腹泻儿童肠道菌群动态分析及相关巴黎链球菌全基因组研究

发布时间：2018-02-14 02:43

本文关键词： 肠道菌群动态分析巴黎链球菌全基因组毒力岛　出处：《中国疾病预防控制中心》2012年博士论文　论文类型：学位论文

【摘要】：通过对连续采集的粪便标本中16S rDNA的扩增、克隆和序列分析,我们可以了解腹泻儿童肠道菌群的动态变化,这是常规分离培养方法所不能实现的,同时为研究未知的腹泻病原菌提供了可能。本文使用细菌16S rDNA序列分析方法,对33名感染性腹泻儿童粪便标本的细菌菌群进行了研究。通过常见腹泻病原菌的筛查,11名患儿被诊断为致泻性大肠杆菌或志贺菌感染,其他22名腹泻儿童被诊断为未知病原感染性腹泻。在这22名腹泻儿童中,有12名只采集到入院首日的标本,另外10名采集到三份连续标本,分别是入院首日、病情恢复中和恢复后或者是出院后的粪便标本。在10名患儿入院首日的粪便标本中,大肠杆菌和克雷伯菌占优势的有2份,唾液链球菌为优势的有2份,牛链球菌群及链球菌属某种占优势各有3份。通过对连续采集的粪便标本分析发现,10例患儿中有8例其入院时标本的优势菌种随着治疗的过程比例降低,其中以牛链球菌群为入院时优势菌种的三名腹泻儿童,随着病情的好转其粪便中的牛链球菌群序列消失不见。我们对16S rDNA提示的优势菌群进行分离培养,并对分离到的菌株进行生化反应和16S rDNA近似全长序列测定。通过分析发现,3份牛链球菌群为优势的标本分别是巴黎链球菌1份,解没食子酸链球菌巴氏亚种2份。我们对分离的巴黎链球菌进行全基因组序列分析,发现巴黎链球菌基因组上存在20个基因组岛。其中基因组岛7(编码糖基转移酶)与基因组岛18(编码菌毛相关基因)被认为是可能的毒力岛。同时发现其他8个可能的致病基因。我们首次报道巴黎链球菌是部分未知病原感染性腹泻儿童肠道菌群的优势菌种,其比例随着治疗过程下降。我们对分离的巴黎链球菌进行全基因组分析,发现了可能的毒力岛和致病基因。我们分离了腹泻病人及动物宿主粪便中牛链球菌群菌株,并对其进行了分子流行病的研究。
[Abstract]:By amplification, cloning and sequence analysis of 16s rDNA in fecal samples collected continuously, we can understand the dynamic changes of intestinal flora in children with diarrhea, which can not be realized by conventional isolation and culture methods. At the same time, it is possible to study the unknown diarrhea pathogens. The 16s rDNA sequence analysis method of bacteria was used in this paper. The bacterial flora in fecal specimens of 33 children with infectious diarrhea was studied. 11 children were diagnosed as cathartic Escherichia coli or Shigella infection through screening of common diarrhea pathogens. The other 22 children with diarrhea were diagnosed with infectious diarrhea of unknown etiology. Of the 22 children with diarrhoea, 12 were collected only on the first day of admission and 10 received three consecutive specimens on the first day of admission. Stool samples from the patients recovered and recovered or discharged from hospital. Of the 10 children, 2 were Escherichia coli and Klebsiella, and 2 were Streptococcus saliva, out of the 10 children who were hospitalized on the first day of hospitalization, 2 were Escherichia coli and 2 were Klebsiella. There were 3 strains of Streptococcus Bovis and 3 strains of Streptococcus Bovis respectively. By analyzing the fecal samples collected continuously, it was found that 8 out of 10 cases had decreased the proportion of dominant bacteria in the samples when they were admitted to hospital. Among them, three diarrhea children with Streptococcus bovis as the dominant bacteria on admission disappeared with the improvement of their condition. We isolated and cultured the dominant flora of 16s rDNA, and determined the biochemistry reaction and the approximate full-length sequence of 16s rDNA. Two strains of Streptococcus Galulicus Pasteurus subspecies. We analyzed the whole genome sequence of streptococcus Paris isolated. It was found that there were 20 genomic islands in the genome of Streptococcus Paris, of which 7 (encoding glycosyltransferase) and 18 (encoding genes associated with fimbriae) were considered to be possible virulence islands, and 8 other possible pathogenicity genes were found. We report for the first time that Streptococcus Paris is the dominant bacteria in the intestinal flora of children with infectious diarrhea of unknown pathogens, and the proportion of Streptococcus Paris is decreasing with the course of treatment. Possible virulence islands and pathogenicity genes were identified. We isolated Streptococcus Bovis strains from feces of diarrhea patients and animal hosts and studied their molecular epidemiology.
【学位授予单位】：中国疾病预防控制中心
【学位级别】：博士
【学位授予年份】：2012
【分类号】：R725.1

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