Prevalence and Distribution Characteristics of and Genes in .

Background: Carbapenem-resistant infections have caused major concern and posed a global threat to public health. As and genes are the most widely reported carbapenem resistant genes in , it is crucial to study the prevalence and geographical distribution of these two genes for further understanding of their transmission mode and mechanism.

Purpose: Here, we investigated the prevalence and distribution of and genes in carbapenem-resistant strains from a tertiary hospital and from 1579 genomes available in the NCBI database, and further analyzed the possible core structure of or genes among global genome data.

Materials And Methods: strains from a tertiary hospital in China during 2013-2018 were collected and their antimicrobial susceptibility testing for 28 antibiotics was determined. Whole-genome sequencing of carbapenem-resistant strains was used to investigate the genetic characterization. The phylogenetic relationships of these strains were investigated through pan-genome analysis. The epidemiology and distribution of and genes in based on 1579 global genomes and carbapenem-resistant strains from hospital were analyzed using bioinformatics. The possible core structure carrying or genes was investigated among global data.

Results: A total of 19 carbapenem-resistant were isolated in a tertiary hospital. All isolates had a multi-resistant pattern and eight kinds of resistance genes. The phylogenetic analysis showed all isolates in the hospital were dominated by two lineages composed of ST11 and ST25, respectively. ST11 and ST25 were the major ST type carrying and genes, respectively. Among 1579 global genomes data, 147 known ST types (1195 genomes) have been identified, while ST258 (23.6%) and ST11 (22.1%) were the globally prevalent clones among the known ST types. Genetic environment analysis showed that the / and may be the core structure in the horizontal transfer of and , respectively. In addition, DNA transferase () may be involved in the horizontal transfer or the expression of .

Conclusion: There was clonal transmission of carbapenem-resistant in the tertiary hospital in China. The prevalence and distribution of and varied by countries and were driven by different transposons carrying the core structure. This study shed light on the genetic environment of and and offered basic information about the mechanism of carbapenem-resistant dissemination.