Suchitra Hourigan, M.D.

Clinical Microbiome Unit (CMU)

NIH Main Campus, Bethesda, MD

Suchitra Hourigan, M.D.

Chief, Clinical Microbiome Unit (CMU)
Lasker Clinical Research Scholar

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Specialty(s): Pediatric Gastroenterology, Pediatrics
Provides direct clinical care to patients at NIH Clinical Center

Suchitra Hourigan, M.D.

Major Areas of Research

  • Clinical microbiome interventions to mitigate chronic inflammatory diseases
  • Early life microbiome therapies to improve future health
  • Advanced exploration of microbiome and host physiology interactions in humans

Program Description

The Clinical Microbiome Unit focuses on microbiome interventions to mitigate chronic inflammatory diseases. 

The immune system and inflammatory processes are involved in a wide variety of diseases that dominate worldwide morbidity and mortality. It is well documented in animal models and observational studies that dysbiosis or imbalance of the gut microbiome is associated with many chronic diseases with an inflammatory or immune mediated etiology. The Clinical Microbiome Unit aims to translate this science in humans beyond descriptive and associative studies to clinical microbiome interventions to improve health and change the trajectory of these diseases. Our novel integrative approach allows for advanced exploration of microbiome and host physiology interactions in humans anchored by objective assessments of health consequences of clinical microbiome interventions.

Early life represents a critical window for dynamic gut microbiome development and subsequent immune and inflammatory regulation. As such, our unit particularly focuses on early life microbiome interventions with the hypothesis that such timing is most likely to protect against subsequent inflammatory diseases. Therefore, a major aim is our 600-subject randomized placebo-controlled clinical trial of the microbiome intervention, “vaginal seeding,” in babies born by Cesarean Section, who are at increased risk of inflammatory diseases including obesity and atopy. We also lead studies investigating other microbiome interventions including fecal transplant and early life antibiotics.  
Together, these efforts not only investigate microbiome interventions to improve health in humans, but also support translational research to help understand mechanisms of changes in microbiota composition and function, and host-microbiota immune and inflammatory interactions resulting from these novel clinical interventions.



M.D., University of Oxford, UK

Dr. Suchitra (Suchi) Hourigan was born in the UK and received her medical degree from the University of Oxford.  She is a board-certified physician in pediatrics and pediatric gastroenterology, having completed her pediatric residency and pediatric gastroenterology fellowship training at the Johns Hopkins Hospital in Baltimore, MD. Prior to coming to NIH, Dr. Hourigan held faculty positions at the Johns Hopkins School of Medicine and the University of Virginia and served as Vice Chair of Research at Inova Children’s Hospital, VA. She joined NIAID in 2021 as a Lasker Clinical Research Scholar and an NIH Distinguished Scholar.

Selected Publications

Hourigan SK, Nicholson MR, Kahn SA, Kellermayer R. Updates and Challenges in Fecal Microbiota Transplantation for Clostridioides difficile Infection in Children. J Pediatr Gastroenterol Nutr. 2021 Jul.

Nicholson MR, Mitchell PD, Alexander E, Ballal S, Bartlett M, Becker P, Davidovics Z, Docktor M, Dole M, Felix G, Gisser J, Hourigan SK, Jensen MK, Kaplan JL, Kelsen J, Kennedy M, Khanna S, Knackstedt E, Leier M, Lewis J, Lodarek A, Michail S, Oliva-Hemker M, Patton T, Queliza K, Russell GH, Singh N, Solomon A, Suskind DL, Werlin S, Kellermayer R, Kahn SA. Efficacy of Fecal Microbiota Transplantation for Clostridium difficile Infection in Children. Clin Gastroenterol Hepatol. 2020 Mar;18(3):612-619.e1.

Mueller NT, Dominguez-Bello MG, Appel LJ, Hourigan SK. 'Vaginal seeding' after a caesarean section provides benefits to newborn children: FOR: Does exposing caesarean-delivered newborns to the vaginal microbiome affect their chronic disease risk? The critical need for trials of 'vaginal seeding' during caesarean section. BJOG. 2020 Jan;127(2):301.

Wong WSW, Sabu P, Deopujari V, Levy S, Shah AA, Clemency N, Provenzano M, Saadoon R, Munagala A, Baker R, Baveja R, Mueller NT, Dominguez-Bello MG, Huddleston K, Niederhuber JE, Hourigan SK. Prenatal and Peripartum Exposure to Antibiotics and Cesarean Section Delivery Are Associated with Differences in Diversity and Composition of the Infant Meconium Microbiome. Microorganisms. 2020 Jan;8(2):179.

Hourigan SK, Ahn M, Gibson KM, Pérez-Losada M, Felix G, Weidner M, Leibowitz I, Niederhuber JE, Sears CL, Crandall KA, Oliva-Hemker M. Fecal Transplant in Children With Clostridioides difficile Gives Sustained Reduction in Antimicrobial Resistance and Potential Pathogen Burden. Open Forum Infect Dis. 2019 Aug;6(10):ofz379.

Hourigan SK, Chen LA, Grigoryan Z, Laroche G, Weidner M, Sears CL, Oliva-Hemker M. Microbiome changes associated with sustained eradication of Clostridium difficile after single faecal microbiota transplantation in children with and without inflammatory bowel disease. Aliment Pharmacol Ther. 2015 Sep;42(6):741-52.

Visit PubMed for a complete publication list.

Research Group

Our diverse, talented research group support the vision and clinical and translational studies of the lab.

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