鲍曼不动杆菌基因组突变和移动元件在多重耐药形成中的作用

The isolation rate and infection caused by multi-drug resistance Acinetobacter baumannii (MDRAB) continuously increased, and the reports about the resistance to three major antimicrobial agents which available to MDRAB were also increased quickly, and the rise of pan-drug resistance strain had resulted difficulty in clinical treatment. Previously, researchers focused on resistant mechanism to single antibiotic, and did not pay attention to the emergence and dissemination of multidrug resistance. We already got the resistance strains which showed resistance to one of the three major antimicrobial agents via stepwise selection, and found the resistance mutation included the chromosomal mutation and mobile elements via whole genome sequencing. This study will investigate the novel gene and mechanism involved resistance evolution through selected resistant mutants via different drug using genomic analysis, mutant construction and so on. Second, detected the insertion distribution of mobile element via conjunction and high-throughput sequencing, explore the role of mobile element in resistance evolution. the resistant isolates are induced via serial passage in low concentration antibiotic. The resistant evolution process in A. baumannii will be explored by genomic analysis for novel gene and mechanism involved in resistance. Third, the epistasis effect between chromosome mutation and mobile elements was calculated for the emergence process of multidrug resistant A. baumannii. At last, we will combine fitness cost and compensatory mutation to predict the ability of emergence and dissemination of the mutation in clinical. The result of this study would provide new scientific evidence for the resistance control and treatment of multidrug resistant A. baumannii.

多重耐药鲍曼不动杆菌（MDRAB）分离率和感染率逐年攀升，MDRAB感染仅有的三种有效治疗药物（替加环素、多粘菌素和舒巴坦包括舒巴坦制剂）的耐药报告迅速增加，出现对现有抗菌药物均耐药的全耐药菌，给抗感染治疗带来严峻的挑战。现有耐药机制研究，大多着眼于单个药物的研究，忽视不同抗生素耐药的相互影响。我们在前期研究中已获得MDRAB对上述三种抗菌药物阶梯诱导耐药株，已明确耐药株耐药突变（染色体突变和移动元件）情况。本研究将采用基因组学、突变体构建等方法对不同药物诱导进化获得耐药突变株进行系统研究，发现参与耐药进化的新基因及新机制；随后利用接合，高通量测序等技术研究移动元件的插入位点分布，明确移动元件在耐药进化中的作用；同时通过染色体突变和移动元件的上位效应研究，揭示鲍曼不动杆菌多重耐药形成历程，最后结合适应性代价和补偿突变，预测该突变在临床上发生传播的可能性，为MDRAB 耐药控制策略提供依据。

多重耐药鲍曼不动杆菌（MDRAB）分离率和感染率逐年攀升，出现对现有抗菌药物均耐药的全耐药菌，给抗感染治疗带来严峻的挑战。本研究采用基因组学、突变体构建等方法对不同药物诱导进化获得耐药突变株进行系统研究，发现参与耐药进化的新基因及新机制；利用接合、高通量测序等技术研究移动元件的插入位点分布，明确移动元件在耐药进化中的作用；最后结合适应性代价和补偿突变，预测该突变在临床上发生传播的可能性。我们完成了国内经典多重耐药鲍曼不动杆菌MDR-ZJ06的重测序工作，纠正了之前因为技术受限导致的错误；并在一株临床菌株中发现由一个AbGRI5耐药岛的插入导致了管家基因gdhB的缺失；在舒巴坦耐药研究中我们发现，ISAba1-blaADC的阳性率在舒巴坦非敏感组和敏感组间存在显著性差异；blaOXA-23基因能使鲍曼不动杆菌的舒巴坦敏感性降低但舒巴坦MIC与转座子结构(Tn2006, Tn2008或Tn2009)并不是简单关联；在伊拉环素的耐药研究中我们发现，adeS三个碱基的缺失突变能导致伊拉环素的耐药。我们的结果可以预测突变在临床上发生传播的可能性，为MDRAB 耐药控制策略提供依据。