blaIMP-4合并膜孔蛋白OmpK36缺失介导产酸克雷伯菌碳青霉烯类的耐药研究  

Study on the resistance of carbapenem-resistant Klebsiella oxytoca to carbapenems caused by bla IMP-4 combined with the deletion of membrane pore protein OmpK36

作　　者：孙明月 肖伟强 许青霞 SUN Mingyue;XIAO Weiqiang;XU Qingxia(Affiliated Cancer Hospital of Zhengzhou University/Henan Cancer Hospital,Zhengzhou 450000,Henan Province,China)

机构地区：[1]郑州大学附属肿瘤医院检验科,河南郑州450000

出　　处：《微生物学免疫学进展》2023年第4期5-11,共7页Progress In Microbiology and Immunology

基　　金：河南省医学科技攻关计划联合共建课题(LHGJ20220209)。

摘　　要：目的旨在对1株碳青霉烯类耐药产酸克雷伯菌(carbapenem-resistant Klebsiella oxytoca,CRKOX)的耐药机制及耐药基因分子特征进行分析。方法该产酸克雷伯菌株(wzx-IMP)是从1例2岁急性髓系白血病-M7患儿血培养中分离出来,采用全自动细菌鉴定/药敏系统和基质辅助雷射解吸电离飞行时间质谱(matrix-assisted laser desorption/ionization time of flight mass spectrometry,MALDI-TOF-MS)对该CRKOX菌株进行鉴定和抗生素敏感试验(antimicrobial susceptibility testing,AST);通过PCR和DNA序列分析其耐药基因,并采用多位点序列分型(multilocus sequence typing,MLST)分析菌株的变异;全基因组测序(whole genome sequencing,WGS)分析菌株耐药基因,比较基因组学对耐药基因进行研究;分析质粒接合转移模块,用大肠埃希菌EC600作为受体菌对菌株wzx-IMP进行接合实验来证实质粒可转移性。结果全自动细菌鉴定药敏系统和MALDI-TOF-MS鉴定菌株wzx-IMP为产酸克雷伯菌,亚胺培南、美罗培南对其最小抑菌浓度(minimum inhibitory concentration,MIC)分别为8μg/mL和>8μg/mL;PCR和DNA序列分析发现,该菌株拥有blaIMP-4型耐药基因,该基因位于62892 bp质粒的IS26相关的Ⅰ类整合子上,该质粒属于IncN1型;MLST分型为ST85型;接合实验显示,blaIMP-4基因可转移至大肠埃希菌EC600;全基因组测序显示,此菌株染色体含有blaOXY-1-1型β内酰胺酶基因,同时伴有OmpK36膜孔蛋白的缺失。结论该株细菌为ST85型碳青酶烯类耐药产酸克雷伯菌,其对碳青霉烯类抗生素耐药的机制为IMP-4型β内酰胺酶的产生合并OmpK36膜孔蛋白缺失。Objective To analyze the resistance mechanism and molecular characteristics of resistance genes of a carbapenem-resistant Klebsiella oxytoca(CRKOX)strain.Methods The acid-producing Klebsiella oxytoca strain(wzx-IMP)was isolated from the blood culture of a 2-year-old girl diagnosed with acute myeloid leukemia-M7 and was analyzed by a automatic bacterial identification/drug sensitivity system and matrix-assisted laser desorption/ionization time of flight mass spectrometry(MALDI-TOF-MS)to identify a CRKOX strain and antimicrobial susceptibility testing(AST).The resistance gene and the variation of the strain were analyzed by polymerase chain reaction(PCR)and multilocus sequence typing(MLST).Whole genome sequencing(WGS)and comparative genomics is used to analyze resistance genes of the strain.The plasmid splice transfer module was analyzed.The plasmid transferability was confirmed by a splicing assay using E.coli EC600 asthe recipient bacterium against strain wzx-IMP.Results The strain wzx-IMP was identified as acid-producing Klebsiella by the fully automated bacterial identification system and MALDI-TOF-MS,the minimum inhibitory concentration(MIC)of imipenem and meropenem to wzx-IMP were 8μg/mL and>8μg/mL,respectively;PCR and DNA sequence analysis revealed that the strain possessed blaiMP-4 resistance gene,which was located on the IS26-related class I integron of 62892 bp plasmid,which belonged to IncN1 type;MLST typing was ST85 type;splicing assay showed that blaimP4 gene could be transfered to E.coli EC600;whole-genome sequencing showed that the wzx-IMP isolate include the blaox-1 gene,accompanied by OmpK36 absence.Conclusion This strain is a ST85 carbapenem-resistant acid-producing Klebsiella,and its mechanism of resistance to carbapenem antibiotics is the production of IMP-4β-lactamase combined with the deletion of OmpK36 membrane pore protein.

关 键 词：产酸克雷伯菌 碳青霉烯类耐药 全基因组测序 Β内酰胺酶 耐药机制 

分 类 号：R378[医药卫生—病原生物学]