The threat of multiresistant microorganisms.

Enthusiasm about newly developed antimicrobial agents and disappointment because of the development of resistance have been alternating in the decades since the introduction of antibacterial chemotherapy around 1940. During the last few years several mechanisms of bacterial resistance have been elucidated, and new insights into the genetic basis of multiresistance have been gained. The clinical implications of multiresistance depend on timely recognition of the problem, i.e. knowledge of the epidemiology of multiresistant microorganisms and the availability of alternative drugs. A particular problem arises from the fact that infections with multiresistant microorganisms often occur in the most critically ill patients.