大肠埃希菌质粒编码的blakpc-2基因介导碳青酶烯类药物低水平耐药的分子机制

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中图分类号：S859 文献标志码：A 文章编号：1001-411X（2025）03-0326-10

Molecular mechanism of plasmid-encoded gene mediating lowlevel resistance to carbapenems in Escherichia coli

BAI Shuancheng'， YANGLan’，LUO Xiang'，HUANGLiya'，WANG Yuxin'， WANG Rong'， LIAO Fengting1， LIAO Xiaoping² （1 Smart Agriculture Colege， Yulin Normal College， Yulin 5370o0， China; 2 College of Veterinary Medicine， South China Agricultural University， Guangzhou 510642， China）

Abstract： 【Objective】 To elucidate the molecular mechanism by which the carbapenemase-encoding plasmid p21QH43K-KPC is transferred from Klebsiella pneumoniae to Escherichia coli，and mediates low-level resistance to carbapenem drugs in E. coli.【Method】 The construction of EZ-Tn5 transposon mutation library， CRISPR-Cas9-mediated gene knockout， transcriptome sequencing and whole genome sequencing （WGS） were used to determine the regulatory mechanism of low-level resistance to meropenem mediated by the gene in E ，coli.【Result】 A transposon mutant EC600/p21QH43K-KPC-130 with enhanced meropenem resistance ） was obtained by constructing the EZ-Tn5 transposon mutation library of the EC600/ p21QH43K-KPC conjugon. WGS and Mauve analysis revealed that the transposon had inserted into one chromosomal gene ompR，and two point mutation genes of iron and ltrA were found. However，through gene knockout， only ompR deletion mutants exhibited reduced sensitivity to carbapenem that could be restored by gene complementation. 【Conclusion】 The molecular mechanism of the gene encoded on the plasmid mediating low-level resistance to carbapenems in E coli is related to the regulation of gene by ompR.

Key Words： Escherichiacoli; OmpR gene; Klebsiell pneumoniae carbapenemase-2; Carbapenems; Drug resistance; Molecularmechanism

碳青霉烯耐药肺炎克雷伯菌（Carbapenem-resistantKlebsiellapneumoniae，CRKP）已构成全球公共卫生威胁[1-2]，其主要耐药机制是携带碳青霉烯酶基因 ，其中，在临床CRKP中，Klebsiellapneumoniaecarbapenemase-2（KPC-2）亚型最为普遍，可以水解所有已知的 β - 内酰胺类药物，包括碳青霉烯类[3]。（剩余17101字）