CTX-M–producing Klebsiella spp. in a Brazilian hospital: what has changed in 6 years?

CTX-M–encoding genes from Klebsiella spp. strains isolated in 2000 and 2006 were characterized as well as their genetic environment. CTX-M-2 variants were predominant in Klebsiella pneumoniae strains, which showed a greater variability in blaCTX-M genes, integrons, and plasmids in 2006 when compared to strains collected in 2000. CTX-M-9–producing Klebsiella oxytoca was identified in 2000 as clonal dissemination.