Dissertation > Excellent graduate degree dissertation topics show

Epidemiological Investigation of Streptococcus Suis and Its Classification by PCR-RFLP

Author: YangZhen
Tutor: FanWeiXing；JiangPing
School: Nanjing Agricultural College
Course: Preventive Veterinary Medicine
Keywords: Streptococcus suis PCR serum agglutination test MLST RFLP genotype
CLC: S852.61
Type: Master's thesis
Year: 2009
Downloads: 50
Quote: 1
Read: Download Dissertation

Abstract


Streptococcus suis (S. suis) is a conditional pathogen and usually settles in the upper tonsil of infected swine. When the immunity of infected swine falls, it will cause disease and subsequently lead to the prevalence of Streptococcus suis. Therefore, it is of great significance to detect and isolate S. suis from swine tonsil for the epidemiological surveillance of the disease. Some studies show that the virulence differs among the strains of different serotypes. But this phenomenon also exists in the same serotypes and some strains of the same serotype do not entirely cause the same disease. The current serotyping methods do not adequately reflect the characteristics of S. suis. So this work is sought to establish a new genotyping method for the study of Streptococcus suis by using PCR-RFLP.1. Epidemiological investigation of Streptococcus suis in carried swine:248 tonsils or lymph were collected from 20 slaughterhouses in different regions of China Streptococcus suis were isolated from collected samples and purified in sheep blood plate. And then species and serotypes of suspected colony were identified by PCR assay on the basis of gene squences of GDH、CPSli、CPS2j、CPS7h、CPS9g, followed by serum agglutination test and virulence factors detection by PCR. Genetic relationships of isolates were studied by multilocus sequence typing (MLST). The results were as followed:14 strains of Streptococcus suis were identified by PCR assay, including 3 strains of ss2,2 strains of ss7, 1 strain of ss9 and 8 strains of non-serotype Streptococcus suis. The serum typing result of 6 isolates by serum agglutination test were consistent with the results by PCR assay.5 kinds of virulence genotypes were generated from 6 known serotype isolates during detecting 6 virulence factors(mrp、epf、sly、orf2、fbps、gapdh)by PCR:A1 Cps2+mrp-epf+sly+orf2+fbps+gapdh; A2 Cps2+mrp-epf+sly-orf2-fbps+gapdh-; A3 Cps7+mrp+epf-sly-orf2-fbps-gapdh+; A4 Cps9-mrp-epf-sly-orf2-fbps+gapdh+; A5 Cps7+mrp-epf-sly-orf2+fbps+gapdh+. Strains belonging to A1 and A2 were mild strains,and others weren’t known. Analyzed by MLST, the results implied that 3 strains of ss2 belonged to ST1,1 strain of ss7 belonged to ST29 and 1 strain of ss9 (CQ15) belonged to a new ST type, which was not reported in previous publications. The new ST was submitted to MLST database of Streptococcus suis (http://ssuis.mlst.net) and assigned to ST128.2. Development and application of PCR-RFLP in genotype research of Streptococcus suis:16S-23S ISR rDNA squences of 32 serotypes (1-31,1/2) reference strains and 47 isolates with clear background were amplified by PCR.1) The establishment and optimization of system and condictions of PCR and enzymatic reaction.2) The digestion of PCR products of reference strains with Rsal and HinfI.3) The observation of different patterns gained by gel electrophoresis.The results in this work were as followed:22 genotypes were generated after digestion with RsaI and HinfI, including 25 strains Aa (31.6%); 20 strains Ib (25.3%); 7 strains Bf (8.9%); 4 strains Ga (5.1%); 3 strains Be and 3 strains Ka (3.8%); 2 strains Bh (2.5%); 1 strain Eb、Bb、Gg、Di、Hc、Fj、Ca、Bd、Jk、Ll、Ie、Bm. Ag、Mn、Io, respectively. After analyzing enymatic patterns according to Simpsom’s index of diversity (DI), DI of PCR-RFLP was 0.83. The patterns of serotype 1/2 and 2 of reference and isolate were different. So serotype 1/2 could be distinguished from serotype 2. But other serotypes could not be discriminated.18 virulent isolates included 1 strain SS7,1 strain SS9 and 16 strains SS2. The patterns of virulent and avirulent SS7 strains were the same, and so were SS2. Therefore, virulent or avirulent strains could not be discriminated by PCR-RFLP.

Related Dissertations

  1. Cloning and Expression of CHS and CHI Genes and Their Regulation on the Accumulation of Flavonoids in ’Cara Cara’ Navel Orange (Citrus Sinensis Osbeck) and ’Guoqing NO.4’ Satsuma Mandarin (Citrus Unshiu Marcow),S666.4
  2. Directed Evolution of Lipase from Penicillium Expansum FS1884 by Error Prone PCR,Q78
  3. Mutagenesis of a Laccase Gene from Pleurotus eryngii in Vitro and Expression in Pichia Pastoris,TQ925
  4. Survey in Nanjing and Analysis of the Mitochondrial Genome of Frankliniella Occidentalis (Pergande),S433
  5. GIH cDNA Cloning and Mrna Expression in Litopenaeus Vannamei,S917.4
  6. Gene Prediction and Sequence Analysis of Insect OBP CSP and sid-1,Q78
  7. Cloning and Expression Analysis of Scavenger Receptor Class B Type Ⅰ and Antifreeze Proteinstype Ⅱ Genes in Lutjanus Sanguineus,S917.4
  8. Isolation, Identification and Molecular Characteristics of Japane Encephalitis Virus in Henan Province,S852.65
  9. Detection of Exogenous Recombinan DNA of Transgenic Rice and Its Rice Product,S511
  10. Development of Subunit Vaccine of Streptococcus Suis Type 2 and Actinobacillus Pleuropneumoniae,S858.28
  11. Analysing Sequence Characters of ADSL and PurH Gene and Correlation between Genes Expression and IMP Content in Duck,S834
  12. Studies on the Difference of PRRSV Infectious and PRRSV ADE,S858.28
  13. Isolationand Identification of Porcine Parvovirus and Parts of Its Biological Characteristics,S852.65
  14. Red Soil Microbial Diversity of Peanut Continuous Cropping and Effects of Microorganisms on Growth of Continuous Cropping Peanut,S565.2
  15. Studies on Microbial Contamination and Microbial Decontamination of Chemical Substances of Fresh Chicken,TS251.1
  16. Effect of Organic Nutritiveadditives on Soil Micro-ecological Restoration and Its Mechanism.,S143
  17. Ecological Control of Tobacco Bacterial Wilt in Continous-cropping Field and the Microecological Mechanisms,S435.72
  18. Investigation of Cereal Cyst Nematode on Wheat in Jiangsu Province and the Sequence Analysis of rDNA-Its Region from Jiangsu Populations,S435.121
  19. Identification、Diversity and Phylogenetic Analysis of Antagonistic Bacillus Isolated from Different Chinese Areas,S476.1
  20. Identification of the Causal Organism of Soybean Bacterial Spots and Two Type Ⅲ Secreted Effectors’s Clone and Functional Analysis,S435.651
  21. Gene Cloning and Expression Analysis of Odorant Receptor and Arginine Kinase Gene from Helicoverpa Assulta (Guenée),S433.4

CLC: > Agricultural Sciences > Livestock, animal medicine,hunting,silkworm,bee > Animal Medicine ( Veterinary Medicine) > Basic Veterinary Science > Animal Microbiology ( Veterinary Microbiology, ) > Pathogenic bacteria
© 2012 www.DissertationTopic.Net  Mobile