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Lactobacillus bacteremia in critically ill patients does not raise questions about safety for general consumers

By Dan Merenstein MD, Professor of Family Medicine, Georgetown University Medical Center, Washington DC, USA; Eamonn Quigley MD, Professor of Medicine, Houston Methodist Hospital and Weill Cornell Medical College, Texas USA; Gregory Gloor PhD, Professor of Biochemistry, Schulich School of Medicine and Dentistry, The University of Western Ontario, Canada; Hania Szajewska MD, Professor of Paediatrics, The Medical University of Warsaw, Poland;  and Mary Ellen Sanders PhD, Executive Science Officer, ISAPP, Colorado, USA.

A recent Nature Medicine paper reported blood cultures positive for L. rhamnosus GG in six critically ill patients at Children’s Hospital in Boston.

About this study

Patients (aged 1, 2, 4, 12, 19 and 19 years) with L. rhamnosus-associated bacteremia suffered from different chronic conditions (mitochondrial disorder, cerebral palsy, congenital heart disease, cystic fibrosis) and were located either in the ICU (cardiac or medical/surgical ICU) or ICP (intermediate care program) at the hospital at the time of bacteremia. The bacteremia was discovered during routine blood culture screens. Clinical presentations were not described in detail; however, none had endocarditis or died from the bacteremia, although one did get a central line infection. Two of the six cases of bacteremia in probiotic-consuming patients were determined by attending physicians to be transient or due to contaminants, and were not treated. The other four cases were treated with antibiotics. A further 516 patients dosed with the same probiotic did not develop bacteremia.

The researchers examined the blood isolates and using whole genome sequencing were able to confirm that the Lactobacillus isolated from the blood of these patients was genetically identical – with the exception of a few SNPs – to L. rhamnosus GG present in the probiotic product. This is the preferred approach to confirming the source of blood culture isolates.

Important questions arising from critical review of this paper

  1. Was the study appropriately controlled?

The authors report a seemingly high rate (1.1%) of Lactobacillus bacteremia among the 522 L. rhamnosus-consuming patients compared with 0.009%, the rate of Lactobacillus bacteremia among 21,652 patients who did not receive probiotics.  However, the paper does not justify the legitimacy of comparing these two groups to each other. Indeed, other underlying factors could contribute to the different rates of bacteremia, as these were not matched cohorts. It is important to recognize the limitations of the retrospective design used here, which limits the ability to match controls, and to control for cofounders such as underlying illness, severity of clinical illness and co-therapies (including antibiotics).

  1. What is the mechanism of transmission of the probiotic to the patients’ blood?

Most of the patients had a central line venous catheter. The paper reported that probiotics were mostly administered via tube feeding. If a probiotic is able to readily translocate the gut barrier in such patients, this would be a safety concern. But if the observed bacteremia was due to contamination of a central line, this may say more about hospital procedures than safety of the probiotic. Indeed, 16 years ago, central line contamination leading to fungemia was reported. In a 2005 paper, 92% of cases of fungemia associated with Saccharomyces cerevisiae var boulardii administration had an IV catheter. Based on such reports, handling dried probiotics in a hospital environment with critically ill patients should be done with caution. However, with proper administration procedures, certain probiotics are medically recommended in this setting.

  1. What was the clinical impact of administration of L. rhamnosus GG?

Important clinical parameters such as all-cause mortality (the outcome of greatest importance), length of hospital stay, abscesses, required medications, and others were not reported (although central line infection was reported) for the patients studied. The clinical context of this study would be more easily understood if information on the indications driving probiotic administration was provided. The authors question the risk/benefit of probiotic administration to ICU patients in a children’s hospital yet focus solely on risk and do not measure benefit. This suggests an underlying assumption by the authors that when it comes to probiotics, any risk is too much. Did the patients given L. rhamnosus GG suffer negative clinical outcomes more often than age and condition-matched controls? If so, then giving this probiotic to these patients cannot be recommended. But if not, then even though risk of bacteremia may be higher, if the patients given the probiotic fared better than matched patients, then the probiotic should be considered a reasonable option.

Lastly, the finding of a rate of Lactobacillus bacteremia of 1.1% needs to be viewed in the context of a 20% rate of nosocomial infections in the ICU (here and here).

Lessons regarding probiotic safety

Two main issues are raised by this study. The first is whether the evidence suggests opportunistic pathogenic properties of L. rhamnosus GG or rather that procedures used to administer probiotics in the ICU environment resulted in contamination, which caused bacteremia. No conclusions can be made from this study regarding this. The second is the importance of placing the results of this study into a clinical framework. The study implies risk from probiotic administration, even though the study was not powered for clinical outcomes and could not place any perceived increased risk into the context of any achieved benefit. Further, reporting rates of Lactobacillus bacteremia between cohorts unmatched for important characteristics except for probiotic use does not inform on relative risk.

Importantly for the broader situation of probiotic use, the ICU population is not reflective of the general population, so this study does not allow us to draw conclusions about safety of L. rhamnosus GG use in non-ICU patients.

We recognize the value of careful tracking of potential probiotic-associated infections and appreciate the application of bacterial genomic sequencing to identify the probiotic in the blood. Used more widely, this approach could resolve many purported claims of probiotic bacteremia.

This paper serves as an important reminder that use of probiotics in critically ill patients must be carefully considered and practice must align with learnings from the past, including the risk of central line contamination with probiotics. In addition, this paper highlights the importance of knowing the exact strain (including its antibiotic resistance profile and preferentially also its genome sequence), so that in the rare case of bacteremia, appropriate antibiotics can be administered.

See here for an additional related open-access publication: Probiotic use in at-risk populations. Sanders et al. 2014.

 

 

 

 

Reflections on a career in probiotic science, from ISAPP founding board member Prof. Gregor Reid

Past President and founding board member Prof. Gregor Reid is stepping down from the ISAPP Board in Banff in June 2020, as he retires from Western University and his Endowed Chair position at Lawson Health Research Institute the following month. In this blog post, he shares thoughts on his career and the opportunities for his replacement and for others to continue probiotic research.

By Gregor Reid BSc (Hons), PhD, MBA, ARM CCM, Dr HS, FCAHS, FRSC

A mere blue dot. A pinhead, if that. But it’s us, all we have been and all we will be – for a while at least. The planet Earth.

Its magnificence is there for all to see.

Creative Commons Earth Illustration, Pixabay

Creative Commons Earth Illustration, by Pixabay

I’ve been fortunate to have visited over 60 of the countries on this majestic globe. One of the perks of being a scientist. And for those who know me well, I’ve taken my camera and my music with me on the journey. In this blog post, I’ll share some pieces of both and how they form part of who we are and what we study.

Across the vast surface of our planet, and within it, there are countless microbes. As life emerges from the surface, we shouldn’t be surprised that microbes climb on board. Whether plants, honey bees, fish, birds, lions, humans, microbes accompany each.

Photo by Andrew Pitek. Used with permission.

Just being human is a guest house1.

Understandably, since some of these microbes can be deadly to humans, our ancestors had to find ways to stop them. Whether plague, diphtheria, smallpox, influenza, wound infections, or other fatal diseases. And so, the marvels of vaccination and antibiotics were born.

Arguably, these miraculous interventions also brought complacency as a societal side-effect, despite the warnings of people like Alexander Fleming. The greatest possibility of evil in self-medication is the use of too small doses so that instead of clearing up infection the microbes are educated to resist penicillin2.

We all but ignored the collateral damage, pacified by label warnings of diarrhea and nausea until Clostridium difficile woke us from our slumber. When the antibiotics stopped working, we went out into left field and started using human poop! Too ridiculous to work, until it worked. Really well.

We’re running through the dark, and that’s how it starts. Don’t know what you’re doing to me. And it might be getting better3.

Prior to that radical step, an awakening had occurred through people like Metchnikoff but more recently Savage, Tannock, McKay, Costerton, Bruce, and others who led us to the microbes that have been helping us all along. In the case of Andrew Bruce, he wondered if replenishment of lactobacilli into the urogenital tract of women might help prevent recurrence of infection. But in the late seventies and early eighties, the collective ‘we’ wasn’t ready to listen.

You came like a comet, blazing your trail. Too high, too far, too soon, you saw the whole of the moon4.

In 2001 in the city of Cordoba, Argentina, a group of experts were assembled and asked to come up with a definition for probiotics5. This helped set a path that we remain on today.

But a definition is nothing without application and acceptance and stewardship. It requires passage to voices across the world. That is why the International Scientific Association for Probiotics and Prebiotics (ISAPP) has been a mountain overseeing the field. Led so wonderfully by Mary Ellen Sanders, Glenn Gibson and other outstanding scientists, it is symbolic of the climb many have had to make.

If you understand or if you don’t. If you believe, or if you doubt. There’s a universal justice, and the eyes of truth are always watching you6.

There’s always gonna be another mountain. I’m always gonna wanna make it move. Always gonna be an uphill battle. Sometimes I’m gonna have to lose. Ain’t about how fast I get there, ain’t about what’s waiting on the other side. It’s the climb7.

It has certainly been a climb. For each of us. Cynicism too often outweighing optimism. Hype outweighing truth. Profit ahead of science. Ignorance over understanding. But together, we have reiterated the message, the importance of studies and data. Not in experimental mice or test tubes, but in the ultimate host where benefits are sought.

The road has taught me to fight our corner, but also that there is a magnificence and mystery in this planet we share. From the birth of a baby to the honey bee that pollinates our crops, to the salmon that crosses from salt to fresh water and back. All from the Mother we share8.

I’ve been fortunate that my career has allowed me to pursue my dream, although it’s never quite as it seems9. One song sums it up for me: While I’m alive I’ll make tiny changes to earth10.

I hope that I have made some tiny changes, especially in the poorest regions of Africa where the probiotic fermented foods of Western Heads East and Yoba-for-life are impacting lives of the young and old. Such inspiring people!

I think if each person is able to make tiny changes, we can leave this life better than whence we came.

As retirement looms, it’s funny how the same question is asked repeatedly. “So, what will you do now?” My answer is I’m moving to America. It’s an empty threat11. Actually, I think back to second year of my honours’ degree at Glasgow University and second year of my PhD at Massey University when my answer was “I don’t know for sure, but I’ll do my best.” I think we need to follow the voice inside us and hope that tomorrow brings wellness and satisfaction.

I won’t fill my walls with framed degrees or awards. Those are for photo albums of a blessed past. They were made possible because of hard work, an incredible family, and a set of friends and talented colleagues too numerous to name.

I’m proud of my publications and students, and hope they inspire others. But I only have two hands12, and we need the Big Ideas for you and me13. So, the laboratory, supplies, offices, and amazing staff and students at the St. Joseph’s Hospital site in London, Ontario await a new direction and someone to carry the fire14. For whoever is my successor, I will wish that tomorrow brings another day, another ray of hope15 and that he or she remembers you only get what you give16, and you only get one shot, do not miss your chance17.

Scientific endeavour, an open mind, supportive colleagues, and taking chances all make for an exciting career. I followed a path barely walked. It ostracized me from many in mainstream microbiology. When grant panel reviewers don’t believe your work has value or is needed, life gets challenging. So, you follow your heart, you lean on those who agree with you, and publish on peripheral topics to stay noticed. Then you smile when your critics actually start studying beneficial microbes and probiotics, and understand what you’ve been saying all along.

Probiotics are more than science. They encompass a philosophy, an anthropological perspective, a bridge between past and future. They are a mountain range of possibilities. As researchers we are still people. We should never shut out the disciplines and sounds and voices that surround us. We need to awaken them like adding medium to a dried Lactobacillus and watching it grow.

The possibilities are just as endless as when I started. But they need younger hands with the latest and future technical skill-sets to pursue the big ideas and to be a steward in defending probiotic science and excellence. These are indeed exciting times.

In closing, I hope you enjoy the music selection — and the irony of some of the album names.

As for me heading into the sunset of this journey: Let the music play. I just wanna dance the night away18.

References (unlike any you’ve seen before)

  1. Coldplay. 2017. Kaleidoscope, from A Head Full of Dreams.
  2. Alexander Fleming. 1945. In, The New York Times.
  3. British Sea Power. 2017. What You’re Doing, from Let the Dancers Inherit the Party.
  4. The Waterboys. 1985. The Whole Of The Moon, from This is the Sea.
  5. Food and Agriculture Organization of the United Nations and World Health Organization. 2001. Probiotics in Food. http://www.fao.org/3/a-a0512e.pdf
  6. Enigma. 1993. The Cross Of Changes from album of the same name.
  7. Miley Cyrus. 2009. The Climb, from Hannah Montana: The Movie.
  8. Chvrches. 2013. The Mother We Share, from The Bones of What You Believe.
  9. The Cranberries. 1992. Dreams, from Everybody Else is Doing It.
  10. Frightened Rabbit. 2008. Head Rolls Off, from Midnight Organ Fight.
  11. Kathleen Edwards. 2012. Empty Threat, from Voyageur.
  12. Avicii. 2013. Wake Me Up, from True.
  13. The Boxer Rebellion. 2016. Big Ideas, from Ocean by Ocean.
  14. Editors. 2010. No Sound But The Wind, from the Twilight Saga: New Moon.
  15. Bill Nelson. 1983. Another Day, Another Ray of Hope, from Chimera.
  16. New Radicals. 1998. You Get What You Give, from Maybe You’ve Been Brainwashed Too.
  17. Eminem. 2002. Lose Yourself, from the movie 8 Mile.
  18. Barry White. 1975. Let The Music Play, from the album of the same name.

For information on the position of Director of Human Microbiome and Probiotics at the Lawson Health Research Institute, contact Dr. David Hill: David.hill@nulllawsonresearch.com

Those probiotics may actually be helping, not hurting

By Mary Ellen Sanders PhD, Executive Science Officer, ISAPP, and Gregory B. Gloor PhD, Department of Biochemistry, Schulich School of Medicine and Dentistry, The University of Western Ontario, London

 

A recent Wall Street Journal essay posits that probiotics are harmful, but does so by misrepresenting probiotic and microbiome science in some important ways.

The focus of this essay was an anecdotal report showing that consuming probiotic products (the composition of which was not disclosed), as well as making other dietary modifications, was associated with lower fecal microbiota diversity. This equates, in the author’s mind, to an “unhealthier gut” and leads to the sensational article title “Those Probiotics May Actually Be Hurting Your ‘Gut Health’”.

How important is fecal microbiota diversity to gut health? There is no evidence in humans that increased gut microbiota diversity is causally linked to any better health outcome. In hunter-gatherer populations, the diversity of the gut microbiome cycles seasonally with diet, yet both the low and high diversity microbiomes are presumably equally ‘healthy’. Many different gut diseases are associated with microbiota compositions that differ from those from healthy subjects. But importantly, we don’t know if the different microbiota is the cause of or the result of the disease. So contrary to the author’s assertion, to speak of gut health is not to speak “really…about the gut microbiome”. Scientists don’t even know what a “healthy microbiome” looks like (see review here).

Perhaps more importantly, it is not at all surprising that consuming high numbers of a few probiotics would result in lower fecal microbial diversity. Probiotics typically survive intestinal transit and are observed in fecal samples when the microbiota is measured. A quirk of measuring the microbiome is that it is typically measured as relative abundance, and the thing about relative abundance is that as the number of one microbe goes up, others appear to decline. They don’t decline in absolute number, but their percentage of the total measured is reduced and hence our ability to detect them is also reduced. So, when you add probiotic microbes to your gut microbiota, and then measure the species present, the probiotic organisms appear at the expense of others. As illustrated in the figure, the probiotic species will appear to displace many rare species because the probiotic species comprise a high percentage of the total population. Although the other resident bacteria are all still there, they are more difficult to detect because they are now below the detection limit after probiotics were added to the community.

 

We are not aware of any evidence that probiotics will increase the diversity of fecal microbiota. In fact, based on the rationale above, we expect that probiotics may appear to decrease fecal microbiota diversity. Does that mean probiotics are harmful? No.

The author glosses over another weakness in his anecdotal report. He treats his fecal microbiota as if it is equivalent to his gut microbiota. Fecal samples represent a terminal microbial community with diminishing nutrients and many dead, but measurable, bacteria. This community is much different from what occurs farther upstream in the colon, and likely has little in common with small intestinal microbial communities. Granted, this is a weakness of much research on the gut microbiome, but discerning scientific reporting should call this what it is: fecal microbiota, not gut microbiome.

Are probiotics actually good for us? To answer this question, consult the literature that evaluates specific probiotics for the health outcome that interests you. Some good evidence exists for several clinical endpoints including antibiotic-associated diarrhea, reduced risk of C. difficile, treatment of colic in infants, reduced incidence in upper respiratory tract infections, and others (see review here).

We agree with one conclusion of the essay, that eating a diverse, whole-food, high-fiber diet likely promotes gut health. But there is nothing new about this recommendation and it seems hardly worth column space in the Wall Street Journal.

 

 

Researchers submit recommendations for revised Lactobacillus taxonomy

By Mary Ellen Sanders PhD, Executive Science Officer, ISAPP

A team of researchers has submitted their recommendations for new classification for the heterogeneous group of species currently considered to belong to the genus Lactobacillus. The paper is under review by the International Journal of Systematic and Evolutionary Microbiology, the premier journal for bacterial taxonomy.

Three research teams that were independently working on comparative genomics and taxonomic inconsistencies among lactobacilli (see here, here, here, here, here, and here) came together to openly collaborate on this publication. These teams included scientists from Italy, Canada, Belgium, Germany, China, Ireland, and Japan.

Several species important from a commercial perspective will be impacted, including Lactobacillus casei, Lactobacillus plantarum, Lactobacillus sakei, Lactobacillus salivarius, Lactobacillus reuteri and Lactobacillus brevis. New genus names are expected for these. Lactobacillus delbrueckii, Lactobacillus acidophilus, Lactobacillus gasseri, Lactobacillus johnsonii, Lactobacillus helveticus and Pediococcus are not expected to undergo name changes. Since L. delbrueckii (which includes the subspecies L. delbrueckii subspecies bulgaricus, the yogurt starter culture) was the first Lactobacillus named, convention in naming bacterial genera requires that species from this taxonomic clade will keep the Lactobacillus name.

Driving this effort is the pressing need to apply modern phylogenetic methods to establishing relationships among the many species of Lactobacillus (see previous post). The genus Lactobacillus currently comprises more than 240 species, and has been growing rapidly for decades. In 1980, 36 Lactobacillus species were recognized. By 2012, there were 152. Scientists recognized the need to reorganize the phylogenetic assignments of this genus; they are proposing splitting the Lactobacillus genus into more than 20 genera.

Once the paper is published, the task of disseminating the message about new genus names for commercially important species will begin.

See here for a detailed article on this topic.

Is probiotic colonization essential?

By Prof. Maria Marco, PhD, Department of Food Science & Technology, University of California, Davis

It is increasingly appreciated by consumers, physicians, and researchers alike that the human digestive tract is colonized by trillions of bacteria and many of those bacterial colonists have important roles in promoting human health. Because of this association between the gut microbiota and health, it seems appropriate to suggest that probiotics consumed in foods, beverages, or dietary supplements should also colonize the human digestive tract. But do probiotics really colonize? What is meant by the term “colonization” in the first place? If probiotics don’t colonize, does that mean that they are ineffective? In that case, should we be searching for new probiotic strains that have colonization potential?

My answer to the first question is no – probiotics generally do not colonize the digestive tract or other sites on the human body. Before leaping to conclusions on what this means for probiotic efficacy, “colonization” as defined here means the permanent, or at least long-term (weeks, months, or years) establishment at a specific body site. Colonization can also result in engraftment with consequential changes to the gut microbiota composition and function. For colonization to occur, the probiotic should multiply and form a stably replicating population. This outcome is distinct from a more transient, short-term (a few days to a week or so) persistence of a probiotic. For transient probiotics, it has been shown in numerous ways that they are metabolically active in the intestine and might even grow and divide. However, they are not expected to replicate to high numbers or displace members of the native gut microbiota.

Although some studies have shown that digestive tracts of infants can be colonized by probiotics (weeks to months), the intestinal persistence times of probiotic strains in children and adults is generally much shorter, lasting only few days. This difference is likely due to the resident gut microbiota that develops during infancy and tends to remain relatively stable throughout adulthood. Even with perturbations caused by antibiotics or foodborne illness, the gut microbiome tends to be resilient to the long-term establishment of exogenous bacterial strains. In instances where probiotic colonization or long-term persistence was found, colonization potential has been attributed more permissive gut microbiomes specific to certain individuals. In either case, for colonization to occur, any introduced probiotic has to overcome the significant ecological constraints inherent to existing, stable ecosystems.

Photo by http://benvandenbroecke.be/ Copyright, ISAPP 2019.

This leads to the next question: Can probiotics confer health benefits even if they do not colonize? My answer is definitely yes! Human studies on probiotics with positive outcomes have not relied on intestinal colonization by those microbes to cause an effect. Instead of colonizing, probiotics can alter the digestive tract in other ways such as by producing metabolites that modulate the activity of the gut microbiota or stimulate the intestinal epithelium directly. These effects could happen even on short-time scales, ranging from minutes to hours.

Should we be searching for new probiotic strains that have greater colonization potential? By extension of what we know about the resident human gut microbiota, it is increasingly attractive to identify bacteria that colonize the human digestive tract in the same way. In some situations, colonization might be preferred or even essential to impacting health, such as by engrafting a microbe that performs critical metabolic functions in the gut (e.g. break down complex carbohydrates). However, colonization also comes with risks of unintended consequences and the loss of ability to control the dose, frequency, and duration of exposure to that particular microbe.

Just as most pharmaceutical drugs have a transient impact on the human body, why should we expect more from probiotics? Many medications need to be taken life-long in order manage chronic conditions. Single or even repeated doses of any medication are similarly not expected to cure disease. Therefore, we should not assume a priori that any observed variations in probiotic efficacy are due to a lack of colonization. To the contrary, the consumption of probiotics could be sufficient for a ripple effect in the intestine, subtly altering the responses of the gut microbiome and intestinal epithelium in ways that are amplified throughout the body. Instead of aiming for engraftment directly or hand-wringing due to a lack of colonization, understanding the precise molecular interactions and cause/effect consequences of probiotic introduction will lead to a path that ultimately determines whether colonization is needed or just a distraction.

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ISAPP launches new website, furthering its mission of educating stakeholders on probiotic and prebiotic science

The ISAPP Board of Directors is pleased to announce the launch of the organization’s new website, which has now gone live at ISAPPscience.org. The website has been redesigned for easier navigation by different stakeholder groups—scientists, consumers, clinicians, and students—enabling ISAPP to continue with its mission of providing accurate, science-based information to its readers about probiotics, prebiotics and fermented foods.

ISAPP Executive Science Officer Dr. Mary Ellen Sanders says, “The scientists comprising the ISAPP Board of Directors realize that consumers and clinicians often struggle to find science-based information on probiotics and prebiotics. ISAPP is working to fill this gap, and we have streamlined our website to help individuals from each of these groups easily find the information they’re looking for.”

At the ISAPP annual meeting held earlier this year, advancing probiotic and prebiotic evidence to a variety of audiences was the topic of a special ‘springboard discussion’ session.

“Probiotic and prebiotic science has made significant progress in the past few decades,” says Sanders, “but this progress has not always been communicated effectively or correctly to those outside the scientific community.” Sanders continues, “Some studies describe an expanding array of health benefits but other studies show the limits of these interventions. Our goal is to counter the abundance of misinformation and be the go-to source of accurate materials about probiotics and prebiotics.”

ISAPP is building its capacity to produce more science-focused educational materials tailored to different audiences. Infographics, some of which are translated into 10 different languages, short videos and targeted blogs are featured on the new website. In coming weeks, ISAPP will make additional resources available on the website, including frequently asked questions about probiotics and prebiotics, and a downloadable white paper for clinicians. Signing up for the ISAPP newsletter is the best way to stay up to date on educational materials being added to the website.

ISAPP’s 2019 annual meeting in Antwerp, Belgium: Directions in probiotic & prebiotic innovation

Kristina Campbell, Microbiome science writer, Victoria, British Columbia

We live in a time when a simple Google search for ‘probiotics’ produces over 56.8 million hits; a time when almost everyone has heard of probiotics through one channel or another, and when an ever-increasing variety of probiotic and prebiotic products is available in different regions of the world.

The next five to ten years will be telling: will probiotics and prebiotics join the ranks of other trendy health products that experienced a wave of popularity before something else took their place? Or will they be recognized as important contributors to health through the lifespan, and establish a permanent position in the clinical armamentarium?

According to the global group of 175 academic and industry scientists who met for the ISAPP annual meeting in Antwerp (Belgium) May 14-16, 2019, one thing above all is necessary for the world to recognize the significance of probiotics and prebiotics for health: scientific innovation. Not only are technological capabilities advancing quickly, but also, new products are being evaluated by better-educated consumers who demand more transparency about the health benefits of their probiotics and prebiotics.

Participants in the ISAPP conference came together to talk about some of the leading innovations in the world of probiotics and prebiotics. Here are three of the broad themes that emerged:

Better health through the gut-brain axis

Gut-brain axis research is rapidly growing, with many investigators in search of probiotic and prebiotic substances capable of modulating brain function in meaningful ways. Phil Burnett of Oxford (UK) presented on “Prebiotics, brain function and stress: To what extent will prebiotics replace or complement drug therapy for mental health?”. Burnett approached the challenge by administering prebiotics to healthy adults and giving them a battery of psychological tests; in one experiment he found people who consumed a prebiotic (versus placebo) showed benefits that included reduced salivary cortisol and positively altered emotional bias. For those with diagnosed brain disorders, Burnett concludes from the available data that prebiotics have potential anxiolytic and pro-cognitive effects in these populations, and that prebiotics may eventually be used to complement the established treatments for some mental disorders.

Short-chain fatty acids (SCFAs) are of interest as potential modulators of brain function, but so far very little research has been carried out in this area. Kristin Verbeke of Leuven (Belgium) gave a talk entitled “Short-chain fatty acids as mediators of human health”, which covered the extent to which interventions with fermentable carbohydrates can alter systemic SCFA concentrations (rather than gut SCFA concentrations)—since the former are more relevant to effects on the brain.

Also, a students and fellows feature talk by Caitlin Cowan of Cork (Ireland) explored a role for the microbiota in psychological effects of early stress. She spoke on the topic “A probiotic formulation reverses the effects of maternal separation on neural circuits underpinning fear expression and extinction in infant rats”.

A clear definition of synbiotics

Immediately before the main ISAPP meeting, a group of experts met to propose a consensus definition of ‘synbiotic’, with the objective of clarifying for stakeholders a scientifically valid approach for the use of the increasingly-popular term. A key point of discussion was whether the probiotic and prebiotic substances that make up a synbiotic are complementary or synergistic. And if the two substances have already been tested separately, must they be tested in combination to give evidence of their health effect? The group’s conclusions, which will undoubtedly steer the direction of future R&D programs, will be published in a forthcoming article in Nature Reviews Gastroenterology & Hepatology.

Probiotics and prebiotics for pediatric populations

Probiotics and prebiotics have been studied for their health benefits in pediatric populations for many years, but in this area scientists appear to have a renewed interest in exploring new solutions. Maria Carmen Collado of Valencia (Spain) covered “Probiotic use at conception and during gestation”, explaining some of the most promising directions for improving infant health through maternal consumption of probiotics.

In recent years, technical advancements have made possible the large-scale production of some human milk oligosaccharides (HMOs); it is now an option to administer them to infants. Evelyn Jantscher-Krenn of Graz (Austria) presented a novel perspective on HMOs, with “HMOs in pregnancy: Roles for maternal and infant health”, giving a broad overview of the many ways in which HMOs might signal health status and how they might be fine-tuned throughout a woman’s pregnancy.

A discussion group on “prebiotic applications in children”, chaired by Dr. Michael Cabana of San Francisco (USA) and Gigi Veereman of Brussels (Belgium), discussed evidence-based uses of prebiotics in children in three areas: (1) prevention of chronic disease; (2) treatment of disease; and (3) growth and development. While the latter category has the best support at present (specifically for bone development, calcium absorption, and stool softening), the other two areas may be ripe for more research and innovation. The chairs are preparing a review that covers the outcomes of this discussion group.

Next year in Banff

ISAPP’s next annual meeting is open to scientists from its member companies and will be held on June 2-4, 2020 in Banff, Canada.

 

Photo by http://benvandenbroecke.be/ Copyright, ISAPP 2019.

L. rhamnosus GG for treatment of acute pediatric diarrhea: the totality of current evidence

By Mary Ellen Sanders PhD, Executive Science Officer, ISAPP

For the past several years, studies have been adding to the evidence base on the efficacy of Lactobacillus rhamnosus GG for the treatment of pediatric diarrhea. A new systematic review and meta-analysis led by Prof. Hania Szajewska concluded that Lactobacillus rhamnosus GG is effective for treating acute diarrhea in hospitalized children, even when a 2018 null trial (Schnadower et al. 2018) was included.

“Despite a recent large RCT demonstrating no effect of L rhamnosus GG, current evidence shows that, overall, L rhamnosus GG reduced both the duration of diarrhoea (with a higher impact in European countries) and hospitalisation in inpatients.”

The authors acknowledge that the quality of evidence for this conclusion is low: 13 of 18 included studies suffered from problems with randomization, allocation concealment, blinding, and/or follow‐up. However, the rigorous process used to assess the current state of evidence provides confidence in the paper’s conclusions.

In an editorial in Alimentary Pharmacology & Therapeutics, Prof. Eamonn Quigley suggests that reports dismissing L. rhamnosus GG as ineffective (for example, see The Washington University School of Medicine opinion, “Probiotics no help to young kids with stomach virus“) were premature.

As Prof. Quigley points out, it is necessary to put the findings of the null study into context. He states several reasons why the Schnadower et al. 2018 study may not have shown an effect of L rhamnosus GG, even though previous studies had. Notably, the rotavirus vaccination status of the subjects – with two-thirds of the study population having been vaccinated – seemed important. Subgroup analysis showed that the probiotic was more effective among children who had not been vaccinated for rotavirus.

In addition, as discussed in a previous ISAPP blog, the timing of initiating probiotic therapy is likely an important factor. In the null trial, the average time of diarrhea prior to treatment was 53 hours, and subjects were enrolled up to 72 hours after onset of diarrhea – likely too late to have a possibility of positive impact by the probiotic.

For now the ESPGHAN recommendation to initiate L. rhamnosus GG treatment in conjunction with rehydration therapy early after the onset of diarrhea in children can still be supported by the totality of evidence.

Both Prof. Hania Szajewska and Prof. Eamonn Quigley serve on the ISAPP board of directors.

Effects of the food matrix on probiotic’s efficacy: how much should we care?

By Gabriel Vinderola PhD, Researcher at the Dairy Products Institute (National Scientific and Technical Research Council – CONICET) and Associate Professor at the Food Technology and Biotechnology Department, Faculty of Chemical Engineering, National University of Litoral, Santa Fe, Argentina.

The issue of to what extent food components may affect probiotic efficacy when compared to the strain delivered as supplement has lately been the subject of debate. This is especially so in the context of the Codex Alimentarius guidelines on probiotics, presently under development.

When considering the importance of the food formulation delivering the probiotic, it’s worthwhile to keep in mind that people may get their daily probiotic together with an enormous variety of foods. For instance, one person may get the probiotic at breakfast along with a yoghurt or with cereal, whereas another person may choose to consumer a fruit juice, while a third may get the probiotic dose before a meal consisting of pasta, meat and vegetables. In those cases, the same strain can undergo gastrointestinal passage in the context of very different food exposures. Does this suggest that perhaps the specific food format is not so critical? What does research tell us?

An interesting, however in vitro, study was conducted by Grześkowiak et al. (2011). In this work, Lactobacillus rhamnosus GG was recovered from more than 12 foods and supplements and its ability to inhibit food pathogens was assessed in vitro. Authors showed that even when the inhibitory capacity was quantitatively different among isolates, the qualitative probiotic capacity of inhibiting pathogens was present in all of them. That is to say, the probiotic capacity had been retained to a somewhat greater or lesser degree, regardless the matrix.

Few human studies have measured to what extent a health endpoint changes when a probiotic is delivered in different food matrixes. For instance, Saxelin et al. (2010) showed that the administration matrix (capsules, yogurt or cheese) did not influence the faecal quantity of lactobacilli, but affected faecal counts of propionibacteria and bifidobacteria. However no health endpoint was considered in this study. Several studies demonstrate that dairy products are able to confer enhanced protection during gastrointestinal transit in in vitro settings (Vinderola et al., 2000; Sagheddu et al., 2018; da Cruz Rodrigues et al., 2019), suggesting that dairy products may be better at delivering an efficacious dose of probiotic. But again, no clinical endpoint was measured in these studies.

The first comparative study on the probiotic capacity of a strain delivered in food or supplement was reported by Isolauri et al. (1991). Authors demonstrated that Lactobacillus GG either in fermented milk or freeze-dried powder was effective in shortening the course of acute diarrhea. Later on, Meng et al. (2016) found similar patterns of immune stimulation when studying the impact of Bifidobacterium animalis subsp. lactis BB12 administration in yoghurt or capsules on the upper respiratory tract of healthy adults.

As these kinds of studies are scarce, we can look to meta-analysis where the same strain is compared for the same clinical endpoint, but in studies conducted by different groups in different matrixes. For instance, Szajewska et al. (2013) concluded that Lactobacillus GG delivered in capsules or fermented milk significantly reduced the duration of diarrhea and Urbańska et al. (2016) reported that L. reuteri DSM 17938 delivered in either capsules or infant formula reduced the duration of diarrhoea and increased the chance of cure.

In vitro studies find that survival of the probiotic delivered in different food matrices through a (simulated) gastrointestinal transit may quantitatively differ, but no matrix completely eliminates probiotic capacity. Human clinical trials comparing different matrices with a clear health endpoint are scarce, but a general conclusion seems to emerge: regardless of the food matrix, the probiotic effect is achieved.  When the data are assessed through meta-analysis, the top of the “levels of evidence” in the pyramid of evidence-based studies, the probiotic capacity exists for the same strain among different studies, conducted by different research groups, using different food matrices.

In many countries regulators require that the probiotic effect be demonstrated in the same food or supplement that will be offered to consumers. This is a conservative approach in the lack of other evidence, but it may be challenging at the same time for probiotic food development, as any new food, even similar to one already existing, may require new human clinical studies to demonstrate efficacy. This approach may raise economic and ethical concerns too, and be discouraging for the future of probiotics.

Surely additional clinical trials directly comparing effects among different delivery matrices would provide clarity on the importance of this factor to probiotic functionality. Until that time, regulators should enable probiotic food manufacturers to offer a sound scientific rationale that bio-equivalency of different matrices could be expected, and thereby circumvent the requirement need to re-conduct human clinical trials on probiotics delivered in new matrices.

 

References

da Cruz Rodrigues VC, Salvino da Silva LG, Moreira Simabuco, F, Venema K, Costa Antunes AE. Survival, metabolic status and cellular morphology of probiotics in dairy products and dietary supplement after simulated digestion. J Funct. Foods, 2019, 55, 126-134.

Grześkowiak Ł, Isolauri E, Salminen S, Gueimonde M. Manufacturing process influences properties of probiotic bacteria. Br J Nutr. 2011, 105(6):887-94.

Isolauri E, Juntunen M, Rautanen T, Sillanaukee P, Koivula T. A human Lactobacillus strain (Lactobacillus casei sp strain GG) promotes recovery from acute diarrhea in children.

Meng H, Lee Y, Ba Z, Peng J, Lin J, Boyer AS, Fleming JA, Furumoto EJ, Roberts RF, Kris-Etherton PM, Rogers CJ. Consumption of Bifidobacterium animalis subsp. lactis BB-12 impacts upper respiratory tract infection and the function of NK and T cells in healthy adults. Mol Nutr Food Res. 2016, 60(5):1161-71.

Pediatrics. 1991 , 88(1):90-7.

Sagheddu V, Elli M, Biolchi C, Lucido J, Morelli L. Impact of mode of assumption and food matrix on probiotic viability. J Food Microbiol. 2018, 2.

Saxelin M, Lassig A, Karjalainen H, Tynkkynen S, Surakka A, Vapaatalo H, Järvenpää S, Korpela R, Mutanen M, Hatakka K. Persistence of probiotic strains in the gastrointestinal tract when administered as capsules, yoghurt, or cheese. Int J Food Microbiol. 2010, 144(2): 293-300.

Szajewska H, Skórka A, Ruszczyński M, Gieruszczak-Białek D. Meta-analysis: Lactobacillus GG for treating acute gastroenteritis in children-updated analysis of randomised controlled trials. Aliment Pharmacol Ther. 2013 Sep;38(5):467-76.

Urbańska M, Gieruszczak-Białek D, Szajewska H. Systematic review with meta-analysis: Lactobacillus reuteri DSM 17938 for diarrhoeal diseases in children. Aliment Pharmacol Ther. 2016, 43(10):1025-34.

Vinderola G, Prosello W, Ghiberto D, Reinheimer J. Viability of  probiotic- (Bifidobacterium, Lactobacillus acidophilus and Lactobacillus casei) and non probiotic microflora in Argentinian Fresco Cheese (2000). J Dairy Sci. 2000, 83 (9), 1905-1911.

Another day, another negative headline about probiotics?

By Prof. Colin Hill, PhD, APC Microbiome Ireland, University College Cork, Ireland

Scientists have a particular job. We try to discover what is unknown and we want to help to create a better understanding of the underlying forces, both physical and biological, that underpin our amazing universe. It is usually a slow and meticulous process. Gathering data usually takes weeks, or months, or years of work and so there is plenty of time to consider the numerous possible interpretations and the limitations and gaps in our understanding. Everything has to be repeated and subjected to statistical analysis. Finally, we publish our findings and our interpretation of that carefully accumulated data. Even this process takes weeks or months (or years) because of discussions with fellow authors and colleagues, numerous drafts of the manuscript, peer review and editorial comment. We are very aware that whatever we have published will almost certainly be repeated, or built upon, and if we are wrong (in either our data or our interpretation) that it will not withstand the test of time. Thus, we are slow and cautious and often qualify our findings with “this suggests” or “this strongly suggests” and we often finish with the unavoidable conclusion that “more research needs to be done”.

Journalists have a particular job. Journalists have to react quickly, perhaps in minutes or hours, to a breaking story or a commission from their editors, on topics with which they may not be familiar, and write short articles or present short pieces to camera that will appeal to the public and have a clear message. Nuance and complexity must often be left for long-form journalism or that as-yet unwritten novel. Being slow and complete and debating all of the possible interpretations is simply not an option. Finishing up with a cautious, equivocal “on the one hand, but also on the other hand” is also not really an option. Very few journalistic pieces end with “more journalism needs to be done”. It may also be difficult to construct a story along the lines of “some good science was well performed and led to careful and understated conclusions, which should really be repeated before we get too excited”.

It is not surprising then that scientists and journalists can sometimes find themselves at loggerheads. “Do probiotics work?” is a very reasonable question that a journalist can ask a scientist. “Well,” responds the scientist, “that depends on what you mean by ‘work’, and which probiotic you are asking about, and for what condition, and quite often strains are called probiotics but they do not fit the definition, and of course, there was that paper published last year which showed ……”. Cue frustration on both sides. Why can’t the scientist just answer the question? And why can’t the journalist understand that just because a question can be simply stated does not mean that it has a simple answer? Ask a doctor “do pills work?” and you might very well get a similarly convoluted answer, but no one would think it evasive. No wonder the scientist sometimes ends up reading the resultant article in frustration – how did the journalist come to that conclusion, where did all my careful explanations go? Of course, most scientists are imagining his or her scientific colleagues reading the article and wondering at the ‘incomplete’ or ‘trivial’ response. While the journalist may well wonder what planet the scientist lives on if he or she thinks that the editor is going to publish a long essay capturing all of the subtlety of the research.

This almost certainly comes across as me implying that scientists are impeccable purveyors of truth and that journalists are willing to sacrifice truth for simplicity, but I truly am not suggesting that. In almost every instance there is no bad faith involved from either party, it is simply the consequence of the different demands placed on two very different and very valuable roles in society.

So, these things will happen. We will see newspaper articles and online pieces (or editorial comments in journals) that do not contain all the nuance and complexity of the complex paper which it is based. We will see press articles that draw simple and reader-friendly conclusions. “Probiotics quite useless”, “Are probiotics money down the toilet? Or worse?”, etc. So, how should we respond? Do we write erudite articles pointing out the limitations of the commentator, coming across perhaps as arrogant or supercilious? [And yes, of course I use the words erudite and supercilious because it makes me feel better than you.] Do we send angry missives complaining about the article, and perhaps risk drawing further attention to it?

If you are asked by a journalist to comment on a paper, or if your local/national paper or favourite website has published an article that you think is unfair, perhaps the way to respond is to have a few simple questions of your own which can be put to journalists and/or readers. Perhaps we can use a checklist such as the following:

  • Is the article describing an original piece of research and was it published in a reputable, peer-reviewed journal?
  • What evidence is there that the strain or strain mix in question is actually a probiotic? Does it fit the very clear probiotic definition?
  • Was the study a registered human trial? How many subjects were involved? Was it blinded and conducted to a high standard?
  • What evidence was presented of the dose administered and was the strain still viable at the time of administration.
  • Were the end points of the study clear and measurable? Are they biologically or clinically significant to the subjects?
  • Did the authors actually use the words contained in the headline? “Useless”, or “waste of money”, etc?

Once these relatively simple questions are answered, then we can move on to the details and the complexities, but that is not where we should start. Of course, if a study is well performed and reaches a negative conclusion we should absolutely acknowledge that. But we can still point out that one strain or strain mix not working under one set of conditions is only evidence of the fact that one particular strain or strain mix does not work under one particular set of conditions. It does not warrant a blanket condemnation or criticism of all probiotics. Maybe ask the journalist to think about the obvious flaws in the headline ‘Headache pill does not cure cancer, all pills obviously a waste of money!”, and ask why the same standards should not be applied to probiotics?

Scientists and journalists have different roles in society, that is clear, but we can assume a priori that both have clear motives and do not want to mislead readers. Let’s start from there and make it easier for both sides to work together to make the public aware of the very real potential, and very real limitations, of probiotics and prebiotics in preserving health in a society in dire need of practical solutions.

Thank You to ISAPP’s 2019 Industry Advisory Committee Members

by Dr. Mary Ellen Sanders

This year, a record 50 companies that are dedicated to a science-based approach to the probiotic and prebiotic industries joined ISAPP. As members of the Industry Advisory Committee (IAC), these companies provide critical insights to ISAPP’s all-academic board of directors as they leverage ISAPP to address challenges facing these and related industries.

ISAPP will welcome representatives from each IAC company at the ISAPP Annual Meeting – taking place next week May 14th-16th in Antwerp, Belgium.

Industry dues provide support for ISAPP activities, which would not be possibly without funding by our IAC members. Summaries of ISAPP activities are found here.

Thank you IAC!

ISAPP Tests the Water with a New Session Format at Annual Meeting: The Springboard

By Mary Ellen Sanders PhD, Executive Science Officer, ISAPP

Along with more traditional lectures, the distinctive five-minute rapid-fire late breaking news session and the small, topical discussion groups have been staples of the annual ISAPP meetings. This year in Antwerp, ISAPP is trying yet another innovative approach – a session we are calling “The Springboard.” The witty Prof. Glenn Gibson will chair, sure to make the session entertaining as well as inspiring.

The Springboard is a session designed to integrate audience and facilitators’ viewpoints in an interactive format. The topic:  What can scientists and industry do to spring probiotics and prebiotics into mainstream health management? Four facilitators, each focused on a different perspective (industry, politics, medical/clinical or science/research), will present their visions. The audience, which will be divided into 10 subgroups, is challenged with the task of generating innovative ways to achieve the visions.

ISAPP plans to write up the most interesting solutions for publication. Watch for the output from this new session after the 2019 ISAPP annual meeting – May 14-16.

“A healthy woman, a healthy baby, a healthy generation” lessons learned from the 4th Annual Women and their Microbes Conference

By Dr. Mariya Petrova, Microbiome insights and Probiotics Consultancy, Bulgaria

The 4th annual Women and their Microbes conference took place at the beginning of March celebrating the International Women’s day. The first-ever conference outside Europe in Hamilton, Canada brought together top scientists to discuss the importance of women’s health through the prism of women’s specific microbiomes. The theme of the conference was Microbiome Management in Pregnancy with a uniquely designed high-quality program translating the latest research into the clinical setting. I was honored to serve on the organizing committee for this meeting, and I provide highlights below.

Our health starts long before birth. The developing fetus receives information from the mother in the form of hormones and nutrients and uses these to predict the external environment. The fetus then uses this information to adapt its development to better its chances of survival after birth. However, the developing fetus can be “misinformed.” This happens through the maternal factors such as her use of drugs, stress, and diseases such as obesity and asthma. For example, both absolute maternal weight and weight gain during pregnancy affect microbiota development in infants (Carmen Collado et al., 2010). Maternal microbiota can also shape the immune system of the newborns. Therefore, keeping women on the right course before pregnancy and healthy during pregnancy must be a priority. This will later be translated into a healthier life for the infant through adulthood. Many of us associate healthy pregnancy with women taking the right nutrients and minerals such as folic acid, B12 vitamins, and iron and we are not wrong. But microbes also play an essential role in health. Microbes are a crucial factor providing nutrients, immune protection and regulating host physiology. Particular strains of Lactobacillus sp. and Bifidobacteria sp. can produce vitamin B12 and folic acid in the gut (Magnusdottir et al., 2015), which may be very beneficial during pregnancy. Of interest, this production increases when paired with prebiotics. Not only that, but microbes are increasingly recognized as important in reproduction, pregnancy, and development. Fertilization doesn’t happen in a sterile environment. Distinct bacterial communities are present in the female reproductive tract, but semen health and male fertility are also important (Weng et al., 2014). So don’t forget the “Y” in the equation – fathers also play a role in the health of their offspring. Gestational tissue microbes can also play an important role in development. More research is needed to better understand these microbiomes and the extent to which they can be influenced by maternal diet and health state.

What if the things go wrong – adverse pregnancy outcomes. Preterm birth is an ongoing challenge with rates steadily growing and with limited approaches for prevention. It results in 75% of neonatal morbidity and mortality. High numbers (55-80 %) of preterm births are associated with dysbiosis and a shift of the vaginal microbiota towards a more diverse state (Freitas et al., 2018). It seems likely that the vaginal microbiome can protect against adverse pregnancy outcomes. However, it appears that both antibiotics and probiotic therapy used to date are not effective at preventing preterm birth. “How to prevent adverse pregnancy outcomes?” is a million dollar question. We need a highly discriminatory diagnostic test that defines versions of ‘abnormal’ vaginal microbiomes. This test needs to be significantly associated with adverse health outcomes. The type of abnormal profile that results in preterm birth needs to be distinguishable from other possible ‘abnormal’ profiles. Such a diagnostic tool needs to be simple enough for a clinical environment and cost-effective. We need to have a safe intervention that can ‘treat’ or normalize a microbiome ideally preconception or early pregnancy.

Where do probiotics fit? Probiotics and prebiotics can enhance the nutrient status of the mother via increasing micronutrient and mineral absorption. During pregnancy, about 3.6% of North American women, 14% of The Netherlands women and 23% of Australian women consume probiotics. A lot of studies focus on the role of probiotics for preventing Group B Streptococcus infections, maternal obesities, postpartum depression, and mastitis. Although results are promising, more studies are needed to make clear conclusions and select the best strains for each condition. Importantly, currently used probiotics do not appear to pose safety concerns for pregnant and lactating women. Nevertheless, consumers’ knowledge regarding probiotics is not very precise. This confusion often may stem from a probiotic market with many different manufacturers, some of which are not legitimate, selling products that are not well defined, with very little clinical evidence. A major effort in educating clinicians, pharmacists and the consumers has been made by creating probiotic guidelines. Dragana Skokovic Sunjic has been working in the last ten years in publishing and updating the “probiotic chart.” The probiotic chart summarizes commercially available probiotic supplements or foods sold in Canada or the USA that have published clinical evidence for the particular strain(s) present in each product. Of note, for products containing multiple strains, evidence must be provided for the specified combination and not extrapolated from the evidence for the separate probiotic strains. At present these guidelines are used by primary care providers, specialists (pediatrics, GI), academic teaching hospitals, universities and others.

With the increasing number of microbiome studies, we are witnessing a paradigm shift in the scientific literature with more people focusing on the importance of microbes in human health. Women’s health is a cornerstone for successful reproduction, with important implications for the health of the next generation. Initiatives such as Women and their Microbes are crucial to link the science and medicine together to bring awareness within the healthcare and academic community.

University confers Distinguished University Professor status on ISAPP board of directors member Gregor Reid

ISAPP board of directors member Dr. Gregor Reid has received a Distinguished University Professorship (DUP) award from his institution, University of Western Ontario in Canada, in honour of his exceptional scholarly career achievements. Reid, a Professor of Microbiology & Immunology, and Surgery, was aptly described as ‘a Canadian and international pioneer’ in research related to probiotics and the microbiome. A special area of research focus is how these relate to women’s health.

The many letters after Reid’s name reflect his extensive qualifications: BSc Hons, PhD, MBA, ARM CCM, Dr HS, FCAHS, FRS; he also has over 500 scientific publications to his name. But more than that, the impact of Reid’s work is seen all over the world. He has researched novel probiotic therapies that are now being used in different countries and settings, and his innovations have resulted in numerous probiotic-related patents. Reid also makes a point of empowering those in need: in Uganda, Kenya, and Tanzania, for example, he participated in a project to establish probiotic yogurt kitchens that allowed local women to further build sustainable yogurt businesses.

Reid’s connection with ISAPP goes back a long way—he hosted the first ever ISAPP meeting in London, Canada in May of 2002, and served as ISAPP’s second president. Still a dedicated member of the ISAPP board of directors, he is respected for his innovative ideas to move ISAPP forward and his incredible efficiency. As his colleagues know, no one gets more done more quickly than Gregor!

Today he is known as a steward of the proper use of the term ‘probiotic,’ a fitting description since he chaired the FAO/WHO expert consensus that published the now globally-recognized definition of the word probiotic back in 2001.

The ISAPP colleagues of Dr. Gregor Reid extend a warm congratulations on his Distinguished University Professorship award; they applaud his remarkable scientific accomplishments, his energy, and his determination to help the field advance.

See here for the full news article about the award.

Reading, writing, and making an impact

Bob Hutkins, University of Nebraska-Lincoln, Department of Food Science and Technology and Leslie Delserone, University of Nebraska-Lincoln, University Libraries

For scientists who study probiotics and prebiotics, these are exciting times.  Every day, there are new discoveries and new opportunities.  There certainly are many challenges – obtaining grants, recruiting and mentoring students and postdocs, editorial duties, and maintaining competitive research programs.

But perhaps the most challenging activity is keeping up with the literature. Back in our respective graduate school days, there were only a handful of journals that required regular reading (and most arrived via regular mail in print).  One of us even remembers waiting for mail delivery to learn about the latest science.

There are now dozens of journals that publish high-quality papers on probiotics, prebiotics, fermented foods, gut health, and other relevant topics.  No longer does one have to wait for the latest scientific report – most of us are bombarded with emailed journal highlights, tables of contents, and latest science alerts.

The figure below illustrates this situation.  In 2001 (when ISAPP was formed), there was about 1 probiotic-oriented paper published per day. Now, with prebiotics included, there are more than ten new papers in the literature every single day!

Indeed, just since 2015, there have been more than 12,000 papers on probiotics and prebiotics listed in PubMed. Add in fermented foods, gut health, and methods papers, and those numbers will easily double or triple.

For researchers, clinicians, and other scientists, there are simply too many papers to read and digest.  Thus, for better or worse, many scientists perform a literature triage of sorts, reading papers mainly from so-called high-impact journals.

As a result, probiotic and prebiotic papers published in the top journals inevitably get the most attention, whether deserved or not.  An unfortunate consequence is that papers in other journals sometimes are over-looked.  Perhaps that’s one reason why, based on searches of several citation indexes, about a fourth of all papers published in our field never get cited at all!

So which papers in our field attracted the most attention or had the greatest impact?  Until recently, the only metrics used to assess impact were the journal’s impact factor and an article’s citation score – how many times a particular paper had been cited by other papers. This is no longer the case, as noted below.  But assuming citation numbers actually reflect impact, we’ve compiled a short list of the most important papers in our field.

To do this, we used two multidisciplinary online indexes, Web of Science Core Collection (WoS) and Scopus. The WoS indexes more than 20,000 journals, while Scopus covers more than 30,000 peer-reviewed journals; we limited the WoS search to its Science Citation Index Expanded.  We separately searched the terms probioti* and prebioti* in the article title, looking for papers and reviews published since 1990, and sorting the results for “times cited” or “cited by” from highest to lowest.

For probiotics, there were more than 10,000 (WoS) and 13,600 (Scopus) articles and reviews. As expected, several of the most cited papers were reviews.  Surprisingly, two were reviews on use of probiotics in aquaculture. Indeed, Verschuere et al. (2000) was the second and third most cited study in WoS and Scopus, respectively.  The 2014 ISAPP consensus paper (Hill et al., 2014) was the 2nd and 3rd most cited paper (Scopus and WoS respectively, with 920 and 1,034 citations as of late March 2019).

And the top probiotic paper in our field since 1990?  That would be a Lancet report that described results of an RCT in which Lactobacillus GG was administered to pregnant women and newborns with atopic eczema as the clinical end-point (Kalliomäki et al., 2001). This paper garnered more than 1,500 citations within the WoS, and 1,953 as tracked by Scopus. Among the authors of this study is current ISAPP president, Seppo Salminen. Incidentally, the 4-year follow-up to that same study (Kalliomaki et al., 2003) was the 4th most cited paper in both indexes!

For prebiotics, there were more 3,000 papers listed.  Leading the list of most cited papers is the seminal Gibson and Roberfroid (1995) paper in the Journal of Nutrition that “introduced the concept”.  Papers by Glenn Gibson and his colleagues dominate the list of most cited prebiotic papers.  But the most cited primary research paper on prebiotics was another clinical study from Finland (Kukkonen et al., 2007).

As noted above, citations are no longer the only way to measure impact.  After all, clinicians, industry scientists, and government regulators and policy makers also read and apply published information.  If a paper leads to a new treatment or technology, could there be a greater impact for the social good?

Consider the science paper with perhaps the greatest overall societal impact in the past 20 years. That would be Brin and Page’s 1998 paper published in what at the time was a relatively obscure journal, Computer Networks and ISDN Systems. The article began, in case you haven’t read it, with these six simple words, “In this paper, we present Google”.

Until recently, paper impacts were difficult to measure. But now we have Altmetrics, Twitter, and other ways to assess impact. Given that it usually takes at least a year before a published paper receives a citation in the WoS and Scopus environments, social media provide a way to gauge impact in real-time.  Indeed, a recent editorial in Nature Cell Biology (2018) suggests that plenty of scientists embrace social media. Evidently, many use it to sort through information as quickly as their fingers can tap.

 

Anonymous. 2018. Social media for scientists. Nature Cell Biology 20(12): 1329. doi: 10.1038/s41556-018-0253-6

Brin, S., and L. Page. 1998. The anatomy of a large-scale hypertextual Web search engine. Computer Networks and ISDN Systems 30(1-7):107-117. doi: 10.1016/S0169-7552(98)00110-X

Gibson, G.R., and M.B. Roberfroid. 1995. Dietary modulation of the human colonic microbiota: Introducing the concept of prebiotics. Journal of Nutrition 125(6):1401-1412. doi: 10.1093/jn/125.6.1401

Hill, C., F. Guarner, G. Reid, G.R. Gibson, D.J. Merenstein, B. Pot, L. Morelli, R.B. Canani, H.J. Flint, S. Salminen, P.C. Calder, and M.E. Sanders. 2014. Expert consensus document: The International Scientific Association for Probiotics and Prebiotics (ISAPP) consensus statement on the scope and appropriate use of the term probiotic. Nature Reviews Gastroenterology and Hepatology 11(8):506-514. doi: 10.1038/nrgastro.2014.66

Hutkins, R.W. 2019. Microbiology and Technology of Fermented Foods, 2nd ed.; Hoboken, N.J., Ed.; Wiley-Blackwell: Hoboken, NJ, USA

Kalliomäki, M., S. Salminen, H. Arvilommi, P. Kero, P. Koskinen, and E. Isolauri. 2001. Probiotics in primary prevention of atopic disease: A randomised placebo-controlled trial. Lancet 357(9262):1076-1079. doi: 10.1016/S0140-6736(00)04259-8

Kalliomaki, M., S. Salminen, T. Poussa, H. Arvilommi, and E. Isolauri. 2003. Probiotics and prevention of atopic disease: 4-year follow-up of a randomised placebo-controlled trial. Lancet 361(9372): 1869-1871. doi: 10.1016/S0140-6736(03)13490-3

Kukkonen, K., E. Savilahti, T. Haahtela, K. Juntunen-Backman, R. Korpela, T. Poussa, T. Tuure, and M. Kuitunen. 2007. Probiotics and prebiotic galacto-oligosaccharides in the prevention of allergic diseases: A randomized, double-blind, placebo-controlled trial. Journal of Allergy and Clinical Immunology 119(1):192-198. doi: 10.1016/j.jaci.2006.09.009

Verschuere, L., G. Rombaut, P. Soorgeloos, and W. Verstraete.  2000. Probiotic bacteria as biological control agents in aquaculture.  Microbiology and Molecular Biology Reviews 64(4):655-671. doi: 10.1128/MMBR.64.4.655-671.200

Probiotics: Money Well-Spent For Some Indications

Eamonn M M Quigley MD, Houston Methodist Hospital and Weill Cornell Medical College, Houston, Texas, USA; Hania Szajewska MD, The Medical Univesrity of Warsaw, Department of Paediatrics, Poland; Dan Merenstein MD, Department of Family Medicine, Georgetown University

We read with interest and some concern the Medical News and Perspectives article by Jennifer Abbasi titled “Are Probiotics Money Down the Toilet? Or Worse?” (Abbasi 2019).  As researchers committed to the study of fecal microbiota transplant, prebiotics and probiotics, we find the title overly sensationalist for an article that ultimately provides a more nuanced view. It is unfortunate that the author focused on studies which either did not report on any clinical outcome and hence provide limited insight on the effectiveness of probiotics, or, whose null results likely reflect the late timing of the intervention while failing to refer to many high-quality studies that illustrate the subtlety of commensal and probiotic bacterial actions or clinical efficacy. Tanoue and colleagues provide a reminder that commensal engagement with the immune system is selective and precise (Tanoue et al. 2019). As Dr Knight points out, it would be surprising to witness the same response to any intervention in all individuals (Abbasi 2019). Efforts to individualize medical interventions, including probiotics, are worthwhile, but not yet realized. Until then, available evidence must be critically considered, but not ignored.  We wholeheartedly agree with the call for high quality clinical studies of probiotics but assert that it is also important to stress the challenges of performing clinical studies that seek to demonstrate clinical benefits in healthy human subjects; they require large study populations and are consequently very expensive. That clinical studies have been performed and demonstrated robust and clinically meaningful outcomes was illustrated by the study of Panigrahi where they demonstrated that an intervention comprising a probiotic plus prebiotic reduced sepsis among high-risk infants in rural India (Panigrahi et al. 2017). In the meantime, meta-analyses of smaller studies can provide insights into clinical benefit or harm. For example, systematic reviews and meta-analyses have consistently supported a role for probiotics in the prevention of Clostridium difficile–related illness, leading a JAMA review to state: “moderate-quality evidence suggests that probiotics are associated with a lower risk of C. difficile infection” (Goldenberg et al. 2018). Balanced with the low number needed to harm, probiotic interventions are attractive clinical options. We also question Abbasi’s focus on colonization as there is little, if any, evidence that this is necessary for probiotic activity.

We stress the obligation to provide a balanced view of the field which provides equal emphasis on successes as well as failures. No two probiotics (or probiotic cocktails) are alike; we should not expect they all have the same clinical impact.

 

References

  1. Abbasi J. Are probiotics money down the toilet? Or worse. JAMA 321(7):633-635. doi:10.1001/jama.2018.20798
  2. Tanoue T, Morita S, Plichta DR, et al. A defined commensal consortium elicits CD8 T cells and anti-cancer immunity. Nature. 2019;565:600-605.
  3. Panigrahi P, Parida S, Nanda NC, et al. A randomized synbiotic trial to prevent sepsis among infants in rural India. Nature. 2017;548:407-412.
  4. Goldenberg JZ, Mertz D, Johnston BC. Probiotics to prevent Clostridium difficile infection in patients receiving antibiotics. JAMA 2018;320:499-450. 

 

Acknowledgements:

Conflicts of interest:

All three authors are members of the Board of Directors of ISAPP

Eamonn M M Quigley holds equity in Alimentary Health and has served as a consultant to Alimentary Health, Allergan, Axon Pharma, Biocodex, Glycyx, Menarini, Pharmasierra, Salix and Vibrant.

Hania Szajewska reports no conflicts

Dan Merenstein has served as a consultant to Bayer, Debevoise & Plimpton, Pharmavite and Reckitt Benckiser

New ISAPP video gives an overview of fermented foods and their health benefits

Fermented foods are not the same as probiotic-containing foods. So what’s the difference? Do both of them confer the same health benefits?

These topics are addressed in ISAPP’s latest video, which takes viewers through the scientific basics of fermented foods (see here). Yogurt, kimchi, and cheese fall into this category of foods, which are transformed by growth and metabolic activity of microbes.

Some fermented foods contain live microbes that travel through the digestive tract, interact with cells, and support the intestinal microbiota. Their potential health benefits are of interest, too: not only do fermented foods improve digestibility, but initial studies show they also improve the immune system and prevent acute illnesses.

The upshot? Naturally fermented foods are worth incorporating in your daily diet.

This educational video was commissioned by the ISAPP board of directors with input from several additional scientific experts.

Challenges ahead in the probiotic field – insights from Probiota2019

By Dr. Mariya Petrova, Microbiome insights and Probiotics Consultancy (MiP Consultancy), Bulgaria.

Recently, I attended the Probiota Conference, which brings together representatives from industry and academia on the topic of probiotics and related fields. The goal of many of the speakers at the conference was to provide insight about how to translate scientific discoveries for, and share commercial insights with, end consumers. I would like to share a few points that caught my attention.

Do good science. End-consumers rely on news coverage of science, which unfortunately is too often more sensationalist than accurate. Prof. Gregor Reid’s talk, “Disentangling facts from fake news,” noted that news article titles such as “Probiotics labeled ‘quite useless’” and “Probiotics ‘not as beneficial for gut health as previously thought’” – after research was published last year in Cell (here and here) – were misleading to end-users and of great concern to people in the field of probiotics who are familiar with the totality of the data. Researchers have a responsibility to situate their results in the context of existing evidence. However, Prof. Reid also observed that “too many products are called probiotics with strains not tested in humans”; “too many products are making un-verified claims”; “too many journalist don’t have expertise in science”; “too many rodent studies making association with human health”; “researchers making up their own terms without defining them”. So how do we solve this? Do good science and communicate results clearly, accurately and without bias – to journalists, to peers and to end-users. (See related ISAPP blogs here and here).

Understand the probiotic mode of action. Understanding probiotic modes of action may be the most challenging issues ahead of us. Currently, we have too little understanding of mechanisms by which probiotics provide health benefits. Probiotic strains are living microorganisms, which most likely work through multiple mechanisms and molecules, but we indeed need more in-depth research. When I reflect on my own experience and the struggles to do molecular studies, I can appreciate how difficult this research is. Although others may be focused on screening the microbiome and developing bioinformatics tools, I applaud the researchers trying to develop deeper understandings of how probiotics function, which will enable more rational approaches to probiotic selection and use. (See related ISAPP blog here.)

New names, new glory. The forthcoming reclassification of the Lactobacillus genus was discussed. We are faced with the largest taxonomic upheaval of this genus in history, including many economically important species. The current Lactobacillus genus will be split into at least ten genera. The species and strain names will not change, but many species will have different genus names. Researchers are expected to propose that all new genera names will begin with the letter “L.” The reclassification can help us better understand the mode of action of industrially important probiotics and help tailor probiotic applications. The changes will be communicated with regulatory bodies such as EFSA and FDA. Name changes could also have consequences for medical stakeholders and may lead to potential issues with intellectual properties. Consumers of probiotic products will likely be less affected by this change, but an educational website targeted to consumers could be beneficial. (See related ISAPP blog here.)

EFSA claims as expected. EFSA claims and regulations were also discussed. To date, approximately 400 health claims applications have been submitted to EFSA without any approved. Experts advised to keep the claims simple and easy. EFSA’s strict approach to claims may have the advantage of compelling industry to conduct studies that better support health claims. Responsible companies are adapting to regulatory requirements and are developing good products, and they will probably succeed in meeting claim standards. Nevertheless, it seems that although health claims are deemed important to companies and medical representatives, end-users of probiotics obtain information from other sources. Obtaining health claims is only one piece of the puzzle. Also important is providing science-based information to end-users, especially those keen on keeping their good health through nutrition.

Be transparent. Don’t forget to disclose the strains you use on product labels. Strains designation is one key way to distinguish your product and it is an important way to communicate to your consumer exactly what is in your product. Surprisingly still, some scientific papers fail to report the strains they used to perform their clinical trials. The field is moving towards more transparency with high-quality clinical trials, the best-selected strains for certain condition and clear designation of the probiotic strain on the label. (See related ISAPP infographics here, here and here)

Educate, educate and again educate. Often discussed at the conference was the subject of educating the end consumers. Companies should take a proactive approach to engage consumers and promote understanding of the available evidence where probiotics can promote health. It is difficult for consumers to differentiate science-based evidence from journalistic sensationalism or researcher self-aggrandizement. A major obstacle is also the ready availability in the marketplace of unproven products containing strains that have been tested only in animal models or not proven experimentally at all. Taking the need for reliable communications on probiotics and probiotics to end-users very seriously, ISAPP has developed a range of science-based videos and infographics. The infographics include topics such as how to read the labels of the probiotics products (USA and EU versions) and a probiotic checklist. Thanks to the enthusiastic work of many volunteers, some ISAPP infographics can now be found in 10 different languages.

Despite having great discussions, one thing keeps troubling my mind: Where is the field of probiotics going and how will it look like in 10 or 20 years? The fight for probiotics is not over, despite the progress we have made so far.

Limitations of microbiome measurement: Prof. Gloor shares insights with ISAPP

February 20, 2019

The number of papers published on the human microbiome is growing exponentially – but not all of the studies are equally well designed or reported. Evaluating the latest research requires a basic understanding of the latest approaches to microbiome methods and data analysis.

To help equip scientists not conducting microbiome research with the tools to understand microbiome-focused publications, ISAPP hosted a webinar titled Understanding microbiome experiments: a critical assessment of methods and data analysis. The webinar featured Gregory Gloor, PhD., Professor, Department of Biochemistry, Schulich School of Medicine and Dentistry, The University of Western Ontario, Canada.

A recording of the webinar is available here, and Prof. Gloor’s slides are available here.

Prof. Gloor opened his talk with a sobering perspective: the current body of microbiome publications is fraught with problems. There is a fundamental lack of reproducibility in the microbiome field (Sinha et al. 2017). This is largely due to the large number of tools available and a lack of an a priori established research plan for microbiome analysis, which should be consistently followed throughout a project. At every step of the way, many decisions must be made regarding wet lab methods, bioinformatics toolsets and statistics to use. Different choices lead to different results. Once the biological specimens are assayed, choices for bioinformatics and statistical analyses can greatly influence the conclusions. In short, it’s possible to view the data through so many different lenses that eventually a researcher can find a story worth telling. How close that story comes to the truth is a principle that sometimes is sacrificed for the sake of an interesting story.

Another important challenge to the field is representative sampling. Too few samples are typically taken, often because of cost limitations, so that the samples do not reasonably approximate the truth about the environment being sampled. Conclusions from such studies result in both many false positives and many false negatives.

Prof. Gloor also warned about outsourcing microbiome analysis. Commercial entities often use every metric, hoping the customer will get some outcome they hoped for. Further, their tools are often outdated or proprietary. So caution must be used – there is no substitute for expertise.

Some suggestions for improving outcomes were offered:

  • Each project should stipulate a research approach and outcome a priori, which is consistently followed throughout the project.
  • Methodological consistency is important within a lab, but analytical methods do not necessarily need to be standardized across all labs. If all labs use the same methods, consistent, but incorrect, outcomes may result. So use of different metrics is good, but methods should be consistent within a project. The value of different research groups using different methods to ask particular research questions is that if the same result emerges from different approaches, it increases confidence that the results are true.
  • Gloor cautioned that microbiome datasets are compositional, and compositional data approaches must be used (Gloor et al 2017).
  • Functional readouts have less methodological variation than taxonomic readouts. Therefore, functional analysis of shotgun metagenomics or shotgun metatranscriptomics is typically a more reproducible, and also more informative, readout.
  • Recent advances have significantly decreased the cost of performing shotgun metagenomics for both taxonomic and functional readouts (Hillmann et al 2018).
  • There are now near-complete microbial genomic datasets available for European, North American and Asian populations (Almeida et al 2019) that will make it easier to functionally map datasets.

Prof. Gloor mentioned an interesting aside: prior clinical trial registration, ~60% of large clinical trials showed benefit of the intervention being tested. After the registration process required declaration of primary research outcomes, that number dropped to closer to 10% (Kaplan and Irvin 2015). This suggests that primary outcomes and analysis methods need to be in place to restrict researcher bias. Right now such mechanisms are insufficient in the microbiome field.

Prof. Gloor’s paper, Microbiome Datasets Are Compositional: And This Is Not Optional, provides great background reading for this webinar.

This webinar was developed by ISAPP Industry Advisory Committee representatives as an extension of the annual IAC Learning Forum.

Dr. Gloor is a professor of biochemistry with broad experience in molecular biology, genetics and genomics. His research is focused on the development of tools to examine 16S rRNA gene composition, gene expression of mixed population samples and metabolomic analysis of clinical samples. He is currently working on developing and adapting principled methods to characterize correlation and differential abundance in sparse, high throughput sequencing data as generated in 16S rRNA gene sequencing surveys, meta-genomics and meta-transcriptomics. One of his primary contributions has been the ALDEx2 tool in Bioconductor for the analysis of high-throughput experiments that generate counts per sequence tag: 16S rRNA gene sequencing, metagenomics, transcriptomics and selex-type experiments.

The Children of Masiphumelele Township

Gregor Reid PhD MBA FCAHS FRSC, Professor, Western University and Scientist, Lawson Health Research Institute, London, Canada

Just off the main road from Cape Town, South Africa to Simon’s Town, sits Masiphumelele township where challenges of poverty, malnutrition, HIV and the risk of violence face people every day.

It is also the location for the Desmond Tutu HIV Foundation Youth Centre, a safe haven that provides adolescent-friendly sexual and reproductive health services alongside educational and recreational activities for youth living in Masiphumelele and surrounding areas.

To understand some of the dangers that children face, in 2017, about 270,000 people in South Africa were newly infected with HIV, adding to one of the highest HIV prevalence rates in the world. The Tutu Youth Centre aims at helping educate youth to reduce their risk of becoming another HIV statistic.

I was invited there by University of Cape Town Professor Jo-Ann Passmore, a woman not only recognized for her research but whose passion for helping others is reflected in her warm smile (4th from left in group photo). She asked if I would be interested in holding a workshop to illustrate to the youth how using sachets of probiotic bacteria could empower them. I jumped at the chance. On an afternoon break from the Keystone Symposium, thirty researchers joined me along with Jo-Ann and my wife Debbie, a teacher of children with learning disabilities.

After a tour of the areas where children learn on computers, play games in safety, or have personal discussions about sexual health, everyone filled the room with a stunning backdrop of the Nobel Laureate’s image. Having been privileged to meet the Archbishop when he was hosted by St. Joseph’s Healthcare Foundation in 2008, it was a nerve-tingling experience for me.

Giving a lecture on beneficial microbes is hard enough to peers sitting in the back of the room, but to do so with young South Africans was more somewhat daunting. However, it proved to be a lot of fun especially when we had to identify kids who were good leaders (the boys all pointed to a girl), who liked to make stuff and sell it to others (two boys stood out). By the end, we had picked the ‘staff’ of a new company.

The next step was for four groups to decide on the company’s name, what products they’d make from the probiotic sachets (the options were many including yoghurt, cereals, fruit juices, maize), what marketing tools they would use and who they would target to obtain a respectable income.

Interestingly, several of the conference participants seemed less engaged, as if they had never considered how microbiology research could affect real lives. In front of them were children facing huge challenges on a day-to-day basis. In one group, the kids were quiet until my wife brought out pens and paper, then they went to town designing products, names and labels. A lesson for me on how different people need different stimuli to become engaged. The faculty left early to beat the traffic back to Cape Town, so unfortunately, they did not hear the outcome of the children’s work.

When we re-assembled to present the results, I was impressed with what could be created in such a short time. My favourite was the Amazing Maize, a bottle shaped like a corn cob with the idea it would contain fermented maize. It emphasized the importance of marketing and for products to taste and look good to be purchased.

It has been over ten years since Archbishop Tutu applauded us for the Western Heads East project and thanked us for empowering women and youth and contributing to nutrition in Africa. Since then, thanks to the huge efforts of Western staff and students, and more recently IDRC funding and partnerships especially with Yoba-for-life, Heifer International and Jomo Kenyatta University of Agriculture and Technology, over 260,000 people in east Africa are now consuming probiotic yoghurt every week. The children of the South African townships were maybe too young to join in this new wave of microenterprises, but at least now they have heard about it and the importance of fermented food and beneficial bacteria.

In the background of the workshop several wonderful women committed to start up a new production unit using the Yoba/Fiti sachets developed by Yoba-for-life. I left them some sachets for them to try out the process.

But it was me who left with the biggest lesson on how precious each life is, and how those of us with the knowledge, need to provide the means for others to use their own talents to fulfill the purposes of their lives.

No better way than to start with the children.

Prof. Maria Marco joins the ISAPP board of directors

ISAPP happily announces that Prof. Maria Marco Ph.D. from the Department of Food Science and Technology at UC Davis has joined the ISAPP board of directors.

Prof. Marco has broad expertise in probiotics, prebiotics, and fermented foods. She has a special interest in lactic acid bacteria (from plant and animal sources) and the mechanisms of their interaction with their hosts.  She is one of the few researchers globally to tackle the important issue of the role of delivery matrix in probiotic functionality. She has more than 70 publications and book chapters.

Prof. Marco serves as the Chair of the Food Science Graduate Group and has mentored over 50 undergraduates, MS students, and visiting scholars, 11 PhD students, and 13 post-docs. She is active in education and public outreach on fermented foods and is a founder of a start-up company on microbial detection.

Prof. Marco serves as an Editor of mSphere and has served as the Guest Editor – Special issue on Food Biotechnology for Current Opinion in Biotechnology (2018). As guest editor of COB, she mediated publication of outcomes from several ISAPP discussion groups.

See her profile here. For more details on what her lab is up to, see here.

See here for the list of ISAPP’s all-academic board of directors.

ISAPP’s prebiotics & probiotics infographic now available in Russian

‘International’ is the first word in ISAPP’s title—and the organization takes seriously its commitment to advancing education about probiotics and prebiotics in countries around the world. ISAPP members are happy to announce that the infographic “Effects of Prebiotics and Probiotics on our Microbiota” is now available in Russian. See here.

In an effort to reach broader global populations with its science-based communications on probiotics, prebiotics and fermented foods, ISAPP is undertaking steps to translate its infographics into multiple languages. Expected in the next month are translations of ISAPP’s popular “Probiotics” and “Prebiotics” infographics, which will be available in Bulgarian, Chinese, Dutch, French, Indonesian, Italian, Polish, Portuguese, Russian, and Spanish. (See here for all available translations of ISAPP infographics.)

The translation efforts, led by Dr. Roberta Grimaldi from University of Reading (UK), are made possible by many translators who are contributing generously of their time and skills.

Humpty Dumpty and the Microbiome

Prof. Colin Hill, Microbiology Department and Alimentary Pharmabiotic Centre, University College Cork, Ireland (@colinhillucc)

When I use a word,” Humpty Dumpty said, in rather a scornful tone, “it means just what I choose it to mean—neither more nor less.”

Microbiome science is an evolving discipline, and new terminology is an important part of any developing field.  But precise language is important, especially in a multidisciplinary field with researchers from many diverse scientific backgrounds.  Language provides us a means of communicating with brevity and accuracy, but this is effective only if the reader is deriving the correct (intended) information from the author.

For example, is there a difference between ‘microbiome’, ‘microbiota’ and ‘microflora’?  Are the terms interchangeable, or would it be useful to have them mean related but distinctly different concepts?  I have heard people state that ‘microbiota’ refers to the microbial content of an environment, whereas ‘microbiome’ refers to the microbes AND their environment (the biome).  I have heard others suggest that ‘microbiome’ actually refers to the genetic content of a particular microbiota, in the same way that the genome is the genetic content of an organism.  Some definitions assert that the microbiome/microbiota/microflora only describes the microbial cells (bacteria, archaea and fungi) in a particular niche, while others include non-cellular microbes such as viruses and bacteriophage in their definition.  It has also been pointed out that ‘microflora’ is a misnomer, since technically the term ‘flora’ is reserved for the kingdom Plantae.

A few other examples.  Do we all know what is meant when someone uses the term ‘metagenomics’?  Also, people often refer to analysing the microbiome by 16S – but they are really only analysing the bacterial fraction of the microbiome, the ‘bacteriome’.  Of course ‘16S’ itself is not a valid term – it is 16S rRNA genes that are being analysed.  Would a clear distinction between microbiome, bacteriome, phageome, mycome, virome, archaeome and all the other ‘omes’ help or hinder our understanding of the subject under discussion?  Should most studies actually use the term ‘faecal bacteriome’ rather than ‘gut microbiome’, since it is almost always faeces that is under investigation, and usually only the bacterial component?

I am not going to call out any individuals for abuse of language, since I am pretty sure I could look at my own output and find lots of examples of poorly expressed concepts.  But does any of this matter or am I simply being pedantic? I think it does matter, since if terms are poorly defined it may lead to confusion on the part of the reader (or listener), whereas the authors (or speakers) may know exactly what they mean – neither more or less, as suggested by Humpty Dumpty.

ISAPP has convened consensus panels on the meaning of some very commonly used terms such as probiotic1 and prebiotic2, but there is a limit to this activity, and consensus panels cannot be convened for every new term.  Even with these consensus papers, we still have a plethora of additional terms surrounding beneficial microbes, including paraprobiotics (killed microbes), psychobiotics (originally defined as probiotics with a mental health benefit, but the definition has recently been expanded to any exogenous influence whose effect on the brain is bacterially-mediated3), synbiotics (probiotics and prebiotics administered simultaneously – a term for which ISAPP is convening another Consensus Panel in 2019), live biotherapeutics, etc, etc.  One site I saw referred to bacteriophage as a prebiotic, using the argument that they can influence a microbiome in a selective manner to achieve a beneficial outcome.  This is surely a good example of where the ISAPP definition could provide clarity since prebiotics have to be utilised in order to qualify for the term. Other terms we often use without an agreed consensus as to their meaning are ‘dysbiotic’ (when we could use disturbed, or different, or disrupted), ‘unculturable’ (when we usually mean ‘not yet cultured as far as I know but I haven’t really tried’), ‘hypothetical genes’ (when we actually mean ‘function unknown’), ‘stability’, ‘resilience’, etc.  It may be useful to have some kind of standardised microbiome dictionary, or an accepted glossary of terms.  This is not a new idea (so few of mine ever are), and Julian Marchesi and Jacques Ravel published a lovely short paper to this effect in 20154.  The World Microbiome Day website also has a very short Glossary5.

Obviously, words must be the servants of the author and should not restrict expression or limit our ideas, and in many instances context can make it abundantly clear what meaning is intended by the author.  But in general, a strict definition is not the enemy of understanding, but makes it easier for author and reader to share common ground.

Who should create and curate such a Microbiome Glossary?  Ideally it would be interactive, perhaps along the line of a wiki page, where people could provide their newly coined terms along with a strict definition and arrive at a consensus for commonly used terms.  Reviewers of journal papers and reviews could help, by challenging authors on what terms they use, and whether or not they are the appropriate ones.

Meanwhile, I have to go back to the lab to do some comprehensive metagenomics on the gut microbiome – by which I mean that a competent scientist who works with me is going to go into the lab and conduct a particular form of 16s rRNA gene analysis to profile the more abundant members of the bacteriome of a portion of a faecal sample which has been collected, stored and extracted according to our in-house protocols.  Obviously!

 

  1. Hill et al., 2014. Expert consensus document: The International Scientific Association for Probiotics and Prebiotics (ISAPP) consensus statement on the scope and appropriate use of the term probiotic.  Nat. Rev. Gastroenterol. Hepatol. 11, 506.
  2. Gibson et al., 2017. Expert consensus document: The International Scientific Association for Probiotics and Prebiotics (ISAPP) consensus statement on the definition and scope of prebiotics.  Nat. Rev. Gastroenterol. Hepatol. 14, 491.
  3. Sarkar et al., 2016. Psychobiotics and the Manipulation of Bacteria–Gut–Brain Signals.  Trends in Neurosciences 39, 763
  4. Marchesi JR and J. Ravel. 2015. The vocabulary of microbiome research: a proposal.  Microbiome 3, 31
  5. http://worldmicrobiomeday.com/glossary-of-microbiome-terms/
hospital_room

Late initiation of probiotic therapy for acute pediatric gastroenteritis may account for null results

Francisco Guarner, MD, PhD, University Hospital Vall d’Hebron, Barcelona, Spain; Michael Cabana, MD, MPH, University of California, San Francisco, CA, USA; and Mary Ellen Sanders, PhD, International Scientific Association for Probiotics and Prebiotics, Centennial, CO, USA. 

Schnadower et al (1) and Freedman et al (2) conclude that probiotics given to children who presented to emergency departments with gastroenteritis are not effective; however, these new well-conducted trials used probiotics in children who were symptomatic much longer than when current recommendations suggest initiating therapy.  Both studies recruited children that were symptomatic for up to 72 hours or more at time of randomization. Half the cohort of Freedman (2) had diarrhea for 43 hours at randomization. In the study by Schnadower, (1) children were symptomatic at randomization for a median of 53 hours. It is not surprising that probiotic intervention at this late stage was not successful, since most children were close to spontaneous remission. Acute gastroenteritis in high-income countries is usually benign and after 48 hours typically remits spontaneously. These new studies should not change current recommendations (3,4,5) to use probiotics early after onset of pediatric gastroenteritis in conjunction with oral rehydration, consistent with previous beneficial trials.

 

  1. Schnadower D, Tarr PI, Casper TC, et al. Lactobacillus rhamnosus GG versus placebo for acute gastroenteritis in children. N Engl J Med. 2018; 379(21):2002-2014.
  2. Freedman SB, Williamson-Urquhart S, Farion KJ, et al. Multicenter trial of a combination probiotic for children with gastroenteritis. N Engl J Med. 2018;379(21):2015-2026.
  3. Allen SJ, Martinez EG, Gregorio GV, Dans LF. Probiotics for treating acute infectious diarrhoea. Cochrane Database Syst Rev. 2010 Nov 10;(11):CD003048.
  4. Szajewska H, Guarino A, Hojsak I, et al. Use of probiotics for management of acute gastroenteritis: a position paper by the ESPGHAN Working Group for Probiotics and Prebiotics. J Pediatr Gastroenterol Nutr. 2014;58(4):531-9.
  5. Lo Vecchio A, Dias JA, Berkley JA, et al. Comparison of recommendations in clinical practice guidelines for acute gastroenteritis in children. J Pediatr Gastroenterol Nutr. 2016;63(2):226-35.

 

Importance of understanding probiotic mechanisms of action

By Prof. Sarah Lebeer, Universiteit Antwerpen, Belgium

At present, we do not fully understand the mechanistic basis of many well established probiotic health benefits. This limits our ability to predict which probiotics are likely to be effective.

For instance, prevention of antibiotic-associated diarrhea and necrotizing enterocolitis are health benefits that are well substantiated by meta-analyses, which combine results on many probiotic strains. But what the effective strains have in common from a mechanistic perspective is not known. We cannot yet pinpoint one or a few molecules produced by these strains that might drive the clinical effects. This is likely due to interplay between both host and probiotic factors. These health conditions are complex pathologies and the probiotic strains are living micro-organisms likely working through multiple mechanisms and molecules.

This is in contrast to some more clearly defined situations. Lactose maldigestion results from a deficiency in the enzyme lactase, which is required for converting lactose to glucose and galactose in the small intestine. If lactose is not broken down, it reaches the colon and is fermented by the gut microbiota, leading to symptoms. Some probiotic bacteria (including those present in yoghurt) contain lactase, which can reduce the typical symptoms of lactose digestion.

Several colleagues and I published a recent paper (Kleerebezem et al. 2019) discussing the importance of understanding mechanisms of action. We argue that such knowledge will enable: “(i) selection of more effective probiotic strains; (ii) optimization of probiotic product manufacturing and quality assurance, (iii) improved design of probiotic formulation, and (iv) support of the design of effective clinical trials with the best chance of realizing benefits to human health.”

While knowledge of the mechanism of action is not necessary for translation to effective products, it provides important insights that can improve actions throughout the translational pipeline.

The strain-specificity of different mechanisms of action is another point that will be clarified by future mechanism-focused research. Different probiotic strains clearly express different mechanisms, but some mechanisms are also shared (Sanders et al. 2018). How different host- and probiotic-specific factors interact to achieve a clinically successful intervention remains to be unraveled.