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Tundra lists 61 Microbial Colonization clinical trials. Each listing includes eligibility criteria, study locations, and direct links to research sites in the Tundra directory.
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NCT05167318
Frequent Standardized Oral Care to Improve Health Outcomes in Premature Infants in the Neonatal Intensive Care Unit
Premature very low birth weight (VLBW) infants are susceptible to complications related to infrequent and non-standardized oral care. Although the benefits of frequent standardized oral care are known to reduce oral dybiosis (increased level of potentially pathogenic bacteria) and its associated complications in critically ill adults leading to established evidence-based guidelines, no such information exists for VLBW infants. The proposed study will prospectively follow 40 VLBW infants for 4 weeks following birth. Infants will be randomized into 1 of 2 groups. Standardized oral care will be performed every 3-4 hours (Group 1) and every 12 hours (Group 2). Aim 1 will evaluate the feasibility of frequent standardized oral care, Aim 2 will compare the oral microbiome between groups, and Aim 3 will compare respiratory outcomes including the incidence of ventilator associated pneumonia, bronchopulmonary dysplasia and need for respiratory support between infants receiving standardized oral care every 3-4 hours and every 12 hours. Issues related to recruitment, retention, randomization, acceptance by nursing staff, and treatment fidelity will be examined. Saliva samples will be obtained weekly and analyzed using 16S sequencing, respiratory cultures will be obtained weekly on ventilated infants, and respiratory outcomes will be collected from the medical records.
Gender: All
Ages: 12 Hours - 72 Hours
Updated: 2026-05-18
1 state
NCT04130165
Matching Donor Human Milk On Maternal Secretor Status (MMOMSS) Study
This study will evaluate the impact of matching donor human milk to the maternal secretor status of very preterm infants (\<34 weeks gestation) on the gut microbiome. Half of enrolled infants will receive donor human milk which is matched their mother's secretor status and half will receive standard (unmatched) donor human milk, which is standard care in the neonatal intensive care unit.
Gender: All
Ages: 18 Years - Any
Updated: 2026-05-08
1 state
NCT06970262
FMT for Lung and Associated-organ Rescue Efficacy in MDRO-infected Ventilated Patients
Multidrug-resistant organism (MDRO)-infection represents a substantial global health burden. In the intensive care unit (ICU), the concurrent administration of antibiotics, opioids, proton pump inhibitors (PPIs), vasoconstrictors, and parenteral nutrition-compounded by the intrinsic severity of critical illness-induces profound gut microbiota dysbiosis. Accumulating preclinical and clinical evidence indicates that such intestinal dysregulation may trigger distal immunomodulatory and microbial shifts in the lung via the gut-lung axis, thereby contributing to pulmonary microecological imbalance and impairing recovery trajectories. Although pulmonary microecology has garnered increasing scientific attention, the causal and temporal relationship between gut dysbiosis and the establishment or exacerbation of pulmonary microbial dysbiosis in MDRO-infecction remains inadequately characterized. As a result, it is currently unclear whether gut dysbiosis serves as a primary pathogenic driver, a disease-amplifying factor, or a secondary epiphenomenon in the context of MDRO-infecction-associated lung injury. Fecal microbiota transplantation (FMT) is a targeted microbiome-modulating intervention that involves the transfer of functionally diverse, minimally processed microbial communities from comprehensively screened healthy donors to restore ecological stability and functional redundancy in the recipient gut. Robust clinical data demonstrate that FMT effectively decolonizes the gastrointestinal tract of MDROs and reduces the incidence of secondary infections in immunocompetent, non-critically ill populations. Over the past decade, FMT has demonstrated reproducible efficacy in recurrent Clostridioides difficile infection and emerging promise in select extra-intestinal inflammatory conditions-highlighting its capacity as a mechanism-informed strategy for systemic host-microbe recalibration. Given the established role of the gut as a reservoir for enteric pathogens implicated in sepsis, hospital-acquired bloodstream infections, and ventilator-associated pneumonia (VAP), we propose a prospective, single-center, open-Label, randomized controlled trial (RCT) enrolling mechanically ventilated adults with MDRO-infeccted ventilated patients. The primary objective is to evaluate whether adjunctive FMT-delivered via nasojejunal tube-decrease 28-day mortality.
Gender: All
Ages: 18 Years - 70 Years
Updated: 2026-05-05
NCT06541808
Balance, Autonomic Response, and Sensory Modulation to Dosage of Mechanical Vagal Stimulation in Healthy Adults
The vagus nerve (VN) plays a crucial role in regulating vital functions (heart rate, blood pressure, digestion, and immune response) and maintaining communication between internal organs and the brain. Recent studies have highlighted the therapeutic potential of VN stimulation (VNS) in treating various conditions such as drug-resistant epilepsy, postural control deficit, COVID-19 infection, chronic pain, and intestinal disorders. In addition, there is growing evidence that the molecules released by the VN neurons affect the function of the gut microbiota and that the molecules released by the bacteria in our gut affect the activity of the VN neurons. In particular, Dr. Giacomo Carta (the leader of this study) has shown how painless neck movements, i.e. mechanical VNS (mVNS), can be applied without adverse effects, representing a potential alternative to invasive methods commonly used today. To further investigate the impact of this novel mVNS, this study aims to evaluate the changes induced by three mVNS protocols on physiological parameters such as resting heart rate, and Heart Rate Variability (HRV) at rest, balance in standing, the perceived intensity of mechanical stimuli using the established clinical method of QST (quantitative sensory testing), fecal transit speed, and the molecular composition of stool (for this, stool samples are analyzed). In particular, stool analysis is very relevant for understanding normal digestion. The present research aims to define the optimal intensity of mVNS and to investigate the therapeutic potential of VNS in the treatment of autonomic dysfunction (such as too low or too high heart rate, too low or too fast digestion, throbbing headaches), as well as falls prevention and pain.
Gender: All
Ages: 18 Years - 60 Years
Updated: 2026-04-29
1 state
NCT04992104
Microbiome and Malnutrition in Pregnancy
This study is being conducted to investigate how a mother's nutritional status and her gut microbiome during pregnancy contribute to the birth outcomes and health of her baby. The gut microbiome is the totality of microorganisms (e.g. bacteria, viruses, fungi) living in the gastrointestinal tract. This study will focus on pregnant women, 28 years and younger living in the Toronto and greater Toronto area. The focus is on younger women due to their vulnerability to undernutrition. Pregnant participants, and upon delivery, their newborns will be followed throughout pregnancy and for a year afterwards. Throughout this period, the investigators will collect stool samples, rectal swabs, blood samples, health assessments, nutritional and dietary assessments and birth/ labour details. The goal is to define the relationship between a mother's nutritional status and her microbiome dynamics during pregnancy and how they contribute to the birth outcomes and growth of her newborn. With the hypothesis that alterations of the microbiota in the maternal gut (dysbiosis) exacerbated by nutritional status or pathogen exposure during pregnancy, impacts weight gain because of impaired nutrient absorption, leading to corresponding negative birth outcomes.
Gender: FEMALE
Ages: Any - 28 Years
Updated: 2026-04-28
NCT07092046
Minimal Flow Anesthesia and Infection Risk
This study is being done to find out if the heat and moisture that build up during minimal flow anesthesia can lead to the growth of germs (microorganisms) inside the anesthesia equipment. Minimal flow anesthesia (using fresh gas flow of 0.5 liters per minute or less) is known to help protect the lungs and the environment. However, it may also cause water to collect in the equipment, which could allow germs to grow. In this study, we want to see whether this type of anesthesia is safe when it comes to the risk of germs in the equipment.
Gender: All
Ages: 18 Years - 65 Years
Updated: 2026-04-28
NCT05401292
Skin Preparation for Elective Foot and Ankle Surgery
Surgical site infections (SSIs) make about 31% of all nosocomial infections and they are the most common hospital-acquired infection. For foot and ankle elective interventions, SSI rate is reported between 0.4% and 3.6%. This study will investigate the effectiveness of skin cleaning with isopropyl alcohol and scrubbing with chlorhexidine soap before standard skin preparation in reducing microbial load and surgical site infections for elective foot and ankle surgeries. Current standard of care includes skin preparation with iodine or chlorhexidine solution prior to sterile draping and the start of surgery. Standard of care will be applied to all patients. The use of an additional "pre-scrub" with isopropyl alcohol and scrubbing with chlorhexidine soap will be applied to the experimental group. The control group will receive only the standard of care skin preparation with iodine or chlorhexidine solution prior to draping.
Gender: All
Ages: 18 Years - Any
Updated: 2026-04-27
1 state
NCT06381882
The Role of the Human Microbiome in Patients After Pancreatic Resection.
The goal of this observational study is to classify patients that undergo pancreatic resection for presumed pancreatic or periampullary malignancy into high and low risk groups for postoperative complications based on longitudinal saliva, rectal/faecal, tumor, blood and/or bile microbiome profiles. To identify the dynamics of the microbiome, as well as the possibly related short-term and long-term complications, multiple samples at different timepoints are needed from the patients.
Gender: All
Ages: 18 Years - Any
Updated: 2026-04-27
NCT03997266
NICU Antibiotics and Outcomes Trial
The goal of the NANO trial is to study the longstanding clinical practice of empirically administering intravenous antibiotics to extremely low birthweight (ELBW) infants in the first days of life. In this 802-subject multicenter placebo-controlled randomized clinical trial, the hypothesis to be tested is that the incidence of adverse outcomes is higher in babies receiving empiric antibiotics (EA) in the first week of life compared to babies receiving placebo. The study targets a population of ELBW infants in whom the clinical decision to use or not use EA is currently most challenging -- infants that are clinically stable that did not have a known exposure to intraamniotic infection and were not born preterm for maternal indications. The primary outcome is the composite outcome of late-onset sepsis (LOS), necrotizing enterocolitis (NEC), or death during the index hospitalization. Secondary safety outcomes will include total antibiotic days, days to full enteral feedings, and common morbidities in preterm infants that have previously been linked to EA, e.g. retinopathy of prematurity and bronchopulmonary dysplasia. Weight and length z-score, and head circumference, are standard measures to be collected weekly by clinical team per a standardized protocol.
Gender: All
Ages: Any - 4 Hours
Updated: 2026-04-24
9 states
NCT06920641
Effects of Tagatose on Glycemic Response and Gastrointestinal Microbiota in Healthy Adults
The primary objective of this clinical-trial is to determine, in subjects with impaired fasting glucose (IFG) and/or insulin resistance (IR), if tagatose meets the definition of a prebiotic, namely that consuming tagatose for 4 weeks selectively stimulates the selective growth of bacteria in the colon and is associated with a health benefit (oral glucose tolerance) when compared to consuming the control treatment (10g sucrose) for 4 weeks.
Gender: All
Ages: 18 Years - 50 Years
Updated: 2026-04-21
1 state
NCT07512050
Oral Lactobacillus Reuteri for Skin Barrier Dysfunction in Obesity
This clinical trial aims to evaluate the safety and efficacy of oral Lactobacillus reuteri supplementation for treating obesity-induced skin barrier impairment in individuals aged 18-40 with a BMI ≥30. The study focuses on the following questions: Can oral Lactobacillus reuteri supplementation reduce skin barrier damage (measured by transepidermal water loss/TEWL) in obese participants? Does modulation of gut microbiota with Lactobacillus reuteri impact skin barrier function and systemic inflammation? Researchers will compare outcomes across two groups: Intervention Group (Obese): Oral Lactobacillus reuteri capsules. Placebo Control Group (Obese): Oral inactive (heat-killed) Lactobacillus reuteri. Participant Procedures: Take daily oral capsules (Lactobacillus reuteri or inactive strain) for 4 weeks. Undergo non-invasive skin testing (TEWL measurements) at baseline and study completion. Provide stool and samples for analyses. Complete weekly check-ins to report adverse effects (e.g., gastrointestinal discomfort, skin irritation).
Gender: All
Ages: 18 Years - 40 Years
Updated: 2026-04-06
NCT05966649
Synbiotics in Patients at RIsk fOr Preterm Birth
Prematurity remains the main cause of death and serious health problems in new-borns. Besides the need for hospitalization and medical interventions in the first weeks or months of the new-borns' life, prematurity can cause long-lasting health problems (e.g. multiple hospital admissions, developmental delay, learning difficulties, motor delay, hearing or eye problems, ...). Moreover, prematurity places an enormous economic burden on the society. Aside from the medical problems and the financial cost, the emotional stress and psychological impact on the parents, siblings and other family members should not be underestimated. Previous preterm delivery (before 37 weeks of pregnancy) increases the risk for recurrent preterm delivery in a subsequent pregnancy. Therefore, these women should be considered as 'high risk' for preterm birth. Infections ascending from the vagina may be an important cause of preterm delivery in certain cases. Some women have an abnormal vaginal microbiome and are therefore at risk for infections and preterm birth. On the other hand, the vaginal flora is more stable and resistant to infections in healthy pregnant women who deliver at term (after 37 weeks of gestation). Synbiotics are a mixture containing probiotics and prebiotics. Probiotics are living bacteria with potential beneficial effects that can be used safely in pregnancy, while prebiotics are consumed by the bacteria. It is known that probiotics, when used for a long period of time, can maintain a healthy and stable vaginal flora that may protect against infections. In this study, pregnant patients with a history of preterm birth will be included in the first trimester of pregnancy to start with synbiotics or placebo. The investigators will examine the effect of synbiotics on the vaginal flora and on the pregnancy duration. The hypothesis is that synbiotics, when started early in the pregnancy, can change the disturbed vaginal flora into a stable micro-environment.
Gender: FEMALE
Ages: 18 Years - Any
Updated: 2026-02-27
5 states
NCT07429864
Changes in Bile Acids and Microbiota in Patients With Hepatitis D Treated With Bulvertide
HDV is an RNA virus that infects only in the presence of HBV, affecting about 13% of HBsAg carriers. In Italy, prevalence ranges from 3.2% to 9.3%. It increases the risk of cirrhosis, fulminant hepatitis, and HCC, particularly in high-risk groups (HIV, HCV, drug users, dialysis patients). Until 2020, pegIFN was the only therapy; since 2022, bulevirtide (BLV) has been available, blocking viral entry into hepatocytes and reducing HDV RNA and liver stiffness, with efficacy in 45-48% of patients, though the optimal treatment duration remains uncertain. The gut microbiota and bile acids also play a role in fibrosis and cirrhosis progression: dysbiosis, typical in cirrhotic patients, alters bile acid metabolism and increases intrahepatic toxicity.
Gender: All
Ages: 18 Years - Any
Updated: 2026-02-24
NCT06177184
DOnor Milk to REpair the Full-term Infant MIcrobiome in Infants Born Via Cesarean Section.
The objective of this novel study is to establish proof of concept using a pilot randomized controlled trial to determine the effect of DHM compared to formula supplementation on the microbiome in full-term infants who are born via caesarean section and require supplementation. Secondarily, this study aims to compare the infant health outcomes of sleep and growth between groups to assess if these outcomes are mediated by infant feeding type or potential differences in microbial signatures. Finally, this study will compare maternal outcomes of depression, anger, breastfeeding self-efficacy and breastfeeding rates between groups. The infant gut microbiome plays a critical role in the developing immune, neurologic, and endocrine systems. Yet, most infants experience early life disruptions (ELDs) to their microbiome that have potential long-term health and development impacts. A major source of disruption is caesarean section (c-section) delivery because the infant is born surgically and is not exposed to important commensal bacteria required to establish the infant microbiome. Currently in Canada, over 28% of infants are born via c-section. Exclusive breastfeeding can improve gut microbiota composition in infants who are born via c-section. However, approximately 60% of infants born via c-section require formula supplementation in their first week of life. Evidence indicates that even one bottle of formula can further disrupt the gut microbiome. Donor human milk (DHM) is a superior alternative to formula when supplementation is required as its biotic properties minimize perturbations to the infant gut microbiome and may help to repair the microbiome in infants who experience ELDs. Yet, while DHM is well researched in preterm populations, evidence on the impact of DHM as a therapeutic intervention on the full-term infant gut microbiome is lacking. The hypothesis of this study is: that replacing formula with DHM supplementation will minimize gut microbiome dysbiosis and foster homeostasis following supplementation. In addition, it is hypothesized that improved homeostasis will promote improved sleep and growth outcomes in participant infants. Finally, mothers whose infants receive DHM will have lower depression and anger scores and higher breastfeeding self-efficacy and exclusive breastfeeding rates compared to mothers whose infants receive formula.
Gender: All
Ages: 37 Weeks - Any
Updated: 2026-02-20
1 state
NCT05414994
Assessment of the Ocular Microbiome in Health and Disease
The objective of this application is to illustrate the core constituents of the ocular surface microbiome, describe factors that promote colonization, and assess the ocular microbiome's role in the health of the anterior segment. We will conduct a prospective, observational cohort study, including a longitudinal analysis of the ocular microbiome in adults.
Gender: All
Ages: 18 Years - Any
Updated: 2026-01-22
1 state
NCT07043712
Effects of Pulse Consumption, Gut Microbiome, and Appetite in Healthy Participants
The purpose of the study is to investigate the effects of pulse consumption versus no pulse consumption on the gut microbiome, meal satiety, and short-chain fatty acid metabolomics.
Gender: All
Ages: 20 Years - 55 Years
Updated: 2026-01-15
1 state
NCT05743374
Micronutrient and Additive Modifications May Optimize Diet To Health
This is a prospective clinical intervention trial where patients with moderately active ulcerative colitis are randomized to either normal healthy diet or a diet with elimination of emulsifying agents within the E 400-group with special respect to carragenan, CMC and polysorbates. At study start and end after one month their diet, clinical characteristics and microbiota will be analysed. The hypotheses are that their disease activity measured with calprotectin and their microbiota will improve after intervention.
Gender: All
Ages: 18 Years - Any
Updated: 2026-01-12
1 state
NCT05603650
Effects of Mouthrinse on the Microbiome of the Oral Cavity and GI Tract
The purpose of this research study is to identify the effects of 2 over-the-counter mouthwashes on bacteria and 3 viruses in the participant's mouth and gut. The participant will be randomly allocated to rinse their mouth twice daily either with Listerine mouthwash, Lumineux Oral Essentials mouthwash, or water. The overall duration of the study will be approximately 180 days and will include approximately 5 visits and 15-30 minutes for each visit with a total of approximately 2.5 hours of your time. Additionally, fecal matter will also be collected in some subjects using a commercial collection kit.
Gender: All
Ages: 18 Years - Any
Updated: 2025-12-17
1 state
NCT05695196
Feasibility and Safety Study of Parent-to-Child Nasal Microbiota Transplant
This feasibility and safety pilot study looks to determine whether transferring a parents healthy, diverse nasal microbiota to the participant's infant(s) will create a healthy, diverse neonatal nasal microbiome.
Gender: All
Ages: Any - 60 Years
Updated: 2025-12-11
1 state
NCT03229863
An Examination of Infants' Microbiome, Nutrition, and Development Study.
This study is examining the relationship between infant nutrition, gut health, and development. The fecal microbiota changes and develops, in large part due to the food that infants eat. These changes are important for many aspects of development. This study is designed to examine how the fecal microbiota changes when exclusively breastfed infants are first introduced to solid food, and how changes of the fecal microbiota are related to other aspects of development.
Gender: FEMALE
Ages: 21 Years - 45 Years
Updated: 2025-12-05
1 state
NCT04325308
Early Protein Supplementation in Extremely Preterm Infants Fed Human Milk
The central hypothesis of this clinical trial is that, in extremely preterm infants, protein-enriched human milk diets compared to usual human milk diets during the first 2 weeks after birth increase fat-free mass (FFM)-for-age Z scores and promote maturation of the gut microbiome at term corrected age.
Gender: All
Ages: 1 Day - 4 Days
Updated: 2025-09-23
1 state
NCT06283355
Comparing Single Versus Repeat NMT on the Diversity of the Neonatal Nasal Microbiome
This study aims to determine whether a parent-to-child nasal microbiota transplant (NMT) can seed and engraft parental organisms into the neonatal microbiome and increase the neonatal microbiome diversity.
Gender: All
Ages: 0 Years - 60 Years
Updated: 2025-09-11
1 state
NCT06805994
Administering NMT to Reestablish Infant Nasal Microbiome Diversity Following Intranasal Mupirocin Treatment
This protocol aims to evaluate how NMT affects pediatric nasal microbiome diversity following intranasal mupirocin treatment
Gender: All
Ages: 0 Years - 60 Years
Updated: 2025-09-04
1 state
NCT06938386
Pilot Haskap Metabolite Timing Project
Diet is a key factor in managing health and individuals at risk of developing metabolic syndrome or other chronic diseases have the opportunity to use diet as a tool to improve their health. This can be complicated when considering the numerous variables that impact digestion and absorption of key health-promoting compounds in foods. One of these variables is the gut microbiome, a microbial community in the digestive tract that interacts with the foods we consume. The mechanisms the microbiome uses to interact with bioactive compounds in foods, like polyphenols, can modulate the health-promoting benefits of polyphenols. Polyphenols are secondary plant metabolites, commonly found in fruit, legumes, chocolate, coffee, and nuts among other foods that have been shown to improve cardiovascular and metabolic health, as well as reduce inflammation and oxidative stress.
Gender: All
Ages: 18 Years - 45 Years
Updated: 2025-08-19
1 state