Genotypic characterization of a Proteus mirabilis strain harboring blaKPC-2 on the IncN plasmid isolated from a patient with bloodstream infection in China

Background: Carbapenemase is the predominant enzyme in the mechanism leading to Enterobacterales resistance to carbapenems, and the rapid spread of the blaKPC gene is a major public health concern. Here, we describe a carbapenem-resistant Proteus mirabilis strain XH983, which harbored a blaKPC-2-producing IncN plasmid, isolated from a bloodstream infection. Methods: Whole-genome sequencing and bioinformatics analysis were performed to assess the genetic environment of P. mirabilis XH983. Conjugation and transfer experiments were performed and the corresponding strains were confirmed by antimicrobial susceptibility testing. Phylogenetic and comparative genomic analysis were performed to explore the characteristics of carbapenem-resistant P. mirabilis isolates worldwide. Results: P. mirabilis XH983 was isolated from the blood of a patient in Hangzhou, China. The genome of XH983 contained one 4128,916 bp circular chromosome and one 24,225 bp IncN plasmid harboring blaKPC-2. P. mirabilis XH983 had multiple resistance genes, conferring resistance to aminoglycosides [aph(3')-Ia, aph(3'')-Ib, aph(6)-Id, aac(3)-IId, aadA5, aadA1], β-lactams (blaKPC-2, blaTEM-1B), phenicol (cat, catA1), sulphonamide/trimethoprim (drfA1, drfA17, sul1, sul2) and tetracycline [tet(J)]. The phylogenetic tree showed that XH983 was present in a cluster of 30 isolates, all of which carried blaKPC-2 and most of them came from the same hospital as XH983, indicating the clonal spread of the cluster. Conclusion: We characterized carbapenem-resistant P. mirabilis clinical isolate XH983. The genome sequence of P. mirabilis XH983 provides information about resistance mechanisms of P. mirabilis carrying the blaKPC-2 plasmid and the potential spread of blaKPC-2.