Phenotypic and genotypic diversity in Neisseria gonorrhoeae: Using population biology to understand antimicrobial resistance and pathogenesis

抗生素耐药性的全球传播是对全球人类健康的一个重大且日益严重的威胁。一个日益增长的威胁是性传播疾病淋病，许多国家都报告了这种疾病的最后一种手段治疗失败(即第三代头孢菌素)。世卫组织强调，由于目前没有疫苗或新药可用，淋病可能很快就无法治疗。淋病奈瑟菌的种群结构是复杂的和非克隆的，因为分离株之间发生了高度的基因重组。大量的基因重组会扰乱淋球菌的种群研究，特别是这种研究往往集中在有限的基因数量上，如多位点序列分型(MLST)。基因可塑性允许淋球菌通过基因分期和重组快速产生一系列表型，其中最适合的可以在体内选择，促进在这些细菌感染的不同粘膜生态位中的快速适应。本博士学位论文旨在分析不同粘膜部位淋球菌分离株的耐药性，并研究这些分离株的基因组和毒力相关表型。这些特征与感染传播动力学的联系将通过数学模型进行检查。成功的候选人将通过不同的免疫分析和蛋白质组学来确定关键毒力因子的存在，并用不同的Ng临床分离株感染具有代表体内培养条件的男性和女性粘膜表面的细胞系。将测定临床相关抗生素的最小抑菌浓度(MIC)。对于每个分离株的选择，将对基因组进行测序，并对任何相关的质粒进行鉴定。最后，MIC、毒力因子存在、基因组多样性和细胞系感染力的数据将提供数学模型，以研究潜在的作用进化机制。结果具有翻译重要性：我们将提高对体内选择与抗菌素敏感性和毒力的关系的理解。此外，我们将确定生态位特异性是否是细菌表型的一个重要考虑因素，然后可用于使用抗菌剂。总体而言，这个项目将提供多学科培训，并提高我们对淋球菌种群生物学的理解。

The global spread of antibiotic resistance is a significant and increasing threat to global human health.Amongst increasing threats is the sexually transmitted disease gonorrhoea, for which last resorttreatment failures (i.e. third generation cephalosporins) have been reported in numerous countries.The WHO has highlighted that gonorrhoea may soon become untreatable as no vaccine or new drugsare currently available. The population structure of the causative pathogen Neisseria gonorrhoeae iscomplex and non-clonal due to the high level of genetic recombination that occurs between isolates.Prolific genetic recombination can confound population studies on gonococci, especially as suchstudies often focus on limited gene numbers such as Multi-locus sequence typing (MLST). Geneticplasticity allows gonococci to quickly generate a range of phenotypes though gene phasing andrecombination, the fittest of which can be selected for in vivo, facilitating rapid adaptation within thedifferent mucosal niches infected by these bacteria. This PhD aims to profile the antibiotic resistanceof gonococcal isolates from distinct mucosal sites and study the genomic and virulence relatedphenotype of these isolates. Linkage of these traits to the dynamics of infection transmission will beexamined through mathematical modelling. The successful candidate will determine the presence ofkey virulence factors by distinct immunoassays and proteomic, and infect cell lines representative ofthe male and female mucosal surfaces mimicking in vivo culture conditions with a diverse range ofclinical isolates of Ng. Minimal inhibitory concentrations (MICs) for clinically relevant antibiotics willbe assayed. For each isolate selection the genome will be sequenced plus any associated plasmididentified. Finally, data for MIC, virulence factor presence genomic diversity and cell line infectivitywill inform mathematical models to investigate potential evolutionary mechanisms of action.The outcomes are of translational importance: we will improve understanding of in vivo selection inrelation to antimicrobial susceptibility and virulence. In addition, we will identify if niche specificity isan important consideration for bacterial phenotypes that may then be utilised in using antimicrobials.Overall this project will provide multi-discipline training and improve our understanding of gonococcalpopulation biology.