[The widening challenge of extended spectrum β-lactamases].

Since 1980, the prescription of new semi-synthetic molecules of third generation cephalosporins changed the course of modern medicine. However, the acquired resistance against these antibiotics was rapidly developed with the production of extended spectrum β-lactamases (ESBL) (TEM and SHV types) disseminated mainly by nosocomial Klebsiella pneumoniae clones. Since around 2000, we are facing a watershed in ESBL epidemiology because of the widespread of the CTX-M enzymes among Escherichia coli isolates in community as well as in hospitals. The dissemination of these new ESBL in community within a commensal bacterium is a threat for the public health. The risk is to be in front of an uncontrollable resistance existing everywhere. It is the purpose of this review to focus, in particular, on the changing epidemiology and the spread of ESBL(s) and to provide updated data on definition, classification and laboratory detection of ESBL(s) that will help to control this resistance.