食源性与医源性大肠埃希菌相关性分析

发布时间：2018-12-12 03:09

【摘要】：目的:1.采集本地区食品,评估其大肠埃希菌污染情况。2.了解本地区食源性和医源性大肠埃希菌中致腹泻大肠埃希菌的分布情况。3.根据相关毒力基因的检测,了解两种来源大肠埃希菌中肠外致病性大肠埃希菌的分布情况。4.应用PFGE方法比较两种来源肠外致病性大肠埃希菌相似性,初步建立本地区肠外致病性大肠埃希菌PFGE数据库。方法:1.参照GB4789.38-2012方法采集、检测本地区5所超市市售生鲜、蔬菜等共128份;参照《全国临床检验操作规程》相关方法,收集本地区医源性大肠埃希菌86株。2.应用玻片凝集法鉴定食源性和医源性大肠埃希菌的致腹泻大肠埃希菌血清型;应用PCR法检测肠外致病大肠埃希菌特征性毒力基因,鉴定食源性和医源性菌株中的肠外致病大肠埃希菌。3.参照Pulse Net推荐方法建立肠外致病性大肠埃希菌PFGE分子分型图谱,初步建立本地区肠外致病性大肠埃希菌PFGE数据库。结果:1.在128份食品样品中,共40份样品检出大肠埃希菌,检出率31.3%,以肉类和豆制品为主。2.经血清学鉴定,共检出致腹泻大肠埃希菌17株:食源性菌株检出肠侵袭型大肠埃希菌6株、肠毒素型大肠埃希菌3株、肠致病性大肠埃希菌1株;医源性菌株检出肠侵袭型大肠埃希菌1株、肠毒素型大肠埃希菌2株、肠致病性大肠埃希菌4株。3.经PCR技术鉴定出肠外致病性大肠埃希菌42株,其中食源性菌株4株,医源性菌株38株。4.应用PFGE方法对食源性和医源性共42株肠外致病性大肠埃希菌进行分子分型,根据电泳产生的条带的位置和数量的不同,应用Quantity One软件对电泳图谱进行相似度分析,相似值在19%-95%。结论:1.本地区部分食品均不同程度受到大肠埃希菌的污染。2.致腹泻大肠埃希菌污染了本地区食品,也导致了本地区患者肠道外不同组织、器官的感染,推测食品可能存在致腹泻大肠埃希菌致肠道外疾病的潜在风险。3.根据毒力基因的检测结果,食品与病患样本中存在肠外致病性大肠埃希菌菌株,推测食品也可能是肠外致病性大肠埃希菌致病的传播媒介。4.应用PFGE技术对42株肠外致病性大肠埃希菌分子分型后相似度分析发现,食源性菌株与医源性菌株表现出较大的遗传多样性且存在相关性。运用该方法初步建立了本地肠外致病性大肠埃希菌的PFGE数据库,为今后该类细菌的公共卫生学调查提供了依据。
[Abstract]:Objective: 1. Collect the food in our area and evaluate the contamination of Escherichia coli. 2. To understand the distribution of Escherichia coli caused by diarrhea in this area. 3. 3. According to the detection of virulence genes, the distribution of two kinds of Escherichia coli was studied. 4. The PFGE method was used to compare the similarity of two kinds of Escherichia coli from different sources, and the PFGE database of Escherichia coli was preliminarily established in this area. Methods: 1. Referring to the GB4789.38-2012 method, 128 fresh and vegetable samples were collected from 5 supermarkets in this area, and 86 strains of iatrogenic Escherichia coli were collected according to the relevant methods of the National procedure for Clinical examination. The serotypes of Escherichia coli caused by food and iatrogenic Escherichia coli were identified by slide agglutination. PCR method was used to detect the characteristic virulence genes of Escherichia coli and to identify the pathogenic Escherichia coli in food and iatrogenic strains. 3. According to the method recommended by Pulse Net, the PFGE molecular typing map of Escherichia coli was established, and the PFGE database of Escherichia coli in this area was preliminarily established. Results: 1. Escherichia coli was detected in 40 out of 128 food samples, and the detection rate was 31.3%, mainly in meat and soybean products. A total of 17 strains of Escherichia coli were identified by serology: 6 strains of enteroinvasive Escherichia coli, 3 strains of enterotoxin Escherichia coli and 1 strain of enteropathogenic Escherichia coli. One strain of enteroinvasive Escherichia coli, 2 strains of enterotoxin type Escherichia coli and 4 strains of enteropathogenic Escherichia coli were identified by iatrogenic strains. 42 strains of Escherichia coli were identified by PCR, including 4 foodborne strains and 38 iatrogenic strains. A total of 42 strains of Escherichia coli from food and iatrogenic were classified by PFGE. According to the location and quantity of the bands produced by electrophoresis, the similarity of the electrophoretic patterns was analyzed by Quantity One software. The similarity is between 19 and 95. Conclusion: 1. Some foods in this area were contaminated by Escherichia coli to varying degrees. 2. 2. Diarrhea caused by Escherichia coli contamination of food in the region, but also caused by patients in the region outside the intestinal tissue, organ infection, food may have the potential risk of diarrhoeal Escherichia coli caused extraintestinal diseases. 3. According to the detection results of virulence genes, there is a pathogenic Escherichia coli strain in food and patient samples, and it is speculated that food may also be the transmission vector of pathogenic Escherichia coli. 4. The similarity analysis of 42 strains of Escherichia coli by PFGE showed that there were significant genetic diversity and correlation between foodborne strains and iatrogenic strains. Using this method, the PFGE database of local Escherichia coli was established, which provided the basis for the public health investigation of this kind of bacteria in the future.
【学位授予单位】：贵阳医学院
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：R446.5

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