Abstract

CELIS BUSTOS, Yamile Adriana et al. The bla_CTX-M-12 gene's genetic environmnt in Klebsiella pneumoniae hospital isolates. Rev. colomb. biotecnol [online]. 2009, vol.11, n.1, pp.48-58. ISSN 0123-3475.

Genes from CTX-M-1 group have been detected with great frequency in Colombia in intrahospital infection- causing Klebsiella pneumoniae isolates. Knowledge regarding the genetic factors favouring such genes' dissemination amongst bacterial species is an important issue for resistance control bla_CTX-M-12 gene- carrying plasmids were identified in this study in 21 clinical K. pneumoniae isolates. Antibiotic resistance transfer was evaluated by mating. Integrons, insertion sequences and other genetic elements were detected by plasmid DNA amplification using polymerase chain reaction (PCR). The relationship between the bla_CTX-M-12 gene and other genetic elements was determined by PCR analysis. The bla_CTX-M-12 gene was disemifound on 52 to 106 Kpb conjugative plasmids in all isolates. These mobile elements' transfer by mating may explain their wide dissemination amongst nosocomial infection-causing enterobacteria in hospitals in Bogota, Colombia. The bla_CTX-M-12 gene was found downstream from ISEcp1, this being an insertion sequence which has been associated with resistance genetic determinants' mobilisation. ISEcp1 promoters (detected by sequence analysis) may increase the expression of cefotaximase encoded by this gene.

Keywords : antibiotic resistance; mobile genetic element; the bla_CTX-M-12 gene; conjugal plasmid; Klebsiella pneumoniae.

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