Clostridium difficile is a major nosocomial pathogen that causes severe diarrheal disease that is highly infectious and difficult to treat. C. difficileis easily transmitted due to its ability to form dormant spores. The spore form of C. difficile is resistant to most disinfectants and is critical for the survival of the bacterium outside of the hot. The only natural environment known to support C. difficile spore formation is the gastrointestinal tract, yet we know very little about how spore formation occurs. We hypothesize that sporulation of C. difficile is initiated in response to signals found within the host intestine, through an unknown and unique genetic mechanism. The long-term goal of this project is to uncover how C. difficile forms spores in the host so that molecular targets can be identified to disrupt the sporulation process. The specific objectives of this application are to identify the genetic mechanisms required for spore initiation and determine where sporulation is initiated in the host. Capitalizing on our previous experience with Bacillus subtilis sporulation, Gram-positive intestinal pathogenesis and C. difficile molecular genetics, we will meet these objectives through the experiments detailed in two specific aims. First, we will reveal the genetic mechanisms of spore initiation in C. difficile through genetic analysis of sporulation-defective mutants and newl identified early sporulation regulators. In parallel, we will define the progression of spore formation and explore the activation of sporulation regulators within the intestinal environment. The research proposed in this application is innovative because it represents a departure from the model sporulation paradigm as the archetypal standard for spore initiation by C. difficile and seeks to uncover the unique mechanisms that regulate sporulation this pathogen. The expected contribution of the proposed research is a detailed understanding of the genes required for spore initiation and the development of spores within the host. This contribution is significant because it is the first step in the development of strategies to prevent spore formation by C. difficile.

Public Health Relevance

The experiments in this proposal are designed to uncover the mechanisms used by Clostridium difficile to form an infectious spore. The project is relevant to the NIH's mission of understanding and preventing bacterial infections and digestive diseases.

Agency
National Institute of Health (NIH)
Institute
National Institute of Allergy and Infectious Diseases (NIAID)
Type
High Priority, Short Term Project Award (R56)
Project #
1R56AI109526-01
Application #
8897724
Study Section
Bacterial Pathogenesis Study Section (BACP)
Program Officer
Ranallo, Ryan
Project Start
2014-08-15
Project End
2015-07-31
Budget Start
2014-08-15
Budget End
2015-07-31
Support Year
1
Fiscal Year
2014
Total Cost
$383,420
Indirect Cost
$133,420
Name
Emory University
Department
Microbiology/Immun/Virology
Type
Schools of Medicine
DUNS #
066469933
City
Atlanta
State
GA
Country
United States
Zip Code
30322
Ghose, Chandrabali; Eugenis, Ioannis; Edwards, Adrianne N et al. (2016) Immunogenicity and protective efficacy of Clostridium difficile spore proteins. Anaerobe 37:85-95
Ghose, Chandrabali; Eugenis, Ioannis; Sun, Xingmin et al. (2016) Immunogenicity and protective efficacy of recombinant Clostridium difficile flagellar protein FliC. Emerg Microbes Infect 5:e8
Childress, Kevin O; Edwards, Adrianne N; Nawrocki, Kathryn L et al. (2016) The Phosphotransfer Protein CD1492 Represses Sporulation Initiation in Clostridium difficile. Infect Immun 84:3434-3444
Edwards, Adrianne N; Tamayo, Rita; McBride, Shonna M (2016) A novel regulator controls Clostridium difficile sporulation, motility and toxin production. Mol Microbiol 100:954-71
Woods, Emily C; Nawrocki, Kathryn L; Suárez, Jose M et al. (2016) The Clostridium difficile Dlt Pathway Is Controlled by the Extracytoplasmic Function Sigma Factor σV in Response to Lysozyme. Infect Immun 84:1902-16
Edwards, Adrianne N; McBride, Shonna M (2016) Isolating and Purifying Clostridium difficile Spores. Methods Mol Biol 1476:117-28
Edwards, Adrianne N; Karim, Samiha T; Pascual, Ricardo A et al. (2016) Chemical and Stress Resistances of Clostridium difficile Spores and Vegetative Cells. Front Microbiol 7:1698
Nawrocki, Kathryn L; Edwards, Adrianne N; Daou, Nadine et al. (2016) CodY-Dependent Regulation of Sporulation in Clostridium difficile. J Bacteriol 198:2113-30
Edwards, Adrianne N; Pascual, Ricardo A; Childress, Kevin O et al. (2015) An alkaline phosphatase reporter for use in Clostridium difficile. Anaerobe 32:98-104
Edwards, Adrianne N; Nawrocki, Kathryn L; McBride, Shonna M (2014) Conserved oligopeptide permeases modulate sporulation initiation in Clostridium difficile. Infect Immun 82:4276-91

Showing the most recent 10 out of 11 publications