resistant pathogens will provide a major challenge for both the medical community and society in general. The implication of a failure to meet this challenge is the eventual arrival of the "post antibiotic era."