1a. Objectives (from AD-416):
1: Molecular identification and characterization of the genetic factors that influence biofilm formation by Shiga toxin-producing Escherichia coli (STECs). 1.1 Genomic, transcriptomic, and molecular analyses to identify novel genetic factors and regulatory mechanisms for biofilm formation in STEC. 2: Examination of the influence of extrinsic (biotic and abiotic) and intrinsic factors on biofilm formation by STECs. 2.1 Microbiological properties and comparative transcriptomic analyses of serotype O157:H7 biofilms on abiotic and biotic surfaces, and in various environmental conditions. 2.2 Evaluation of the roles and interactions of various plasmids (conjugative or mobilizable) carried by mixed-biofilm partners (intrinsic factors). 2.3 Mixed culture biofilm of STEC with beef-associated biofilm-forming flora. 3: Qualitative and quantitative characterization of microbial communities associated with beef, and how the various populations influence the presence of STECs. 3.1 16S rDNA-targeted metagenomic studies of microbiomes on ground and intact beef. 3.2 16S rDNA-targeted metagonomic studies of microbiomes associated with beef slaughter facilities (and their correlation with the presence of STEC). 3.3 16S rDNA-targeted metagonomics studies of biofilm forming bacteria associated with beef and beef slaughter facilities. 3.4 Quantitative computational analyses of microbiomes by whole-genome metagenomics.
1b. Approach (from AD-416):
Microbes rarely exist in the environment as a monoculture but in complex microbial communities that are often attached to solid surfaces. The association of pathogenic bacteria within these biofilm communities is known to lead to their persistence in food processing environments, ultimately resulting in the contamination of foods and foodborne illness. The goal of this research project is to better understand microbial communities and community structures by which Shiga toxin-producing Escherichia coli (STEC) persist in beef and result in human illness by 1) determining the unique mechanisms of biofilm formation in STEC; 2) evaluating the role of antibiotic resistance in biofilm formation and persistence; 3) determining the composition of microbial communities in beef and beef processing facilities; 4) testing for a correlation between community composition and the presence of STEC; 5) determining the presence of biofilm forming bacteria in beef and beef processing facilities; and 6) testing if biofilm-forming flora from beef and beef processing facilities can contribute to the association and persistence of STEC with mixed biofilms.
3. Progress Report:
This new Project Plan was recently certified through ARS Office of Scientific Quality Review (OSQR). For further details on current work see the 2016 annual report for project 8072-42000-067-00D.
5. Significant Activities that Support Special Target Populations: