江苏部分地区猪源沙门菌的分离鉴定及相关生物学特性研究

发布时间：2018-05-21 18:58

本文选题：沙门菌 + 血清型　；参考：《扬州大学》2015年硕士论文

【摘要】：沙门菌能广泛感染包括人在内的多种动物,是现在具有重要公共卫生学意义的人畜共患病病原之一。人能够通过食入沙门菌污染的食品感染沙门菌。沙门菌曾在国内外多次引起重大食物中毒事件。在中国,猪肉长期占据肉类消费第一位,因此,猪沙门菌的研究对养猪业和食品安全具有十分重要的意义。本研究旨在调查部分地区猪沙门菌的携带及致病情况,为大规模的流行病学调查提供资料。本文共涉及2014年从扬州某屠宰场和扬州大学动物医院共采集样品527份,分离出沙门菌42株。所有分离株生化试验结果显示均符合沙门菌的生化特性,但多数分离株(24/42)与丙二酸盐呈阳性反应,不符合典型的沙门菌生化反应；并有少数分离株不产硫化氢,赖氨酸脱羧酶试验结果阴性,生化反应结果典型的沙门菌分离株仅占19.05%(8/42),显示出本次实验分离株与常见致病性菌株在生化特性方面的差异。所有分离株进行血清型鉴定,共有28株分离株能够根据抗原式确定菌名,其中比例最高的是列克星敦沙门菌(52.38%),其抗原式为10:Z10：1,5,其次为仅测出O抗原为02的分离株,共10株(23.81%),其余血清型的分离株为单个或两个的散在分布。所有分离株中常见的对猪致病的沙门菌仅有鼠伤寒沙门菌一株,其余分离株在一般情况下均为在健康猪体内携带但不致病,部分菌株可对其他宿主致病。根据对细菌类型和不同类别抗菌药和临床用药情况选择了羧苄西林、阿莫西林、头孢唑林、头孢噻肟、痢特灵、卡那霉素、庆大霉素、链霉素、丁胺卡那霉素、四环素、复方新诺明、环丙沙星、恩诺沙星、萘啶酸、氯霉素、多粘菌素B、氟苯尼考、氨苄青霉素、先锋Ⅳ、左旋氧氟沙星等20种抗生素的药敏试验,这些抗生素均是针对革兰氏阴性菌的药物。结果显示,分离株的耐药情况非常普遍,在所选择的抗生素中,共有14种的抗菌药耐药率在50%以上,其中对氨苄青霉素抗性为100%,对四环素和复方新诺明的耐药率也达到90%以上,并且分离株表现出来的耐药表型与国内外相关报道一致。同时,绝大多数分离株(39/42)还表现出多重耐药性,最高可达14重耐药,其中13重耐药最多,占52.38%(22/42),10重以上耐药率达到73.81%(31/42),分离株的耐药情况非常严重。针对所有分离株进行遗传相关性和致病性的研究,首先确定相同抗原式的不同分离株的遗传相关性。通过对分离株进行其毒力岛的核心蛋白基因扩增和脉冲场凝胶电泳,发现相同抗原式的不同分离株,其毒力岛分布完全相同,PFGE条带相似度在95%以上,表明相同血清型不同分离株之间同源性高,其生物学特性及致病性一致,可用单个分离株代表同种血清型的分离株,可取代各血清型代表菌株作为致病性实验的受试菌株。选取有代表性的分离株以108CFU的剂量腹腔注射攻毒6-8周龄昆明系小鼠,结果只有鼠伤寒分离株攻毒小鼠出现死亡,其余分离株攻毒后均未表现出对小鼠的致死性。通过LDso的测定和细菌体内动态分布实验,比较鼠伤寒沙门菌分离株与猪霍乱沙门菌标准株的致病性差别,发现鼠伤寒沙门菌的致死剂量较猪霍乱沙门菌高近200倍,但是细菌进入小鼠体内后增殖和转移速度远比猪霍乱沙门菌标准株快,在进入体内的6h即可达到高峰,之后逐渐降低。鼠伤寒沙门菌分离株能够导致小鼠在攻毒后一周内急性死亡,但病程短,耐过小鼠表现正常。猪霍乱标准株致病性高但致死速度慢,病程长,耐过小鼠仍可长期带菌,攻毒后一个月在肠道及粪便内仍可检测到攻毒细菌存在,有继续传播的风险。
[Abstract]:Salmonella can infect a wide variety of animals including human beings. It is one of the pathogenic zoonosis pathogens of important public health. People can infect Salmonella through food that is contaminated by Salmonella. Salmonella has caused major food poisoning incidents both at home and abroad. In China, pork has long occupied the first meat consumption. Therefore, the study of Salmonella porcine is of great significance to the pig industry and food safety. The purpose of this study was to investigate the portability and pathogenicity of Salmonella in some areas, and to provide information for a large epidemiological survey. A total of 527 samples were collected from a slaughterhouse in Yangzhou and the animal hospital of Yangzhou University in 2014. 42 strains of Salmonella were produced. All the biochemical test results showed that all the isolates were in accordance with the biochemical characteristics of Salmonella, but most of the isolates (24/42) were positive with malonate, and did not conform to the typical biochemical reaction of Salmonella. The isolates accounted for only 19.05% (8/42), showing the differences in biochemical characteristics of the isolated and common pathogenic strains. All the isolates were serotype identification. A total of 28 isolates were able to determine the bacterial name according to the antigen type. The highest proportion was Lexington serobacteria (52.38%), its antigen was 10:Z10:1,5, and the next was only the only one. A total of 10 strains (23.81%) were detected with O antigen 02. The remaining serotype isolates were single or two scattered. The only Salmonella Salmonella isolated from all the isolates was the only Salmonella typhimurium. The remaining isolates were generally carried in healthy pigs but not pathogenic, and some strains could be used in other hosts. Selection of carboxybenzillin, amoxicillin, cefazoxixime, cefotaxime, timoxime, gentamicin, gentamicin, streptomycin, amikanamycin, tetracycline, compound neoxicillin, ciprofloxacin, enrofloxacin, nalofloxacin, chloramphenicine, polymyxin B, florfenicol, The drug sensitivity tests of ampicillin, vanguard IV, levofloxacin and other 20 kinds of antibiotics were all drugs against Gram-negative bacteria. The results showed that the drug resistance of the isolated strains was very common. Among the selected antibiotics, 14 kinds of antibiotics were more than 50%, of which the resistance to ampicillin was 100% and four. The resistance rate of cyclin and compound novomine reached more than 90%, and the resistance phenotype of the isolated strains was consistent with the related reports at home and abroad. At the same time, most of the isolates (39/42) also showed multiple resistance, up to 14 heavy resistance, of which 13 were most resistant, 52.38% (22/42), and 10 more than 73.81% (31/42). The drug resistance of isolated strains is very serious. In the study of genetic correlation and pathogenicity of all the isolates, the genetic correlation of the different isolates of the same antigen is determined first. By amplification of the core protein gene of the isolates and the pulse field gel electrophoresis of the isolates, the virulence of the different isolates of the same antigens is found. The island distribution is exactly the same. The similarity of PFGE strip is above 95%. It shows that the homology of the same serotype is high, its biological characteristics and pathogenicity are consistent. Single isolates can be used to represent the homologous serotype isolate, and the representative strains of the serotypes can be substituted as the tested strains of the pathogenicity test. 6-8 weeks old Kunming mice were attacked by intraperitoneal injection at the dose of 108CFU. The result was that only the isolated strains of typhus were killed, and the other isolated strains were not lethal to mice after attack. By the determination of LDso and the dynamic distribution of bacteria in the bacteria, the standard strain of Salmonella typhimurium was compared with the standard strain of swine cholera Salmonella. It was found that the lethal dose of Salmonella typhimurium was nearly 200 times higher than that of swine cholera Salmonella, but the proliferation and metastasis rate of Salmonella typhimurium was much faster than that of the standard strain of Salmonella cholerae in mice. The 6h could reach the peak in the body and then gradually decrease. The isolated Salmonella typhimurium strain could cause the mice to attack the virus after attack. Acute death in the week, but the course of the disease is short, the resistance to mice is normal. The pig cholera standard strain has high pathogenicity but a slow death rate, long disease course, and the mice can still carry the bacteria for a long time. In the first month after attack, the infection bacteria can still be detected in the intestines and feces, and there is a risk of continued spread.
【学位授予单位】：扬州大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：S852.61

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