四川地区猪链球菌流行调查及其病原特性研究

发布时间：2018-02-14 16:09

本文关键词： 猪链球菌血清学调查分离鉴定毒力基因致病性耐药性　出处：《四川农业大学》2015年硕士论文　论文类型：学位论文

【摘要】：猪链球菌病是猪场的一种常见细菌性传染病,呈世界性分布,给全球养猪业带来巨大损失。该病主要引起猪的脑膜炎、关节炎、败血症、心内膜炎、脑炎、流产、多发性浆膜炎和支气管肺炎等。该菌可分为35个血清型,血清1型～34型和1/2型。研究发现,对猪致病的血清型主要有1型、2型、7型和9型,尤其2型毒性最强,其中3型还与肺炎有关。为了解四川地区猪链球菌病的感染情况、流行的血清型、致病性和耐药性,本实验主要做了以下研究。1、四川地区猪2型链球菌血清流行病学调查为了解四川地区猪2型链球菌的流行情况,本研究应用商品化猪2型链球菌ELISA检测试剂盒对近两年从四川成都、雅安、资阳等15市(共32个区县)43家猪场采集526份猪血清进行猪2型链球菌血清抗体检测。结果猪2型链球菌阳性猪场33个,猪场阳性检出率为76.74%。212份血清样品检测阳性,阳性检出率为40.30%,表明四川地区猪2型链球菌感染严重。其中种母猪的阳性检出率最高,其次为育肥猪和保育猪,分别为65.77%、39.88%、29.15%。2、四川地区流行猪链球菌病原优势血清型调查对四川成都、雅安、广安等12个市(18县)猪场采集的病料进行猪链球菌的分离,共分离到34株猪链球菌。用PCR分型方法对分离株进行血清1型、2型、7型、9型和3型鉴定,结果2型16株,占47.1%,7型9株,占26.5%,1株9型,占2.9%,3型4株,占11.8%,未定型4株,占11.8%。表明四川地区存在多种血清型猪链球菌感染,其中2型为主要流行血清型,其次为血清7型和3型。3、猪链球菌四川分离株主要毒力基因检测分析及2型代表株致病性研究对34株猪链球菌3种主要毒力基因mrp、epf和sly进行PCR检测,结果9株为mrp+(26.5%)、14株为epf+(41.2%)、26株为sly+(76.5%)。16株猪2型链球菌中存在3个毒力基因表型,mrp+epf+sly+为9株(56.3%)、mrp-epf+sly+为5株(31.3%)、mrp-epf-sly-为2株(12.5%),其中mrp+epf+sly+为优势基因型。对16株猪2型链球菌分离株的4种毒力基因cps 2J、mrp、epf和sly的PCR扩增产物进行测序分析,16株分离株的4种毒力基因核苷酸序列与国内外猪链球菌参考株相应毒力基因序列同源性分别为98.5%～100%、99.6%-100%、99.4%-100%、98.2%-100%,表明四川地区流行的猪2型链球菌的毒力基因相对稳定,变异程度小。对3株猪2型链球菌代表株进行小鼠致病性试验表明毒力基因型为mrp+epf+sly+的菌株毒力最强,其次是mrp-epf+sly+, mrp-epf-sly-菌株致病力最弱。4、四川地区猪链球菌耐药普调查用18种临床常用抗生素对34株猪链球菌进行药物敏感性试验,结果四川地区猪链球菌对多种抗生素耐药,耐药性严重。多重耐药谱(70%以上分离株耐药)为庆大霉素-卡那霉素-丁胺卡那霉素-四环素-多西环素-红霉素-阿奇霉素-林可霉素-磺胺甲恶唑。而对阿莫西林、氨苄西林、先锋霉素V、头孢曲松等的敏感率在90%以上,在猪场发生猪链球菌病时,可以使用这些抗生素进行治疗。
[Abstract]:Streptococcus suis is a common bacterial infectious disease in pig farms, which has a worldwide distribution and brings great losses to the global pig industry. The disease mainly causes meningitis, arthritis, septicemia, endocarditis, encephalitis, abortion in pigs. Polyserositis and bronchopneumonia. The strain can be divided into 35 serotypes, serotype 1, serotype 34 and serotype 1/2. Among them, type 3 is also related to pneumonia. In order to understand the infection situation of streptococcus suis in Sichuan, the prevalent serotype, pathogenicity and drug resistance, In order to understand the epidemic situation of Streptococcus suis type 2 in Sichuan province, the seroepidemiology of Streptococcus suis type 2 was investigated. In this study, commercial Streptococcus suis type 2 (ELISA) detection kit was used to detect Streptococcus suis from Chengdu, Sichuan Province in recent two years. 526 pig serum samples were collected from 43 pig farms in 32 districts of Ziyang and other cities. Results there were 33 positive swine farms for Streptococcus suis type 2, and 76.74.212 serum samples were positive in pig farms. The positive rate was 40.30, which indicated that the infection rate of Streptococcus type 2 in Sichuan pigs was serious. The positive rate of sows was the highest, followed by fattening pigs and conservation pigs. 65.77 and 39.88, respectively. A survey of the predominant serotypes of streptococcus suis in Sichuan area was carried out to isolate Streptococcus suis from pig farms in Chengdu, Ya'an, Guangan and other 12 cities and 18 counties in Sichuan Province. A total of 34 strains of Streptococcus suis were isolated and identified by PCR typing. The results showed that 16 strains of serotype 2, 9 strains of serotype 2, 9 strains of serotype 2, 9 strains of serotype 2, 9 strains of serotype 2, 9 strains of serotype 2, 9 strains of serotype 26.5, 4 strains of serotype 2, accounted for 11. 8 strains, 4 strains of undefined type, 4 strains of serotype 2, 4 strains of serotype 2, 4 strains of serotype 2 and 4 strains of serotype 3 were identified by PCR typing. The results showed that there were many serotypes of Streptococcus suis infection in Sichuan, among which serotype 2 was the main prevalent serotype. The main virulence genes of Streptococcus suis isolated from Sichuan Province and the pathogenicity of the representative strain 2 were detected by PCR in 34 strains of Streptococcus suis. Results among the 9 strains, 14 strains were mrp strain 26.50.14 strains were epf strain 41.2 and 26 strains were sly 76.5 strains and 16 strains of Streptococcus suis type 2. There were 3 virulence gene phenotype mrp epf sly 9 strains 56.3mrp-epf sly 5 strains 31.3mrp-epf-sly-2 strains, in which mrp epf sly was the dominant genotype of Streptococcus suis type 2. The nucleotide sequences of the four virulence genes cps 2J mrpP epf and sly were sequenced. The nucleotide sequences of the four virulence genes of 16 isolates were homologous to the corresponding virulence genes of the reference strains of Streptococcus suis at home and abroad. The sequence homology of the four virulence genes of the four virulence genes from the four virulence genes to the reference strains of Streptococcus suis at home and abroad were 98.50.4-99.4- 99.2- 1000.The results showed that. The virulence gene of Streptococcus suis type 2, which is prevalent in Sichuan Province, is relatively stable. The pathogenicity test of three representative strains of Streptococcus suis type 2 in mice showed that the virulence genotype of the strain with mrp epf sly was the most virulent. Secondly, mrp-epf sly, mrp-epf-sly- strain virulence was the weakest. 4. The susceptibility tests of 34 strains of Streptococcus suis were carried out with 18 kinds of commonly used antibiotics in Sichuan Province. The results showed that Streptococcus suis in Sichuan area was resistant to multiple antibiotics. Serious drug resistance. More than 70% of the isolates were resistant to gentamicin-kanamycin-amikacin-tetracycline-doxycycline-erythromycin-azithromycin-lincomycin-sulfamethoxazole. Ampicillin, vancomycin V and ceftriaxone are more sensitive than 90%, and can be treated with these antibiotics in pig farms with streptococcus suis.
【学位授予单位】：四川农业大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：S858.28

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