Abstract:
The prevalence of blaCTX-M, blaTEM and blaSHV genes among extended-spectrum β-lactamase (ESBL)-producing clinical isolates of Escherichia coli (n = 50) and Klebsiella spp. (n = 50) from Lebanon was 96percent, 57percent and 67percent, and 40percent, 82percent and 84percent, respectively. Genotyping revealed that the clonal diversity was unrelated to the presence of bla genes. Sequence analysis of 16 selected isolates identified the blaCTX-M-15, blaTEM-1, blaOXA-1 and six blaSHV genes, as well as the gene encoding the quinolone-modifying enzyme AAC(6′)-Ib-cr. The genes encoding CTX-M-15 and AAC(6′)-Ib-cr were carried on a 90-kb plasmid of the pC15-1a or pCTX-15 type, which transferred both ESBL production and quinolone resistance from donors to transconjugants. © 2008 European Society of Clinical Microbiology and Infectious Diseases.