Casey Thierot Profile


Casey Theriot

Casey M. Theriot, PhD

Assistant Professor of Infectious Diseases


Casey M. Theriot is an expert in Clostridioides difficile infections (CDIs) and interactions between the host and the gastrointestinal (GI) microbiome. 

Theriot has a multidisciplinary background in molecular microbiology, protein biochemistry, microbial ecology and bacterial pathogenesis. Throughout her research career, she has explored different mechanisms of how the gut microbiota protects us from colonization of pathogenic bacteria to improve public and global health. 

Her main focus is the bacterial pathogen C. difficile, a significant and re-emerging global health problem. Using in vitro and high throughput methods, animal models and human biological specimens, she and her team are exploring new opportunities to improve the treatment and prevention of CDIs and GI diseases. Her work with C. difficile spans a variety of projects, from epidemiological studies investigating the role of dogs as reservoirs for C. difficile, to manipulation of bile acids by probiotics to facilitate colonization resistance against CDIs. 

Theriot works with collaborators in both academia and industry to bridge basic science with translational research. At NC State, she is working with Megan Jacobs to explore C. difficile prevalence and antimicrobial resistance patterns in dogs. She is also working with Rodolphe Barrangou and Sarah O’Flaherty in the Department of Food, Bioprocessing and Nutrition Sciences to explore the therapeutic potential of bile acid manipulation to treat CDIs and other metabolic disorders. Outside of NC State, she is collaborating with UNC-Chapel Hill on a NCTraCSCMI project to investigate the mechanisms of fecal microbiota transplantation, a highly effective but poorly understood treatment for recurrent CDIs. Finally, she and her team are also working with Locus Biosciences to explore novel CRISPR-based therapeutics for CDIs. 

Altogether, Theriot’s expertise in GI diseases, the GI microbiome and metabolome, and a number of microbiological and epidemiological techniques are core components of global health research at the College of Veterinary Medicine.


Main Areas of Expertise

  • Bacterial genetics
  • Clostridioides difficile infections
  • In vitro bacterial physiology
  • Manipulation of gut microbiome to improve host health
  • Metabolomics
  • Mouse models
  • Transcriptomics

Global Health Research Interests

  • Improving treatment and prevention of gastrointestinal (GI) diseases by developing targeted bacterial approaches.
  • Using a range of experimental techniques and animal models of C. difficile infection to examine the role of the gut microbiome and metabolome on host defense and health.

Ongoing Projects

  • Developing novel CRISPR-based therapeutics for C. difficile infections
  • Elucidating the mechanisms of fecal microbiota transplants for recurrent C. difficile infections (NCTraCS-CMI)
  • Examining antimicrobial resistance in GI bacteria isolated from animal populations
  • Exploring the therapeutic potential of bile acid manipulation to treat metabolic disorders
  • Investigating the epidemiological analysis of C. difficile in dogs and the role of dogs as reservoirs of C. difficile
  • Targeted bacterial restoration of colonization resistance against C. difficile in the gastrointestinal tract.

Network (collaborators)

Selected Publications

Seekatz AM, Theriot CM, Rao K, Chang YM, Freeman AE, Kao JY, Young VB. Restoration of short chain fatty acid and bile acid metabolism following fecal microbiota transplantation in patients with recurrent Clostridium difficile infection. Anaerobe 2018 Oct; 53: 64-73 (Pubmed)

Callahan BJ, Wong J, Heiner C, Oh S, Theriot CM, Gulati AS, McGill SK, Dougherty MK. High-throughput amplicon sequencing of the full-length 16S rRNA gene with single-nucleotide resolution. bioRxiv 2018 Aug; DOI: (Article)

O’Flaherty S, Briner Crawley A, Theriot CM, Barrangou R. The Lactobacillus bile salt hydrolase repertoire reveals niche-specific adaptation. mSphere 2018 May; 3(3): pii: e00140-18 (Pubmed)

Fletcher JR, Erwin S, Lanzas C, Theriot CM. Shifts in the gut metabolome and Clostridium difficile transcriptome throughout colonization and infection in a mouse model. mSphere 2018 Mar; 3(2): pii: e00089-18 (Pubmed)

Theriot CM. Beyond structure: Defining the function of the gut using omic approaches for rational design of personalized therapeutics. mSystems 2018 Mar; 6: (3)2 (Pubmed)

Thanissery R, Winston JA, Theriot CM. Inhibition of spore germination, growth, and toxin activity of clinically relevant C. difficile strains by gut microbiota derived secondary bile acids. Anaerobe 2017 Jun; 45:86-100. (Pubmed)

Winston JA, Thanissery R, Montgomery SA, Theriot CM. Cefoperazone-treated mouse model of clinically-relevant Clostridium difficile strain R20291. J Vis Exp 2016 Dec; 10: (118) (Pubmed)

Theriot CM, Young VB. Interactions between the Gastrointestinal Microbiome and Clostridium difficile. Annu Rev Microbiol 2015 Oct; 69:445-61 (Pubmed)

View more on Google Scholar

Global Health Memberships


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