Abstract: The emergence of mobile colistin resistance mcr  genes undermines the efficacy of colistin as the last-resort drug for multi-drug resistance infections and constitutes a great public health concern. Plasmids play a critical role in the transmission of mcr  genes among bacteria. One colistin-resistant Klebsiella pneumoniae  strain of chicken origin was collected and analyzed by antimicrobial susceptibility testing, PCR, conjugation assay and S1-PFGE. Whole-genome sequencing (WGS) approach combining Illumina and MinION platforms was utilized to decipher the underlying colistin resistance mechanism and genetic context. A novel mcr-8.2 -bearing plasmid p2019036D-mcr8-345kb with 345 655 bp in size encoding various resistance genes including floR, sul1, aadA16, aadA2, bla _CTX-M-27, bla _DHA-1, tet (D), dfrA12  and qnrB4  was identified responsible for the colistin resistance phenotype. Plasmid comparison has shown that the mcr-8.2 -bearing plasmid differed from other reported plasmids positive for mcr-8.2  but shared the same core mcr-8.2 -bearing conserved region. This study demonstrates the emergence of mcr-8.2 -bearing K. pneumoniae  of animal origin is a potential risk to humans.
Keywords: mcr-8.2 , Klebsiella pneumoniae , plasmids, animal origin