Survival of and interactions between microorganisms in environmental biofilms

大肠杆菌是世界范围内最常用的粪便指示生物之一，一些致病菌株可以是水媒病原体。我们所知道的大部分关于E。大肠杆菌生物膜是基于在实验室条件下生长的K-12菌株。目前对生物膜的形成、环境和O 157 E的存活和扩散知之甚少。大肠杆菌菌株。已知rpoS对于某些细菌物种的生物膜发育和扩散是重要的。然而，rpoS对非K12菌株的生物膜形成和分散的作用尚不清楚。本文研究了归化E.大肠杆菌的生物膜基质，并将有助于了解和预防大肠杆菌的爆发。淡水系统中的大肠杆菌。 本研究的目的是：（1）分离和鉴定归化E.（1）比较了苏必利尔湖两个上级海滩自然化大肠杆菌的时间动态;（2）比较自然转化、瞬时转化和O 157大肠杆菌的生物膜形成能力。（3）检测自然转化、瞬时转化和O 157大肠杆菌的转化能力。大肠杆菌在生物膜群落中存活和脱离生物膜群落的能力; coli和具有良好生物膜形成能力的驯化E.大肠杆菌或天然微生物生物膜群落;（5）确定rpoS对大肠杆菌的作用。coli（自然化、瞬时和O 157 E.大肠杆菌菌株）在环境条件下的生物膜发育、存活和脱离。

Escherichia coli is one of the most commonly used fecal indicator organisms worldwide and some pathogenic strains can be waterborne pathogens. Most of what we know about E. coli biofilm is based on the K-12 strain grown under laboratory conditions. Little is known about biofilm development, survival and dispersal of environmental and O157 E. coli strains under environmental conditions. The rpoS is known to be important for biofilm development and dispersal for some bacterial species. However, the role of rpoS on biofilm formation and dispersal of non-K12 strains is not clear. This proposal studies the persistence and detachment of naturalized E. coli in biofilm matrices and will contribute to the understanding and prevention of outbreaks of E. coli in fresh water systems. The objectives of this proposal are to: (1a) isolate and characterize the sources of the naturalized E. coli in two Lake Superior beaches; (1b) compare the temporal dynamics of the naturalized E. coli populations in biofilm and planktonic phases; (2) characterize and compare the biofilm forming ability of the naturalized, transient and O157 E. coli under laboratory and environmental conditions; (3) examine the ability of the naturalized, transient and O157 E. coli to survive in and detach from biofilm communities; (4) determine the co-adhesion mechanisms between the biofilm-deficient E. coli and the proficient biofilm-forming naturalized E. coli or natural microbial biofilm communities; and (5) determine the role of rpoS on E. coli (naturalized, transient and O157 E. coli strains) biofilm development, survival and detachment under environmental conditions.