Co-infections of two carbapenemase-producing clinical strains isolated from the same diabetes individual in China.

Since was first reported in China, there have been ten variants of MCR appearing nationwide so far. Multidrug-resistant bacteria carrying both NDM and MCR have become a serious threat to global public health. The genetic structure of needs to be better understood in order to better prevent and control the transmission of drug-resistant genes. The aim of this study was to characterize the presence of two isolates, which carries CME2 and the coexistence of and strain CMD2, which were isolated from a patient with diabetes in Sichuan, China. The microbroth dilution method was used for antibiotic susceptibility. Conjugation experiment was used to investigate the transferability of , and . Whole-genome sequencing was performed on Illumina HiSeq platform. The ability of biofilm formation was detected by crystal-violet staining, the virulence of the bacteria was measured by killing assay. carrier CME2 and CMD2 with and were resistant to carbapenems, β-lactam, aminoglycoside, quinolone and tetracycline, while CMD2 was also resistant to colistin. Conjugation assay and plasmid replicon typing further demonstrated that both and were respectively present on the self-transferrable IncX3 plasmid, was located on the self-transferrable IncHI2 plasmid. Through the analysis of gene context, the structure was -IS-Δ-IS, context was IS-ΔIS-IS --ΔIS structure, structure was IS --ΔIS-IS. Biofilm formation of CME2 was stronger than CMD2. There was no significant difference in virulence between the two strains. This study reveals two multiple drug-resistant isolates from diabetes patient samples. carrying two NDM-resistant genes is already a serious threat, where MCR is an important cause of treatment failure in bacterial infections. This study is a reminder not only to prevent infection in patients with diabetes, but also to constantly monitor the epidemic and spread of the drug-resistant gene.