Dissemination of in through the IncX3 Plasmid from Different Regions in China.

The spread of NDM-5-producing has become a severe challenge in clinical therapy, which necessitates reliable detection and surveillance methods. However, limited information is available regarding the prevalence and dissemination of the gene in in China. Therefore, we investigated the dissemination of the gene in carbapenem-resistant isolates from different regions. A total of 1,180 carbapenem-resistant enterobacteriaceae strains were obtained from patients admitted to the 20 sentinel hospitals in 8 cities. Strains positive for were detected using the Vitek 2 compact system, 16S ribosomal RNA (rRNA) gene sequencing, polymerase chain reaction, the S1 pulsed-field gel electrophoresis assay, and Southern blot hybridization. The horizontal-transfer capability of the gene was assessed by filter mating with a standard J53 azide-resistant strain as the recipient. Genotyping, susceptibility testing, and whole genome sequencing were performed. Seven strains of -positive were detected in 1,180 clinical strains from different regions in China. The -carrying strains showed resistance to multiple tested antibiotics and belonged to two widespread sequence types, sequence type (ST)167 and ST405. Antimicrobial resistance genes, including , , , and two novel variants ( and ) were also identified. Southern blotting located the gene on 46 kb IncX3 plasmids in all isolates, which showed only two single nucleotide differences between EJN003 and the other strains. This study further confirms the increasing occurrence of -carrying IncX3 plasmids and the dissemination of carbapenem resistance in isolates using the plasmid from different parts in China, which warrants stringent surveillance and control measures.