Molecular characterization of an outbreak caused by CTX-M-12-producing Klebsiella pneumoniae in a Colombian hospital's neonatal intensive care unit

Molecular characterisation of Klebsiella pneumoniae strains is a tool that assits in the reduction of the disemination of drug resistance and the control of nosocomial infections that are caused by this pathogen. Objective. Molecular description of an outbreak of nosocomial infection caused by Klebsiella pneumoniae in a neonatal intensive care unit in a tertiary level hospital in Bogotá. Eleven Klebsiella pneumoniae isolates were analysed. Production of Extended Spectrum Beta-Lactamases was verified by agar diffusion tests. Isoelectric points of the enzymes were determined by isoelectric focusing. The bla(CTX-M-12) gene was detected by PCR and pulsed field gel electrophoresis genotyping was done. All the isolates were Extended Spectrum Beta-Lactamase producers. Pulsed field gel electrophoresis and BOX-PCR genotyping grouped two isolates from hospital objects and eight infection-causing isolates into a single epidemic clone. The isolate from a thermometer was not grouped into the epidemic clone and showed a different resistance pattern. Isoelectric focusing revealed simultaneous beta-lactamase production having different isoelectric points. PCR amplification revealed the presence of the bla(CTX-M-12) gene in the 11 isolates studied. This is the first report of a molecularly characterised outbreak of CTX-M-12-producing Klebsiella pneumoniae from Colombia. The results of this study provide additional evidence of the global dissemination of CTX-M ESBL and the need for epidemiological follow-up in our hospitals.