Identification of factors that control Mycobacterium tuberculosis biofilm growth

描述（由申请人提供）：结核病（TB）的治疗需要6至9个月的多药方案。长期化疗的主要原因之一是结核分枝杆菌（结核病的病原体）对药物暴露的非凡生存能力。细菌在其自然栖息地中的持久性部分是由它们在称为生物膜的多细胞结构群落中的生长促进的。几种微生物病原体如假单胞菌属的慢性感染持续存在，念珠菌或链球菌属（Streptococcus spp.）这归因于它们在宿主体内形成生物膜的能力。因此，为了理解M.结核病对药物暴露的影响我们一直在研究其生物膜在体外生长模型中的发展。我们的初步观察表明，病原菌生物膜的形成是由环境和遗传因素控制的。通过对M.抗利福平和异烟肼的结核病生物膜我们发现，生物膜中大量的杆菌对这两种抗生素产生了表型抗性，而生长在无菌悬浮液中的细胞仍然敏感。这一观察结果提出了一个基本的问题，这些持久性如何在生物膜内发展。回答这个问题的方法之一是了解M.结核我建议调查的环境和遗传因素，控制生物膜的发展M。结核这些因素的识别将是非常有用的，在理解的持续发展的威尔斯以及设计合适的战略，以针对他们。公共卫生相关性：由结核分枝杆菌引起的结核病（TB）每年在世界上造成近200万人死亡，并且需要6至9个月的强化化疗来治疗。M.结核病的化疗是有效治疗结核病的关键障碍。在这个项目中，我们正在解决M的持久性问题。通过研究其在生物膜中的生长和发育-表面附着的多细胞结构，其具有比非渗透性培养物显著更多的耐药性持久物，来研究结核病。

DESCRIPTION (provided by applicant): Treatment of tuberculosis (TB) requires multi-drug regimen for a period of 6 to 9 months. One of the primary reasons for a long-term chemotherapy is the extraordinary ability of Mycobacterium tuberculosis, the causative agent of TB, to survive against drug exposure. Persistence of bacteria in their natural habitat is, in part, facilitated by their growth in multicellular structured community called biofilms. Persistence of chronic infections by several microbial pathogens such as Pseudomonas spp., Candida spp. or Streptococcus spp. has been attributed to their ability to form biofilms inside host. Therefore, in order to understand the persistence of M. tuberculosis against drug exposure we have been studying the development of its biofilms in an in vitro growth model. Our preliminary observation suggests that the biofilm formation by pathogen is controlled by both environmental and genetic factors. Upon evaluation of tolerance properties of M. tuberculosis biofilms against rifampicin and isoniazid we found that a significantly large number of bacilli in biofilms developed phenotypic resistance against both the antibiotics, whereas cells growing in planktonic suspension remained susceptible. This observation raises a fundamental question as to how these persisters develop within biofilms. One of the approaches in answering this question will be to understand the molecular basis of biofilm development by M. tuberculosis. I propose to investigate the environmental and genetic factors that control the biofilm development of M. tuberculosis. Identification of such factors will be very useful in understanding the development of persisters as wells as designing suitable strategies to targeting them. PUBLIC HEALTH RELEVANCE: Tuberculosis (TB), caused by Mycobacterium tuberculosis, kills nearly 2 million people in the world every year and takes 6 to 9 months of intensive chemotherapy for the treatment. Long-term persistence of M. tuberculosis against chemotherapy is a key hurdle in an effective treatment of TB. In this project we are addressing the persistence issue of M. tuberculosis by studying its growth and development in biofilms- the surface attached multicellular structures with significantly more drug tolerant persisters than planktonic cultures.