食源性金黄色葡萄球菌及其肠毒素基因分布研究

发布时间：2019-05-23 03:43

【摘要】：金黄色葡萄球菌（Staphyloccocus aureus）是与人类密切相关的病原菌，可引起多种严重感染。近些年来，在我国关于金黄色葡萄球菌引发的食品中毒事件屡见不鲜，呈现涉及范围越来越广、感染人群越来越多的趋势。而新食品安全国家标准调整了金黄色葡萄球菌（Staphyloccus aureuss）的限量规定在社会各界的争议中于2011年底颁布。这一从零检出到限量检出的规定大大增加了食源性葡萄球菌污染的可能性。为了避免金葡菌病暴发流行，能够快速追踪污染源，对金黄色葡萄球菌的进一步深入的研究是十分必要的。本研究总共对采集自保定地区的生鲜肉、速冻食品、生牛乳、人体化脓组织、生活环境、豆制品等六类不同来源共计760份样品进行了金黄色葡萄球菌的分离与鉴定，并且在此基础上对金葡菌SEk、SEr、SEj、SEq和SEo等五种肠毒素基因型进行了检测分析。实验结果显示：（1）检出携带金黄色葡萄球菌的样品总共292株，携带率为34.0%，且该菌在六类样品中均有分布，我们可以得知保定地区金葡菌污染率相对较高而且分布广泛。（2）不同来源之间的金黄色葡萄球菌检出率是有差异的，生鲜肉及制品为52.5%、生牛奶为36%、速冻食品为35%、人体化脓组织为31.3%、生活环境为12%、豆制品为6.7%。在生鲜肉及制品中检出率最高，生牛奶和速冻食品次之，这三大类容易感染金葡菌的食物都是人类的日常饮食中较为常见的，以上数据告诉我们更应该对这三大类食物的质量安全保持时刻的警觉，以免食品中毒事件的发生。（3）虽然其他几类中金葡菌的检出率相对较低，但是在我们完全掌握该菌的各种性征之前，我们不应对与之相关的食品安全问题放松警惕。（4）在分离得到的292株金黄色葡萄球菌基础上，本试验检测了SEk、SEr、SEj、SEq和SEo五种肠毒素基因。其中SEj被检出49株、检出率为16.8%，SEr被检出37株、检出率为12.7%，SEq被检出25株、检出率为8.6%，SEo和SEk的检出率均为0%。SEk和SEo在任何一种样品中均未检出。（5）同时携带三种基因型的菌株总共检出22株，检出率为7.5%、同时携带SEr、SEj的菌株有15株，检出率为5.1%。（6）追溯可被检出的肠毒素来源，可以得出被检出的三种肠毒素均在生鲜肉及肉制品中检出率最高（SEj为34.7%、SEr为54.1%、SEq为56%），速冻食品次之（SEj为24.5%、SEr为29.7%、SEq为32%）。在这几类食源样品中，羊肉以及羊肉馅速冻食品的肠毒素携带率均要大于其他类型的样品。金黄色葡萄球菌所生长的环境状况对于肠毒素类型的形成有重要影响，不同食品来源的金黄色葡萄球菌的产肠毒素情况和类型存在很大差别。这些样品虽然数量少，但都属于原始和二次加工食品，并且含蛋白质丰富。另外，这些样品采集的自然环境都不是很好，虽然有些样品还是在低温下保存，，但是存放食品的容器不卫生，周围的人活动也比较频繁。
[Abstract]:Staphylococcus aureus (Staphyloccocus aureus) is a pathogen closely related to human beings, which can cause a variety of serious infections. In recent years, food poisoning caused by Staphylococcus aureus is common in China, which involves more and more people. The new food safety national standard adjusted the limit of Staphylococcus aureus (Staphyloccus aureuss) in the controversy from all walks of life at the end of 2011. This rule from zero detection to limited detection greatly increases the possibility of food-borne staphylococci contamination. In order to avoid the outbreak of Staphylococcus aureus and to track the pollution sources quickly, it is necessary to further study Staphylococcus aureus. In this study, 760 samples from fresh meat, frozen food, raw milk, human pus tissue, living environment and soybean products from Baoding area were isolated and identified. On this basis, five enterotoxin genotypes, such as SEk,SEr,SEj,SEq and SEo, were detected and analyzed. The results showed that: (1) 292 strains of Staphylococcus aureus were detected, the carrying rate was 34.0%, and the bacteria were distributed in all six kinds of samples. We can know that the contamination rate of Staphylococcus aureus in Baoding area is relatively high and widely distributed. (2) the detection rate of Staphylococcus aureus from different sources was 52.5% for fresh meat and products, 36% for raw milk, 35% for frozen food, 31.3% for human pus tissue and 12% for living environment. Soybean products were 6.7%. The detection rate of raw meat and products was the highest, followed by raw milk and frozen food. These three kinds of foods, which are easy to infect Staphylococcus aureus, are more common in human diet. The above data tell us that we should be vigilant about the quality and safety of these three categories of food so as to avoid the occurrence of food poisoning. (3) although the detection rate of Staphylococcus aureus in other categories is relatively low, we should not relax our vigilance against the related food safety problems until we fully master the various sexual characteristics of the bacteria. (4) on the basis of 292 strains of Staphylococcus aureus isolated, five enterotoxin genes, SEk,SEr,SEj,SEq and Seo, were detected in this experiment. Among them, 49 strains were detected, the detection rate was 16.8%, 37 strains were detected, the detection rate was 12.7%, 25 strains were detected, the detection rate was 8.6%. The detection rates of SEo and SEk were 0%.SEk and SEo, which were not detected in any kind of samples. (5) A total of 22 strains carrying three genotypes were detected, the detection rate was 7.5%, and 15 strains carrying SEr,SEj at the same time, the detection rate was 5.1%. (6) tracing back to the source of enterotoxin detected, it can be concluded that the three enterotoxins detected were the highest in fresh meat and meat products (SEj 34.7%, SER 54.1%, SEQ 56%). Quick-frozen food (SEj 24.5%, SER 29.7%, SEQ 32%). In these kinds of food samples, the enterotoxin carrying rate of mutton and mutton filled frozen food was higher than that of other types of samples. The environmental conditions of Staphylococcus aureus have an important impact on the formation of enterotoxin types. The enterotoxin production of Staphylococcus aureus from different food sources is very different. Although the quantity of these samples is small, they all belong to raw and secondary processed food, and are rich in protein. In addition, the natural environment of these samples is not very good, although some samples are still preserved at low temperature, but the containers for storing food are not hygienic, and the activities of people around them are more frequent.
【学位授予单位】：河北农业大学
【学位级别】：硕士
【学位授予年份】：2013
【分类号】：R155.5

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