Department of Pathogenic Biology, School of Basic Medicine, Southwest Medical University, Luzhou, Sichuan 646000, PR China.
The first affiliated hospital of Chengdu medical college, Chengdu 610500, Sichuan, PR China.
J Med Microbiol. 2021 Mar;70(3). doi: 10.1099/jmm.0.001316. Epub 2021 Jan 29.
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.
自 2011 年在中国首次报道以来，目前全国已出现 10 种 MCR 变异体。同时携带 NDM 和 MCR 的多重耐药 细菌已成为全球公共卫生的严重威胁。为了更好地预防和控制耐药基因的传播，需要更好地了解 的遗传结构。本研究旨在对来自中国四川的一名糖尿病患者的两个 分离株进行研究，这两个分离株分别携带 CME2 和 和 CMD2 的共存。采用微量肉汤稀释法进行药敏试验。通过接合实验来研究 、 和 的可转移性。使用 Illumina HiSeq 平台进行全基因组测序。结晶紫染色法检测细菌生物膜形成能力，细菌毒力通过 杀伤试验测定。携带 CME2 和 CMD2 的 对碳青霉烯类、β-内酰胺类、氨基糖苷类、喹诺酮类和四环素类耐药，而 CMD2 对黏菌素也耐药。接合试验和质粒复制子分型进一步证实， 和 分别位于可自主转移的 IncX3 质粒上， 位于可自主转移的 IncHI2 质粒上。通过对 基因结构的分析，其结构为 -IS-Δ-IS， 结构为 IS-ΔIS-IS --ΔIS， 结构为 IS --ΔIS-IS。CME2 的生物膜形成能力强于 CMD2。两株菌的毒力无显著差异。本研究揭示了两株来自糖尿病患者样本的多重耐药 分离株。携带两种 NDM 耐药基因的 已经构成严重威胁，而 MCR 是导致细菌感染治疗失败的重要原因。本研究不仅提醒人们要预防糖尿病患者的感染，还应不断监测耐药基因的流行和传播。
