Antibiotic-resistant gram-negative pathogens in the hospital environment

Gram-negative pathogens in the hospital environment belong to such distinct families as Enterobacteriaceae, Pseudomonas, Acinetobacter and Stenotropho monas. They differ in virulence but all present natural (or intrinsic) resi stance and the capacity to develop rapidly acquired resistance? the main fa ctor in their selection in the hospital environment. Dissemination of resis tance is due either to dissemination of a clonal strain or dissemination of the gene of resistance amongst bacteria belonging to unrelated species. In medical practice, the development of resistance poses various problems: a therapeutic problem for the physician who must prescribe an active antibiot ic that does not select resistant mutants; a microbiological problem in rel ation to the difficulty of detecting particular resistances such as the pro duction of extended spectrum beta -lactamase; a problem for the infection c ontrol team whose task is to limit the dissemination of multi-resistant bac teria. Against the complexity and efficacy of bacterial resistance strategies agai nst antimicrobial agents, the combined competences of clinicians, microbiol ogists and the infection control team are needed.