Presentation from the Research Group for Genomic Epidemiology – 25 September 2023
Antimicrobial resistance (AMR) in bacteria seriously threatens global public health, with significant economic effects. Major critically important antimicrobial-resistant Enterobacteriaceae include third-generation cephalosporins, carbapenems, fluoroquinolones, and colistin resistance. Moreover, mcr-carrying ESBL-producing Escherichia coli from samples of pig slaughterhouses has become a significant concern.
Therefore, the objective of my study was to find the genetic environment and transfer characteristics of target genes in mcr-carrying ESBL-producing E. coli. The results from the conjugation experiment and whole genome analysis showed that the genetic environment affects the conjugation frequency of both blaCTX-M and mcr genes, not only in plasmids but also in the chromosomes. The mcr-1 gene located on the IncX4-type plasmid exhibited the highest conjugation frequency. This may be due to the strain containing only the mcr-1 gene, along with the pir gene promoting plasmid replication within bacteria. Additionally, the genetic patterns of mcr genes within a single flankophile cluster showed a broader distribution across various SNP clusters than blaCTX-M genes.