多药耐药IncHI2型和IncHI5型质粒的测序及比较基因组学分析
发布时间：2018-08-23 12:30
【摘要】：近年来多重耐药菌株和泛耐药菌株层出不穷且播散速度快,进一步增加了临床感染性疾病治疗的困难。携带耐药基因的质粒所导致的水平基因传播在细菌耐药中起着重要的作用,耐药基因一般通过插入序列、整合子和转座子等移动元件进行水平转移,质粒可以介导耐药基因在不同的细菌个体间转移,而移动元件则只能介导耐药基因在细菌个体内的DNA分子间转移。IncHI质粒是肠杆菌科细菌对抗生素耐药的重要载体。IncHI型质粒先前根据研究的次序分为IncHI1、IncHI2和IncHI3。本研究中,根据代表性质粒的复制起始基因及骨架保守序列特征将IncHI质粒进一步分为五类亚组,增加IncHI4和IncHI5两个亚型。经分析显示每个亚型内质粒骨架区域序列均存在着很高的遗传保守性,同时,五类IncHI质粒均保留有接合转移区tra1和tra2,还有碲耐药基因簇ter;即便如此,五类IncHI亚型质粒之间还是存在着很大的差异。从中国三家教学医院临床病人分离出来的三株多重耐药菌:阴沟肠杆菌T5282,弗氏柠檬酸杆菌112298和解鸟氨酸拉乌尔菌YNKP001,分别得到了 IncHI2型质粒pT5282-mphA、p112298-catA 和 IncHI5 型质粒 pYNKP001-dfrA;根据三个质粒的序列从全球核酸数据库中挑选出IncHI2型参考质粒R478和IncHI5型参考质粒pKOX_R1,并对该五个质粒序列进行精细的生物学信息分析及比较基因组学分析。序列分析显示整合子,转座子和以插入序列介导的移动元件等一系列插入区域分布在质粒骨架区的不同位置,而这些元件构建起来的多重耐药区里一般携带着三种及其三种以上不同的耐药基因,其种类包括氨基糖苷类抗性基因、氯霉素抗性基因、四环素抗性基因、β内酰胺类抗性基因、大环内酯类抗性基因、磺胺类抗性基因、喹诺酮抗性基因、利福平抗性基因、甲氧苄啶抗性基因、磷霉素抗性基因、季铵盐类抗性基因等。在了解多重耐药质粒结构的同时,发现并命名了一系列新的移动元件,包括7个转座子Tn6321、Tn6322、Tn6338-Tn6340、Tn6346 Tn6347;还有插入序列 ISEc16、ISCfr8-ISCfr11、ISKox1-ISKox3。自抗生素应用于临床感染性疾病的治疗,临床上不久便出现其相应耐药菌株,细菌在不同的抗生素选择压力及环境条件的变化下,使其快速获得并保留不同的抗性基因,并因此加速耐药菌株的持续扩散。本课题把目前出现具有代表性IncHI型质粒进行整理,重新定义划分标准,添加至5个亚型;精细分析呈现了多药耐药IncHI型质粒的特征性及多样性,揭示IncHI型质粒是临床分离菌多药耐药特征的重要载体,为肠杆菌科细菌性感染疾病的治疗提供分子依据,为临床上多药耐药肠杆菌科细菌的传播提供研究依据,以期预防或延缓细菌耐药发展的趋势。
[Abstract]:In recent years, multidrug resistant strains and pan-resistant strains have emerged in endlessly and spread rapidly, which has further increased the difficulties in the treatment of clinical infectious diseases. Horizontal gene transmission caused by plasmids carrying drug resistance genes plays an important role in bacterial drug resistance. Drug resistance genes are generally transferred horizontally by inserting sequences, integrons and transposons, etc. Plasmids can mediate the transfer of drug resistance genes between different bacterial individuals. However, the mobile element can only mediate the transfer of drug resistance genes between DNA molecules. IncHI plasmid is an important vector of Enterobacteriaceae for antibiotic resistance. Previously, it was classified into IncHI1, IncHI 2 and IncHI3 according to the order of research. In this study, IncHI plasmids were further divided into five subgroups according to the characteristics of replication initiation genes and cytoskeleton conserved sequences of representative plasmids, and two subtypes of IncHI4 and IncHI5 were added. Analysis showed that the sequence of plasmid skeleton region in each subtype was highly conserved, and that the five IncHI plasmids retained the conjugate transfer region tra1 and tra2, and the tellurium resistance gene cluster, ter. even so, There are still great differences among the five subtypes of IncHI plasmids. Three strains of multidrug resistant bacteria, Enterobacter cloacae T5282, Citrobacter flexneri 112298 and ornithine Laurus YNKP001, were isolated from clinical patients in three schools of education in China. The IncHI2 plasmid pT5282-mphAp112298-catA and the IncHI5 plasmid pYNKP001-dfrA were obtained respectively. According to the sequences of the three plasmids, the IncHI2 type reference plasmids R478 and IncHI5 type reference plasmids pKOXR1 were selected from the global nucleic acid database, and the five plasmids were analyzed for detailed biological information analysis and comparative genomics analysis. Sequence analysis showed that a series of insertion regions, such as integron, transposon and inserted sequence-mediated moving elements, were distributed in different positions in the plasmid skeleton region. The multidrug resistance region constructed by these elements generally carries three or more different resistance genes, including aminoglycoside resistance gene, chloramphenicol resistance gene, tetracycline resistance gene and 尾 -lactam resistance gene. Macrolides resistance genes, sulfonamides resistance genes, quinolone resistance genes, rifampicin resistance genes, trimethoprim resistance genes, fosfomycin resistance genes, quaternary ammonium salt resistance genes and so on. In order to understand the structure of multidrug resistant plasmids, a series of new mobile elements were identified and named, including seven transposons Tn6321, Tn6322, Tn6338-Tn6340, Tn6346 Tn6347, and the inserted sequence ISEc16, ISCfr8-ISCfr11ISKox1-ISKox3. Since antibiotics were used in the treatment of clinical infectious diseases, the corresponding drug-resistant strains appeared in clinic soon. Under the change of different antibiotic selection pressure and environmental conditions, bacteria could quickly obtain and retain different resistance genes. And thus accelerate the sustained spread of drug resistant strains. In this study, the representative IncHI type plasmids were sorted out, and the classification criteria were redefined and added to five subtypes. The fine analysis showed the characteristics and diversity of multidrug resistant IncHI type plasmids. It is revealed that IncHI plasmid is an important carrier of multidrug resistance in clinical isolates, which provides molecular basis for the treatment of bacterial infections in Enterobacteriaceae, and provides a basis for the study on the transmission of multidrug resistant Enterobacteriaceae in clinic. In order to prevent or delay the development of bacterial drug resistance.
【学位授予单位】：南方医科大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：R378
本文编号：2199087
[Abstract]:In recent years, multidrug resistant strains and pan-resistant strains have emerged in endlessly and spread rapidly, which has further increased the difficulties in the treatment of clinical infectious diseases. Horizontal gene transmission caused by plasmids carrying drug resistance genes plays an important role in bacterial drug resistance. Drug resistance genes are generally transferred horizontally by inserting sequences, integrons and transposons, etc. Plasmids can mediate the transfer of drug resistance genes between different bacterial individuals. However, the mobile element can only mediate the transfer of drug resistance genes between DNA molecules. IncHI plasmid is an important vector of Enterobacteriaceae for antibiotic resistance. Previously, it was classified into IncHI1, IncHI 2 and IncHI3 according to the order of research. In this study, IncHI plasmids were further divided into five subgroups according to the characteristics of replication initiation genes and cytoskeleton conserved sequences of representative plasmids, and two subtypes of IncHI4 and IncHI5 were added. Analysis showed that the sequence of plasmid skeleton region in each subtype was highly conserved, and that the five IncHI plasmids retained the conjugate transfer region tra1 and tra2, and the tellurium resistance gene cluster, ter. even so, There are still great differences among the five subtypes of IncHI plasmids. Three strains of multidrug resistant bacteria, Enterobacter cloacae T5282, Citrobacter flexneri 112298 and ornithine Laurus YNKP001, were isolated from clinical patients in three schools of education in China. The IncHI2 plasmid pT5282-mphAp112298-catA and the IncHI5 plasmid pYNKP001-dfrA were obtained respectively. According to the sequences of the three plasmids, the IncHI2 type reference plasmids R478 and IncHI5 type reference plasmids pKOXR1 were selected from the global nucleic acid database, and the five plasmids were analyzed for detailed biological information analysis and comparative genomics analysis. Sequence analysis showed that a series of insertion regions, such as integron, transposon and inserted sequence-mediated moving elements, were distributed in different positions in the plasmid skeleton region. The multidrug resistance region constructed by these elements generally carries three or more different resistance genes, including aminoglycoside resistance gene, chloramphenicol resistance gene, tetracycline resistance gene and 尾 -lactam resistance gene. Macrolides resistance genes, sulfonamides resistance genes, quinolone resistance genes, rifampicin resistance genes, trimethoprim resistance genes, fosfomycin resistance genes, quaternary ammonium salt resistance genes and so on. In order to understand the structure of multidrug resistant plasmids, a series of new mobile elements were identified and named, including seven transposons Tn6321, Tn6322, Tn6338-Tn6340, Tn6346 Tn6347, and the inserted sequence ISEc16, ISCfr8-ISCfr11ISKox1-ISKox3. Since antibiotics were used in the treatment of clinical infectious diseases, the corresponding drug-resistant strains appeared in clinic soon. Under the change of different antibiotic selection pressure and environmental conditions, bacteria could quickly obtain and retain different resistance genes. And thus accelerate the sustained spread of drug resistant strains. In this study, the representative IncHI type plasmids were sorted out, and the classification criteria were redefined and added to five subtypes. The fine analysis showed the characteristics and diversity of multidrug resistant IncHI type plasmids. It is revealed that IncHI plasmid is an important carrier of multidrug resistance in clinical isolates, which provides molecular basis for the treatment of bacterial infections in Enterobacteriaceae, and provides a basis for the study on the transmission of multidrug resistant Enterobacteriaceae in clinic. In order to prevent or delay the development of bacterial drug resistance.
【学位授予单位】：南方医科大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：R378
【参考文献】
相关期刊论文 前1条
1 ;2015年全国细菌耐药监测报告[J];中国执业药师;2016年03期
相关博士学位论文 前1条
1 陈淑丹;碳青霉烯类耐药肠杆菌科细菌的分子生物学及其临床感染特征研究[D];复旦大学;2011年
，本文编号：2199087
本文链接：https://www.wllwen.com/yixuelunwen/jichuyixue/2199087.html
