Identification, Characterization, and Antioxidant Potential of Bifidobacterium longum subsp. longum Strains Isolated From Feces of Healthy Infants

Isolation, identification, and in vitro probiotic characterization of forty novel Bifidobacterium strains from neonatal feces in Erzurum province, Türkiye

BACKGROUND

Neonatal feces are one of the most important sources for probiotic isolation. The purpose of this study was the isolation and identification of Bifidobacterium spp. from neonatal feces and the evaluation of in vitro probiotic properties of strains including safety tests.

RESULTS

A total of 40 isolates were obtained from 14 healthy newborns' feces in Erzurum province, Türkiye. By their rep-PCR patterns and 16S rRNA gene sequences, isolates were identified as 26 Bifidobacterium breve and 14 Bifidobacterium longum. Fifteen of the isolates tolerated bile salts and showed high resistance to simulated gastric juice. Isolates exhibited varying rates of auto-aggregation and hydrophobicity. In addition, most of the isolates displayed antibacterial activity against Escherichia coli O157:H7, Staphylococcus aureus ATCC 29213, Salmonella Typhimurium RSHMB 95091, and Pseudomonas aeruginosa ATCC 9027. However, only one strain showed bile salt hydrolase activity and two strains showed the ability to produce H2O2. Bifidobacterium strains were generally sensitive to the tested antibiotics and lacked kanamycin, gentamicin, and streptomycin resistance genes, and hemolytic and DNAse activities. On the other hand, it was determined that five strains had various virulence genes including gelE, esp, efaAfs, hyl, and ace.

CONCLUSION

Results of the present study suggested that B. longum BH28, B. breve BH4 and B. breve BH5 strains have the potential as probiotic candidates for further studies. © 2024 The Authors. Journal of The Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Bifidobacterium longum K5 Prevents Enterohaemorrhagic Escherichia coli O157:H7 Infection in Mice through the Modulation of the Gut Microbiota

Enterohemorrhagic Escherichia coli (EHEC) serotype O157:H7 is a commonly encountered foodborne pathogen that can cause hemorrhagic enteritis and lead to hemolytic uremic syndrome (HUS) in severe cases. Bifidobacterium is a beneficial bacterium that naturally exists in the human gut and plays a vital role in maintaining a healthy balance in the gut microbiota. This study investigated the protective effects of B. longum K5 in a mouse model of EHEC O157:H7 infection. The results indicated that pretreatment with B. longum K5 mitigated the clinical symptoms of EHEC O157:H7 infection and attenuated the increase in myeloperoxidase (MPO) activity in the colon of the mice. In comparison to the model group, elevated serum D-lactic acid concentrations and diamine oxidase (DAO) levels were prevented in the K5-EHEC group of mice. The reduced mRNA expression of tight junction proteins (ZO-1, Occludin, and Claudin-1) and mucin MUC2, as well as the elevated expression of virulence factors Stx1A and Stx2A, was alleviated in the colon of both the K5-PBS and K5-EHEC groups. Additionally, the increase in the inflammatory cytokine levels of TNF-α and IL-1β was inhibited and the production of IL-4 and IL-10 was promoted in the K5-EHEC group compared with the model group. B. longum K5 significantly prevented the reduction in the abundance and diversity of mouse gut microorganisms induced by EHEC O157:H7 infection, including blocking the decrease in the relative abundance of Roseburia, Lactobacillus, and Oscillibacter. Meanwhile, the intervention with B. longum K5 promoted the production of acetic acid and butyric acid in the gut. This study provides insights into the use of B. longum K5 for developing probiotic formulations to prevent intestinal diseases caused by pathogenic bacterial infections.

In Vitro Hypoglycemic Activities of Lactobacilli and Bifidobacterium Strains from Healthy Children's Sources and Their Effect on Stimulating GLP-1 Secretion in STC-1 Cells

A long-term use of chemical drugs cannot cure type II diabetes mellitus (T2DM) and their numerous toxic side effects can be harmful to human health. In recent years, probiotics have emerged as a natural resource to replace chemical drugs in alleviating many human ailments. Healthy children's intestines have a lot of colonized Lactobacilli and Bifidobacterium, and these beneficial bacteria can help promote overall health. The objective of this study was to isolate potential antidiabetic probiotic strains from healthy children and evaluate their application prospects. Firstly, Lactobacillus and Bifidobacterium strains were isolated from healthy children's feces and identified by the pheS or clpC genes with their respective 16S rRNA genes. Then, hydrophobicity, artificial gastrointestinal fluid tolerance, α-Glucosidase and Dipeptidyl peptidase IV (DPP-IV) inhibitory activities of isolated strains were determined, and antioxidant activities and promoting secretion of GLP-1 in STC-1 cells of candidate strains were tested. Results showed that 6 strains of Lactobacillus and Bifidobacterium were obtained from the feces of healthy children aged 3 years, respectively, including Lacticaseibacillus paracasei L-21 and L-25, Levilactobacillus brevis L-16, Lentilactobacillus buchneri L-9, Lactiplantibacillus plantarum L-8 and L-3, Bifidobacterium bifidum 11-1 and B-84, Bifidobacterium longum subsp. longum 6-1, 6-2, B42 and B53. The hydrophobicity and auto-aggregation levels of all these strains were higher than 30% and 50%, respectively, and the decrease in the number of colonies of all strains in the artificial gastrointestinal fluid was less than 2 log CFU/mL. Strains L-3, L-8, L-9, L-21, 6-1, 11-1, B53 and B84 were selected based on their high α-glucosidase inhibitory activity and DPP-IV inhibitory activity, and results of the antioxidant capacity assay showed that the remaining strains all had intense comprehensive antioxidant activity. Additionally, Lacticaseibacillus paracasei L-21 and Bifidobacterium longum subsp. longum B-53 had the most substantial prompting effect on GLP-1 secretion in the STC-1 cell line. These results indicated that Lacticaseibacillus paracasei L-21 and Bifidobacterium longum subsp. longum B-53 could be used as a potential antidiabetic strain; thus, its application as a food supplement and drug ingredient could be recommended after in vivo mitigation of type II diabetes test.

Protective effect of Bifidobacterium animalis CGMCC25262 on HaCaT keratinocytes

Bifidobacteria are the most prevalent members of the intestinal microbiota in mammals and other animals, and they play a significant role in promoting gut health through their probiotic effects. Recently, the potential applications of Bifidobacteria have been extended to skin health. However, the beneficial mechanism of Bifidobacteria on the skin barrier remains unclear. In this study, keratinocyte HaCaT cells were used as models to evaluate the protective effects of the cell-free supernatant (CFS), heat-inactivated bacteria, and bacterial lysate of Bifidobacterium animalis CGMCC25262 on the skin barrier and inflammatory cytokines. The results showed that all the tested samples were able to upregulate the transcription levels of biomarker genes associated with the skin barrier, such as hyaluronic acid synthetase (HAS) and aquaporins (AQPs). Notably, the transcription of the hyaluronic acid synthetase gene-2 (HAS-2) is upregulated by 3~4 times, and AQP3 increased by 2.5 times when the keratinocyte HaCaT cells were co-incubated with 0.8 to 1% CFS. In particular, the expression level of Filaggrin (FLG) in HaCaT cells increased by 1.7 to 2.7 times when incubated with Bifidobacterial samples, reaching its peak at a concentration of 0.8% CFS. Moreover, B. animalis CGMCC25262 also decreased the expression of the proinflammatory cytokine RANTES to one-tenth compared to the levels observed in HaCaT cells induced with tumor necrosis factor alpha (TNF-α) and interferon gamma (IFN-γ). These results demonstrate the potential of B. animalis CGMCC25262 in protecting the skin barrier and reducing inflammatory response.

Oral administration of Bifidobacterium longum ES1 reduces endometrial inflammation in women with recurrent pregnancy loss

BACKGROUND

Over-activation of endometrial inflammasome NALP-3 (Nod-like receptor family pyrin domain containing 3) can be found in recurrent pregnancy loss (RPL) women probably due to leaky gut and passage into circulation of lipopolysaccharides (LPS). Leaky gut can be caused by exposure to gluten in RPL women genetically predisposed to celiac disease, positive for Human Leukocyte Antigen (HLA)-DQ2/DQ8 haplotype. Oral administration of Bifidobacterium longum ES1 (GliadinES®) can inactivate gluten peptides toxicity to epithelial gut cells and improve gut barrier.

METHODS

We investigated by enzyme-linked immunoassay: (a) serum levels of LPS and zonuline (a marker of leaky gut); (b) LPS, NALP-3, caspase-1, interleukine (IL)-1β and IL-18 concentration in endometrial fluids, in untreated women with uncomplicated pregnancies (negative HLA-DQ2/DQ8 haplotype) (n = 22) and in women with unexplained RPL, HLA-DQ2/DQ8 positive (n = 22), before and after daily oral administration for 3 months of GliadinES®.

RESULTS

RLP women showed higher serum levels of LPS (p < 0.0001) and higher concentration of LPS (p < 0.0001), NALP-3 (p < 0.01); Caspase-1 (p < 0.0001), IL-1β (p < 0.0001), and IL-18 (p < 0.0001) in endometrial fluids compared to controls. GliadinES® treatment significantly reduced serum levels of both LPS (p < 0.0001) and zonuline (p < 0.01), as well as LPS (p < 0.5), NALP-3 (p < 0.01), Caspase-1 (p < 0.001), IL-1β (p < 0.001), and IL-18 (p < 0.01) concentrations in endometrial fluids of RPL women.

CONCLUSIONS

RPL women positive for HLA-DQ2/DQ8 haplotype show increased circulating and endometrial levels of LPS and endometrial inflammasome NALP-3 over-activation. Oral administration of GliadinES® can reduce gut permeability, decrease serum levels of LPS and, contextually, improve endometrial inflammation in this specific subset of RPL women.

The pivotal role of Bifida Ferment Lysate on reinforcing the skin barrier function and maintaining homeostasis of skin defenses in vitro

BACKGROUND

The semiactive or inactive probiotics or their extracts used in dermatology have interesting properties to ameliorate signs of irritated skin and enhance the skin barrier. Bifidobacterium, as the most common probiotics, which has been found to be effective in reducing acne and improving the skin barrier function of atopic dermatitis. Bifida Ferment Lysate (BFL) can be obtained from Bifidobacterium by fermentation and extraction.

PURPOSE

In this study, we investigated the effect of a topically used BFL on the skin using in vitro evaluation methods.

RESULTS

The results showed that upregulation of skin physical barrier gene (FLG, LOR, IVL, TGM1, and AQP3) and antimicrobial peptide gene (CAMP and hBD-2) in HaCaT cells by BFL might be responsible for skin barrier resistance. In addition, BFL had strong antioxidant properties representing a dose-dependent increasing of the scavenging capacity of DPPH, ABTS, hydroxyl, and superoxide radicals. BFL treatment also fundamentally inhibited the intracellular ROS and MDA production and improved the activities of antioxidant enzymes (CAT and GSH-Px) in H2 O2 -stimulated HaCaT cells. As a good immunomodulatory factor, BFL efficiently decreased the secretion of IL-8 and TNF-α cytokines, and COX-2 mRNA expression in LPS-induced THP-1 macrophages.

CONCLUSION

BFL can strengthen the skin barrier function and stimulate skin barrier resistance, to reinforce the skin against oxidative stress and inflammatory stimuli.

Evaluation of cholesterol transformation abilities and probiotic properties of Bacteroides dorei YGMCC0564

Hypercholesterolemia, a risk factor for cardiovascular disease (CVD), often requires therapeutic agents with varying degrees of side effects. This has created a need for safe and natural alternatives such as medications or functional foods that can improve lipid metabolism and reduce cholesterol levels. In recent years, Next-generation probiotics (NGPs) have recently emerged as a potential solution, offering distinct mechanisms compared to traditional probiotics. Among the NGPs, Bacteroides, a dominant bacterial genus in the human gut, has gained significant attention due to its prevalence, ability to break down plant polysaccharides, and production of short-chain fatty acids (SCFAs). Recent evidence has demonstrated that Bacteroides effectively reduces cholesterol levels, prevents obesity, and lowers the risk of CVD. However, research on Bacteroides is currently limited to a few species, leaving rooms for exploration of the beneficial functions of different species in this genus. In this study, we isolated 66 Bacteroides strains, including 9 distinct species, from healthy adults' fecal samples. By comparing their ability to assimilate cholesterol, we found that the transformation ability was not specific to any particular species. Notably, Bacteroides dorei YGMCC0564 revealed superior cholesterol-lowering capabilities and bile salt hydrolase (BSH) activity in vitro, surpassing that of Lactobacillus GG (LGG). YGMCC0564 exhibited favorable probiotic characteristics, including high survival rate in vitro simulation of gastrointestinal digestion, excellent adhesion ability, susceptibility to antibiotics, absence of hemolysis or virulence genes, and substantial production of SCFAs. The strain also demonstrated remarkable bile salt deconjugation activities and upregulation of the BT_416 gene associated with cholesterol, providing insights into a possible molecular mechanism underlying its cholesterol-reducing activity. These findings establish YGMCC0564 as a promising NPG candidate for improving cardiovascular health.

Identification and evaluation of probiotic potential of Bifidobacterium breve AHC3 isolated from chicken intestines and its effect on necrotizing enterocolitis (NEC) in newborn SD rats

Necrotizing enterocolitis (NEC) is a severe intestinal disease of the newborn infants, associated with high morbidity and mortality. It has been reported that Bifidobacterium could protect the intestinal barrier function and reduce the risk of NEC. This study aimed to evaluate the probiotic potential of Bifidobacterium strains isolated from the chicken intestines and its effect on necrotizing enterocolitis in newborn SD rats. Out of 32 isolates, B. breve AHC3 not only exhibited excellent probiotic potential, including tolerance to artificial simulated gastric conditions, adhesion to HT-29 cells, antioxidant capacity and antibacterial activity, but also possessed reliable safety. Additionally, NEC model was established to further investigate the effect of B. breve AHC3 on necrotizing enterocolitis in newborn SD rats. It was illustrated that administration of B. breve AHC3 significantly not only reduced the incidence of NEC (from 81.25% to 34.38%) (P< 0.05), but also alleviated the severity of ileal injury (P< 0.05). Compared with NEC model, B. breve AHC3 could significantly decrease the level of proinflammatory factor TNF-α (P< 0.05) and increase the level of antiinflammatory factor IL-10 (P< 0.05) in the ileum of NEC rats. Through the intervention of B. breve AHC3, the gray value of inducible nitric oxide synthase (iNOS) in intestinal tissue of NEC rats was significantly reduced (P< 0.05). It was indicated that B. breve AHC3 exhibited prominent probiotic potential and reliable safety. In the neonatal SD rat model of NEC, B. breve AHC3 had an available protective effect on the intestinal injury of NEC, which might be related to reducing the inflammatory reaction in the ileum and inhibiting the expression of iNOS in intestinal tissue cells. B. breve AHC3 could be used as a potential treatment for human NEC.

Genome Analysis of Bifidobacterium Bifidum E3, Structural Characteristics, and Antioxidant Properties of Exopolysaccharides

In this study, the antioxidant properties of intact cells (IC), cell-free supernatant (CFS), and cell-free extracts (CFE) and whole genome sequencing of Bifidobacterium bifidum E3 (B. bifidum E3), as well as the structural characteristics and antioxidant properties of EPS-1, EPS-2, and EPS-3, were evaluated. The results revealed that intact cells (IC), cell-free supernatant (CFS), and cell-free extracts (CFE) had potent DPPH (1,1-Diphenyl-2-picrylhydrazyl radical), hydroxyl, and superoxide anion radical scavenging capacities, among which CFS was the best. At the genetic level, we identified a strong carbohydrate metabolism capacity, an EPS synthesis gene cluster, and five sugar nucleotides in B. bifidum E3. Therefore, we extracted cEPS from B. bifidum E3 and purified it to obtain EPS-1, EPS-2, and EPS-3. EPS-1, EPS-2, and EPS-3 were heteropolysaccharides with an average molecular weight of 4.15 × 104 Da, 3.67 × 104 Da, and 5.89 × 104 Da, respectively. The EPS-1 and EPS-2 are mainly comprised of mannose and glucose, and the EPS-3 is mainly comprised of rhamnose, mannose, and glucose. The typical characteristic absorption peaks of polysaccharides were shown in Fourier transform infrared spectroscopy (FT-IR spectroscopy). The microstructural study showed a rough surface structure for EPS-1, EPS-2, and EPS-3. Furthermore, EPS-1, EPS-2, and EPS-3 exhibited potent DPPH, hydroxyl, and superoxide anion radical scavenging capacities. Correlation analysis identified that antioxidant capacities may be influenced by various factors, especially molecular weight, chemical compositions, and monosaccharide compositions. In summary, the EPS that was produced by B. bifidum E3 may provide insights into health-promoting benefits in humans.

Lactic acid bacteria with a strong antioxidant function isolated from "Jiangshui," pickles, and feces

Excessive free radicals and iron death lead to oxidative damage, which is one of the main causes of aging and diseases. In this field of antioxidation, developing new, safe, and efficient antioxidants is the main research focus. Lactic acid bacteria (LAB) are natural antioxidants with good antioxidant activity and can regulate gastrointestinal microecological balance and immunity. In this study, 15 LAB strains from fermented foods ("Jiangshui" and pickles) or feces were evaluated in terms of their antioxidant attributes. Strains with strong antioxidant capacity were preliminarily screened by the following tests: 2,2-diphenyl-1-picrylhydrazyl (DPPH), hydroxyl radical, superoxide anion radical scavenging capacity; ferrous ion chelating assay; hydrogen peroxide tolerance capacity. Then, the adhesion of the screened strains to the intestinal tract was examined using hydrophobic and auto-aggregation tests. The safety of the strains was analyzed based on their minimum inhibitory concentration and hemolysis, and 16S rRNA was used for molecular biological identification. Antimicrobial activity tests showed them probiotic function. The cell-free supernatant of selected strains were used to explore the protective effect against oxidative damage cells. The scavenging rate of DPPH, hydroxyl radicals, and ferrous ion-chelating of 15 strains ranged from 28.81-82.75%, 6.54-68.52%, and 9.46-17.92%, respectively, the scavenging superoxide anion scavenging activity all exceeded 10%. According to all the antioxidant-related tests, strains possessing high antioxidant activities J2-4, J2-5, J2-9, YP-1, and W-4 were screened, these five strains demonstrated tolerance to 2 mM hydrogen peroxide. J2-4, J2-5, and J2-9 were Lactobacillus fermentans and γ-hemolytic (non-hemolytic). YP-1 and W-4 were Lactobacillus paracasei and α-hemolytic (grass-green hemolytic). Although L. paracasei has been proven as a safe probiotic without hemolytic characteristics, the hemolytic characteristics of YP-1 and W-4 should be further studied. Due to the weak hydrophobicity and antimicrobial activity of J2-4, finally, we selected J2-5, J2-9 for cell experiment, J2-5 and J2-9 showed an excellent ability that resistant to oxidative damage by increasing SOD, CAT, T-AOC activity of 293T cells. Therefore, J2-5, and J2-9 strains from fermented foods "Jiangshui" could be used as potential antioxidants for functional food, health care, and skincare.

Genomic and in-vitro characteristics of a novel strain Lacticaseibacillus chiayiensis AACE3 isolated from fermented blueberry

Numerous different species of LAB are used in different fields due to their unique characteristics. However, Lacticaseibacillus chiayiensis, a newly established species in 2018, has limited microorganism resources, and lacks comprehensive evaluations of its properties. In this study, L. chiayiensis AACE3, isolated from fermented blueberry, was evaluated by genomic analysis and in vitro assays of the properties. The genome identified genes associated with biofilm formation (luxS, ccpA, brpA), resistance to oxidative stress (tpx, trxA, trxB, hslO), tolerance to acidic conditions (dltA, dltC), resistance to unfavorable osmotic pressure (opuBB, gbuA, gbuB, gbuC), and adhesion (luxS, dltA, dltC). The AACE3 showed 112 unique genes, relative to the other three L. chiayiensis strains. Among them, the presence of genes such as clpP, pepO, and feoA suggests a possible advantage of AACE3 over other L. chiayiensis in terms of environmental adaptation. In vitro evaluation of the properties revealed that AACE3 had robust antibacterial activity against eight common pathogens: Streptococcus agalactiae, Staphylococcus aureus, Escherichia coli, Salmonella enteritidis, Salmonella choleraesuis, Shigella flexneri, Pseudomonas aeruginosa, and Klebsiella pneumoniae. In addition, AACE3 showed more than 80% survival rate in all tests simulating gastrointestinal fluid, and it exhibited high antioxidant capacity. Interestingly, the cell culture supernatant was superior to intact organisms and ultrasonically crushed bacterial extracts in all tests of antioxidant capacity. These results suggested that the antioxidant capacity may originate from certain metabolites and extracellular enzymes produced by AACE3. Moreover, AACE3 was a moderate biofilm producer due to the self-agglomeration effect. Taken together, L. chiayiensis AACE3 appears to be a candidate strain for combating the growing incidence of pathogen infections and antioxidant production.

The gut metagenomics and metabolomics signature in patients with inflammatory bowel disease

Inflammatory bowel disease (IBD), a chronic gut immune dysregulation and dysbiosis condition is rapidly increasing in global incidence. Regardless, there is a lack of ideal diagnostic markers, while conventional treatment provides scarce desired results, thus, the exploration for better options. Changes in the gut microbial composition and metabolites either lead to or are caused by the immune dysregulation that characterizes IBD. This study examined the fecal metagenomics and metabolomic changes in IBD patients. A total of 30 fecal samples were collected from 15 IBD patients and 15 healthy controls for 16S rDNA gene sequencing and UHPLC/Q-TOF-MS detection of metabolomics. Results showed that there was a severe perturbation of gut bacteria community composition, diversity, metabolites, and associated functions and metabolic pathways in IBD. This included a significantly decreased abundance of Bacteroidetes and Firmicutes, increased disease-associated phyla such as Proteobacteria and Actinobacteria, and increased Escherichiacoli and Klebsiellapneumoniae in IBD. A total of 3146 metabolites were detected out of which 135 were differentially expressed between IBD and controls. Metabolites with high sensitivity and specificity in differentiating IBD from healthy individuals included 6,7,4′-trihydroxyisoflavone and thyroxine 4′-o-.beta.-d-glucuronide (AUC = 0.92), normorphine and salvinorin a (AUC = 0.90), and trichostachine (AUC = 0.91). Moreover, the IBD group had significantly affected pathways including primary bile acid biosynthesis, vitamin digestion and absorption, and carbohydrate metabolism. This study reveals that the combined evaluation of metabolites and fecal microbiome can be useful to discriminate between healthy subjects and IBD patients and consequently serve as therapeutic and diagnostic targets.