Epidemiology of expanded-spectrum beta-lactamases: The rise of CTX-M

beta-lactam are the first-line antibiotic therapy for infections involving enterobacteria, yet as soon as they were Large-scale used, they were challenged by the production of beta-lactamases i.e. specific inactivating enzymes. Among them, extended-spectrum beta-lactamases (ESBL) hydrolyze most of beta-lactam in sparing only cephamycins (such as cefoxitin) and carbapenems. Epidemiology of ESBL-producing enterobacteria (ESBL-E) has recently changed with the emergence and rise of a certain type of ESBL named CTX-M. Unlike former TEM or SHV-derived ESBLs, CTX-M have massively spread over community environments especially through the E. coli host. The steadily increasing prevalence in the community led to an original situation in creating an influx of CTX-M carriers/infected patients from the community to healthcare structures. Plus, CTX-M prediction based on healthcare-related risk factors appears to be weakly effective. Aside community and hospital environments, CTX-M-type beta-lactamases have successfully spread over long-term care facilities. The present review will focus on the origin of the ESBL switch, its consequences and the different epidemiological routes of CTX-M in the community, hospitals and long-term care facilities. (C) 2010 Elsevier Masson SAS. All rights reserved.