Dissemination of the <i>bla</i> _NDM-5 Gene via IncX3-Type Plasmid among <i>Enterobacteriaceae</i> in Children

Abstract

The emergence of CRE strains resistant to multiple antibiotics is considered a substantial threat to human health. Therefore, all the efforts to provide a detailed molecular transmission mechanism of specific drug resistance can contribute positively to prevent the further spread of multidrug-resistant bacteria. Although the new superbug harboring bla NDM-5 has been reported in many countries, it was mostly identified among E. coli strains, and the gene transfer mechanism has not been fully recognized and studied. In this work, we identified 22 bla NDM-5 -positive strains in different species of Enterobacteriaceae , including 16 Klebsiella pneumoniae strains, four Klebsiella aerogenes strains, and two Escherichia coli strains, which indicated the horizontal gene transfer of bla NDM-5 among Enterobacteriaceae strains in pediatric patients. Moreover, bla NDM-5 was located on a 46-kb IncX3 plasmid, which is possibly responsible for this widespread horizontal gene transfer. The different genetic contexts of the bla NDM-5 gene indicated some minor evolutions of the plasmid, based on the complete sequences of the bla NDM-5 plasmids. These findings are of great significance to understand the transmission mechanism of drug resistance genes, develop anti-infection treatment, and take effective infection control measures.