Infant-gut associated Bifidobacterium dentium strains utilize the galactose moiety and release lacto-N-triose from the human milk oligosaccharides lacto-N-tetraose and lacto-N-neotetraose

Much evidence suggests a role for human milk oligosaccharides (HMOs) in establishing the infant microbiota in the large intestine, but the response of particular bacteria to individual HMOs is not well known. Here twelve bacterial strains belonging to the genera Bifidobacterium, Enterococcus, Limosilactobacillus, Lactobacillus, Lacticaseibacillus, Staphylococcus and Streptococcus were isolated from infant faeces and their growth was analyzed in the presence of the major HMOs, 2′-fucosyllactose (2′FL), 3-fucosyllactose (3FL), 2′,3-difucosyllactose (DFL), lacto-N-tetraose (LNT) and lacto-N-neo-tetraose (LNnT), present in human milk. Only the isolated Bifidobacterium strains demonstrated the capability to utilize these HMOs as carbon sources. Bifidobacterium infantis Y538 efficiently consumed all tested HMOs. Contrarily, Bifidobacterium dentium strains Y510 and Y521 just metabolized LNT and LNnT. Both tetra-saccharides are hydrolyzed into galactose and lacto-N-triose (LNTII) by B. dentium. Interestingly, this species consumed only the galactose moiety during growth on LNT or LNnT, and excreted the LNTII moiety. Two β-galactosidases were characterized from B. dentium Y510, Bdg42A showed the highest activity towards LNT, hydrolyzing it into galactose and LNTII, and Bdg2A towards lactose, degrading efficiently also 6′-galactopyranosyl-N-acetylglucosamine, N-acetyl-lactosamine and LNnT. The work presented here supports the hypothesis that HMOs are mainly metabolized by Bifidobacterium species in the infant gut.

Bifidobacterium infantis Maintains Genome Stability in Ulcerative Colitis via Regulating Anaphase-Promoting Complex Subunit 7

Probiotics represents a promising intestinal microbiota-targeted therapeutic method for the treatment of ulcerative colitis (UC). Several lines of evidence implicate that Bifidobacterium infantis serves as a probiotic strain with proven efficacy in maintaining the remission of UC. However, the exact mechanisms underlying the beneficial effects of B. infantis on UC progression have yet to be elucidated. Herein, we provide evidence that B. infantis acts as a key predisposing factor for the maintenance of host genome stability. First, we showed that the fecal microbiota transplantation (FMT) of UC-derived feces contributes to more severely DNA damage in dextran sodium sulfate (DSS)-induced mice likely due to mucosa-associated microbiota alterations, as reflected by the rapid appearance of DNA double strand breaks (DSBs), a typical marker of genome instability. Genomic DNA damage analysis of colon tissues derived from healthy controls, patients with UC or dysplasia, and colitis associated cancer (CAC) patients, revealed an enhanced level of DSBs with aggravation in the degree of the intestinal mucosal lesions. To evaluate whether B. infantis modulates the host genome stability, we employed the DSS-induced colitis model and a TNFα-induced intestinal epithelial cell model. Following the administration of C57BL/6 mice with B. infantis via oral gavage, we found that the development of DSS-induced colitis in mice was significantly alleviated, in contrast to the colitis model group. Notably, B. infantis administration decreased DSB levels in both DSS-induced colitis and TNF-treated colonial cell model. Accordingly, our bioinformatic and functional studies demonstrated that B. infantis altered signal pathways involved in ubiquitin-mediated proteolysis, transcriptional misregulation in cancer, and the bacterial invasion of epithelial cells. Mechanistically, B. infantis upregulated anaphase-promoting complex subunit 7 (APC7), which was significantly suppressed in colitis condition, to activate the DNA repair pathway and alter the genome stability, while downregulation of APC7 abolished the efficiency of B. infantis treatment to induce a decrease in the level of DSBs in TNFα-induced colonial cells. Collectively, our results support that B. infantis orchestrates a molecular network involving in APC7 and genome stability, to control UC development at the clinical, biological, and mechanistic levels. Supplying B. infantis and targeting its associated pathway will yield valuable insight into the clinical management of UC patients.

Feeding Activated Bifidobacterium infantis EVC001 to Very Low Birth Weight Infants is Associated with Significant Reduction in Rates of Necrotizing Enterocolitis

Objectives: To assess the effects of Bifidobacterium infantis EVC001 administration on the rate of necrotizing enterocolitis (NEC) in preterm infants in a single Level IV NICU. Study Design: This was a retrospective observational analysis of 2 cohorts of VLBW infants (+/- B. infantis EVC001 probiotic) at OHSU from 2014 to 2020. Outcomes included NEC rates and NEC-associated mortality, including subgroup analysis of ELBW infants. Fishers exact test and log binomial models were used to determine differences between cohorts and risk reduction of NEC. Adjusted number needed to treat was calculated from the cohort coefficient of the model. Results: In this analysis of 483 infants, the difference in rates of NEC between cohorts was statistically significant (11.0% vs. 2.7%, P = 0.0008). The EVC001-fed cohort had a 73% risk reduction of NEC compared to the No EVC001 cohort (adjusted risk ratio 0.270, 95% CI 0.094, 0.614, P = 0.0054) resulting in an adjusted number needed to treat of 12.4 (95% CI 10.0, 23.5) for B. infantis EVC001. There was no NEC-related mortality in the EVC001-fed cohort, yielding statistically significant differences from the No EVC001 cohort overall (0% vs. 2.7%, P = 0.0274) and the ELBW subgroup (0% vs. 5.6%, P = 0.0468). Conclusion(s): B. infantis EVC001 feeding was associated with a significant reduction in the rate of NEC and NEC-related mortality in an observational study of 483 VLBW infants. B. infantis EVC001 supplementation may be considered safe and effective for reducing morbidity and mortality in the NICU.

Symptomatic relief from at-home use of activated Bifidobacterium infantis EVC001 probiotic in infants: results from a consumer survey on the effects on diaper rash, colic symptoms, and sleep

The gut microbiome during infancy is directly involved in the digestion of human milk, development of the immune system, and long-term health outcomes. Gut dysbiosis in early life has been linked to multiple short-term ailments, from diaper dermatitis and poor stooling habits, to poor sleep and fussiness, with mixed results in the scientific literature on the efficacy of probiotics for symptom resolution. Despite the growing interest in probiotics for consumer use, observed symptomatic relief is rarely documented. This study aims to evaluate observed symptomatic relief from at-home use of activated Bifidobacterium infantis EVC001 in infants. Consumer feedback was collected over a 2-year period via a 30-day post-purchase online survey of B. infantis EVC001 (Evivo®) customers. Outcome measures included observed changes in diaper rash, symptoms of colic, and sleep behaviours in infants fed B. infantis EVC001. A total of 1,621 respondents completed the survey. Before purchasing B. infantis EVC001, the majority of respondents visited the product website, researched infant probiotics online, or consulted with their doctor or other healthcare professional. Of the participants whose infants had ever experienced diaper rash, 72% (n=448) reported improvements, and 57% of those reported complete resolution of this problem. Of those who responded to questions about gassiness/fussiness, naptime sleep, and night-time sleep behaviours, 63% (n=984), 33% (n=520), and 52% (n=806) reported resolution or improvements, respectively. Although clinical data regarding probiotic use are often inconclusive for symptom resolution, home use of B. infantis EVC001 in infants improved diaper rash, gassiness/fussiness, and sleep quality within the first week of use in a significant number of respondents who engaged in a voluntary post-purchase survey. These outcomes may be a result of the unique genetic capacity of B. infantis EVC001 to colonise the infant gut highlighting the importance of strain selection in evaluating the effects of probiotic products.

Evaluación del efecto antimicrobiano de una mezcla de probióticos frente a Cronobacter sakazakii y Salmonella enterica en preparados para lactantes reconstituidos para lactantes

Cronobacter sakazakii y Salmonella enterica son considerados patógenos capaces de causar sepsis y meningitis en lactantes. Se han descrito casos de infección por estos patógenos asociados al consumo de preparados para lactantes contaminados. La inclusión de probióticos en los preparados, además de su papel en la modulación de la microbiota intestinal, podría ser útil para contrarrestar la contaminación de microorganismos patógenos de estos productos una vez reconstituidos y, por lo tanto, reducir el riesgo de infección. El objetivo de esta investigación fue evaluar el efecto antimicrobiano de una mezcla de probióticos (Lactobacillus rhamnosus y Bifidobacterium infantis) frente a Cronobacter sakazakii y Salmonella enterica en preparados reconstituidos para lactantes. Las muestras (con o sin probióticos) se inocularon con C. sakazakii o S. enterica y se incubaron a 30 o 40ºC durante 72 horas. Los resultados muestran que la presencia de probióticos en los preparados lácteos no tiene un marcado efecto en el crecimiento de los patógenos. Sin embargo sí se ve potenciado su efecto inhibitorio frente a C. sakazakii por la interacción entre la temperatura de incubación y los probióticos. Los probióticos empleados fueron viables durante todo el período de incubación, por lo que el agotamiento de los nutrientes se descartó como posible mecanismo de inhibición. La disminución del pH en los preparados lácteos inoculados no explica de manera satisfactoria un comportamiento tan diferente entre ambos patógenos. Por lo tanto, se sugiere como posible mecanismo inhibidor la liberación de bacteriocinas específicas con acción contra C. sakazakii pero sin efecto contra Salmonella. Se deben realizar estudios adicionales para probar esta hipótesis. Cronobacter sakazakii and Salmonella enterica have been implicated in outbreaks causing sepsis and meningitis in infants. Several infection cases have been associated with the consumption of contaminated powdered infant formulae. Besides its role in modulating gut microbiota, the inclusion of probiotics in infant formulae may be useful to counteract pathogen contamination in these products and thus to reduce the risk of infection. The aim of this research was to evaluate the antimicrobial effect of a mixture of the probiotics Lactobacillus rhamnosus and Bifidobacterium infantis against Cronobacter sakazakii and Salmonella enterica in reconstituted follow-on formulae. For that, infant formulae (with or without probiotics) were inoculated with either C. sakazakii or S. enterica and incubated at 30 or 40ºC for 72 hours. Overall, the results showed the presence of probiotics inhibiting the growth of C. sakazakii together with incubation temperature (interaction between both factors). Probiotics were viable throughout the incubation period so that nutrient exhaustion could be ruled out as the mechanism of C. sakazakii inhibition. Thus, the acidification of media observed during the study was hypothesized to be responsible for pathogen growth inhibition. However, since in the case of formulae inoculated with Salmonella the behavior of probiotics and pH values was similar to C. sakazakii, the decrease of pH does not satisfactorily explain such a different behavior. So, it is suggested that the production of specific bacteriocins by probiotics against C. sakazakii but not against Salmonellla could be the underlying inhibitory mechanism. Further studies should be carried out to test this hypothesis.

Cross-feeding between Bifidobacterium infantis and Anaerostipes caccae on lactose and human milk oligosaccharides

The establishment of the gut microbiota immediately after birth is a dynamic process that may impact lifelong health. At this important developmental stage in early life, human milk oligosaccharides (HMOs) serve as specific substrates to shape the gut microbiota of the nursling. The well-orchestrated transition is important as an aberrant microbial composition and bacterial-derived metabolites are associated with colicky symptoms and atopic diseases in infants. Here, we study the trophic interactions between an HMO-degrader, Bifidobacterium infantis and the butyrogenic Anaerostipes caccae using carbohydrate substrates that are relevant in the early life period including lactose and total human milk carbohydrates. Mono- and co-cultures of these bacterial species were grown at pH 6.5 in anaerobic bioreactors supplemented with lactose or total human milk carbohydrates. A. caccae was not able to grow on these substrates except when grown in co-culture with B. infantis, leading to growth and concomitant butyrate production. Two levels of cross-feeding were observed, in which A. caccae utilised the liberated monosaccharides as well as lactate and acetate produced by B. infantis. This microbial cross-feeding points towards the key ecological role of bifidobacteria in providing substrates for other important species that will colonise the infant gut. The progressive shift of the gut microbiota composition that contributes to the gradual production of butyrate could be important for host-microbial crosstalk and gut maturation.