Genomic Characterization of Wild Lactobacillus delbrueckii Strains Reveals Low Diversity but Strong Typicity.

Investigating the diversity of a given species could give clues for the development of autochthonous starter cultures. However, few studies have focused on the intraspecies diversity of Lactobacillus delbrueckii strains, a technologically important lactic acid bacterium for the dairy industry. For this reason, Lactobacillus delbrueckii strains from the Saint-Nectaire Protected Designation of Origin (PDO) area were isolated and characterized. Genetic diversity was determined based on core genome phylogenetic reconstruction and pangenome analysis, while phenotypic assessments encompassed proteolysis and volatile compound production potential. A total of 15 L. delbrueckii ssp. lactis unique new strains were obtained. The genetic analysis and further proteolytic activities measurement revealed low variability among these Saint-Nectaire strains, while substantial genetic variability was observed within the L. delbrueckii ssp. lactis subspecies as a whole. The volatile compound profiles slightly differed among strains, and some strains produced volatile compounds that could be of particular interest for cheese flavor development. While the genetic diversity among Saint-Nectaire strains was relatively modest compared to overall subspecies diversity, their distinct characteristics and pronounced differentiation from publicly available genomes position them as promising candidates for developing autochthonous starter cultures for cheese production.

Dataset about the Life Cycle Assessment of new fermented food products mixing cow milk and pea protein sources.

In recent years, the food industry has expended considerable effort to design novel products that replace animal proteins with legumes; however, the actual environmental benefits of such products are often not quantified. Here, we performed Life Cycle Assessments (LCA) to evaluate the environmental performance of four new fermented food products based on different mixtures of animal (cow milk) and plant (pea) protein sources (100% Pea, 75% Pea-25% Milk, 50% Pea-50% Milk, 25% Pea-75% Milk). The system perimeter encompassed all stages from agricultural production of the ingredients to the creation of the final ready-to-eat products. Impacts were calculated for all environmental indicators included in the EF 3.0 Method in SimaPro software based on a functional unit of 1 kg of ready-to-eat product. Life cycle inventories included all of the flows analyzed by the LCA (raw materials, energy, water, cleaning products, packaging, transport, waste). Foreground data were acquired directly on the manufacturing site; background data were taken from the Ecoinvent 3.6 database. The dataset contains details on the products, processes, equipment, and infrastructure considered; mass and energy flows; Life Cycle Inventories (LCI); and Life Cycle Impact Assessment (LCIA). These data improve our understanding of the environmental impact of plant-based alternatives to dairy products, which is currently poorly documented.

Dietary Live Yeast Supplementation Influence on Cow's Milk, Teat and Bedding Microbiota in a Grass-Diet Dairy System.

The supplementation of animal feed with microbial additives remains questioning for the traditional or quality label raw milk cheeses with regard to microbial transfer to milk. We evaluated the effect of dietary administration of live yeast on performance and microbiota of raw milk, teat skin, and bedding material of dairy cows. Two balanced groups of cows (21 primiparous 114 ± 24 DIM, 18 multiparous 115 ± 33 DIM) received either a concentrate supplemented with Saccharomyces cerevisiae CNCM I-1077 (1 × 1010 CFU/d) during four months (LY group) or no live yeast (C group). The microbiota in individual milk samples, teat skins, and bedding material were analysed using culture dependent techniques and high-throughput amplicon sequencing. The live yeast supplementation showed a numerical increase on body weight over the experiment and there was a tendency for higher milk yield for LY group. A sequence with 100% identity to that of the live yeast was sporadically found in fungal amplicon datasets of teat skin and bedding material but never detected in milk samples. The bedding material and teat skin from LY group presented a higher abundance of Pichia kudriavzevii reaching 53% (p < 0.05) and 10% (p < 0.05) respectively. A significant proportion of bacterial and fungal ASVs shared between the teat skin and the milk of the corresponding individual was highlighted.

Genetic and technological diversity of Streptococcus thermophilus isolated from the Saint-Nectaire PDO cheese-producing area.

Streptococcus thermophilus is of major importance for cheese manufacturing to ensure rapid acidification; however, studies indicate that intensive use of commercial strains leads to the loss of typical characteristics of the products. To strengthen the link between the product and its geographical area and improve the sensory qualities of cheeses, cheese-producing protected designations of origin (PDO) are increasingly interested in the development of specific autochthonous starter cultures. The present study is therefore investigating the genetic and functional diversity of S. thermophilus strains isolated from a local cheese-producing PDO area. Putative S. thermophilus isolates were isolated and identified from milk collected in the Saint-Nectaire cheese-producing PDO area and from commercial starters. Whole genomes of isolates were sequenced, and a comparative analysis based on their pan-genome was carried out. Important functional properties were studied, including acidifying and proteolytic activities. Twenty-two isolates representative of the diversity of the geographical area and four commercial strains were selected for comparison. The resulting phylogenetic trees do not correspond to the geographical distribution of isolates. The clustering based on the pan-genome analysis indicates that isolates are divided into five distinct groups. A Kyoto Encyclopedia of Genes and Genomes (KEGG) functional annotation of the accessory genes indicates that the accessory gene contents of isolates are involved in different functional categories. High variability in acidifying activities and less diversity in proteolytic activities were also observed. These results indicate that high genetic and functional variabilities of the species S. thermophilus may arise from a small (1,800 km2) geographical area and may be exploited to meet demand for use as autochthonous starters.

A proof of concept infant-microbiota associated rat model for studying the role of gut microbiota and alleviation potential of Cutibacterium avidum in infant colic.

Establishing the relationship between gut microbiota and host health has become a main target of research in the last decade. Human gut microbiota-associated animal models represent one alternative to human research, allowing for intervention studies to investigate causality. Recent cohort and in vitro studies proposed an altered gut microbiota and lactate metabolism with excessive H2 production as the main causes of infant colic. To evaluate H2 production by infant gut microbiota and to test modulation of gut colonizer lactose- and lactate-utilizer non-H2-producer, Cutibacterium avidum P279, we established and validated a gnotobiotic model using young germ-free rats inoculated with fecal slurries from infants younger than 3 months. Here, we show that infant microbiota-associated (IMA) rats inoculated with fresh feces from healthy (n = 2) and colic infants (n = 2) and fed infant formula acquired and maintained similar quantitative and qualitative fecal microbiota composition compared to the individual donor's profile. We observed that IMA rats excreted high levels of H2, which were linked to a high abundance of lactate-utilizer H2-producer Veillonella. Supplementation of C. avidum P279 to colic IMA rats reduced H2 levels compared to animals receiving a placebo. Taken together, we report high H2 production by infant gut microbiota, which might be a contributing factor for infant colic, and suggest the potential of C. avidum P279 in reducing the abdominal H2 production, bloating, and pain associated with excessive crying in colic infants.

Stepwise establishment of functional microbial groups in the infant gut between 6 months and 2 years: A prospective cohort study.

The early intestinal colonization of functional microbial groups plays an essential role in infant gut health, with most studies targeting the initial colonization period from birth to 6 months of age. In a previous report, we demonstrated the metabolic cross-feeding of lactate and identified keystone species specified for lactate utilization in fecal samples of 40 healthy infants. We present here the extension of our longitudinal study for the period from 6 months to 2 years, with a focus on the colonization of functional groups involved in lactate metabolism and butyrate production. We captured the dynamic changes of the gut microbiota and reported a switch in the predominant lactate-producing and lactate-utilizing bacteria, from Veillonella producing propionate in the first year to Anaerobutyrycum hallii producing butyrate in the second year of life. The significant increase in butyrate producers and fecal butyrate concentration was also pinpointed to the weaning period between 6 and 10 months. Correlation analyses further suggested, for the first time, the metabolic cross-feeding of hydrogen in infants. In conclusion, our longitudinal study of 40 Swiss infants provides important insights into the colonization of functional groups involved in lactate metabolism and butyrate production in the first 2 years of life.

Functional changes in Bleu d'Auvergne cheese during ripening.

The authentic characteristics of the famous Bleu d'Auvergne cheese were studied. Many parameters were analysed during the ripening of cheeses. Migrations of Na and Ca ions, associated with a pH gradient, occurred between the rind and the core. At 34 days, this cheese had a high salt content (2.87 %), contributing to 23 % of the recommended sodium intake for adults, but significant calcium (6.14 g/kg) and vitamin B12 (1.14 µg/100 g) levels. Thus, a 40 g serving contributed to 25 % of the population reference intake for Ca and 11 % of the adequate intake for B12. Proteolysis, yeast and mould counts strongly increased. Lactococcus and Streptococcus were predominant and correlated with B2 and B6 levels. Bleu d'Auvergne was characterised by salty taste, blue odour and aroma. This cheese has a noticeable B vitamins concentration, but the level of salt should be reduced to meet the nutritional guidelines, possibly by implementing alternative salting methods.

Lacticaseibacillus casei CNCM I-5663 supplementation maintained muscle mass in a model of frail rodents.

The aim of this study was to identify a probiotic-based strategy for maintaining muscle anabolism in the elderly. In previous research, we found that individuals experiencing short bowel syndrome (SBS) after an intestinal resection displayed beneficial metabolic adjustments that were mediated by their gut microbes. Thus, these bacteria could potentially be used to elicit similar positive effects in elderly people, who often have low food intake and thus develop sarcopenia. Gut bacterial strains from an SBS patient were evaluated for their ability to (1) maintain Caenorhabditis elegans survival and muscle structure and (2) promote protein anabolism in a model of frail rodents (18-month-old rats on a food-restricted diet: 75% of ad libitum consumption). We screened a first set of bacteria in C. elegans and selected two Lacticaseibacillus casei strains (62 and 63) for further testing in the rat model. We had four experimental groups: control rats on an ad libitum diet (AL); non-supplemented rats on the food-restricted diet (R); and two sets of food-restricted rats that received a daily supplement of one of the strains (∼109 CFU; R+62 and R+63). We measured lean mass, protein metabolism, insulin resistance, cecal short-chain fatty acids (SCFAs), and SCFA receptor expression in the gut. Food restriction led to decreased muscle mass [-10% vs. AL (p < 0.05)]. Supplementation with strain 63 tempered this effect [-2% vs. AL (p > 0.1)]. The mechanism appeared to be the stimulation of the insulin-sensitive p-S6/S6 and p-eIF2α/eIF2α ratios, which were similar in the R+63 and AL groups (p > 0.1) but lower in the R group (p < 0.05). We hypothesize that greater SCFA receptor sensitivity in the R+63 group promoted gut-muscle cross talk [GPR41: +40% and GPR43: +47% vs. R (p < 0.05)]. Hence, strain 63 could be used in association with other nutritional strategies and exercise regimes to limit sarcopenia in frail elderly people.

Gut microbes and muscle function: can probiotics make our muscles stronger?

Evidence suggests that gut microbiota composition and diversity can be a determinant of skeletal muscle metabolism and functionality. This is true in catabolic (sarcopenia and cachexia) or anabolic (exercise or in athletes) situations. As gut microbiota is known to be causal in the development and worsening of metabolic dysregulation phenotypes such as obesity or insulin resistance, it can regulate, at least partially, skeletal muscle mass and function. Skeletal muscles are physiologically far from the gut. Signals generated by the gut due to its interaction with the gut microbiome (microbial metabolites, gut peptides, lipopolysaccharides, and interleukins) constitute links between gut microbiota activity and skeletal muscle and regulate muscle functionality via modulation of systemic/tissue inflammation as well as insulin sensitivity. The probiotics able to limit sarcopenia and cachexia or promote health performances in rodents are mainly lactic acid bacteria and bifidobacteria. In humans, the same bacteria have been tested, but the scarcity of the studies, the variability of the populations, and the difficulty to measure accurately and with high reproducibility muscle mass and function have not allowed to highlight specific strains able to optimize muscle mass and function. Further studies are required on more defined population, in order to design personalized nutrition. For elderly, testing the efficiency of probiotics according to the degree of frailty, nutritional state, or degree of sarcopenia before supplementation is essential. For exercise, selection of probiotics capable to be efficient in recreational and/or elite athletes, resistance, and/or endurance exercise would also require further attention. Ultimately, a combination of strategies capable to optimize muscle functionality, including bacteria (new microbes, bacterial ecosystems, or mix, more prone to colonize a specific gut ecosystem) associated with prebiotics and other 'traditional' supplements known to stimulate muscle anabolism (e.g. proteins), could be the best way to preserve muscle functionality in healthy individuals at all ages or patients.

Integration of Multiomic Data to Characterize the Influence of Milk Fat Composition on Cantal-Type Cheese Microbiota.

A previous study identified differences in rind aspects between Cantal-type cheeses manufactured from the same skimmed milk, supplemented with cream derived either from pasture-raised cows (P) or from cows fed with maize silage (M). Using an integrated analysis of multiomic data, the present study aimed at investigating potential correlations between cream origin and metagenomic, lipidomic and volatolomic profiles of these Cantal cheeses. Fungal and bacterial communities of cheese cores and rinds were characterized using DNA metabarcoding at different ripening times. Lipidome and volatolome were obtained from the previous study at the end of ripening. Rind microbial communities, especially fungal communities, were influenced by cream origin. Among bacteria, Brachybacterium were more abundant in P-derived cheeses than in M-derived cheeses after 90 and 150 days of ripening. Sporendonema casei, a yeast added as a ripening starter during Cantal manufacture, which contributes to rind typical aspect, had a lower relative abundance in P-derived cheeses after 150 days of ripening. Relative abundance of this fungus was highly negatively correlated with concentrations of C18 polyunsaturated fatty acids and to concentrations of particular volatile organic compounds, including 1-pentanol and 3-methyl-2-pentanol. Overall, these results evidenced original interactions between milk fat composition and the development of fungal communities in cheeses.

In vitro models of gut digestion across childhood: current developments, challenges and future trends.

The human digestion is a multi-step and multi-compartment process essential for human health, at the heart of many issues raised by academics, the medical world and industrials from the food, nutrition and pharma fields. In the first years of life, major dietary changes occur and are concomitant with an evolution of the whole child digestive tract anatomy and physiology, including colonization of gut microbiota. All these phenomena are influenced by child exposure to environmental compounds, such as drugs (especially antibiotics) and food pollutants, but also childhood infections. Due to obvious ethical, regulatory and technical limitations, in vivo approaches in animal and human are more and more restricted to favor complementary in vitro approaches. This review summarizes current knowledge on the evolution of child gut physiology from birth to 3 years old regarding physicochemical, mechanical and microbial parameters. Then, all the available in vitro models of the child digestive tract are described, ranging from the simplest static mono-compartmental systems to the most sophisticated dynamic and multi-compartmental models, and mimicking from the oral phase to the colon compartment. Lastly, we detail the main applications of child gut models in nutritional, pharmaceutical and microbiological studies and discuss the limitations and challenges facing this field of research.

Corrigendum: Lacticaseibacillus casei CNCM I-5663 supplementation maintained muscle mass in a model of frail rodents.

[This corrects the article DOI: 10.3389/fnut.2022.928798.].

In vivo investigation of Lcr35® anti-candidiasis properties in Caenorhabditis elegans reveals the involvement of highly conserved immune pathways.

Lactic acid bacteria, including the microorganisms formerly designated as Lactobacillus, are the major representatives of Live Biotherapeutic Microorganisms (LBM) when used for therapeutic purposes. However, in most cases, the mechanisms of action remain unknown. The antifungal potential of LBM has already been demonstrated using preclinical models (cell cultures, laboratory animals). Understanding their mechanisms of action is strategic for the development of new therapeutics for humans. Here, Caenorhabditis elegans was used as an in vivo model to analyze pro-longevity, anti-aging and anti-candidiasis effects of the LBM Lacticaseibacillus rhamnosus (formerly Lactobacillus rhamnosus) Lcr35®. A high-throughput transcriptomic analysis revealed a specific response of C. elegans depending on whether it is in the presence of the LBM L. rhamnosus Lcr35® (structural response), the yeast Candida albicans (metabolic response) or both (structural and metabolic responses) in a preventive and a curative conditions. Studies on C. elegans mutants demonstrated that the p38 MAPK (sek-1, skn-1) and the insulin-like (daf-2, daf-16) signaling pathways were involved in the extended lifespan provided by L. rhamnosus Lcr35® strain whereas the JNK pathway was not involved (jnk-1). In addition, the anti C. albicans effect of the bacterium requires the daf-16 and sek-1 genes while it is independent of daf-2 and skn-1. Moreover, the anti-aging effect of Lcr35®, linked to the extension of longevity, is not due to protection against oxidative stress (H2O2). Taken together, these results formally show the involvement of the p38 MAP kinase and insulin-like signaling pathways for the longevity extension and anti-Candida albicans properties of Lcr35® with, however, differences in the genes involved. Overall, these findings provide new insight for understanding the mechanisms of action of a probiotic strain with antimicrobial potential.

Lactic Starter Dose Shapes S. aureus and STEC O26:H11 Growth, and Bacterial Community Patterns in Raw Milk Uncooked Pressed Cheeses.

Adding massive amounts of lactic starters to raw milk to manage the sanitary risk in the cheese-making process could be detrimental to microbial diversity. Adjusting the amount of the lactic starter used could be a key to manage these adverse impacts. In uncooked pressed cheeses, we investigated the impacts of varying the doses of a lactic starter (the recommended one, 1×, a 0.1× lower and a 2× higher) on acidification, growth of Staphylococcus aureus SA15 and Shiga-toxin-producing Escherichia coli (STEC) O26:H11 F43368, as well as on the bacterial community patterns. We observed a delayed acidification and an increase in the levels of pathogens with the 0.1× dose. This dose was associated with increased richness and evenness of cheese bacterial community and higher relative abundance of potential opportunistic bacteria or desirable species involved in cheese production. No effect of the increased lactic starter dose was observed. Given that sanitary criteria were paramount to our study, the increase in the pathogen levels observed at the 0.1× dose justified proscribing such a reduction in the tested cheese-making process. Despite this, the effects of adjusting the lactic starter dose on the balance of microbial populations of potential interest for cheese production deserve an in-depth evaluation.

Strong effect of Penicillium roqueforti populations on volatile and metabolic compounds responsible for aromas, flavor and texture in blue cheeses.

Studies of food microorganism domestication can provide important insight into adaptation mechanisms and lead to commercial applications. Penicillium roqueforti is a fungus with four genetically differentiated populations, two of which were independently domesticated for blue cheese-making, with the other two populations thriving in other environments. Most blue cheeses are made with strains from a single P. roqueforti population, whereas Roquefort cheeses are inoculated with strains from a second population. We made blue cheeses in accordance with the production specifications for Roquefort-type cheeses, inoculating each cheese with a single P. roqueforti strain, using a total of three strains from each of the four populations. We investigated differences between the cheeses made with the strains from the four P. roqueforti populations, in terms of the induced flora, the proportion of blue color, water activity and the identity and abundance of aqueous and organic metabolites as proxies for proteolysis and lipolysis as well as volatile compounds responsible for flavor and aroma. We found that the population-of-origin of the P. roqueforti strains used for inoculation had a minor impact on bacterial diversity and no effect on the abundance of the main microorganism. The cheeses produced with P. roqueforti strains from cheese populations had a higher percentage of blue area and a higher abundance of the volatile compounds typical of blue cheeses, such as methyl ketones and secondary alcohols. In particular, the Roquefort strains produced higher amounts of these aromatic compounds, partly due to more efficient proteolysis and lipolysis. The Roquefort strains also led to cheeses with a lower water availability, an important feature for preventing spoilage in blue cheeses, which is subject to controls for the sale of Roquefort cheese. The typical appearance and flavors of blue cheeses thus result from human selection on P. roqueforti, leading to the acquisition of specific features by the two cheese populations. These findings have important implications for our understanding of adaptation and domestication, and for cheese improvement.

Live Biotherapeutic Products, A Road Map for Safety Assessment.

Recent developments in the understanding of the relationship between the microbiota and its host have provided evidence regarding the therapeutic potential of selected microorganisms to prevent or treat disease. According to Directive 2001/83/EC, in the European Union (EU), any product intended to prevent or treat disease is defined as a medicinal product and requires a marketing authorization by competent authorities prior to commercialization. Even if the pharmaceutical regulatory framework is harmonized at the EU level, obtaining marketing authorisations for medicinal products remains very challenging for Live Biotherapeutic Products (LBPs). Compared to other medicinal products currently on the market, safety assessment of LBPs represents a real challenge because of their specific characteristics and mode of action. Indeed, LBPs are not intended to reach the systemic circulation targeting distant organs, tissues, or receptors, but rather exert their effect through direct interactions with the complex native microbiota and/or the modulation of complex host-microbiota relation, indirectly leading to distant biological effects within the host. Hence, developers must rely on a thorough risk analysis, and pharmaceutical guidelines for other biological products should be taken into account in order to design relevant non-clinical and clinical development programmes. Here we aim at providing a roadmap for a risk analysis that takes into account the specificities of LBPs. We describe the different risks associated with these products and their interactions with the patient. Then, from that risk assessment, we propose solutions to design non-clinical programmes and First in Human (FIH) early clinical trials appropriate to assess LBP safety.

Investigation into In Vitro and In Vivo Caenorhabditis elegans Models to Select Cheese Yeasts as Probiotic Candidates for their Preventive Effects against Salmonella Typhimurium.

The design of multiscale strategies integrating in vitro and in vivo models is necessary for the selection of new probiotics. In this regard, we developed a screening assay based on the investigation of the potential of yeasts from cheese as probiotics against the pathogen Salmonella Typhimurium UPsm1 (ST). Two yeasts isolated from raw-milk cheese (Saccharomyces cerevisiae 16, Sc16; Debaryomyces hansenii 25, Dh25), as well as S. cerevisiae subspecies boulardii (CNCM I-1079, Sb1079), were tested against ST by applying in vitro and in vivo tests. Adherence measurements to Caco-2 and HT29-MTX intestinal cells indicated that the two tested cheese yeasts presented a better adhesion than the probiotic Sb1079 as the control strain. Further, the Dh25 was the cheese yeast most likely to survive in the gastrointestinal tract. What is more, the modulation of the TransEpithelial Electrical Resistance (TEER) of differentiated Caco-2 cell monolayers showed the ability of Dh25 to delay the deleterious effects of ST. The influence of microorganisms on the in vivo model Caenorhabditis elegans was evaluated by measuring the longevity of the worm. This in vivo approach revealed that this yeast increased the worm's lifespan and protected it against ST infection, confirming that this in vivo model can be useful for screening probiotic cheese yeasts.

Milk Microbiota: What Are We Exactly Talking About?

The development of powerful sequencing techniques has allowed, albeit with some biases, the identification and inventory of complex microbial communities that inhabit different body sites or body fluids, some of which were previously considered sterile. Notably, milk is now considered to host a complex microbial community with great diversity. Milk microbiota is now well documented in various hosts. Based on the growing literature on this microbial community, we address here the question of what milk microbiota is. We summarize and compare the microbial composition of milk in humans and in ruminants and address the existence of a putative core milk microbiota. We discuss the factors that contribute to shape the milk microbiota or affect its composition, including host and environmental factors as well as methodological factors, such as the sampling and sequencing techniques, which likely introduce distortion in milk microbiota analysis. The roles that milk microbiota are likely to play in the mother and offspring physiology and health are presented together with recent data on the hypothesis of an enteromammary pathway. At last, this fascinating field raises a series of questions, which are listed and commented here and which open new research avenues.

Caenorhabditis elegans, a Host to Investigate the Probiotic Properties of Beneficial Microorganisms.

Caenorhabditis elegans, a non-parasitic nematode emerges as a relevant and powerful candidate as an in vivo model for microorganisms-microorganisms and microorganisms-host interactions studies. Experiments have demonstrated the probiotic potential of bacteria since they can provide to the worm a longer lifespan, an increased resistance to pathogens and to oxidative or heat stresses. Probiotics are used to prevent or treat microbiota dysbiosis and associated pathologies but the molecular mechanisms underlying their capacities are still unknown. Beyond safety and healthy aspects of probiotics, C. elegans represents a powerful way to design large-scale studies to explore transkingdom interactions and to solve questioning about the molecular aspect of these interactions. Future challenges and opportunities would be to validate C. elegans as an in vivo tool for high-throughput screening of microorganisms for their potential probiotic use on human health and to enlarge the panels of microorganisms studied as well as the human diseases investigated.

Curative Treatment of Candidiasis by the Live Biotherapeutic Microorganism Lactobacillus rhamnosus Lcr35® in the Invertebrate Model Caenorhabditis elegans: First Mechanistic Insights.

The resistance of Candida albicans to conventional drug treatments, as well as the recurrence phenomena due to dysbiosis caused by antifungal treatments, have highlighted the need to implement new therapeutic methodologies. The antifungal potential of live biotherapeutic products (LBP) has already been demonstrated using preclinical models (cell cultures, laboratory animals). Understanding their mechanisms of action is strategic for the development of new therapeutics for humans. In this study, we investigated the curative anti-C. albicans properties of Lactobacillus rhamnosus Lcr35® using the in vitro Caco-2 cell and the in vivo Caenorhabditis elegans models. We showed that Lcr35® does inhibit neither the growth (p = 0.603) nor the biofilm formation (p = 0.869) of C. albicans in vitro. Lcr35® protects the animal from the fungal infection (+225% of survival, p < 2 × 10-16) even if the yeast is detectable in its intestine. In contrast, the Lcr35® cell-free supernatant does not appear to have any antipathogenic effect. At the mechanistic level, the DAF-16/Forkhead Box O transcription factor is activated by Lcr35® and genes of the p38 MAP Kinase signaling pathway and genes involved in the antifungal response are upregulated in presence of Lcr35® after C. albicans infection. These results suggest that the LBM strain acts by stimulating its host via DAF-16 and the p38 MAPK pathway.