Suchitra Hourigan, M.D.

Lasker Clinical Research Scholar

Clinical Microbiome Unit (CMU)


Building 50, Room 5511
50 South Drive
Bethesda, MD 20892


Research Topics

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.


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

  1. Nashed L, Mani J, Hazrati S, Stern DB, Subramanian P, Mattei L, Bittinger K, Hu W, Levy S, Maxwell GL, Hourigan SK. Gut microbiota changes are detected in asymptomatic very young children with SARS-CoV-2 infection. Gut. 2022;71(11):2371-2373.
  2. Hourigan SK, Dominguez-Bello MG, Mueller NT. Can maternal-child microbial seeding interventions improve the health of infants delivered by Cesarean section? Cell Host Microbe. 2022;30(5):607-611.
  3. Chaudhary PP, Myles IA, Zeldin J, Dabdoub S, Deopujari V, Baveja R, Baker R, Bengtson S, Sutton A, Levy S, Hourigan SK. Shotgun metagenomic sequencing on skin microbiome indicates dysbiosis exists prior to the onset of atopic dermatitis. Allergy. 2023.
  4. Hourigan SK, Dominguez-Bello MG. Microbial seeding in early life. Cell Host Microbe. 2023;31(3):331-333.
  5. Mueller NT, Differding MK, Sun H, Wang J, Levy S, Deopujari V, Appel LJ, Blaser MJ, Kundu T, Shah AA, Dominguez Bello MG, Hourigan SK. Maternal Bacterial Engraftment in Multiple Body Sites of Cesarean Section Born Neonates after Vaginal Seeding-a Randomized Controlled Trial. mBio. 2023;14(3):e0049123.

Related Scientific Focus Areas

This page was last updated on Monday, August 21, 2023