RESUMEN
Seventy-one isolates of Enterobacteriaceae (17 Escherichia coli, 50 Klebsiella pneumoniae, and 4 Enterobacter cloacae) producing extended-spectrum-ß-lactamases (ESBLs) were collected between April 2008 and March 2010 in an intensive care unit and surgical ward of Tlemcen Hospital (West of Algeria). Sequencing identified the bla(CTX-M-15) determinant in 69 isolates and bla(CTX-M-3) in 2 isolates. None of the studied strains produced the class D carbapenemase OXA-48. Repetitive Extragenic palindromic polymerase chain reaction showed a high degree of genotypic diversity among E. coli strains and two major clonal populations of K. pneumoniae (CKp1 n=11 and CKp5 n=25) which were further identified as members of the multilocus sequence typing types (ST931) and (ST15), respectively. The ST15 isolates harbored more resistance genes and virulence factors than the ST931 isolates. The characterization of the spacer region between ISEcp1 and bla(CTX-M) for CTX-M-15 producers individualized two populations. One that derived from the CTX-M-3 under Algerian clinical context and one that is universally found. The dissemination of ESBLs in the studied Enterobacteriaceae isolates was mainly due to the epidemic clones of K. pneumoniae and to genetic transit of plasmids among unrelated strains.