A novel chicken-origin colistin-resistant Klebsiella pneumoniae ST5982 Co-harboring mcr-3.11 and CTX-M-27.

Klebsiella pneumoniae (K. pneumoniae) is an important zoonotic opportunistic pathogen of Enterobacteriaceae that has become one of the most common infectious diseases causing Enterobacteriaceae after Escherichia coli. In this study, we identified a colistin-resistant, multidrug-resistant ST5982 K. pneumoniae strain of broiler origin. The isolate carried 35 resistance genes of 10 antibiotics classes, detected by whole genome sequencing (WGS); 11.4 % (4/35) of the resistance genes were distributed in the chromosome, and 88.6 % (31/35) of the resistance genes were located in four different resistance plasmids. Among the four plasmids, we found for the first time that CTX-M-27 and mcr-3.11 simultaneously coexisted in K. pneumoniae, and a resistance plasmid of IncI1 carrying a combination of mcr-3.11 and qnrS1 was identified. We successfully transferred mcr-3.11, qnrS1 and CTX-M-27 genes into E. coli J53 through conjugation experiments. In the present study, the co-occurrence of CTX-M-27 and mcr-3.11 in multidrug-resistant K. pneumoniae strain ST5982 was detected for the first time; its drug resistance was evaluated, and the risk of its transmission was assessed to provide a reference for further prevention and treatment of K. pneumoniae.