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Characterization of Haemophilus Parasuis from Central Vietna

发布时间:2024-02-28 01:12
  副猪嗜血杆菌(HPS,H.parasuis)是一种能引起猪的格拉瑟氏病革兰氏阴性细菌,依赖于烟酰胺腺嘌呤二核苷酸生长,,其导致的临床特征主要是纤维素性多发性浆膜炎、脑膜炎和关节炎。越南的生猪产量在世界上排名第五,到目前为止,关于越南HPS的流行病学特征、耐药性(AMR)和耐药性基因(ARGs)的流行情况尚缺乏相关数据。此外,用于预防和控制格拉瑟氏病的疫苗在越南尚未开发。本课题研究包括一下内容:本课题第一部分主要研究了从越南中部广平省和顺化省猪场中分离到的HPS菌株的血清型流行性和毒力相关基因(VGs)的分布。我们从814个肺和鼻腔拭子样本中分离出56株HPS(6.9%).不同地区、不同年龄、不同产地标本的分离率差异有统计学意义(p<0.05)。采用一步多重PCR(m PCR)方法鉴定了这些菌株的血清型。结果表明,主要流行血清型为5型(15/56,26.8%),其次是血清型2型(13/56,23.2%)和4型(10/56,17.9%)。在这些HPS菌株中检测并分析了9个毒力相关基因(VGs),其中vta1基因(35/56,62.5%)检出率最高,其次是vta3基因(24/56,42...

【文章页数】:142 页

【学位级别】:博士

【文章目录】:
Abstract
摘要
Abbreviations used in this dissertation
CHAPTER 1 General introduction and literature review
    1.1 General introduction
        1.1.1 Pig production in China and Vietnam
        1.1.2 Haemophilus parasuis
        1.1.3 Antimicrobial resistance
        1.1.4 Haemophilus parasuis vaccines
        1.1.5 Serial passage,live-attenuated Haemophilus parasuis vaccines
    1.2 Significance of the study
    1.3 General literature review
        1.3.1 Etiology of Haemophilus parasuis
        1.3.2 Cultivation and biochemical characteristics
        1.3.3 Serotypes of Haemophilus parasuis
        1.3.4 Pathogenesis mechanisms of Haemophilus parasuis
        1.3.5 Virulence factors
            1.3.5.1 Outer membrane proteins
            1.3.5.2 Virulence-associated trimeric autotransporters
            1.3.5.3 Oligopeptide binding protein Opp A
            1.3.5.4 Cytolethal distending toxin
            1.3.5.5 Lipooligosaccharide
            1.3.5.6 Type V secretion system
        1.3.6 Epidemiology of Gl?sser’s disease
        1.3.7 Clinical symptoms
        1.3.8 Pathological lesions
        1.3.9 Diagnosis methods
            1.3.9.1 Isolation and identification of bacteria from clinical samples
            1.3.9.2 Serotyping
            1.3.9.3 Genotyping
            1.3.9.4 Antibody detection and molecular biological methods
        1.3.10 Treatment and prevention
            1.3.10.1 Antimicrobial therapy
            1.3.10.2 Vaccination
        1.3.11 Antimicrobial resistance of Haemophilus parasuis
        1.3.12 Mechanisms of antimicrobial resistance
        1.3.13 Serial passage bacteria for development live-attenuated vaccines
CHAPTER 2 Characterization of serotypes and virulence genes of Haemophilus parasuis isolates from swine in Quang Binh and Thua Thien Hue provinces,Vietnam
    2.1 Introduction
    2.2 Materials and methods
        2.2.1 Nicotinamide adenine dinucleotide preparation
        2.2.2 Media preparation
        2.2.3 Sample collection
        2.2.4 Isolation and identification of bacteria
        2.2.5 Serotyping
        2.2.6 Virulence genes identification
        2.2.7 Data analysis
    2.3 Result
        2.3.1 Prevalence of Haemophilus parasuis strains in Central Vietnam
        2.3.2 Distribution of Haemophilus parasuis serotypes
        2.3.3 Virulence gene analysis of the Haemophilus parasuis strains
        2.3.4 Association between serotypes,characteristic serotypes,and virulence genes
    2.4 Discussion
CHAPTER 3 Vaccine against the Vietnamese Strains Prevalence of phenotypes and genotypes of antimicrobial resistance and their relationship in Haemophilus parasuis isolates from swine in Quang Binh and Thua Thien Hue Provinces,Vietnam
    3.1 Introduction
    3.2 Materials and methods
        3.2.1 Bacterial isolates
        3.2.2 Antimicrobial susceptibilities
        3.2.3 Antimicrobial resistance gene amplification
        3.2.4 Data analysis
    3.3 Results
        3.3.1 AMR phenotypes of Haemophilus parasuis strains
        3.3.2 Associations among antimicrobial resistance phenotypes
        3.3.3 Antimicrobial resistance genes of H.parasuis strains
        3.3.4 Associations among resistance genes
        3.3.5 Associations between phenotypes and genotypes of antimicrobial resistance
    3.4 Discussion
CHAPTER 4 Characterization of in vitro serially passaged strains of Haemophilus parasuis
    4.1 Introduction
    4.2 Materials and methods
        4.2.1 Serial passaging
        4.2.2 Growth assay
        4.2.3 Assessment attenuation virulence of sub-strains
            4.2.3.1 Animals and housing
            4.2.3.2 Guinea pig infection assay
            4.2.3.3 Piglet infection assay
            4.2.3.4 Animal monitoring and pathological examination
        4.2.4 Data analysis
    4.3 Results
        4.3.1 Growth
            4.3.2.1 Guinea pig infection model
            4.3.2.2 Piglet infection model
    4.4 Discussion
CHAPTER 5 Efficacy of commercial Chinese inactivated vaccine against experimental challenge with Haemophilus parasuis serotype4 and5 isolates from Central Vietnam
    5.1 Introduction
    5.2 Materials and methods
        5.2.1 Bacterial and vaccine
        5.2.2 Animals,vaccination and challenge of guinea pigs
        5.2.3 Tissues bacterial loads
        5.2.4 Antibody detected
        5.2.5 Cytokine stimulation assay
        5.2.6 Statistical analysis
    5.3 Results
        5.3.1 Serological analysis
            5.3.1.1 Analysis of antibody titers in guinea pigs
            5.3.1.2 Effect of vaccination on INF-g,IL-4 levels and IFN-γ-to-IL-4 ratio in sera of guinea pigs
        5.3.2 Protective efficacy against lethal challenge with H.parasuis serotypes4and5
    5.4 Discussion
Chapter 6 Conclusion
References
Publications
Acknowledgments



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