我国非典型福氏志贺菌的表型和遗传多态性研究

发布时间：2018-05-19 20:28

本文选题：非典型 + 多重耐药　；参考：《浙江大学》2015年博士论文

【摘要】：通过对我国大陆地区2003-2013年收集的1719株福氏志贺菌流行分布的回顾,可以看出,这11年间福氏志贺菌的流行以2a为主,其次是2v、lb、Y variant、3a、4s、4y, lc、6、4a、5b和3b。值得注意的是,福氏志贺菌可通过不断变换血清型的方式长期流行,而非典型福氏志贺菌的流行对我国传染病的监测以及防控更是极大的挑战。目前对非典型福氏志贺菌的相关研究较为匮乏,本研究旨在通过对非典型福氏志贺菌的表型和遗传多态性研究深入了解其生物学特性、进化关系和流行特征,为菌痢防控策略的制定奠定坚实的基础。生化实验结果表明,149株非典型福氏志贺菌(F2v、Flc、F4y、F4s、F1b)分解葡萄糖；对甘露醇,蔗糖,蜜二糖等的利用因不同亚型而异。值得注意的是,血清型为4y和4s的部分菌株可以产生吲哚。药敏实验结果表明,多重耐药菌的比例高达92.6%,另外,通过对各血清型不同时间和地区的耐药谱比较,我们发现,F2v对头孢和喹诺酮类药物的耐药率在2009年之后有了显著地增长；而云南地区Flb的耐药率比新疆地区高很多,这表明,同一血清型的耐药率随空间和时间都会有显著改变,这提示我们应持续地进行耐药性监测,特别是一线用药头孢类药物和喹诺酮类药物的敏感性监测,以便更好地指导临床用药。在耐头孢类的54株志贺菌中,检测到的耐药基因有blaoTEM1, blaOXA1, blaCTX-M-14, blaCTM-M-3,blaCTC-M-79, intll及其携带的基因盒blaOTX-30+aadA1与aacA4+cmlA1, intI2及其携带的基因盒dfrA1+satl+aadA1。在28株耐喹诺酮类药物的菌株中,所有菌株的ParC都发生了Ser80Ile突变；GyrA均有His211Tyr和Ser83Leu位点突变,部分菌株还有Asp87Asn/Gly突变。含有Asp87Asn突变的2株菌不仅对诺氟沙星耐药,还对左氧氟沙星耐药,因此我们推测,GyrA中Asp87Asn突变,可能介导对喹诺酮类药物高水平的耐药。另外,24株菌中检测到aac(6')-Ib-cr基因,2株菌检测到qnrSl基因。本研究结合了3种分子分型方法MLST、PFGE和MLVA对149株菌进行遗传多态性分析,结果表明,所有的Flb和F1c菌株分别具有相同的序列型,ST104和ST100; Flc菌株有ST104和ST100两种序列型；F4s菌株有ST99和ST100两种序列型；F4y菌株有ST99、ST104、ST107和ST108四种序列型。所有菌株中,流行最多的序列型为ST100其次是ST104、ST99、ST108、ST107和ST105。ST100为优势的ST值,它与ST86的亲缘关系最近,ST104次之。ST107与ST99和ST108都只有一个位点的差异。F2v作为一个新的亚型,它与F2a和F2b的亲缘关系比较近；初步证明F2v是由F2a以及F2b进化而来。Flc、F4s、F4y遗传多态性明显,其进化可能来源于多个克隆系。总的看来,MLVA方法的分辨率与PFGE分型方法的分辨率基本一致,比MLST分型方法分辨率高,三者结合起来可有效地应用于细菌性痢疾暴发的溯源分析,为菌痢的防控提供良好的技术支持。
[Abstract]:Through a review of the distribution of 1719 strains of Shigella flexneri collected in 2003-2013 years in the mainland of China, we can see that the prevalence of Shigella flexneri was dominated by 2a in the last 11 years, followed by 2V, LB, Y variant, 3a, 4S, 4Y, LC, 6,4a, 5b and 3b., and it is worth noting that Shigella flexneri can be popular by constantly changing serotypes, and SARS. The epidemic of Shigella flexneri is a great challenge to the monitoring and control of infectious diseases in China. At present, the research on the atypical Shigella flexneri is scarce. The aim of this study is to understand the biological characteristics, evolution and epidemic characteristics through the study of the phenotype and genetic polymorphism of the atypical Shigella flexigella. The formulation of prevention and control strategies lays a solid foundation.
The results of biochemical experiments showed that 149 atypical Shigella flexneri (F2v, Flc, F4y, F4s, F1b) decomposed glucose, and the utilization of mannitol, sucrose and honey two sugar varied with different subtypes. It is worth noting that some strains of serotype 4Y and 4S can produce indoles. The results of drug sensitivity test showed that the proportion of multidrug resistant bacteria was up to 92.6%, in addition, By comparing the drug resistance spectrum of different serotypes and regions, we found that the resistance rate of F2v to cephalosporins and quinolones increased significantly after 2009, while the resistance rate of Flb in Yunnan was much higher than that in Xinjiang, which indicates that the rate of resistance to the same serotype changes significantly with space and time. We should continue to conduct drug resistance monitoring, especially the sensitivity monitoring of first line cephalosporins and quinolones, in order to better guide clinical use. In the 54 strains of Shigella resistant cephalosporins, the detected resistance genes are blaoTEM1, blaOXA1, blaCTX-M-14, blaCTM-M-3, blaCTC-M-79, intll and the genes they carry. Box blaOTX-30+aadA1 and aacA4+cmlA1, intI2 and its carrying gene box dfrA1+satl+aadA1. in 28 strains resistant to quinolones have Ser80Ile mutation in all strains; GyrA has His211Tyr and Ser83Leu site mutations, some strains and Asp87Asn/Gly mutations. 2 strains containing Asp87Asn mutation not only to norfloxacin. Star resistance and resistance to levofloxacin. Therefore, we speculate that Asp87Asn mutation in GyrA may mediate the high level of quinolone drug resistance. In addition, the AAC (6') -Ib-cr gene is detected in 24 strains, and 2 strains detect the qnrSl gene.
The genetic polymorphisms of 149 strains of MLST, PFGE and MLVA were analyzed in this study. The results showed that all Flb and F1c strains had the same sequence type, ST104 and ST100, and Flc strains had two sequences of ST104 and ST100, and F4s strains had ST99 and two sequence types. 8 of the four sequence types. Among all the strains, the most popular sequence type is ST100 followed by ST104, ST99, ST108, ST107 and ST105.ST100 as the dominant ST value. It is closest to ST86, and the difference between ST104 second.ST107 and ST99 and ST108 is a new subtype. It is proved that F2v has evolved from F2a and F2b to.Flc, F4s, F4y genetic polymorphism, and its evolution may come from multiple clone lines. In general, the resolution of MLVA method is basically consistent with the resolution of PFGE typing, which is higher than that of the MLST typing method. The combination of the three can be effectively applied to the traceability analysis of bacillary dysentery outbreak. It provides good technical support for the prevention and control of bacillary dysentery.
【学位授予单位】：浙江大学
【学位级别】：博士
【学位授予年份】：2015
【分类号】：R446.5

【参考文献】