[Multiresistant gram-negative bacteria. A bacterial challenge of the twenty-first century].

The incidence of human-pathogenic microorganisms with resistance or even complete insensitivity to broad-spectrum antibiotics is increasing. This poses a serious challenge to infection control in hospitals and to hygiene strategies in clinical areas with critically ill patients, particularly intensive care or transplant units. These microorganisms create problems that are seemingly impossible to solve at present. The management of gram-positive pathogens such as methicillin-resistant Staphylococcus aureus (MRSA) and vancomycin-resistant enterococci (VRE) has been facilitated by evidence-based recommendations resulting in a measurable decrease in the incidence of infection and, where treatment is concerned, in a selection of reliably effective drugs for clinicians. However, in the more frequent cases of multiresistant gram-negative (MRGN) pathogens, the only option is the use of poorly defined regimens with older drugs, which carry the risk of serious side effects and organ toxicities. This article presents a comparative analysis of hospital hygiene management for MRSA and MRGN pathogens, pointing out both similarities and features which are unique to MRGN pathogens.