Mechanistic insights into the structure-dependant and strain-specific utilization of wheat arabinoxylan by Bifidobacterium longum.

Arabinoxylan (AX), an important dietary fiber from cereal grains, is mainly metabolised in the large intestine by gut bacteria, especially bifidobacteria. This study investigated the uptake and metabolism of wheat AX by a Bifidobacterium longum strain that could grow well with AX as the sole carbon source. The bacterial growth rate showed a significant correlation to the molecular weight (MW) of AX and its acid hydrolysates. Assessment of the key AX degrading enzymes suggested that the uptake and consumption of AX involved extracellular cleavage of xylan backbone and intracellular degradation of both the backbone and the arabinose substitution. The preference for native or partially hydrolysed AX with single substitutions and a sufficiently high MW suggested the structure-dependant uptake by the bacterial cells. Genetic analysis of B. longum showed the lack of ß-xylosidase, suggesting the existence of unknown enzymes or dual/multiple-specific enzymes for hydrolysis of the non-reducing end of xylan backbone.

The complete genome sequence of Bifidobacterium longum LTBL16, a potential probiotic strain from healthy centenarians with strong antioxidant activity.

B. longum LTBL16 is a potential probiotic strain that was isolated from healthy centenarians in Bama, China. In vitro experiments show that B. longum LTBL16 has a strong antioxidant activity and the complete genome of B. longum LTBL16 was sequenced in this work. The genome consists of one 2,430,682 bp circular chromosome that is plasmid free. The circular chromosome has a GC content of 61.23% and contains 2071 coding sequences (CDSs), 4 rRNA manipulators and 55 tRNA coding genes. Genetic analysis showed that at least five protein-coding genes were associated with antioxidant activity, and the abundance of these genes may be related to free radical scavenging rates and oxygen tolerance. In addition, the safety of B. longum LTBL16 was evaluated using a virulence factor database and antibiotic resistance gene database. The results indicate that B. longum LTBL16 has the good potential for the development and utilization as a probiotic.

Apple polysaccharide could promote the growth of Bifidobacterium longum.

It is widely accepted that regulating microbiome could improve human health. We previously observed apple polysaccharide (AP) reversed high-fat-induced microbial dysbiosis, but the mechanism remains to be elucidated. In this study, the function of AP in vitro was evaluated in Bifidobacterium longum (B. longum) and Lactobacillus rhamnosus (L. rhamnosus). The effects of AP on the composition of fecal bacteria of normal SD rats were investigated by qPCR, TA cloning and 16S sequencing. 0.125-2% AP showed no significant effect on the growth of B. longum and L. rhamnosus. DNA concentration of fecal bacteria cultured with 1% AP was significantly higher than that of control group. qPCR revealed that the number of Bifidobacterium and Lactobacillus in fecal flora incubated by 1% AP was significantly higher than that of control group. Three strains of escherichia coli (E. coli) in fecal bacteria were screened out and analyzed. AP can be utilized by one E. coli and the metabolic products of AP could enhance the proliferation of B. longum. These data suggest that AP could promote the growth of B. longum indirectly, and provide another basis to understand the health care function of apple.

Effects of rifaximin-resistant Bifidobacterium longum W11 in subjects with symptomatic uncomplicated diverticular disease treated with rifaximin.

BACKGROUND: In medical practice, the use of rifaximin and a probiotic is quite common in patients with a diagnosis of symptomatic uncomplicated diverticular disease (SUDD), with the latter being administered at the end of the rifaximin cycle. The opportunity of having a probiotic strain (Bifidobacterium longum W11) described as being resistant to rifaximin has prompted us to use it routinely in subjects with SUDD, administering it concomitantly with rifaximin. METHODS: Retrospectively, we have analyzed whether our approach conferred a real clinical advantage to patients. The results seem to confirm the logic of our approach. RESULTS: Patients treated with rifaximin concomitantly receiving strain W11 demonstrated better clinical outcomes than subjects treated with rifaximin followed by strain W11. Moreover, we have observed that the concomitant use of a rifaximin-resistant probiotic has improved the stool consistency of most patients. Finally, the adherence to the given therapy was very different, being very high in subjects undergoing concomitant use of the W11 strain and rifaximin, and being low in the other group. This is probably because of the different duration of therapy (7 days versus 14 days) and due to the fact that after 7 days of rifaximin treatment, patients felt better and decided not to proceed with the probiotic administration. CONCLUSIONS: Despite the many biases that our retrospective analysis presents, we believe that a probiotic strain demonstrating a strong non-transferable resistance to a particular antibiotic should be used along with that specific antibiotic, at least in cases of SUDD diagnosis.

Long Exposure to a Diet Supplemented with Antioxidant and Anti-Inflammatory Probiotics Improves Sperm Quality and Progeny Survival in the Zebrafish Model.

The aim of the present experiment is to study the effects of oral ingestion of a mixture of two probiotic bacteria on sperm quality and progenies. Three homogeneous groups of juvenile zebrafish were created. Once having reached adulthood (3 months postfertilization; mpf), each group received different feeding regimens: a standard diet (control), a maltodextrin-supplemented diet (vehicle control), or a probiotic-supplemented diet (a mixture (1:1) of Lactobacillus rhamnosus CECT8361 and Bifidobacterium longum CECT7347). The feeding regime lasted 4.5 months. Growth parameters (weight and length) were determined at 3, 5, and 7.5 mpf. Sperm motility was evaluated using computer-assisted sperm analysis at 5 and 7.5 mpf. Progeny survival, hatching rate, and malformation rate were also evaluated. Results showed that probiotic-supplemented diet improved growth parameters compared with the standard diet. The highest percentage of motile spermatozoa was reported in the probiotic-fed group. Concomitantly, the percentage of fast sperm subpopulation was significantly lower in samples derived from control males. Furthermore, there was a significant difference in progeny survival between the probiotic-fed group and the control group at three developmental times (24 hours postfertilization (hpf), 5 days postfertilization (dpf) and 7 dpf). In conclusion, in zebrafish, prolonged ingestion of a mixture of Lactobacillus rhamnosus CECT8361 and Bifidobacterium longum CECT7347 has positive effects on growth, sperm quality, and progeny survival.

Prebiotic Effect of Lycopene and Dark Chocolate on Gut Microbiome with Systemic Changes in Liver Metabolism, Skeletal Muscles and Skin in Moderately Obese Persons.

Lycopene rich food and dark chocolate are among the best-documented products with a broad health benefit. This study explored the systemic effect of lycopene and dark chocolate (DC) on gut microbiota, blood, liver metabolism, skeletal muscle tissue oxygenation and skin. 30 volunteers were recruited for this trial, 15 women and 15 men with a mean age of 55 ± 5.7 years and with moderate obesity, 30 < BMI < 35 kg/m2. They were randomized and divided into five equal interventional groups: three received different formulations of lycopene, one of them with a 7 mg daily dose and two with 30 mg; another group was given 10 g of DC with 7 mg lycopene embedded into its matrix, and the last group received 10 g DC. The trial was double-blinded for the three lycopene groups and separately for the 2 DC groups; the trial lasted for 1 month. By the end of the trial there were dose-dependent changes in the gut microbiota profile in all three lycopene groups with an increase of relative abundance of, e.g., Bifidobacterium adolescentis and Bifidobacterium longum. This was also accompanied by dose-dependent changes in the blood, liver metabolism, skeletal muscle and skin parameters. Consumption of DC resulted in increased relative abundance of, e.g., Lactobacillus and a reduction of corneocyte exfoliation. This is the first study which reports the prebiotic potential of lycopene and DC.

Bifidobacterium longum 1714™ Strain Modulates Brain Activity of Healthy Volunteers During Social Stress.

OBJECTIVES: Accumulating evidence indicates that the gut microbiota communicates with the central nervous system, possibly through neural, endocrine, and immune pathways, and influences brain function. B. longum 1714™ has previously been shown to attenuate cortisol output and stress responses in healthy subjects exposed to an acute stressor. However, the ability of B. longum 1714™ to modulate brain function in humans is unclear. METHODS: In a randomized, double-blinded, placebo-controlled trial, the effects of B. longum 1714™ on neural responses to social stress, induced by the "Cyberball game," a standardized social stress paradigm, were studied. Forty healthy volunteers received either B. longum 1714™ or placebo for 4 weeks at a dose of 1 × 10 cfu/d. Brain activity was measured using magnetoencephalography and health status using the 36-item short-form health survey. RESULTS: B. longum 1714™ altered resting-state neural oscillations, with an increase in theta band power in the frontal and cingulate cortex (P < 0.05) and a decrease in beta-3 band in the hippocampus, fusiform, and temporal cortex (P < 0.05), both of which were associated with subjective vitality changes. All groups showed increased social stress after a 4-week intervention without an effect at behavioral level due to small sample numbers. However, only B. longum 1714™ altered neural oscillation after social stress, with increased theta and alpha band power in the frontal and cingulate cortex (P < 0.05) and supramarginal gyrus (P < 0.05). DISCUSSION: B. longum 1714™ modulated resting neural activity that correlated with enhanced vitality and reduced mental fatigue. Furthermore, B. longum 1714™ modulated neural responses during social stress, which may be involved in the activation of brain coping centers to counter-regulate negative emotions.

The MarR Family Regulator BmrR Is Involved in Bile Tolerance of Bifidobacterium longum BBMN68 via Controlling the Expression of an ABC Transporter.

In order to colonize the human gastrointestinal tract and exert their beneficial effects, bifidobacteria must effectively cope with toxic bile salts in the intestine; however, the molecular mechanism underlying bile tolerance is poorly understood. In this study, heterologous expression of a MarR family transcriptional regulator, BmrR, significantly reduced the ox bile resistance of Lactococcus lactis NZ9000, suggesting that BmrR might play a role in the bile stress response. In silico analysis combined with reverse transcription-PCR assays demonstrated that bmrR was cotranscribed with bmrA and bmrB, which encoded multidrug resistance (MDR) ABC transporters. Promoter prediction and electrophoretic mobility shift assays revealed that BmrR could autoregulate the bmrRAB operon by binding to the bmr box (ATTGTTG-6nt-CAACAAT) in the promoter region. Moreover, heterologous expression of bmrA and bmrB in L. lactis yielded 20.77-fold higher tolerance to 0.10% ox bile, compared to the wild-type strain. In addition, ox bile could disrupt the DNA binding activity of BmrR as a ligand. Taken together, our findings indicate that the bmrRAB operon is autoregulated by the transcriptional regulator BmrR and ox bile serves as an inducer to activate the bile efflux transporter BmrAB in response to bile stress in Bifidobacterium longum BBMN68.IMPORTANCE Bifidobacteria are natural inhabitants of the human intestinal tract. Some bifidobacterial strains are used as probiotics in fermented dairy production because of their health-promoting effects. Following consumption, bifidobacteria colonize the lower intestinal tract, where the concentrations of bile salts remain nearly 0.05% to 2.0%. Bile salts, as detergent-like antimicrobial compounds, can cause cellular membrane disruption, protein misfolding, and DNA damage. Therefore, tolerance to physiological bile stress is indeed essential for bifidobacteria to survive and to exert probiotic effects in the gastrointestinal tract. In B. longum BBMN68, the MarR-type regulator BmrR was involved in the bile stress response by autoregulating the bmrRAB operon, and ox bile as an inducer could increase the expression of the BmrAB transporter to enhance the bile tolerance of BBMN68. Our study represents a functional analysis of the bmrRAB operon in the bile stress response, which will provide new insights into bile tolerance mechanisms in Bifidobacterium and other bacteria.

Formation of soy protein isolate-carrageenan complex coacervates for improved viability of Bifidobacterium longum during pasteurization and in vitro digestion.

Soy protein isolate (SPI) and carrageenan (IC) complex coacervates were formed through electrostatic attractions for encapsulating Bifidobacterium longum. The effects of pH (2.0-5.0) and SPI:IC mass ratios (10:1, 15:1, 20:1) on coacervate yield, entrapment efficiency and viability of the probiotic bacteria were investigated. The coacervates produced at pH 3 had higher yields and entrapment efficiency, and a SPI:IC mass ratio of 10:1 produced a complex coacervate with more compact microstructure. Compared to the native ones, the bacteria encapsulated in the coacervates had significantly improved viability during storage (4 °C), pasteurization (85 °C for 5, 10 and 30 min) and in vitro dynamic gastric and intestinal digestion. The findings also suggested that the coacervate with a SPI:IC ratio of 10:1 was more capable to protect the bacteria from loss against different stresses. This study provides a novel approach for designing efficient microcapsules containing probiotic bacteria with enhanced functional properties.

Three Inulin-Type Fructans from Codonopsis pilosula (Franch.) Nannf. Roots and Their Prebiotic Activity on Bifidobacterium longum.

Radix Codonopsis, derived from the roots of Codonopsis pilosula (Franch.) Nannf., Codonopsis pilosula (Franch.) Nannf. Var. modesta (Nannf.) L.T. Shen and Codonopsis tangshen Oliv., has been used as traditional Chinese medicine for improving poor gastrointestinal function, treating gastric ulcers and chronic gastritis in China. Inulin-type fructans are carbohydrates consisting mainly of ß (2→1) fructosyl-fructose links in chemical structure and exhibit a range of properties such as prebiotic activity, fat substitutes in low-calorie foods and disease-modifying effects. The prebiotic effects of inulin-type fructans are hypothesized to improve gastrointestinal function through alterations to gut microbiota composition and metabolism. In the present study, three inulin-type fructans with high degree of polymerization (DP = 16, 22, and 31) were isolated from the roots of Codonopsis pilosula (Franch.) Nannf. and their structures were confirmed by MALDI-TOF-MS, 1D- and 2D-NMR. The prebiotic activity of these fructans was evaluated by detecting growth stimulation on Bifidobacterium longum. The results demonstrated that three fructans at a concentration of 2.0 g/L exhibited significant growth stimulation on Bifidobacterium longum in a time-dependent manner (p < 0.01). The data indicated that inulin-type fructans in Radix Codonopsis could be used as potential prebiotics.

Transcriptomic analysis of Bifidobacterium longum subsp. longum BBMN68 in response to oxidative shock.

Bifidobacterium longum strain BBMN68 is sensitive to low concentrations of oxygen. A transcriptomic study was performed to identify candidate genes for B. longum BBMN68's response to oxygen treatment (3%, v/v). Expression of genes and pathways of B. longum BBMN68 involved in nucleotide metabolism, amino acid transport, protein turnover and chaperones increased, and that of carbohydrate metabolism, translation and biogenesis decreased to adapt to the oxidative stress. Notably, expression of two classes of ribonucleotide reductase (RNR), which are important for deoxyribonucleotide biosynthesis, was rapidly and persistently induced. First, the class Ib RNR NrdHIEF was immediately upregulated after 5 min oxygen exposure, followed by the class III RNR NrdDG, which was upregulated after 20 min of exposure. The upregulated expression of branched-chain amino acids and tetrahydrofolate biosynthesis-related genes occurred in bifidobacteria in response to oxidative stress. These change toward to compensate for DNA and protein damaged by reactive oxygen species (ROS). In addition, oxidative stress resulted in improved B. longum BBMN68 cell hydrophobicity and autoaggregation. These results provide a rich resource for our understanding of the response mechanisms to oxidative stress in bifidobacteria.

Safety Evaluations of Bifidobacterium bifidum BGN4 and Bifidobacterium longum BORI.

Over the past decade, a variety of lactic acid bacteria have been commercially available to and steadily used by consumers. However, recent studies have shown that some lactic acid bacteria produce toxic substances and display properties of virulence. To establish safety guidelines for lactic acid bacteria, the Food and Agriculture Organization of the United Nations (FAO)/World Health Organization (WHO) has suggested that lactic acid bacteria be characterized and proven safe for consumers’ health via multiple experiments (e.g., antibiotic resistance, metabolic activity, toxin production, hemolytic activity, infectivity in immune-compromised animal species, human side effects, and adverse-outcome analyses). Among the lactic acid bacteria, Bifidobacterium and Lactobacillus species are probiotic strains that are most commonly commercially produced and actively studied. Bifidobacterium bifidum BGN4 and Bifidobacterium longum BORI have been used in global functional food markets (e.g., China, Germany, Jordan, Korea, Lithuania, New Zealand, Poland, Singapore, Thailand, Turkey, and Vietnam) as nutraceutical ingredients for decades, without any adverse events. However, given that the safety of some newly screened probiotic species has recently been debated, it is crucial that the consumer safety of each commercially utilized strain be confirmed. Accordingly, this paper details a safety assessment of B. bifidum BGN4 and B. longum BORI via the assessment of ammonia production, hemolysis of blood cells, biogenic amine production, antimicrobial susceptibility pattern, antibiotic resistance gene transferability, PCR data on antibiotic resistance genes, mucin degradation, genome stability, and possession of virulence factors. These probiotic strains showed neither hemolytic activity nor mucin degradation activity, and they did not produce ammonia or biogenic amines (i.e., cadaverine, histamine or tyramine). B. bifidum BGN4 and B. longum BORI produced a small amount of putrescine, commonly found in living cells, at levels similar to or lower than that found in other foods (e.g., spinach, ketchup, green pea, sauerkraut, and sausage). B. bifidum BGN4 showed higher resistance to gentamicin than the European Food Safety Authority (EFSA) cut-off. However, this paper shows the gentamicin resistance of B. bifidum BGN4 was not transferred via conjugation with L. acidophilus ATCC 4356, the latter of which is highly susceptible to gentamicin. The entire genomic sequence of B. bifidum BGN4 has been published in GenBank (accession no.: CP001361.1), documenting the lack of retention of plasmids capable of transferring an antibiotic-resistant gene. Moreover, there was little genetic mutation between the first and 25th generations of B. bifidum BGN4. Tetracycline-resistant genes are prevalent among B. longum strains; B. longum BORI has a tet(W) gene on its chromosome DNA and has also shown resistance to tetracycline. However, this research shows that its tetracycline resistance was not transferred via conjugation with L. fermentum AGBG1, the latter of which is highly sensitive to tetracycline. These findings support the continuous use of B. bifidum BGN4 and B. longum BORI as probiotics, both of which have been reported as safe by several clinical studies, and have been used in food supplements for many years.

Impact of carbohydrates on autoinducer-2 secretion of Bifidobacterium longum subsp. longum BBMN68.

In this study, the regularity of autoinducer-2 (AI-2) secretion during growth and the effect of the addition of various carbohydrates on AI-2 secretion in Bifidobacterium longum subsp. longum BBMN68 were investigated. The results indicated that the AI-2 concentration reached its highest level (2536·60 nmol l-1 ) at the early stationary growth phase, and then decreased to 1263·72 nmol l-1 at the late stationary growth phase in Bifidobacterium cultures. When the density of the cultures which mannose, fructose, sucrose and lactose had been added to reached an OD600 nm of 1·0, the AI-2 concentrations in the cultures were 1953·84, 1637·34, 1200·99 and 1077·60 nmol l-1 , respectively. These concentrations were all significantly higher than that of the control culture (1031·33 nmol l-1 ). Similarly, the addition of fructooligosaccharide significantly increased the AI-2 concentrations to 2094·29 nmol l-1 . This study provides the advanced evidence that certain carbohydrates promote the secretion of AI-2, and that this occurs at the single cell level and is therefore unaffected by cell density. SIGNIFICANCE AND IMPACT OF THE STUDY: This study provided the advanced data of the regularity of autoinducer-2 (AI-2) secretion during growth and the promotion on AI-2 secretion of different added carbohydrates in Bifidobacterium, which may be a new potential strategy to improve the acid resistance of Bifidobacterium applied in the food industry.

Low Cerebral Exposure Cannot Hinder the Neuroprotective Effects of Panax Notoginsenosides.

A bidirectional route of communication between the gastrointestinal tract and the central nervous system, termed the "gut-brain axis," is becoming increasingly relevant to treatment of cerebral damage. Panax Notoginsenoside extract (PNE) is popular for prevention and treatment of cardio-cerebrovascular ischemic diseases although plasma and cerebral exposure levels are extremely low. To date, the mechanisms underlying the neuroprotective effects of PNE remain largely unknown. In the present study, the neuroprotective effects of PNE were systematically studied via investigation of the regulation by PNE of the gastrointestinal microbial community and γ aminobutyric acid (GABA) receptors. The results demonstrated that pretreatment with PNE exerted a remarkable neuroprotective effect on focal cerebral ischemia/reperfusion (I/R) injury in rats, and the efficiency was attenuated in germ-free rats. Pretreatment with PNE could significantly prevent downregulation of Bifidobacterium longum (B.L) caused by I/R surgery, and colonization by B.L could also exert neuroprotective effects. More importantly, both PNE and B.L could upregulate the expression of GABA receptors in the hippocampus of I/R rats, and coadministration of a GABA-B receptor antagonist could significantly attenuate the neuroprotective effects of PNE and B.L. The study above suggests that the neuroprotective effects of PNE may be largely attributable to its regulation of intestinal flora, and oral treatment with B.L was also useful in therapy of ischemia/reperfusion injury (I/R) by upregulating GABA-B receptors.

Effect of antibiotic, probiotic, and human rotavirus infection on colonisation dynamics of defined commensal microbiota in a gnotobiotic pig model.

We developed a gnotobiotic (Gn) pig model colonised with defined commensal microbiota (DMF) to provide a simplified and controlled system to study the interactions between intestinal commensals, antibiotics (ciprofloxacin, CIP), probiotics (Escherichia coli Nissle 1917, EcN) and virulent human rotavirus (VirHRV). The DMF included seven gut commensal species of porcine origin that mimic the predominant species in the infant gut. Gn piglets were divided into four groups: DMF control (non-treated), DMF+CIP (CIP treated), DMF+CIP+EcN (CIP/EcN treated), DMF+EcN (EcN treated) and inoculated orally with 105 cfu of each DMF strain. The pig gut was successfully colonised by all DMF species and established a simplified bacterial community by post-bacteria colonisation day (PBCD) 14/post-VirHRV challenge day (PCD) 0. Overall, Bifidobacterium adolescentis was commonly observed in faeces in all groups and time points. At PCD0, after six days of CIP treatment (DMF+CIP), we observed significantly decreased aerobic and anaerobic bacteria counts especially in jejunum (P<0.001), where no DMF species were detected in jejunum by T-RFLP. Following HRV challenge, 100% of pigs in DMF+CIP group developed diarrhoea with higher diarrhoea scores and duration as compared to all other groups. However, only 33% of pigs treated with EcN plus CIP developed diarrhoea. EcN treatment also enhanced the bacterial diversity and all seven DMF species were detected with a higher proportion of Bifidobacterium longum in jejunum in the DMF+CIP+EcN group on PBCD14/PCD0. Our results suggest that EcN increased the proportion of B. longum especially in jejunum and mitigated adverse impacts of antibiotic use during acute-infectious diarrhoea. The DMF model with a simplified gut commensal community can further our knowledge of how commensals and probiotics promote intestinal homeostasis and contribute to host health.

Molecular Insight into Evolution of Symbiosis between Breast-Fed Infants and a Member of the Human Gut Microbiome Bifidobacterium longum.

Breast-fed infants generally have a bifidobacteria-rich microbiota with recent studies indicating that human milk oligosaccharides (HMOs) selectively promote bifidobacterial growth. Bifidobacterium bifidum possesses a glycoside hydrolase family 20 lacto-N-biosidase for liberating lacto-N-biose I from lacto-N-tetraose, an abundant HMO unique to human milk, while Bifidobacterium longum subsp. longum has a non-classified enzyme (LnbX). Here, we determined the crystal structure of the catalytic domain of LnbX and provide evidence for creation of a novel glycoside hydrolase family, GH136. The structure, in combination with inhibition and mutation studies, provides insight into the molecular mechanism and broader substrate specificity of this enzyme. Moreover, through genetic studies, we show that lnbX is indispensable for B. longum growth on lacto-N-tetraose and is a key genetic factor for persistence in the gut of breast-fed infants. Overall, this study reveals possible evolutionary routes for the emergence of symbiosis between humans and bifidobacterial species in the infant gut.

The Possible Innovative Use of Bifidobacterium longum W11 in Association With Rifaximin: A New Horizon for Combined Approach?

GOALS: The aim of the study was to unequivocally demonstrate the nontransmissibility of the genes mediating the resistance of the strain Bifidobacterium longum W11 (LMG P-21586) to rifaximin. BACKGROUND: Most antibiotic treatments can induce unfavorable side effects such as antibiotic-associated diarrhea, which is largely attributable to the disruption of the intestinal microbiota. The parallel intake of probiotic bacteria might reduce these events, even if with generally very poor results. In this regard, the use of antibiotic-resistant beneficial bacteria could represent a worthy strategy. STUDY: Rifaximin was tested in parallel with rifampicin, rifapentine, and rifabutin, all rifamycin derivates, using 5 different concentrations. Susceptibility tests were performed by the disc diffusion method of Kirby-Bauer, and inhibition zones were measured after incubation at 37°C. B. longum BL03 was used as comparison. The B. longum W11 genome was sequenced on Illumina MiSeq with a 250 PE reads module. After mapping the reads with the reference bacterial genome, the alignment data were processed using FreeBayes software. RESULTS: B. longum BL03 was inhibited by all antibiotics even at the lowest concentration. In contrast, the W11 strain was inhibited by rifampicin, rifabutin, and rifaximin only at the highest concentration (512 µg/mL). The genomic analysis showed a mutation into the chromosomal DNA. No transposable elements were found, and the genetic locus was not flanked by close mobile genetic elements. CONCLUSIONS: B. longum W11 could be used in combined therapy with rifaximin, thus opening new focused frontiers in the probiotic era while preserving the necessary safety of use for consumers.