You may love exploring new destinations, but did you know that your international adventures can also impact the microscopic world within your gut? A fascinating new study ¹ reveals that travel can temporarily alter your gut microbiome and increase antimicrobial resistance genes (ARGs). However, the good news is that these changes tend to be reversible for healthy individuals.

What is antimicrobial resistance?

Antimicrobial resistance occurs when bacteria, viruses, or other microbes develop the ability to resist the effects of medications designed to kill or stop their growth. This can make infections harder to treat and poses a serious global health threat.

The bounce-back effect

The research team followed 89 healthy travelers from Guangzhou, China, collecting stool samples before their trips, immediately after their return, and three months later. This long-term approach allowed them to track how the gut microbiome and ARGs respond over time.

The findings were remarkable: more than half of the travelers acquired at least one new ARG during their journeys. Immediately after travel, there was a significant spike. However, within three months, these resistance genes were shed, and the gut microbiome reverted to its pre-travel state, showcasing the incredible resilience of our inner ecosystems.

The resilience of your gut microbiome

Your gut microbiome is a complex ecosystem of trillions of microorganisms, including bacteria, viruses, and fungi, that play a crucial role in your overall health. This study demonstrates that while travel can temporarily disrupt this delicate balance, ² the gut microbiome has an amazing ability to bounce back to its original state in healthy individuals.
 

Travel health risks

While exploring new destinations is thrilling, let's not forget about the potential souvenirs you might bring back – traveler's diarrhea, food poisoning, respiratory infections... Talk about memorable mementos! Jokes aside, these travel bugs are no laughing matter. It's crucial to take precautions such as consulting a travel health professional (they're like personal travel bodyguards for your immune system), getting recommended vaccinations, and practicing good hygiene. A little prevention can go a long way in ensuring your adventures are filled with happy memories, not feverish hallucinations.

One year after its launch by three international gastroenterologists, the IBS diagnosis tool keeps its momentum. To mark IBS Awareness Month, the Biocodex Microbiota Institute is going a step further providing healthcare professionals and the lay public a dedicated journey to better understand IBS and its link with the microbiota. 

Since 1997, April is irritable bowel syndrome (IBS) Awareness Month. IBS is a complex disorder, its genesis is likely multifactorial and not fully understood.  But there are several lines of evidence that implicate microbiota in IBS. This why, during this month, the Biocodex Microbiota Institute joins patients, healthcare professionals and family members to increase awareness about IBS and its link with gut microbiota.  Patients’ testimonials, experts’ interviews, infographic, certification training courses, articles... Here are some tools to raise the visibility of IBS and microbiota. 

IBS diagnosis tool: a helpful physician resource

Launched in 2023 by three internationally renowned gastroenterologists Professor Jean-Marc Sabaté, Professor Jan Tack, and Dr. Pedro Costa Moreira, with the support of the Biocodex Microbiota Institute, the IBS Diagnosis tool provides physicians an easy-to-use checklist to differential diagnosis (diagnostic criteria, IBS subtypes, checklist of warning signs, etc.) and to improving communication with patients.

Thousands of gastroenterologists but also family physicians, pharmacists, dietitians have already adopted this innovative tool. Available in three formats, this tool has received the endorsement of the World Gastroenterology Organisation.

It can be downloaded here.

IBS infographic, thematic folder, and training courses: tailored educational opportunities! 

Many patients with IBS suffer for years before discussing their symptoms with their physician. However, due to their prominent position in daily patient care, physicians play a crucial role to play in promptly diagnosing and effectively treating patients with IBS. They are also well positioned to establish open and trusting relationships with their patients. This is the reason why, the Biocodex Microbiota Institute provides healthcare professionals with customized tools and content to improve their day-to-day practice and quickly become experts on IBS. IBS certification training course, infographics to share with patients, expert videos, thematic paper, but also the latest scientific news... A range of innovative, updated and easy-to-use contents to become an IBS expert.

Better understand the complex link between microbiota & IBS 

What are the IBS symptoms? Why do I develop IBS? Is it linked to the microbiota? Is there a microbiota-gut-brain axis? To increase awareness about IBS and answer all the questions the lay public may ask, the Biocodex Microbiota Institute is handing the floor to an expert in the field, Pr. Premysl Bercik, clinician and researcher at McMaster University, Canada.

Living with IBS: patients’ testimonies

Aline, Jennifer and Mihai are IBS patients. In a series of video testimonials, they speak openly about how the disease has changed their lives and give advice on how to live with IBS. The first episodes of “patients stories” were produced with the support of the French Association of Irritable Bowel Syndrome Patients (APSSII). 

With this holistic awareness campaign, the Biocodex Microbiota Institute intends to actively encourage all stakeholders (patients and health professionals, as well as family members, caregivers, health authorities, and the general public, etc.) to get a better understanding of the disease itself, and the latest research advances pointing to the role played by the gut microbiota.

If there is still some way to go in terms of managing IBS and considering symptoms, there is no doubt that the development of new diagnostic tools will soon change the game.

About the Microbiota Institute

The Biocodex Microbiota Institute is an international hub of knowledge that aims to foster better health by spreading knowledge about human microbiota. To do so, the Institute addresses both healthcare professionals and the lay public to raise awareness about the central role of this important organ.

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The era of mis-information is ever expanding. In health information shared on platforms like TikTok, the critical evaluation of content becomes paramount, especially concerning gut microbiota. The gut microbiota, composed of trillions of microorganisms, plays a pivotal role in digestion, metabolism, immune function, and mental health.

Here are some stats on the hashtag #guthealth:

Misinformation can be particularly harmful to individuals with conditions such as Irritable Bowel Syndrome (IBS) or Inflammatory Bowel Disease (IBD), where accurate and evidence-based information is crucial for managing symptoms effectively. Evidence-based practice ensures that interventions and treatments are founded on robust scientific evidence, improving patient outcomes and optimizing healthcare delivery.

The goal is to have individuals feel confident in their ability to discern credible information from falsehoods. This not only aids in the better management of gut health conditions but also prevents the potential exacerbation of symptoms caused by following misguided advice.

Research on aloe vera juice and its effects on digestion highlights its potential benefits. Aloe vera juice has been proven to provide a useful source of vitamins and amino acids when consumed orally. ¹ However, while aloe vera's benefits for digestion are noteworthy, it's crucial to recognize this as just a fragment of the complex gut health puzzle. Our lifestyle, diet, stress levels, and other environmental factors impact gut microbiota, underscoring the importance of a holistic approach to digestive health.

Research indicates that beet juice could be beneficial for the digestive system due to its rich content of bioactive compounds, antioxidants, and fibres. Betalains and phenolics in beet juice can positively modulate the gut microbiota and promote gastrointestinal health, making it a healthy choice for improving digestive function. ² 

While sensational claims on platforms like TikTok, such as “drinking beet juice to eliminate 8-10lbs of waste”, lack scientific backing and veer into misinformation, the truth about beets and digestion is grounded in their nutritional composition. The presence of betalains and phenolics in beet juice has been found to influence gut microbiota and bolster gastrointestinal health positively, underscoring the value of beets in promoting digestive function. Therefore, while the extravagant claims about beet juice may not hold up, its legitimate benefits for digestion highlight the importance of integrating such nutrient-rich foods into our diets for overall gut health and well-being.

According to the American Gastroenterological Association, constipation is typically characterized by having fewer than three bowel movements in a week, not by the absence of bowel movements after each meal. ³ However, it's important to note that normal bowel movement frequency can vary greatly from person to person, ranging from several times a day to three times a week. The spread of misinformation such as the claim that not pooping after every meal equates to constipation, underscores the critical need for evidence-based health information.

Research suggests that ginger extract can indeed have beneficial effects on gut health, particularly in ameliorating antibiotic-associated diarrhea, restoring gut microbiota, and improving intestinal barrier function. ⁴ However, it's crucial to highlight that most of this evidence stems from animal trials, which may not directly translate to human health outcomes. Additionally, while ginger shots are generally safe for consumption, excessive intake can lead to gastrointestinal discomfort, including heartburn, diarrhea, or an upset stomach.

There is no evidence to suggest the frequency and quantity of lemon/ginger/honey shots to be beneficial to gut microbiota.

Evidence suggests that while juice can provide some nutritional benefits, its lack of fibre content may limit its effectiveness in supporting digestion. Fibre is crucial in increasing fecal mass and reducing intestinal transit times, contributing to healthier digestion processes. Since juice typically lacks fibre, it might not aid effectively in digestion compared to whole fruits or vegetables that contain soluble and insoluble fibers.

Moreover, while specific juices, such as citrus juices, might offer some health benefits, they can also directly irritate the esophageal mucosa, potentially exacerbating symptoms in individuals with irritable bowel syndrome (IBS) and thus not aiding digestion. ⁵

In summary, while juice may provide some nutritional benefits, its lack of fibre makes it less effective in promoting digestion than whole fruits and vegetables. The emphasis on consuming whole foods with natural fibre remains essential for digestive health and overall well-being.

Could AI revolutionize our understanding, diagnosis, and management of ASD?

This is one of the questions a team of Dutch researchers has tried to shed some light on. The results of their study have just been published in Scientific Reports. ¹ 

Thanks to machine learning, these scientists were able to identify 26 bacterial taxa characteristic of the gut microbiota of children suffering from autism. This discovery opens the door to new diagnostic techniques and provides potential targets for therapeutic intervention.

Overcoming dietary and lifestyle biases

To unearth these findings, Lucia Peralta-Marzal and her team used data on gut microbiota composition from 60 autistic American children aged 2 to 7 years and 57 of their siblings not affected by the disorder (control group). 

By choosing children from the same sibling group, the scientists sought to reduce biases – common in traditional statistical analyses – linked to diet, living environment, and lifestyle. Their goal was to identify a gut microbial signature specifically linked to ASD.

The researchers analyzed raw 16S rRNA gene sequencing data extracted from the gut microbiota of the children in the cohort using an algorithm called recursive ensemble feature selection (REFS) based on machine learning.

This sub-domain of AI, which uses algorithms to discover patterns in datasets, enabled them to identify 26 amplicon sequence variants (ASVs). These ASVs correspond to 26 bacterial taxa capable of differentiating the children with autism from those in the control group.

A precise, robust, and validated predictive tool

By using these 26 taxa to analyze the same type of data, but this time from two Chinese cohorts (223 children, including 125 with ASD), Lucia Peralta-Marzal and her team succeeded in confirming the ability of this signature to identify autistic children, thus demonstrating the signature’s reliability and reproducibility. 

They calculated the average area under the curve (AUC) to be 81.6% in the US cohort and 74.8% and 74%, respectively, in the Chinese cohorts, proving that confounding factors such as lifestyle do not alter this signature.

Further studies will be needed to understand the role of the 26 taxa in the pathophysiology of ASD. However, this signature can already be used for diagnostic purposes and to provide new information on the molecular mechanisms at play in the microbiota-gut-brain axis. 

In any case, the study confirms that the gut microbiota is strongly associated with ASD and should not be overlooked as a potential target for therapeutic intervention.

When a couple has difficulty conceiving, the fertility of both partners is assessed. In men, a sperm analysis called a spermiogram (sidenote: Spermiogram An examination that evaluates the quality of a sperm sample, including its volume (average normal volume = 1.4 mL), pH (which should be equal to or greater than 7.2), sperm concentration (normally greater than or equal to 16 million per mL), sperm motility (at least 30% must be able to move progressively forward, rather than spinning around or not moving forward) and vitality (> 54%). Other factors are also taken into consideration, such as sperm morphology, the overall appearance of the sample and its viscosity. For a given patient, a semen analysis can never confirm fertility or infertility; the person’s fertility potential also depends on several other parameters and the fertility potential of the person’s partner.
  Source: WHO ) is usually prescribed. Despite this examination, almost 1 in 3 cases of male (sidenote: Male infertility A disease most often caused by problems with ejaculation, the absence or low quantity of spermatozoa, or abnormal sperm shape (morphology) or movement (mobility).
  Source: WHO )  infertility (sidenote: Infertility Disease of the male or female reproductive system defined by the inability to achieve pregnancy after 12 months or more of regular unprotected sexual intercourse. 
  Source: WHO ) remain unexplained. But a new avenue is now being explored: that of the sperm microbiota.

L. iners, an anti-fertility bacterium?

As we all know, semen is far from sterile. It is home to a community of microorganisms, with the most numerous being the bacteria Enterococcus faecalis, Staphylococcus epidermidis, Corynebacterium tuberculostearicum and Lactobacillus iners. However, there are subtle differences associated with sperm quality. For example, in men whose sperm have difficulty moving forward (and therefore have difficulty reaching the egg), Lactobacillus iners bacteria are much more prevalent: they account for 9.4% of bacteria in semen, compared with 2.6% in men whose sperm have normal motility.

In a previous study, the high presence of this bacterium in women’s vaginas was associated with less successful medically assisted procreation (MAP). Its harmful effect could be explained by its pro-inflammatory qualities, which generally do not make for a very good nesting place for fertility!

Pseudomonas also involved

The 3 other bacteria singled out by the researchers all belong to the genus Pseudomonas, previously unknown to the fertility police: semen with a low sperm concentration is richer in Pseudomonas stutzeri and P. fluorescens, and less rich in P. putida. Researchers therefore suspect that the first two bacteria of this genus may go hand in hand with low fertility, while the latter could have a beneficial effect.

Male infertility may be common, but it’s still poorly understood in almost 1 in 3 cases. Could sperm microbiota be involved? Until now, it’s been difficult to find out, as few studies have been dedicated to this microbiota. Even rarer were those approaching the subject from a fertility angle. Hence the interest generated by the work of an American team: according to them, a small group of microorganisms could contribute to reduced fertility in men. ¹

Fertility, sperm and microbiota

73 men undergoing fertility evaluation or requesting vasectomy after one or more children were divided into groups according to the results of analysis of their sperm quality. The first finding of the study: sperm abnormalities (sperm concentration, sperm motility) do not necessarily reflect fertility or subfertility. The group with a normal spermiogram included 40% of the men being evaluated for hypofertility. The second finding: contrary to the results of other studies (different populations? methodology?), the researchers did not observe any significant change in the alpha (sidenote: Alpha diversity Number of species coexisting in a given environment ) or beta (sidenote: Beta diversity Rate of variation in species composition, calculated by comparing the number of unique taxa in each ecosystem ) diversity of the microbiota between normal and non-normal sperm. So, according to the authors, it may not be a global dysbiosis that contributes to subfertility, but a more subtle change in certain species.

Bacteria associated with sperm abnormalities

Overall, Enterococcus faecalis, Staphylococcus epidermidis, Corynebacterium tuberculostearicum and Lactobacillus iners are the most abundant bacteria in semen. But there are subtle differences between anomalies. Sperm with poor motility were richer in Lactobacillus iners (9.4% vs. 2.6%). Similarly, semen samples with a low sperm count were richer in Pseudomonas stutzeri (2.1% vs 1.0%) and P. fluorescens (0.9% vs 0.7%), but had a lower abundance of P. putida (0.5% vs 0.8%).

While this observational study provides only correlations, and by no means causal relationships, its results suggest that some bacteria may play a role in the disturbance of sperm parameters. Especially since L. iners, a pro-inflammatory agent, is also implicated in reduced fertility in women undergoing medically assisted procreation (MAP). This study is therefore the first of its kind to demonstrate a relationship between the presence of L. iners and male infertility.

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“Does it tickle, or does it itch?” Dr Knock’s famous question in Jules Romains’ play of the same name may have inspired the authors of a recent study. Their aim? To better understand the mechanisms that trigger itching (sidenote: Itch Itch is an unpleasant sensation that evokes a desire to scratch. Itch originates in the nerve endings just beneath the skin, at dedicated receptors called pruriceptors. It then follows nerve pathways up to the brain, where it activates sensory (feeling the itch), emotional (wanting to scratch), and motor (actually scratching) brain areas.  
Source : Ameli ) and the resulting irresistible urge to scratch. They achieved their results thanks to a series of experiments on mice and samples of human nerves and skin.

From bacteria to scratching...

The focus of their research: the Staphylococcus aureus bacterium, widely present on our skin. Staphylococcus aureus feeds on the skin lesions of those prone to atopic dermatitis and plays a role in impetigo, a contagious skin disease feared in nurseries and kindergartens. To its resume can be added a direct involvement in pruritus, the scientific name for itching.

Its modus operandi has now been revealed: S. aureus produces a protein called V8, which binds to the skin receptor responsible for itching. By activating this receptor, V8 triggers an alert that travels via a nerve pathway to the brain. The response to the itch is immediate: scratching, often frantic, to the point of damaging the skin.

... then to invasion or spread

Isn’t that exactly what the bacterium wanted? While not wanting to impart to a microorganism any sinister intentions, all of this clearly suits Staphylococcus aureus: scratching is the perfect way for it to reach new tissue, such as the hand or paw used to relieve the itch, or even new individuals, if they happen to be close enough to the skin being scratched. Better still, the lesion induced by scratching is a chance for the bacteria to penetrate a little deeper into the skin. In short, whether through spread or invasion, S. aureus has everything to gain by making us scratch.

Although seemingly harmless, itchy skin can be difficult to live with if it lasts long enough to disrupt daily life or even sleep, or if it results in scratching lesions. Pruritus is associated with a dysbiosis of the skin microbiota and is a major factor in the reduced quality of life of patients suffering from skin diseases (atopic dermatitis, psoriasis, etc.). But what causes pruritus? The results of a study published in 2024 show that opportunistic pathogen Staphylococcus aureus triggers itching by activating dedicated sensory neurons, the pruriceptors (sidenote: Pruriceptors Pruriceptors are the sensory neurons that mediate itch and a desire to scratch. Pruriceptor nerve endings are mainly found in the epidermis, unlike nociceptors, which innervate both skin and deeper tissues.
  Source: https://www.has-sante.fr/jcms/c_2579446/fr/zontivity-vorapaxar-antiagregant-plaquettaire ) .

From S. aureus to scratching

To better understand the mechanisms involved, researchers conducted an extensive series of experiments in vivo (mice) and in vitro (skin and neuron samples, including human neurons). It all starts with the S. aureus bacterium, which is capable of producing proteins that facilitate the colonization and invasion of host tissues. These include various toxins (α-hemolysin and phenol-soluble modulins) and around ten proteases. One of these bacterial enzymes, protease V8, is a critical factor in evoking itch. How? Protease V8 induces itch in mice and humans by stimulating pruriceptors via the activation of this neuron’s PAR1 subcutaneous receptor. The bacterium may take advantage of the itch it causes, since scratching potentially enables it to spread to other areas of the body, or even other hosts, while the skin lesions induced may allow the pathogen to penetrate deeper into the injured layer of skin. 

Other mechanisms also considered

As for the toxins secreted by S. aureus, the study showed that α-hemolysin and phenol-soluble modulins are also capable of activating sensory neurons and triggering itch. However, S. aureus bacteria that are unable to produce these toxins still trigger itching in mice, suggesting that bacterial toxin levels alone are not sufficient to trigger itch.

Of course, there are many other protease-secreting bacteria, whose role should be investigated: Staphylococcus epidermidis produces the protease EcpA, which causes skin lesions in patients with atopic dermatitis; while Streptococcus pyogenes produces the protease SpeB, which is involved in skin infections. And what can be said for fungi, viruses and parasites, whose potential contribution of itch-provoking proteases remains unknown?

It turns out, the secret to why the same food can taste differently to different people might just lie within our mouths - not just in our taste buds, but in the microscopic world of our oral microbiota. According to recent research ¹ led by scientists from the French Center for Taste and Food Sciences at Dijon ², the variety of bacteria residing in our saliva and on our tongue (oral microbiota) could play a crucial role in how we perceive basic tastes.

A microbial influence on every bite

Using cutting-edge shotgun metagenomic analysis, scientists comprehensively identified over 650 microbial species inhabiting the tongue and saliva of 100 diverse human test subjects. While the oral microbiota's total richness and biodiversity didn't directly correlate with variations in taste sensitivity, the relative abundances of certain key bacteria species and genera did appear influential. Two bacteria groups in particular, Streptococcus and Prevotella, stood out as having dramatic effects — though impacts varied significantly depending on the specific species.

Sour sensitivities on our tongue

Higher proportions on the tongue of Streptococcus gordonii and S. parasanguinis, two common plaque bacteria, were associated with substantially reduced sensitivity to all five basic taste modalities:

• sweet
• salty
• bitter
• sour
• savory umami

These adept adherers likely alter the structural landscape of the tongue's biofilm in ways that physically hinder diffusion and access of taste molecules to the underlying receptors.

On the flip side, an unclassified Prevotella species had the opposite effect, linking to enhanced intensity of perception of four of the five taste qualities. Intriguingly, comparing microbiota compositions from the tongue itself versus whole saliva, the latter ecosystem actually proved more predictive of multiple taste sensitivities. This suggests that oral bacteria likely modulate flavor perception through microbial community dynamics and metabolic interactions, not just through local influences on taste bud exposures.

While more research is still needed to clarify the mechanisms involved, these compelling findings reveal an underappreciated contributing role for our endogenous oral microbiota in actively shaping flavor experiences — essentially "tasting" for us by differentially processing food cues en route to the taste receptors themselves.

The emergence of multidrug-resistant organisms (MDROs (sidenote: Multidrug-Resistant Organisms (MDROs) Bacteria that are resistant to multiple antimicrobial drugs.
  Source: https://www.science.org/doi/10.1126/scitranslmed.abo2750  ) ) poses a formidable challenge in healthcare, particularly among immunocompromised patients such as those undergoing kidney transplantation. A recent randomized controlled trial has shed light on Fecal Microbiota Transplantation (FMT (sidenote: Fecal Microbiota Transplantation (FMT) A therapeutic procedure to restore the gut microbiota by transferring fecal bacteria from a healthy donor to a recipient. Explore https://www.science.org/doi/10.1126/scitranslmed.abo2750 ) ) as a promising intervention to diminish MDRO colonization in this vulnerable population. The trial involved a meticulous evaluation of FMT's safety, efficacy, and the dynamics of MDRO strain elimination, with compelling outcomes.

Efficacious elimination and engraftment

The study was conducted at the Emory University Hospital, involving a 1:1 randomization of eleven kidney transplant recipients to either an FMT group (n= 6) or an observation group (n= 5), followed by a subsequent FMT for any participants, regardless of initial group assignment, who remained positive for MDROs after the first intervention (day 36), to further assess the efficacy and potential of FMT in eliminating resistant bacterial strains.

The study observed an impressive success rate, with 8 out of 9 patients who received all protocol-specified showing negative results for MDROs post-FMT. This success was attributed to the engraftment of beneficial taxa from the donor, including Akkermansia muciniphila and Faecalibacterium prausnitzii, into the recipients' gut microbiota. These taxa are known for their beneficial roles in the human gut, suggesting a targeted approach to bolstering the recipient's microbiota against MDRO colonization.

A displacement not a replacement

Expanding on the key aspect of how MDRO strains were displaced, the study conducted an in-depth analysis revealing that the introduction of competitive, conspecific bacterial strains from the donor material played a crucial role. This displacement process was not merely a replacement but a strategic displacement leveraging the microbial competition within the gut microbiome. The researchers meticulously reviewed gene content differences between baseline and replacing strains for groups of conspecific isolates, focusing on genes anticipated to enhance strain competition or host cell surface adhesion.

Significant findings were observed in the gene content analysis, particularly concerning colicins, a subset of bacteriocins produced by E. coli that exhibit toxicity towards other E. coli strains and close relatives. Experimental data have shown that colicin-producing E. coli strains can outcompete colicin-susceptible strains, which in turn may be outcompeted by colicin-resistant strains, demonstrating a complex nontransitive competition dynamic similar to a “rock-paper-scissors game”. This dynamic was evident in the study's findings where susceptible replacing strains, possessed multiple colicin and colicin immunity genes absent in the antibiotic-resistant strains.

These findings illustrate the multifaceted nature of FMT's impact on microbial ecology within the gut, highlighting that the displacement of MDROs by FMT involves a complex interplay of microbial competition, genetic determinants of competitiveness, and the gut environment's selective pressures.