Genetic basis involved in host interaction and adaption of Escherichia coli: impact on commensalism, symptomatic and asymptomatic infection

细菌和致病菌的比较提高了我们对致病性和细菌性以及有症状或无症状感染发生的分子基础的理解。我们使用大肠杆菌（E.大肠杆菌）作为模式生物，因为该物种的非致病性大肠杆菌以及致病性变体属于人的正常肠道植物群。将来自症状性或无症状感染的分离株与病原体进行比较，将促进对细菌特性的鉴定以及参与不同形式的宿主-细菌相互作用的分子机制，从而导致不同类型的感染。小生境的成功定殖需要细菌适应所遇到的生长条件，包括感染期间的宿主反应。细菌的适应性来自基因组的可塑性和积极的选择。为了将细菌的遗传灵活性和毒力潜力与宿主反应联系起来，我们计划研究（i）复杂的宿主-病原体相互作用，（ii）大肠杆菌的细菌进化/适应。大肠杆菌在人类宿主的人口规模，（iii）所需的症状感染的细菌性状，（iv）细菌适应背后的驱动力在体内。我们的研究结果将有助于全面理解原核微生物、其宿主和寄生性或致病性之间的分子背景。

The comparison of commensal and pathogenic bacteria improves our understanding of the molecular basis for pathogenicity and commensalism as well as for the occurrence of symptomatic or asymptomatic infections. We use Escherichia coli (E. coli) as a model organism because non-pathogenic commensal as well as pathogenic variants of this species belong to the normal intestinal flora of humans. The comparison of isolates from symptomatic or asymptomatic infection with commensals will promote the identification of bacterial properties and the molecular mechanisms involved in different forms of host-bacterium interaction, thus leading to different types of infection. Successful colonization of a niche requires bacterial adaptation to the growth conditions encountered including the host response during infection. Bacterial adaptation results from genome plasticity and positive selection. To correlate genetic flexibility and virulence potential of the bacteria with host response, we plan to investigate the (i) complex host-pathogen interaction, (ii) bacterial evolution/adaptation of E. coli in the human host on the population scale, (iii) bacterial traits required for symptomatic infection, and (iv) driving forces behind bacterial adaptation in vivo. Our results will contribute to the full comprehension of the molecular context between prokaryotic microorganisms, their hosts and commensalism or pathogenicity.