First Report of the Colistin Resistance Gene Carried by Inc Plasmid pSL12517-mcr10.1 in Enterobacter cloacae in Sierra Leone.

Mobile colistin resistance () gene has been distributed widely since it was initially identified in 2020. The aim of this study was to report the first in Africa and the first in Sierra Leone; furthermore, we presented diverse modular structures of loci. Here, the complete sequence of one -carrying plasmid in one clinical Enterobacter cloacae isolate from Sierra Leone was determined. Detailed genetic dissection and comparison were applied to this plasmid, together with a homologous plasmid carrying from GenBank. Moreover, a genetic comparison of 19 loci was performed. In this study, was carried by an Inc plasmid from one Enterobacter cloacae isolate. A total of 19 loci displayed diversification in modular structures through complex transposition and homologous recombination. A site-specific tyrosine recombinase XerC was located upstream of , and at least one insertion sequence element was inserted adjacent to a conserved --- region. Integration of into a different gene context and carried by various Inc plasmids contributed to the wide distribution of and enhanced the ability of bacteria to survive under colistin selection pressure. Colistin is used as one of the last available choices of antibiotics for patients infected by carbapenem-resistant bacterial strains, but the unrestricted use of colistin aggravated the acquisition and dissemination of mobile colistin resistance () genes. So far, 10 genes have been reported in four continents around the world. This study presented one -carrying Enterobacter cloacae isolate from Sierra Leone. The gene was identified on an Inc plasmid. According to the results of genetic comparison of 19 loci, the gene was found to be located in a conserved --- region, and at least one insertion sequence element was inserted adjacent to this region. To our knowledge, this is the first report of identifying the gene in Africa and the gene in Sierra Leone.