Extended-spectrum beta-lactamase (ESBLs) are defined as ß-lactamase able to hydrolyze all penicillins and cephalosporins with the exception of cephamycins (cefotixin, cefotetan), moxalactam and carbapenems and are encoded by mobile genes. The most frequently encountered ESBLs belong to the CTX-M, SHV, and TEM families. ESBLs were found first in Klebsiella pneumonia and then predominantly in E. coli. The incidence of patients with ESBLs E. coli increase since 2000 in Robert Debré Hospital in Paris. They were mainly implicated in urinary tract infections and less frequently in other infections such as materno-foetal infections or neonatal meningitis. An increase of consumption of carbapenems may lead to spread of carbapenem resistant organisms. Thus alternative to carbapenems for treatment of ESBL producers are needed.