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United States Department of Agriculture

Agricultural Research Service

Research Project: Molecular Biology of Human Pathogens Associated with Food

Location: Produce Safety and Microbiology Research

Project Number: 5325-42000-047-00
Project Type: Appropriated

Start Date: Feb 25, 2011
End Date: Feb 24, 2016

Objective:
Objective 1: Comparative genomic analyses of Campylobacter, Arcobacter, E. coli and S. enterica to identify novel genetic elements or polymorphisms that are associated with virulence, niche specialization or other adaptive traits. Objective 2: Develop sequence-based typing methods to detect and analyze multiple critical food-borne pathogens from multiple sources. Objective 3: Generate gene expression profiles for E. coli, S. enterica, and Campylobacter from varying sources and in response to various environmental stresses to identify factors contributing to virulence and survival in diverse habitats. Objective 4: Develop rapid, simple and inexpensive multiplex assays for pathogen detection and virulence characterization using novel technology for use in surveillance and outbreak epidemiology. Objective 5: Establish proteomic approaches for detecting and typing foodborne pathogens and toxins, and measure pathogen response to environmental stresses by mass spectrometry methods. Objective 6: Investigate mechanisms of bacterial toxicity and evaluate novel methods for inactivating Shiga toxins by developing cell-based assays for assessing toxicity and comparing the relative toxicity of Shiga toxin 1 and 2 variants.

Approach:
Our objectives address fundamental research for comparative genomic analyses of Campylobacter and Arcobacter species, and pathogenic Escherichia coli and Salmonella enterica serovars to identify novel genetic elements or polymorphisms associated within virulence, niche specialization or other adaptive traits. We will analyze the genomic data to develop sequence-based typing methods to detect and analyze multiple critical food-borne pathogens from multiple sources for purposes of improved source tracking to identify reservoirs in food production environments. The genomic data will allow us to develop methods for gene expression profiling of pathogens from different sources and their responses to various environmental stresses to identify factors contributing to virulence and survival in diverse habitats; and develop rapid, simple and inexpensive multiplex assays for pathogen detection and virulence characterization using novel technology for use in surveillance and outbreak epidemiology. The genomic data facilitate developing “top-down” and “bottom-up” mass spectrometry approaches for proteomic analysis for detecting and typing foodborne pathogens and toxins, and measuring pathogen response to environmental stresses. Non-O157 Shiga toxin-producing E. coli (STEC) strains have emerged as a source of more human illness than appreciated previously. Data for isolating and detecting them are a critical need and will be provided through this research. We also will be researching mechanisms of bacterial toxicity to develop and evaluate novel methods for inactivating Shiga toxins by developing cell-based assays for assessing toxicity and comparing the relative toxicity of Shiga toxin 1 and 2 variants. In summary, we will use the latest analytical tools to obtain data for identifying foodborne pathogens, differences in strains related to fitness and virulence, novel interventions related to toxins and, ultimately, approaches for minimizing illness associated with food.

Last Modified: 4/18/2014
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