Microbiologists and clinical laboratory professionals should play a key role in the ordering and use of microbiome testing
International experts in the field of microbiome testing recently published a consensus document that establishes guidelines for the use and distribution of microbiota diagnostics they claim are long overdue. Companies offering direct-to-consumer (DTC) microbiome test kits continue to increase in number and popularity. But some experts in the human microbiome field—including microbiologists and clinical laboratory professionals—remain apprehensive regarding the science behind this type of home testing.
A Gemelli University news release states, “The intestinal microbiota could perhaps one day become a routine tool for the early diagnosis of many diseases and treatment guidance, but at the moment there is a lack of solid scientific evidence to support these indications. Yet, day by day, the offers of commercial kits are multiplying to carry out do-it-yourself tests, at the moment completely devoid of scientific significance and solidity.”
It continues, “To put a stop to this drift, a panel of international experts, coordinated by Dr. Gianluca Ianiro, has drafted the ‘instructions for use’ for best practices related to microbiota testing and recommendations for its indications, analysis methods, presentation of results and potential clinical applications.”
“This document marks a decisive step towards a standardization that has become indispensable making the microbiota an increasingly integrated element in personalized medicine,” said gastroenterologist Antonio Gasbarrini, MD (above), dean of the faculty of medicine and surgery and full professor of internal medicine at Catholic University of the Sacred Heart. “In the clinical context, these guidelines will be essential to translate research progress into concrete applications, improving the management of many gastroenterological and systemic diseases related to the microbiota,” he added. Microbiologists and clinical laboratory managers may want to follow efforts to promote these guidelines, both within healthcare and as they relate to consumers ordering their own microbiome tests. (Photo copyright: Agostino Gemelli University.)
Our Second Brain
The gut microbiome consists of the microorganisms that reside in the human gut and the small and large intestines. This ecosystem plays a major role in an individual’s health as it aids in digestion and metabolism. It also helps control inflammation and can strengthen the immune system.
“[The gut microbiome] contains all the microbes that reside within our intestinal tract. And those microbes are comprised of bacteria, fungi, yeast and viruses,” said Gail Cresci, PhD, RD, Director, Nutrition Research Center for Human Nutrition at the Cleveland Clinic in a Health Essentials article.
“What we’ve learned over the years is that there’s a lot of crosstalk between your gut microbiome and your body,” she added.
A healthy gut microbiome is imperative for good human health. An unhealthy gut microbiome can lead to certain diseases and even have a negative effect on mental health and mood.
“Your gut health is so important because studies really do indicate that our gut health plays a huge role in our overall health,” stated Kristin Kirkpatrick, MS, RDN, a dietician at the Cleveland Clinic Department of Wellness and Preventative Medicine, in the article. “It impacts our risk of chronic conditions, our ability to manage our weight, even our immune system. … There is so much attention and research on the microbiome and gut health now that experts often refer to it as the ‘second brain.’”
Future of Microbiome Testing
In their consensus document, the scientists wrote, “We convened an international multidisciplinary expert panel to standardize best practices of microbiome testing for clinical implementation, including recommendations on general principles and minimum requirements for their provision, indications, pre-testing protocols, method of analyses, reporting of results, and potential clinical value. We also evaluated current knowledge gaps and future directions in this field.”
The team’s intent is to provide guidelines and define quality standards and accuracy for microbiome testing to ensure consumers are receiving factual information.
“In recent years, the intestinal microbiota has taken on a key role as a diagnostic, prognostic and therapeutic tool,” said gastroenterology surgeon Serena Porcari, MD, of Gemelli University Hospital in Italy, in the Gemelli news release. “From this point of view, the first step, for a targeted modulation of the microbiota itself, is to obtain a standardization of its analysis, regulated according to the definition of minimum criteria for performing the test.”
The team also evaluated disparities between various tests and anticipated what lies ahead for the future of microbiome testing. In addition, they assessed ways to minimize inappropriate testing and established a framework for the development of evidence-based testing and the use of human microbiota diagnostics in clinical medicine.
“This consensus document represents a crucial step towards bringing order to the current panorama of diagnostic tests on the intestinal microbiota,” said Maurizio Sanguinetti, MD, director of the department of laboratory and hematological sciences at Gemelli Polyclinic Foundation, in the news release. “The diagnostic characterization of the intestinal microbiota must be based on rigorous standards, in order to guarantee reliable and clinically useful results. It is not a simple laboratory test, but a complex tool that requires a deep understanding of microbial dynamics and their impact on human health.
“This is why these analyses must be conducted by highly qualified personnel with specific expertise in clinical microbiology and bioinformatics,” he emphasized. “In our microbiology laboratory at the Fondazione Policlinico Gemelli, we already apply diagnostic tests on the intestinal microbiota following the principles and best practices outlined in the document.
“It is essential to invest in the training of future physicians and microbiologists so that they acquire the necessary skills to correctly interpret the results of these tests and apply them effectively in clinical practice. This document provides a valuable basis to guide not only the current use of the tests, but also their future development, always with a view to evidence-based and personalized medicine,” Sanguinetti concluded.
With popularity of microbiome testing on the rise, it’s important that microbiologists and clinical laboratory professionals stay informed on the latest developments in the field of microbiome diagnostics to protect healthcare consumers and their patients.
Although it is a non-specific procedure that does not identify specific health conditions, it could lead to new biomarkers that clinical laboratories could use for predictive healthcare
Researchers from the Mayo Clinic recently used artificial intelligence (AI) to develop a predictive computational tool that analyzes an individual’s gut microbiome to identify how a person may experience improvement or deterioration in health.
Dubbed the Gut Microbiome Wellness Index 2 (GMWI2), Mayo’s new tool does not identify the presence of specific health conditions but can detect even minor changes in overall gut health.
Built on an earlier prototype, GMWI2 “demonstrated at least 80% accuracy in differentiating healthy individuals from those with any disease,” according to a Mayo news release. “The researchers used bioinformatics and machine learning methods to analyze gut microbiome profiles in stool samples gathered from 54 published studies spanning 26 countries and six continents. This approach produced a diverse and comprehensive dataset.”
“Our tool is not intended to diagnose specific diseases but rather to serve as a proactive health indicator,” said senior study author Jaeyun Sung, PhD (above), a computational biologist at the Mayo Clinic Center for Individualized Medicine: Microbiomics Program in the news release ease. “By identifying adverse changes in gut health before serious symptoms arise, the tool could potentially inform dietary or lifestyle modifications to prevent mild issues from escalating into more severe health conditions, or prompt further diagnostic testing.” For microbiologists and clinical laboratory managers, this area of new knowledge about the human microbiome may lead to multiplex diagnostic assays. (Photo copyright: Mayo Clinic.)
Connecting Specific Diseases with Gut Microbiome
Gut bacteria that resides in the gastrointestinal tract consists of trillions of microbes that help regulate various bodily functions and may provide insights regarding the overall health of an individual. An imbalance in the gut microbiome is associated with an assortment of illnesses and chronic diseases, including cardiovascular issues, digestive problems, and some cancers and autoimmune diseases.
To develop GMWI2, the Mayo scientists provided the machine-learning algorithm with data on microbes found in stool samples from approximately 8,000 people collected from 54 published studies. They looked for the presence of 11 diseases, including colorectal cancer and inflammatory bowel disease (IBS). About 5,500 of the subjects had been previously diagnosed with one of the 11 diseases, and the remaining people did not have a diagnosis of the conditions.
The scientists then tested the efficacy of GMWI2 on an additional 1,140 stool samples from individuals who were diagnosed with conditions such as pancreatic cancer and Parkinson’s disease, compared with those who did not have those illnesses.
The algorithm gives subjects a score between -6 and +6. People with a higher GMWI2 score have a healthier microbiome that more closely resembles individuals who do not have certain diseases.
Likewise, a low GMWI2 score suggests the individual has a gut microbiome that is similar to those who have specific illnesses.
Highly Accurate Results
According to their study, the researchers determined that “GMWI2 achieves a cross-validation balanced accuracy of 80% in distinguishing healthy (no disease) from non-healthy (diseased) individuals and surpasses 90% accuracy for samples with higher confidence,” they wrote in Nature Communications.
Launched in 2020, the original GMWI (Gut Microbiome Wellness Index) was trained on a much smaller number of samples but still showed similar results.
The researchers tested the enhanced GMWI2 algorithm across various clinical schemes to determine if the results were similar. These scenarios included individuals who had previous fecal microbiota transplants and people who had made dietary changes or who had exposure to antibiotics. They found that their improved tool detected changes in gut health in those scenarios as well.
“By being able to answer whether a person’s gut is healthy or trending toward a diseased state, we ultimately aim to empower individuals to take proactive steps in managing their own health,” Sung said in the news release.
The Mayo Clinic team is developing the next version of their tool, which will be known as the Gut Microbiome Wellness Index 3. They plan to train it on at least 12,000 stool samples and use more sophisticated algorithms to decipher the data.
More research and studies are needed to determine the overall usefulness of Mayo’s Gut Microbiome Wellness Index and its marketability. Here is a world-class health institution disclosing a pathway/tool that analyzes the human microbiome to identify how an individual may be experiencing either an improvement in health or a deterioration in health.
The developers believe it will eventually help physicians determine how patients’ conditions are improving or worsening by comparing the patients’ microbiomes to the profiles of other healthy and unhealthy microbiomes. As this happens, it would create a new opportunity for clinical laboratories to perform the studies on the microbiomes of patients being assayed in this way by their physicians.
As this therapeutic approach gains regulatory approval, clinical laboratory tests to determine condition of patient’s gut microbiota and monitor therapy will be needed
Some developments in the clinical laboratory industry are less about diagnostic tests and more about novel approaches to therapy. Such is the case with a new carbon bead technology developed by researchers from University College London (UCL) and the Royal Free Hospital intended to remove harmful bacteria toxins from the gut before they leak to the liver. The macroporous beads, which come in small pouches, are delivered orally and could be utilized in the future to treat a number of diseases.
Why is this relevant? Once a new treatment is accepted for clinical use, demand increases for a clinical laboratory test that confirms the therapy will likely work and to monitor its progress.
In collaboration with Yaqrit, a UK-based life sciences company that develops treatments for chronic liver disease, the UCL and Royal Free Hospital scientists engineered the carbon beads—known as CARBALIVE—to help restore gut health. They measured the technology’s impact on liver, kidney, and brain function in both rats and mice.
“The influence of the gut microbiome on health is only just beginning to be fully appreciated,” said Rajiv Jalan, PhD, Professor of Hepatology at UCL in a press release. “When the balance of the microbiome is upset, ‘bad’ bacteria can proliferate and out-compete the ‘good’ bacteria that keeps the gut healthy.
“One of the ways [the ‘bad’ bacteria] do this is by excreting endotoxin, toxic metabolites, and cytokines that transform the gut environment to make it more favorable to them and hostile to good bacteria,” he continued. “These substances, particularly endotoxin, can trigger gut inflammation and increase the leakiness of the gut wall, resulting in damage to other organs such as the liver, kidneys, and brain.”
“I have high hopes that the positive impact of these carbon beads in animal models will be seen in humans, which is exciting not just for the treatment of liver disease but potentially any health condition that is caused or exacerbated by a gut microbiome that doesn’t work as it should,” said Rajiv Jalan, PhD (above), Professor of Hepatology, University College London, in a press release. “This might include conditions such as irritable bowel syndrome (IBS), for example, which is on the rise in many countries.” Though not a clinical laboratory diagnostic test, new therapies like CARBALIVE could be a boon to physicians treating patients with IBS and other gastrointestinal conditions.
Developing the Carbon Beads
The team discovered CARBALIVE is effective in the prevention of liver scarring and injury in animals with cirrhosis when ingested daily for several weeks. They also found a reduced mortality rate in test animals with acute-on-chronic-liver-failure (ACLF).
After achieving success with CARBALIVE in animals, the researchers tested the technology on 28 cirrhosis patients. The carbon beads proved to be safe for humans and had inconsequential side effects.
“In cirrhosis, a condition characterized by scarring of the liver, it is known that inflammation caused by endotoxins can exacerbate liver damage,” Jalan explained. “Part of the standard treatment for cirrhosis is antibiotics aimed at controlling bad bacteria, but this comes with the risk of antibiotic resistance and is only used in late-stage disease.”
The beads, which are smaller than a grain of salt, contain an exclusive physical structure that absorbs large and small molecules in the gut. They are intended to be taken with water at bedtime as harmful bacteria is more likely to circulate through the body at night which could result in damage. The carbon beads do not kill bacteria, which decreases the risk of antibiotic resistance. They eventually pass through the body as waste.
“They work by absorbing the endotoxins and other metabolites produced by ‘bad’ bacteria in the gut, creating a better environment for the good bacteria to flourish and helping to restore microbiome health,” said Michal Kowalski, M.Sc.Eng, Director and VP of Operations at Yaqrit, in the UCL news release.
“This prevents these toxins from leaching into other areas of the body and causing damage, as they do in cirrhosis,” he added. “The results in animal models are very positive, with reduction in gut permeability, liver injury, as well as brain and kidney dysfunction.”
Additional Research
The researchers plan to perform further clinical trials in humans to determine if the carbon beads are effective at slowing the progression of liver disease. If the benefits that were observed in lab animals prove to be compelling in humans, the technology may become an invaluable tool for the treatment of liver disease and other diseases associated with poor microbiome health in the future.
According to the American Liver Foundation, 4.5 million adults in the US have been diagnosed with liver disease. However, it is estimated that 80 to 100 million adults have some form of fatty liver disease and are unaware of it. Liver disease was the 12th leading cause of death in the US in 2020 with 51,642 adults perishing from the disease that year.
According to BMC Public Health, globally there were 2.05 million new cases of liver cirrhosis diagnosed in 2019. In that year, 1.47 million people around the world died from the disease.
More research and clinical studies are needed before this novel technology can be used clinically. When and if that happens, the demand for clinical laboratory tests that measure microbiome deficiencies and monitor patient progress during therapy will likely be high.
New technology could enable genetic scientists to identify antibiotic resistant genes and help physicians choose better treatments for genetic diseases
Genomic scientists at the Icahn School of Medicine at Mount Sinai Medical Center in New York City have developed what they call a “smart tweezer” that enables researchers to isolate a single bacterium from a patient’s microbiome in preparation for genetic sequencing. Though primarily intended for research purposes, the new technology could someday be used by clinical laboratories and microbiologists to help physicians diagnose chronic disease and choose appropriate genetic therapies.
The researchers designed their new technology—called mEnrich-seq—to improve the effectiveness of research into the complex communities of microorganisms that reside in the microbiomes within the human body. The discovery “ushers in a new era of precision in microbiome research,” according to a Mount Sinai Hospital press release.
“Imagine you’re a scientist who needs to study one particular type of bacteria in a complex environment. It’s like trying to find a needle in a large haystack,” said the study’s senior author Gang Fang, PhD (above), Professor of Genetics and Genomic Sciences at Icahn School of Medicine at Mount Sinai Medical Center, in a press release. “mEnrich-seq essentially gives researchers a ‘smart tweezer’ to pick up the needle they’re interested in,” he added. Might smart tweezers one day be used to help physicians and clinical laboratories diagnose and treat genetic diseases? (Photo copyright: Icahn School of Medicine.)
Addressing a Technology Gap in Genetic Research
Any imbalance or decrease in the variety of the body’s microorganisms can lead to an increased risk of illness and disease.
In researching the microbiome, many scientists “focus on studying specific types of bacteria within a sample, rather than looking at each type of bacteria present,” the press release states. The limitation of this method is that a specific bacterium is just one part of a complicated environment that includes other bacteria, viruses, fungi and host cells, each with their own unique DNA.
“mEnrich-seq effectively distinguishes bacteria of interest from the vast background by exploiting the ‘secret codes’ written on bacterial DNA that bacteria use naturally to differentiate among each other as part of their native immune systems,” the press release notes. “This new strategy addresses a critical technology gap, as previously researchers would need to isolate specific bacterial strains from a given sample using culture media that selectively grow the specific bacterium—a time-consuming process that works for some bacteria, but not others. mEnrich-seq, in contrast, can directly recover the genome(s) of bacteria of interest from the microbiome sample without culturing.”
Isolating Hard to Culture Bacteria
To conduct their study, the Icahn researchers used mEnrich-seq to analyze urine samples taken from three patients with urinary tract infections (UTIs) to reconstruct Escherichia coli (E. Coli) genomes. They discovered their “smart tweezer” covered more than 99.97% of the genomes across all samples. This facilitated a comprehensive examination of antibiotic-resistant genes in each genome. They found mEnrich-seq had better sensitivity than standard study methods of the urine microbiome.
They also used mEnrich-seq to selectively examine the genomes of Akkermansia muciniphila (A. muciniphila), a bacterium that colonizes the intestinal tract and has been shown to have benefits for obesity and Type 2 diabetes as well as a response to cancer immunotherapies.
“Akkermansia is very hard to culture,” Fang told GenomeWeb. “It would take weeks for you to culture it, and you need special equipment, special expertise. It’s very tedious.”
mEnrich-seq was able to quickly segregate it from more than 99.7% of A. muciniphila genomes in the samples.
Combatting Antibiotic Resistance Worldwide
According to the press release, mEnrich-seq could potentially be beneficial to future microbiome research due to:
Cost-Effectiveness: It offers a more economical approach to microbiome research, particularly beneficial in large-scale studies where resources may be limited.
Broad Applicability: The method can focus on a wide range of bacteria, making it a versatile tool for both research and clinical applications.
Medical Breakthroughs: By enabling more targeted research, mEnrich-seq could accelerate the development of new diagnostic tools and treatments.
“One of the most exciting aspects of mEnrich-seq is its potential to uncover previously missed details, like antibiotic resistance genes that traditional sequencing methods couldn’t detect due to a lack of sensitivity,” Fang said in the news release. “This could be a significant step forward in combating the global issue of antibiotic resistance.”
More research and clinical trials are needed before mEnrich-seq can be used in the medical field. The Icahn researchers plan to refine their novel genetic tool to improve its efficiency and broaden its range of applications. They also intend to collaborate with physicians and other healthcare professionals to validate how it could be used in clinical environments.
Should all this come to pass, hospital infection control teams, clinical laboratories, and microbiology labs would welcome a technology that would improve their ability to detect details—such as antibiotic resistant genes—that enable a faster and more accurate diagnosis of a patient’s infection. In turn, that could contribute to better patient outcomes.
Though they are a mystery, once solved, Obelisks could lead to new biomarkers for clinical laboratory testing
Microbiologists and clinical laboratories know that human microbiota play many important roles in the body. Now, scientists from Stanford University have discovered an entirely new class of “viroid-like” lifeforms residing inside the human body. The researchers detected their presence in both the gut microbiome and saliva samples. Most interesting of all, the researchers are not sure what the lifeforms actually are.
The Stanford researchers, led by PhD student Ivan Zheludev, called the new discovery “Obelisks” due to their RNA structures, which are short and can fold into structures that resemble rods.
The scientists believe the Obelisks went undetected until now in the human microbiome due to their compact genetic elements, which are only around 1,000 characters or nucleotides in size. A typical human DNA structure consists of around three billion nucleotides.
In an article they published on the biology preprint server bioRxiv titled, “Viroid-like Colonists of Human Microbiomes,” the Stanford researchers wrote, “Here, we describe the ‘Obelisks,’ a previously unrecognized class of viroid-like elements that we first identified in human gut metatranscriptomic data. … Obelisks comprise a class of diverse RNAs that have colonized and gone unnoticed in human and global microbiomes.”
The researchers discovered that Obelisks “form their own distinct phylogenetic group with no detectable sequence or structural similarity to known biological agents.”
This is yet another example of how researchers are digging deeper into human biology and finding things never before identified or isolated.
“I am really impressed by the approach. The authors were really creative,” computational biologist Simon Roux, PhD (above) of the Department of Energy (DEO) Joint Genome Institute at Lawrence Berkeley National Laboratory told Science in response to the Stanford researcher’s published findings. “I think this [work] is one more clear indication that we are still exploring the frontiers of this viral universe. This is one of the most exciting parts of being in this field right now. We can see the picture of the long-term evolution of viruses on Earth start to slowly emerge.” How these findings might eventually spark new biomarkers for clinical laboratory testing remains to be seen. (Photo copyright: Berkeley Lab.)
Researchers Bewildered by Obelisks
In their study, “Zheludev and team searched 5.4 million datasets of published genetic sequences and identified almost 30,000 different Obelisks. They appeared in about 10% of the human microbiomes the team examined,” Science reported.
The Stanford researchers found that various types of Obelisks seem to inhabit different areas of the body. In one dataset, the Obelisks were found in half of the oral samples.
The function of Obelisks is unknown, but their discovery is bewildering experts.
Rod-like secondary structures encompassing the entire genome, and
Open reading frames coding for a novel protein superfamily, which the researchers dubbed “Oblins.”
At least half of the genetic material of the Obelisks was taken up by these Oblins. The researchers suspect those proteins may be involved in the replication process of the newly-discovered lifeforms.
The Oblins are also significantly larger than other genetic molecules that live inside cells and they do not have the genes to create protein shells that RNA viruses live within when they are outside of cells.
“Obelisks, therefore, need some kind of host. The researchers managed to identify one: A bacterium called Streptococcus sanguinis that lives mostly in dental plaque in our mouths. Exactly which other hosts obelisks inhabit is yet another mystery, as are what they do to their host and how they spread,” Vice reported.
“While we don’t know the ‘hosts’ of other Obelisks, it is reasonable to assume that at least a fraction may be present in bacteria,” the researchers noted in their bioRxiv paper.
Researchers are Stumped
The Stanford scientists were unable to identify any impact the Obelisks were having on their bacterial hosts—either negative or positive—or determine how they could spread between cells.
“These elements might not even be ‘viral’ in nature and might more closely resemble ‘RNA plasmids,’” they concluded in their paper.
The Stanford scientists are uncertain as to where or what the hosts of the Obelisks are, but they suspect that at least some of them are present in bacteria. However, Obelisks do not appear to be similar to any biological agents that could provide a link between genetic molecules and viruses.
And so, Obelisks are a true mystery—one the Stanford researchers may one day solve. If they do, new biomarkers for clinical laboratory testing may not be far behind.
