鲍曼不动杆菌体内适应性和耐药性进化趋势及机制

The isolation rate and infection rate of multi-drug resistant Acinetobacter baumannii (MDRAB) were increased every year. The resistance rate of three drugs (tigecycline, colistin and sulbactam) which were active against MDRAB were rapid emerged. The emergement of Pan drug resistant bacteria made treatment difficult. Current resistance mechanism research focused on in vitro resistance, and ignored the difference between in vivo and in vitro. Previously, we obtained the strain resistant to three drugs, respectively. The resistance mutations among the strains were identified. This study would perform adaptive evolution and resistance evolution in serum and use animal model and antibiotics induction to identify the novel genes and mechanisms involved in adaptive evolution and resistance evolution in vivo by the second sequencing technology and the third sequencing technology. We also collected the clinical isolates to study the in vivo evolution procedure in human. The study also explored the differential expressed genes in vivo using in vivo transcriptome to provide potential target for antibiotic research and development. At last, the study would combined fitness cost and virulence alteration to predict the clinical trends of MDRAB infections, and to suggest the new treatment and resistance control option.

多重耐药鲍曼不动杆菌（MDRAB）分离率和感染率逐年攀升，MDRAB感染三种主要有效治疗药物（替加环素、多粘菌素和舒巴坦包括舒巴坦制剂）的耐药性迅速增加，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，大多着眼于体外耐药研究，但体外耐药并不能真实反映体内情况。我们在前期研究中已获得MDRAB对上述三种抗菌药物体外阶梯诱导耐药株，已明确耐药株耐药突变情况。本研究拟以胎牛血清为诱导培养基，进行细菌适应性进化和耐药进化研究，以动物模型为基础，结合抗生素诱导，整合利用二代测序和三代测序技术鉴定参与体内适应性进化和耐药进化的新基因及新机制。收集临床进化分离株，研究人体体内进化过程，利用体内转录组学技术，明确MDRAB体内特异性表达基因，为抗生素研发提供潜在的靶标。结合适应性代价和毒力变化，预测MDRAB感染的流行趋势，为MDRAB治疗及耐药控制策略提供新的方案。

多重耐药鲍曼不动杆菌（MDRAB）分离率和感染率逐年攀升，MDRAB感染三种主要有效治疗药物（替加环素、多粘菌素和舒巴坦包括舒巴坦制剂）的耐药性迅速增加，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。我们发现和非黏液型鲍曼不动杆菌相比，经过体内进化的黏液型鲍曼不动杆菌具有明显不同的荚膜结构。黏液型鲍曼不动杆菌多重耐药率高，部分菌株毒力较高，感染后病情重，治疗困难，预后不佳，应予以重视。我们发现gnaA参与鲍曼不动杆菌的耐药和毒力，影响细菌的脂寡糖和荚膜多糖的合成，使得细菌形态发生了变化，为抗生素新药研发提供了药物靶点。我们发现adeS的缺失突变介导外排泵adeABC表达上调，导致Eravacycline敏感性下降。我们发现adeN和adeRS中的IS插入和突变通过对adeABC的调控，从而导致替加环素耐药，明确转录调控基因的突变是鲍曼不动杆菌替加环素耐药的重要机制，同时鉴定参与Eravacycline耐药机制的新基因，发现rpoB，rrf和adeS参与鲍曼不动杆菌Eravacycline耐药机制。我们发现鲍曼不动杆菌新耐药岛AbGRI5和AbGRI3的新亚型AbGRI3-2。耐药岛的分型可以在耐药菌暴发流行的研究中起到重要的示踪作用，而明确MDR-ZJ06不含有质粒，为后续的鲍曼不动杆菌基因组研究提供支持。我们建立了鲍曼不动杆菌血清型鉴定系统（Bautype）以及相应的网站，可以提供鲍曼不动杆菌LOS和CPS的分型服务和基于基因组序列监测鲍曼不动杆菌群体变化，通过跟踪鲍曼不动杆菌菌株的进化，为鲍曼不动杆菌的流行病学研究提供有用的工具。