Small Intestinal Bacterial OvergrowthNCT04910815
Feasibility of a New Diagnostic Device to Assess Small Intestinal Dysbiosis in Routine Clinical Setting.
A study testing Atmo Gas Capsule, Glucose Breath Test and Fructoolifosaccharides (FOS) Breath Test in people with Small Intestinal Bacterial Overgrowth, run by Atmo Biosciences Pty Ltd at 2 sites in 2 countries.
Trial summary
The purpose of this study is to determine if the gas-sensing capsule can be used to identify increased numbers and a change of the composition of microbiota or microorganisms in the gut to assess small intestinal dysbiosis Read more about this study
- Who is it for?
- Ages 18 to 60 years
- Conditions the study is for
- Small Intestinal Bacterial Overgrowth
- What is being tested?
- Atmo Gas Capsule, Glucose Breath Test and Fructoolifosaccharides (FOS) Breath Test
- Type of treatment
- Pill or oral medicine, Medical device, Surgery or procedure
- Could I receive a placebo?
- Yes, some participants may receive a placebo
- How many people
- 110 participants
- Where
- 2 sitesin 2 countries
- Study dates
- 14 Jul 2021to 1 Aug 2025
- Phase
- Interventional
- Are there results?
- None posted in the registry
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 to 60 years
- All sexes
- No healthy volunteers
- Adult
Who may be able to join
- Patients aged over 18 years presenting to the Department of Gastroenterology \& Hepatology at the Princess Alexandra Hospital who require and are booked for an upper gastrointestinal endoscopy as part of the routine diagnostic work up of e.g. otherwise unexplained gastrointestinal symptoms.
Who cannot join
- Radiation Enteritis
- Pregnancy
- Gastric bezoar
- Swallowing disorders/dysphagia to food or pills
- Obese, with BMI over 35
- Suspected or known strictures of the GI tract
Show all 10Show fewer
- Fistulas or physiological/mechanical GI obstruction
- GI surgery within the past 3 months
- Diverticultis
- Patients with implantable or portable electro-mechanical medical devices, e.g. pacemakers
Trial locations and contacts
2 sites in 2 countries.
2 sites in 2 countries
India1 site
Sanjay Gandhi Postgraduate Institute of Medical Sciences
Lucknow, Uttar Pradesh, 226014,
About this study
The purpose of this study is to determine if the gas-sensing capsule can be used to identify increased numbers and a change of the composition of microbiota or microorganisms in the gut to assess small intestinal dysbiosis
Read the detailed description
In order to diagnose an increased bacterial density in the small intestine (e.g small intestinal bacterial overgrowth) metabolic activity of the microbiota colonising the small intestine is measured by exposing these bacteria with readily fermentable carbohydrates and measure subsequently (e.g. for 2 hrs) the change of the concentration of hydrogen (H2) and/or methane in the exhaled breath that results from carbohydrate fermentation in the small intestine. This is the principle of existing breath hydrogen tests, but they are poor at distinguishing where in the intestine the H2 is being produced, and their sensitivity is diminished by 'noise' in the breath H2 as a consequence of hydrogen or methane producing bacteria in the colon and this is frequently observed in the routine clinical setting. These shortcomings can be theoretically overcome by using the Atmo Gas CapsuleR which measures after ingestion gas concentrations during gastrointestinal transit in the lumen of the gut. As a consequence at the site of fermentation parts per hundred can be measured, rather than the parts per million (ppm) when methane or hydrogen are measured in the exhaled breath. An additional advantage is that the location of the capsule is known, and therefore the source of gas production from increased bacterial load can be determined. Preliminary studies using the gas capsule have shown good correlation of patterns of breath H2 with those of regional H2 patterns generated by the gas-sensing capsule. In fact, the capsule demonstrated far greater sensitivity in measuring H2 production and a vastly superior signal-to-noise ratio in response to a fermentable load than breath testing. Hence, investigating the utility of the gas-sensing capsule as a means for 'direct' assessment of microbial density presents an opportunity to overcome the shortcomings associated with the current breath test.
- Conditions
- Small Intestinal Bacterial Overgrowth
- Being tested
- Atmo Gas Capsule, Glucose Breath Test, Fructoolifosaccharides (FOS) Breath Test, Jejunal Aspiration and culture, Rifaximin
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Atmo Gas CapsuleDevice
The Atmo gas capsule is an ingestible electronic device. This capsule consists of gas and temperature sensors, electronic circuits, radio transmitter and silver oxide batteries. It can measure the concentrations and types of intestinal gases in individuals and give an indication of gut transit time. This data is used for research purposes to gain an understanding of the microbiota's localised functionality. The data from the sensors is transmitted out of the body over the radio frequency to a handheld receiver. The capsule passes out of the human body at the end of the measurement and is disposable.
Glucose Breath TestDiagnostic test
Glucose is a sugar that will be broken down by bacteria if present in the small bowel with hydrogen gas as a by-product. The hydrogen produced through fermentation is measured in the patients exhaled breath
Fructoolifosaccharides (FOS) Breath TestDiagnostic test
FOS is a long chain carbohydrate that can only be broken down by bacteria with hydrogen gas as a by-product. The hydrogen produced through fermentation is measured in the patients exhaled breath
Jejunal Aspiration and cultureProcedure or surgery
Endoscopic procedure to determine microbial load of the Small bowel. This is the gold standard to determine the Active SIBO cases
RifaximinDrug
Rifaximin (550g) 1 capsule twice a day for 14 days.
PlaceboDrug
randomised administration of either placebo or Rifaximin (550g) 1 capsule twice a day for 14 days. The placebo will be encapsulated maize starch and pregelatinised maize starch
| Study group | Role | What they receive |
|---|---|---|
| Primary recruitment | Experimental | Capsules will be ingested within 30 minutes prior to endoscopy pre- and post-antimicrobial intervention (if the patients has had a treatment) to determine if it can be used to identify increased microbial load through gas detection, and to identify responders to therapy. Receives: Device: Atmo Gas Capsule; Procedure: Jejunal Aspiration and culture |
| Active SIBO Arm - Rifaximin | Active comparator | If increased microbial load is determined through culture of aspiration during initial endoscopic procedure, randomised administration of Rifaximin (550g) 1 capsule twice a day for 14 days. The post-antimicrobial endoscopic procedure will be conducted at 6 weeks post the start of treatment.
These hydrogen concentration results will be compared to the following conventional breath tests in a crossover study design. Immediately after the endoscopic procedure, the patient will undergo a FOS challenge recording hydrogen breath samples for 2 hours in 20 min intervals while they recover from the endoscopic procedure. A standard Glucose breath test will be performed by the patients at home not earlier that 8 hours after the endoscopic procedure. Receives: Device: Atmo Gas Capsule; Diagnostic Test: Glucose Breath Test; Diagnostic Test: Fructoolifosaccharides (FOS) Breath Test; Procedure: Jejunal Aspiration and culture; Drug: Rifaximin |
| Active SIBO Arm - Placebo | Placebo comparator | If increased microbial load is determined through culture of aspiration during initial endoscopic procedure, randomised administration of placebo capsule twice a day for 14 days. The placebo will be encapsulated maize starch and pregelatinised maize starch. The post-antimicrobial endoscopic procedure will be conducted at 6 weeks post the start of treatment.
These hydrogen concentration results will be compared to the following conventional breath tests in a crossover study design. Immediately after the endoscopic procedure, the patient will undergo a FOS challenge recording hydrogen breath samples for 2 hours in 20 min intervals while they recover from the endoscopic procedure. A standard Glucose breath test will be performed by the patients at home not earlier that 8 hours after the endoscopic procedure. Receives: Device: Atmo Gas Capsule; Diagnostic Test: Glucose Breath Test; Diagnostic Test: Fructoolifosaccharides (FOS) Breath Test; Procedure: Jejunal Aspiration and culture; Drug: Placebo |
What is being measured
The primary outcome is the main question the study is designed to answer.
Structured Assessment of Gastro-Intestinal Symptoms
22 item assessing gastrointestinal symptoms. Response items are on a 5-point scale from (1 )no problem to (5) very severe problem. This is given to patients attending the Department of Gastroenterology \& Hepatology at Princess Alexandra Hospital as part of their routine clinical care.
Measured: 30 minutes prior to endoscopy
Hydrogen fermentation in the small intestine as measured by the Atmo capsule
Approximately 30 minutes before the endoscopic procedure, participants will be asked to swallow the capsule (Atmo capsule), which is the size of a large vitamin pill. If the capsule still is in the stomach at the time of the procedure it will be endoscopically pushed into the small intestine. 5g of Fructooligosaccharide (FOS) in 25mL of water will be flushed via the working channel of the endoscope into the small intestine to ensure that carbohydrates are available for fermentation. Subsequently the capsule is propelled by the normal peristaltic waves through the whole gut and is excreted after several days with the faeces. During transit the capsule transmits data about the concentration of specific gases (e.g. hydrogen) in the gut to a small receiver outside of the body.
Measured: 30 minutes prior to endoscopy
Small Intestine microbial load as assessed by Jejunal Aspiration and Culture
The density of the bacterial colonisation of mucosal biopsies obtained during endoscpoy will be used to determine the role of the bacterial density
Measured: During endoscpoic procedure
Secondary outcomes (2)
FOS Breath samples on the day of the endoscopy
Immediately prior to the endoscopy a baseline breath sample (approximately 400 cc) will be collected. FOS will be administered into the duodenum during endoscopy. After completion of the endoscopic procedure additional samples will be taken every 20 minutes up to 2 hours after the procedure.
Measured: Up to 2 hours after the endescopic procedure
Glucose Breath Test
The patients will be asked to perform (not earlier than at least 8 hours after the endoscopic procedure) at home a standard glucose test consistent with the established clinical protocol for the diagnosis of SIBO (see SOP for Hydrogen Breath Test for Small Intestinal Bacterial Overgrowth). For this test patients will drink 75 g of glucose and breath samples will be taken at baseline and every 20 minutes for 2 hrs.
Samples will be analysed for increased hydrogen, methane and carbon dioxide using a Breathtracker digital microlyser (Quintron Inc USA). If bacteria are present in the upper part of the small intestine, a rise in 12ppm of hydrogen over baseline is indicative of bacterial overgrowth.
Measured: Not earlier than 12 hours after the endoscopic procedure
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted2 Jun 2021
- Study start14 Jul 2021
- Primary completion1 Jun 2025
- Study completion1 Aug 2025
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Small Intestinal Bacterial OvergrowthStudies of the same condition, open and under way.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase N/A
- Primary purpose
- Diagnosis
- Allocation
- Randomised
- Intervention model
- Crossover
- Masking
- Single blind
- Who is masked
- Participant
- Enrolment
- 110 participants (actual)
Sponsor and investigators
- Lead sponsor
- Atmo Biosciences Pty Ltd
- Sponsor type
- Industry (pharma, biotech, devices)
- Responsible party
- Sponsor
- Investigators
- Professor Gerald Holtman, MD, PhD, MBA, Principal investigator, The University of Queensland
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT04910815
- Sponsor's protocol ID
- 72853
- Status last verified
- Oct 2026
- First submitted
- 26 May 2021
- Last updated
- 28 Oct 2026
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- No
Study at a glance
From the registry record, last updated by the sponsor on 28 Oct 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Feasibility of a New Diagnostic Device to Assess Small Intestinal Dysbiosis in Routine Clinical Setting.
- ClinicalTrials.gov ID
- NCT04910815
- Acronym / sponsor ID
- 72853
- Conditions
- Small Intestinal Bacterial Overgrowth
- Study type
- Interventional
- Recruitment status
- Completed
- Enrolment
- 110 participants (actual)
- Lead sponsor
- Atmo Biosciences Pty LtdIndustry (pharma, biotech, devices)
- Study start
- 14 Jul 2021 (actual)
- Primary completion
- 1 Jun 2025 (actual)
- Study completion
- 1 Aug 2025 (actual)
- First posted
- 2 Jun 2021 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
The purpose of this study is to determine if the gas-sensing capsule can be used to identify increased numbers and a change of the composition of microbiota or microorganisms in the gut to assess small intestinal dysbiosis
Detailed description
In order to diagnose an increased bacterial density in the small intestine (e.g small intestinal bacterial overgrowth) metabolic activity of the microbiota colonising the small intestine is measured by exposing these bacteria with readily fermentable carbohydrates and measure subsequently (e.g. for 2 hrs) the change of the concentration of hydrogen (H2) and/or methane in the exhaled breath that results from carbohydrate fermentation in the small intestine. This is the principle of existing breath hydrogen tests, but they are poor at distinguishing where in the intestine the H2 is being produced, and their sensitivity is diminished by 'noise' in the breath H2 as a consequence of hydrogen or methane producing bacteria in the colon and this is frequently observed in the routine clinical setting. These shortcomings can be theoretically overcome by using the Atmo Gas CapsuleR which measures after ingestion gas concentrations during gastrointestinal transit in the lumen of the gut. As a consequence at the site of fermentation parts per hundred can be measured, rather than the parts per million (ppm) when methane or hydrogen are measured in the exhaled breath. An additional advantage is that the location of the capsule is known, and therefore the source of gas production from increased bacterial load can be determined. Preliminary studies using the gas capsule have shown good correlation of patterns of breath H2 with those of regional H2 patterns generated by the gas-sensing capsule. In fact, the capsule demonstrated far greater sensitivity in measuring H2 production and a vastly superior signal-to-noise ratio in response to a fermentable load than breath testing. Hence, investigating the utility of the gas-sensing capsule as a means for 'direct' assessment of microbial density presents an opportunity to overcome the shortcomings associated with the current breath test.
Study design
- Primary purpose
- Diagnosis
- Allocation
- Randomised
- Intervention model
- Crossover
- Masking
- Single blind (participant)
- Number of arms
- 3
| Arm | Type | Receives |
|---|---|---|
| Primary recruitment | Experimental | Device: Atmo Gas Capsule, Procedure: Jejunal Aspiration and cultureCapsules will be ingested within 30 minutes prior to endoscopy pre- and post-antimicrobial intervention (if the patients has had a treatment) to determine if it can be used to identify increased microbial load through gas detection, and to identify responders to therapy. |
| Active SIBO Arm - Rifaximin | Active comparator | Device: Atmo Gas Capsule, Diagnostic Test: Glucose Breath Test, Diagnostic Test: Fructoolifosaccharides (FOS) Breath Test, Procedure: Jejunal Aspiration and culture, Drug: RifaximinIf increased microbial load is determined through culture of aspiration during initial endoscopic procedure, randomised administration of Rifaximin (550g) 1 capsule twice a day for 14 days. The post-antimicrobial endoscopic procedure will be conducted at 6 weeks post the start of treatment. These hydrogen concentration results will be compared to the following conventional breath tests in a crossover study design. Immediately after the endoscopic procedure, the patient will undergo a FOS challenge recording hydrogen breath samples for 2 hours in 20 min intervals while they recover from the endoscopic procedure. A standard Glucose breath test will be performed by the patients at home not earlier that 8 hours after the endoscopic procedure. |
| Active SIBO Arm - Placebo | Placebo comparator | Device: Atmo Gas Capsule, Diagnostic Test: Glucose Breath Test, Diagnostic Test: Fructoolifosaccharides (FOS) Breath Test, Procedure: Jejunal Aspiration and culture, Drug: PlaceboIf increased microbial load is determined through culture of aspiration during initial endoscopic procedure, randomised administration of placebo capsule twice a day for 14 days. The placebo will be encapsulated maize starch and pregelatinised maize starch. The post-antimicrobial endoscopic procedure will be conducted at 6 weeks post the start of treatment. These hydrogen concentration results will be compared to the following conventional breath tests in a crossover study design. Immediately after the endoscopic procedure, the patient will undergo a FOS challenge recording hydrogen breath samples for 2 hours in 20 min intervals while they recover from the endoscopic procedure. A standard Glucose breath test will be performed by the patients at home not earlier that 8 hours after the endoscopic procedure. |
Who may qualify
- Ages
- 18 to 60 years
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Adult
Key inclusion criteria (1 listed)
- Patients aged over 18 years presenting to the Department of Gastroenterology \& Hepatology at the Princess Alexandra Hospital who require and are booked for an upper gastrointestinal endoscopy as part of the routine diagnostic work up of e.g. otherwise unexplained gastrointestinal symptoms.
Key exclusion criteria (10 listed)
- Radiation Enteritis
- Pregnancy
- Gastric bezoar
- Swallowing disorders/dysphagia to food or pills
- Obese, with BMI over 35
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| Atmo Gas CapsuleThe Atmo gas capsule is an ingestible electronic device. This capsule consists of gas and temperature sensors, electronic circuits, radio transmitter and silver oxide batteries. It can measure the concentrations and types of intestinal gases in individuals and give an indication of gut transit time. This data is used for research purposes to gain an understanding of the microbiota's localised functionality. The data from the sensors is transmitted out of the body over the radio frequency to a handheld receiver. The capsule passes out of the human body at the end of the measurement and is disposable. | Device | Active SIBO Arm - Placebo, Active SIBO Arm - Rifaximin, Primary recruitment |
| Glucose Breath TestGlucose is a sugar that will be broken down by bacteria if present in the small bowel with hydrogen gas as a by-product. The hydrogen produced through fermentation is measured in the patients exhaled breath | Diagnostic test | Active SIBO Arm - Placebo, Active SIBO Arm - Rifaximin |
| Fructoolifosaccharides (FOS) Breath TestFOS is a long chain carbohydrate that can only be broken down by bacteria with hydrogen gas as a by-product. The hydrogen produced through fermentation is measured in the patients exhaled breath | Diagnostic test | Active SIBO Arm - Placebo, Active SIBO Arm - Rifaximin |
| Jejunal Aspiration and cultureEndoscopic procedure to determine microbial load of the Small bowel. This is the gold standard to determine the Active SIBO cases | Procedure or surgery | Active SIBO Arm - Placebo, Active SIBO Arm - Rifaximin, Primary recruitment |
| RifaximinRifaximin (550g) 1 capsule twice a day for 14 days. | Drug | Active SIBO Arm - Rifaximin |
| Placeborandomised administration of either placebo or Rifaximin (550g) 1 capsule twice a day for 14 days. The placebo will be encapsulated maize starch and pregelatinised maize starch | Drug | Active SIBO Arm - Placebo |
Primary outcome
Structured Assessment of Gastro-Intestinal Symptoms
Time frame: 30 minutes prior to endoscopy
22 item assessing gastrointestinal symptoms. Response items are on a 5-point scale from (1 )no problem to (5) very severe problem. This is given to patients attending the Department of Gastroenterology \& Hepatology at Princess Alexandra Hospital as part of their routine clinical care.
Hydrogen fermentation in the small intestine as measured by the Atmo capsule
Time frame: 30 minutes prior to endoscopy
Approximately 30 minutes before the endoscopic procedure, participants will be asked to swallow the capsule (Atmo capsule), which is the size of a large vitamin pill. If the capsule still is in the stomach at the time of the procedure it will be endoscopically pushed into the small intestine. 5g of Fructooligosaccharide (FOS) in 25mL of water will be flushed via the working channel of the endoscope into the small intestine to ensure that carbohydrates are available for fermentation. Subsequently the capsule is propelled by the normal peristaltic waves through the whole gut and is excreted after several days with the faeces. During transit the capsule transmits data about the concentration of specific gases (e.g. hydrogen) in the gut to a small receiver outside of the body.
Small Intestine microbial load as assessed by Jejunal Aspiration and Culture
Time frame: During endoscpoic procedure
The density of the bacterial colonisation of mucosal biopsies obtained during endoscpoy will be used to determine the role of the bacterial density
2 secondary outcomes
FOS Breath samples on the day of the endoscopy
Time frame: Up to 2 hours after the endescopic procedure
Glucose Breath Test
Time frame: Not earlier than 12 hours after the endoscopic procedure
Results and safety
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 28 Oct 2026.
- Individual participant dataSharing planned: No
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.
Professor Gerald Holtman, MD, PhD, MBA principal investigator
The University of Queensland
2 sites in 2 countries: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing Atmo Gas Capsule, Glucose Breath Test and Fructoolifosaccharides (FOS) Breath Test in people with Small Intestinal Bacterial Overgrowth, run by Atmo Biosciences Pty Ltd at 2 sites in 2 countries.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 1 inclusion and 10 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: finished, as of the sponsor's last update on 28 Oct 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 2 sites in Australia, India. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. Some participants in this study may receive a placebo. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Structured Assessment of Gastro-Intestinal Symptoms (time frame: 30 minutes prior to endoscopy). The study lists 3 primary outcomes in all. It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 28 Oct 2026.