First report of CTX-M-15 and CTX-M-3 β-lactamases among clinical isolates of Enterobacteriaceae in Béjaia, Algeria

We assessed the prevalence and phenotypic characteristics of extended-spectrum β-lactamase producers among 365 clinical isolates of members of the family Enterobacteriaceae recovered from two hospitals in Béjaia, Algeria, between March 2004 and April 2005. Twenty-one strains were resistant to cefotaxime and/or ceftazidime. A double-disk synergy test yielded a positive result in five cases (three Escherichia coli, one Klebsiella pneumoniae and one Enterobacter cloacae). Using polymerase chain reaction and sequencing, the three E. coli isolates and the K. pneumoniae isolate were found to produce extended-spectrum β-lactamase CTX-M-15 and the E. cloacae isolate produced CTX-M-3. The three CTX-M-15-producing E. coli isolates were not isolated in the same wards, although genotyping by randomly amplified polymorphic DNA analysis revealed that they were clonally related. The blaCTX-M-15 genes were transferred from E. coli by conjugation, whilst conjugative transfer of blaCTX-M genes from K. pneumoniae and E. cloacae was not detectable.