Spore-forming bacteria and their utilisation as probiotics

Genomic and Phenotypic Safety Assessment of Probiotic Bacillus coagulans Strain JBI-YZ6.3

Spore-forming Bacillus coagulans has been widely recognized as an important probiotic, which is commonly used in products for human consumption and animal feeds. B. coagulans exhibits beneficial traits from both Bacillus and lactic acid-producing Lactobacillus. The present study evaluated the safety of the newly isolated B. coagulans strain JBI-YZ6.3, using combined genomic and phenotypic analysis approaches. The taxonomic classification based on genome sequence and biochemical tests identified strain JBI-YZ6.3 as B. coagulans. Comprehensive genome-based analyses established JBI-YZ6.3 as a novel strain of B. coagulans. Antibiotic susceptibility testing showed that the strain JBI-YZ6.3 was sensitive to a panel of fourteen antibiotics, and no genes related to antibiotic resistance were found in its genome. The spores of strain JBI-YZ6.3 exhibited tolerance to acid and bile salts, as well as stability at ambient and elevated conditions of temperature and relative humidity. There were no homologs of Bacillus toxin genes identified in the genome of JBI-YZ6.3, and the strain exhibited no cytotoxicity towards Vero cells and human peripheral blood mononuclear cells. In conclusion, findings from this study support the safety of B. coagulans strain JBI-YZ6.3, which can be developed into new probiotic products for preventive and therapeutic benefits in human and animal hosts.

Intestinal Delivery of Probiotics: Materials, Strategies, and Applications

Probiotics with diverse and crucial properties and functions have attracted broad interest from many researchers, who adopt intestinal delivery of probiotics to modulate the gut microbiota. However, the major problems faced for the therapeutic applications of probiotics are the viability and colonization of probiotics during their processing, oral intake, and subsequent delivery to the gut. The challenges of simple oral delivery (stability, controllability, targeting, etc.) have greatly limited the use of probiotics in clinical therapies. Nanotechnology can endow the probiotics to be delivered to the intestine with improved survival rate and increased resistance to the adverse environment. Additionally, the progress in synthetic biology has created new opportunities for efficiently and purposefully designing and manipulating the probiotics. In this article, a brief overview of the types of probiotics for intestinal delivery, the current progress of different probiotic encapsulation strategies, including the chemical, physical, and genetic strategies and their combinations, and the emerging single-cell encapsulation strategies using nanocoating methods, is presented. The action mechanisms of probiotics that are responsible for eliciting beneficial effects are also briefly discussed. Finally, the therapeutic applications of engineered probiotics are discussed, and the future trends toward developing engineered probiotics with advanced features and improved health benefits are proposed.

Differential Immune-Modulating Activities of Cell Walls and Secreted Metabolites from Probiotic Bacillus coagulans JBI-YZ6.3 under Normal versus Inflamed Culture Conditions

Spore-forming probiotic bacteria, including Bacillus coagulans, are resilient and produce a variety of beneficial metabolites. We evaluated the immune-modulating effects of the novel probiotic strain Bacillus coagulans JBI-YZ6.3, where the germinated spores, metabolite fraction, and cell wall fraction were tested in parallel using human peripheral blood mononuclear cell cultures under both normal and lipopolysaccharide-induced inflamed culture conditions. The expression of CD25 and CD69 activation markers was evaluated via flow cytometry. Supernatants were tested for cytokines, interferons, chemokines, and growth factors using Luminex arrays. The germinated spores were highly immunogenic; both the cell wall and metabolite fractions contributed significantly. Under normal culture conditions, increased levels of immune activation were observed as increased expressions of CD25 and CD69 relative to natural killer cells, suggesting an increased ability to attack virus-infected target cells. On monocytes, a complex effect was observed, where the expression of CD25 increased under normal conditions but decreased under inflamed conditions. This, in combination with increased interleukin-10 (IL-10) and decreased monocyte chemoattractant protein-1 (MCP-1) production under inflamed conditions, points to anti-inflammatory effects. The production of the stem cell-related growth factor granulocyte colony-stimulating Factor (G-CSF) was enhanced. Further research is warranted to characterize the composition of the postbiotic metabolite fraction and document the characteristics of immunomodulating agents secreted by this probiotic strain.

The Effects of Probiotic Bacillus Spores on Dexamethasone-Treated Rats

Glucocorticoids are effective anti-inflammatory and immunosuppressive agents. Long-term exposure is associated with multiple metabolic side effects. Spore-forming probiotic bacteria have shown modulatory properties regarding glycolipid metabolism and inflammation. The aim of this study was to evaluate, for the first time, the effects of Bacillus species spores (B. licheniformis, B. indicus, B. subtilis, B. clausii, and B. coagulans) alone and in combination with metformin against dexamethasone-induced systemic disturbances. A total of 30 rats were randomly divided into 5 groups: group 1 served as control (CONTROL), group 2 received dexamethasone (DEXA), group 3 received DEXA and MegaSporeBiotic (MSB), group 4 received DEXA and metformin (MET), and group 5 received DEXA, MSB, and MET. On the last day of the experiment, blood samples and liver tissue samples for histopathological examination were collected. We determined serum glucose, total cholesterol, triglycerides, tumor necrosis factor-alpha (TNF-α), interleukin-6 (IL-6), interleukin-10 (IL-10), catalase, total antioxidant capacity (TAC), and metformin concentration. DEXA administration caused hyperglycemia and hyperlipidemia, increased inflammation cytokines, and decreased antioxidant markers. Treatment with MSB reduced total cholesterol, suggesting that the administration of Bacillus spores-based probiotics to DEXA-treated rats could ameliorate metabolic parameters.

Effects of Aeriscardovia aeriphila on growth performance, antioxidant functions, immune responses, and gut microbiota in broiler chickens

Aeriscardovia aeriphila, also known as Bifidobacterium aerophilum, was first isolated from the caecal contents of pigs and the faeces of cotton-top tamarin. Bifidobacterium species play important roles in preventing intestinal infections, decreasing cholesterol levels, and stimulating the immune system. In this study, we isolated a strain of bacteria from the duodenal contents of broiler chickens, which was identified as A. aeriphila, and then evaluated the effects of A. aeriphila on growth performance, antioxidant functions, immune functions, and gut microbiota in commercial broiler chickens. Chickens were orally gavaged with A. aeriphila (1×109 CFU/mL) for 21 d. The results showed that A. aeriphila treatment significantly increased the average daily gain and reduced the feed conversion ratio (P<0.001). The levels of serum growth hormone (GH) and insulin-like growth factor 1 (IGF-1) were significantly increased following A. aeriphila treatment (P<0.05). Blood urea nitrogen and aspartate aminotransferase levels were decreased, whereas glucose and creatinine levels increased as a result of A. aeriphila treatment. Furthermore, the levels of serum antioxidant enzymes, including catalase (P<0.01), superoxide dismutase (P<0.001), and glutathione peroxidase (P<0.05), and total antioxidant capacity (P<0.05) were enhanced following A. aeriphila treatment. A. aeriphila treatment significantly increased the levels of serum immunoglobulin A (IgA) (P<0.05), IgG (P<0.01), IgM (P<0.05), interleukin-1 (IL-1) (P<0.05), IL-4 (P<0.05), and IL-10 (P<0.05). The broiler chickens in the A. aeriphila group had higher secretory IgA (SIgA) levels in the duodenum (P<0.01), jejunum (P<0.001), and cecum (P<0.001) than those in the control group. The messenger RNA (mRNA) relative expression levels of IL-10 (P<0.05) and IL-4 (P<0.001) in the intestinal mucosa of chickens were increased, while nuclear factor-‍κB (NF‍-‍κB) (P<0.001) expression was decreased in the A. aeriphila group compared to the control group. Phylum-level analysis revealed Firmicutes as the main phylum, followed by Bacteroidetes, in both groups. The data also found that Phascolarctobacterium and Barnesiella were increased in A. aeriphila-treated group. In conclusion, oral administration of A. aeriphila could improve the growth performance, serum antioxidant capacity, immune modulation, and gut health of broilers. Our findings may provide important information for the application of A. aeriphila in poultry production.

Survivability of freeze- and spray-dried probiotics and their effects on the growth and health performance of broilers

Background and Aim

Many strains of probiotics have been exploited and used as animal dietary supplements for broiler production. The efficacy and survival of probiotics during production may reflect better activities of the probiotics in the host. This study investigated the effects of freeze- and spray-drying on the survivability and properties of probiotics and their ability to improve the growth and health performance of broilers.

Materials and Methods

Probiotic powders of four strains of lactic acid bacteria, Enterococcus faecium CA4, Enterococcus durans CH33, Ligilactobacillus salivarius CH24, Pediococcus acidilactici SH8, and Bacillus subtilis KKU213, were prepared using rice bran/chitosan/carboxy methyl cellulose as the carrier. The survival of each probiotic strain was investigated under stress conditions, including freeze-drying, spray-drying, and simulated gastrointestinal conditions. The body weight gain (BWG) and intestinal histomorphology were determined to assess broiler growth performance.

Results

All dried probiotics yielded a high survival rate during freeze-drying (95.8-98.6%) and spray-drying (94.4-98.2%). In addition, an analysis of the main effect revealed that the effectiveness of freeze-drying was higher than that of spray-drying in minimizing the loss of cell viability. The antimicrobial activity of all immobilized dried probiotic strains against Salmonella was maintained. The immobilized probiotics tolerated a low pH value of 2.0 and 0.5% (w/v) bile salt. Probiotic administration of a mixture of the five dried probiotics to 1-day-old hatched male broilers at early and late ages resulted in potential colonization in the broiler intestine, and enhancements in the BWG, lipid metabolism, and gut health (villus height and cryptal depth) were observed in the probiotic-treated groups.

Conclusion

The administration of three doses of the spray-dried probiotic mixture at days 15, 17, and 19 after hatching was sufficient to achieve long-term growth and health benefits in broilers. This finding might provide a cost-effective alternative to the administration of commonly used antibiotics in broiler production.

Transforming Psoriasis Care: Probiotics and Prebiotics as Novel Therapeutic Approaches

Psoriasis is a chronic inflammatory skin disease with autoimmune pathological characteristics. Recent research has found a link between psoriasis, inflammation, and gut microbiota dysbiosis, and that probiotics and prebiotics provide benefits to patients. This 12-week open-label, single-center clinical trial evaluated the efficacy of probiotics (Bacillus indicus (HU36), Bacillus subtilis (HU58), Bacillus coagulans (SC208), Bacillus licheniformis (SL307), and Bacillus clausii (SC109)) and precision prebiotics (fructooligosaccharides, xylooligosaccharides, and galactooligosaccharides) in patients with psoriasis receiving topical therapy, with an emphasis on potential metabolic, immunological, and gut microbiota changes. In total, 63 patients were evaluated, with the first 42 enrolled patients assigned to the intervention group and the next 21 assigned to the control group (2:1 ratio; non-randomized). There were between-group differences in several patient characteristics at baseline, including age, psoriasis severity (the incidence of severe psoriasis was greater in the intervention group than in the control group), the presence of nail psoriasis, and psoriatic arthritis, though it is not clear whether or how these differences may have affected the study findings. Patients with psoriasis receiving anti-psoriatic local therapy and probiotic and prebiotic supplementation performed better in measures of disease activity, including Psoriasis Area and Severity Index, Dermatology Life Quality Index, inflammatory markers, and skin thickness compared with those not receiving supplementation. Furthermore, in the 15/42 patients in the intervention group who received gut microbiota analysis, the gut microbiota changed favorably following 12 weeks of probiotic and prebiotic supplementation, with a shift towards an anti-inflammatory profile.

Soybean Oil Regulates the Fatty Acid Synthesis II System of Bacillus amyloliquefaciens LFB112 by Activating Acetyl-CoA Levels

[Background] Bacillus LFB112 is a strain of Bacillus amyloliquefaciens screened in our laboratory. Previous studies found that it has a strong ability for fatty acid metabolism and can improve the lipid metabolism of broilers when used as feed additives. [Methods] This study aimed to confirm the fatty acid metabolism of Bacillus LFB112. Sterilized soybean oil (SSO) was added to the Beef Peptone Yeast (BPY) medium, and its effect on fatty acid content in the supernatant and bacteria, as well as expression levels of genes related to fatty acid metabolism, were studied. The control group was the original culture medium without oil. [Results] Acetic acid produced by the SSO group of Bacillus LFB112 decreased, but the content of unsaturated fatty acids increased. The 1.6% SSO group significantly increased the contents of pyruvate and acetyl-CoA in the pellets. Furthermore, the mRNA levels of enzymes involved in the type II fatty acid synthesis pathway of FabD, FabH, FabG, FabZ, FabI, and FabF were up-regulated. [Conclusions] Soybean oil increased the content of acetyl-CoA in Bacillus LFB112, activated its type II fatty acid synthesis pathway, and improved the fatty acid metabolism level of Bacillus LFB112. These intriguing results pave the way for further investigations into the intricate interplay between Bacillus LFB112 and fatty acid metabolism, with potential applications in animal nutrition and feed additive development.

Acute physiological effects following Bacillus subtilis DE111 oral ingestion - a randomised, double blinded, placebo-controlled study

Previous studies using ileostomy samples from study participants demonstrated that the spore-forming probiotic Bacillus subtilis DE111® can germinate in the small intestine as early as 4 hours after ingestion. Metabolomics, proteomics and sequencing technologies, enabled further analysis of these samples for the presence of hypoglycaemic, hypolipidemic, antioxidant, anti-inflammatory and antihypertensive molecules. In the DE111 treatment group, the polyphenols trigonelline and 2,5-dihydroxybenzoic acid, orotic acid, the non-essential amino acid cystine and the lipokine 12,13-diHome were increased. DE111 also reduced acetylcholine levels in the ileostomy samples, and increased the expression of leucocyte recruiting proteins, antimicrobial peptides and intestinal alkaline phosphatases of the brush border in the small intestine. The combination of B. subtilis DE111 and the diet administered during the study increased the expression of the proteins phosphodiesterase ENPP7, ceramidase ASAH2 and the adipokine Zn-alpha-2-glycoprotein that are involved in fatty acid and lipid metabolism. Acute B. subtilis DE111 ingestion had limited detectable effect on the microbiome, with the main change being its increased presence. These findings support previous data suggesting a beneficial role of DE111 in digestion, metabolism, and immune health that appears to begin within hours of consumption.

Immunomodulatory and Antioxidant Properties of a Novel Potential Probiotic Bacillus clausii CSI08

Spore-forming bacteria of the Bacillus genus have demonstrated potential as probiotics for human use. Bacillus clausii have been recognized as efficacious and safe agents for preventing and treating diarrhea in children and adults, with pronounced immunomodulatory properties during several in vitro and clinical studies. Herein, we characterize the novel strain of B. clausii CSI08 (Munispore^®) for probiotic attributes including resistance to gastric acid and bile salts, the ability to suppress the growth of human pathogens, the capacity to assimilate wide range of carbohydrates and to produce potentially beneficial enzymes. Both spores and vegetative cells of this strain were able to adhere to a mucous-producing intestinal cell line and to attenuate the LPS- and Poly I:C-triggered pro-inflammatory cytokine gene expression in HT-29 intestinal cell line. Vegetative cells of B. clausii CSI08 were also able to elicit a robust immune response in U937-derived macrophages. Furthermore, B. clausii CSI08 demonstrated cytoprotective effects in in vitro cell culture and in vivo C. elegans models of oxidative stress. Taken together, these beneficial properties provide strong evidence for B. clausii CSI08 as a promising potential probiotic.

The Use of Probiotics during Rearing of Hermetia illucens: Potential, Caveats, and Knowledge Gaps

Given the novelty of the industrial production of the edible insects sector, research has primarily focused on the zootechnical performances of black soldier fly larvae (BSFL) in response to different substrates and rearing conditions as a basis to optimize yield and quality. However recently, research has started to focus more on the associated microbes in the larval digestive system and their substrates and the effect of manipulating the composition of these communities on insect performance as a form of microbiome engineering. Here we present an overview of the existing literature on the use of microorganisms during rearing of the BSFL to optimize the productivity of this insect. These studies have had variable outcomes and potential explanations for this variation are offered to inspire future research that might lead to a better success rate for microbiome engineering in BSFL.

In vitro and in silico assessment of probiotic and functional properties of Bacillus subtilis DE111®

Bacillus subtilis DE111^® is a safe, well-tolerated commercially available spore-forming probiotic that has been clinically shown to support a healthy gut microbiome, and to promote digestive and immune health in both adults and children. Recently it was shown that this spore-forming probiotic was capable of germinating in the gastrointestinal tract as early as 3 h after ingestion. However, a better understanding of the mechanisms involved in the efficacy of DE111^® is required. Therefore, the present investigation was undertaken to elucidate the functional properties of DE111^® through employing a combination of in vitro functional assays and genome analysis. DE111^® genome mining revealed the presence of several genes encoding acid and stress tolerance mechanisms in addition to adhesion proteins required to survive and colonize harsh gastrointestinal environment including multi subunit ATPases, arginine deiminase (ADI) pathway genes (argBDR), stress (GroES/GroEL and DnaK/DnaJ) and extracellular polymeric substances (EPS) biosynthesis genes (pgsBCA). DE111^® harbors several genes encoding enzymes involved in the metabolism of dietary molecules (protease, lipases, and carbohyrolases), antioxidant activity and genes associated with the synthesis of several B-vitamins (thiamine, riboflavin, pyridoxin, biotin, and folate), vitamin K2 (menaquinone) and seven amino acids including five essential amino acids (threonine, tryptophan, methionine, leucine, and lysine). Furthermore, a combined in silico analysis of bacteriocin producing genes with in vitro analysis highlighted a broad antagonistic activity of DE111^® toward numerous urinary tract, intestinal, and skin pathogens. Enzymatic activities included proteases, peptidases, esterase's, and carbohydrate metabolism coupled with metabolomic analysis of DE111^® fermented ultra-high temperature milk, revealed a high release of amino acids and beneficial short chain fatty acids (SCFAs). Together, this study demonstrates the genetic and phenotypic ability of DE111^® for surviving harsh gastric transit and conferring health benefits to the host, in particular its efficacy in the metabolism of dietary molecules, and its potential to generate beneficial SCFAs, casein-derived bioactive peptides, as well as its high antioxidant and antimicrobial potential. Thus, supporting the use of DE111^® as a nutrient supplement and its pottential use in the preparation of functional foods.

Co-fermented yellow wine lees by Bacillus subtilis and Enterococcus faecium regulates growth performance and gut microbiota in finishing pigs

Fermented yellow wine lees (FYWL) are widely used to increase feed utilization and improve pig performance. Based on the preparation of co-FYWL using Bacillus subtilis and Enterococcus faecalis, the purpose of this study was to investigate the effects of co-FYWL on growth performance, gut microbiota, meat quality, and immune status of finishing pigs. 75 pigs were randomized to 3 treatments (5 replicates/treatment), basal diet (Control), a basal diet supplemented with 4%FYWL, and a basal diet supplemented with 8%FYWL, for 50 days each. Results showed that the 8% FYWL group significantly reduced the F/G and increased the average daily weight gain of pigs compared to the control group. In addition, 8% FYWL improved the richness of Lactobacillus and B. subtilis in the gut, which correlated with growth performance, serum immune parameters, and meat quality. Furthermore, acetate and butyrate in the feces were improved in the FYWL group. Simultaneously, FYWL improved the volatile flavor substances of meat, increased the content of flavor amino acids, and played a positive role in the palatability of meat. In addition, FYWL increased serum IgA, IgM, IL-4 and IL-10 levels. Overall, the growth performance, the gut microbiota associated with fiber degradation, meat quality, and immune status were improved in the 8% FYWL group.

Probiotic mixture (Bacillus subtilis and Bacillus licheniformis) a potential in-feed additive to improve broiler production efficiency, nutrient digestibility, caecal microflora, meat quality and to diminish hazardous odour emission

This research aimed to assess the impact of probiotic supplementation in the broiler diet on growth performance, nutrient utilization, noxious gas emissions, excreta micromiota and meat quality. One thousand six hundred and twenty male Ross 380 broilers (one-day-old, body weight, 42 ± 0.5 g and 5-week trial) were arbitrarily chosen and assigned to three nutritive treatments (basal diet and basal diet included with 0.1%, and 0.2% probiotic mixture [Bacillus subtilis 7.0 × 10⁷ cfu/g, Bacillus licheniformis 4.1 × 10⁷ cfu/g]) with 30 duplicates (18 birds each). Probiotic inclusion linearly increased (p < 0.05) broiler body weight gain (BWG) during Phases 1, 2 and the overall period and decreased (p < 0.05) feed conversion ratio (FCR) linearly on Phase 2 and the overall period. However, feed intake (FI) and mortality rate remained unaffected (p > 0.05). Though nutrient digestibility of nitrogen (N) tendency to increase (p < 0.05), dry matter (DM) and energy (E) did not influence (p > 0.05). Inclusion of a probiotic supplement linearly increased (p < 0.05) Lactobacillus and reduced Salmonella (p < 0.05) counts in broilers. Moreover, broilers fed a diet supplement with probiotic addition linearly decreased (p < 0.05) NH₃ , H₂ S, C₂ O and acetic acid emissions. The graded level of probiotic addition linearly reduced (p < 0.05) cooking loss and the tendency to decrease (p < 0.05) weight of bursa of Fabricius, but had no effect (p > 0.05) on other meat quality measures. These findings indicated that increasing the level of probiotics in feed could improve growth efficiency, nutrient absorption, microbial index, meat quality and reduce gas emissions in broilers.

Different effects of Bacillus coagulans vegetative cells and spore isolates on constipation-induced gut microbiota dysbiosis in mice

Bacillus coagulans (B. coagulans) can improve and prevent functional gastrointestinal disorders. However, there has been little discussion in the literature on the difference between spores and vegetative cells for relieving constipation. The purpose of this study was to determine the efficacy of Bacillus coagulans (B. coagulans) vegetative cells and spores against loperamide-induced constipation in mice. According to our findings, B. coagulans vegetative cells and spores differ in their ability to relieve loperamide-induced constipation. Two of the three strains of B. coagulans spores used in this experiment, B. coagulans GBI-30 6086 and B. coagulans 90, were significantly different from the model group in relieving constipation. This mainly manifested as a decreased time required for first black stool defecation (by 52 and 79 min, respectively), and increased counts of the first black stools in 5 h (by 15 and 8, respectively), the small intestine transit rate (by 23.31% and 20.52%, respectively), and the concentration of SCFAs. While the administration of vegetative cells could only relieve some indicators of intestinal transit disorders and dysbacteriosis caused by constipation. Spores of B. coagulans GBI-30 6086 and B. coagulans 90 had higher survival rates in the simulated gastrointestinal tract environment, which indicated that the functional modes of the three strains were different and had a strong relationship with the morphology of the bacteria. B. coagulans GBI-30 6086 and B. coagulans 90 spores alleviate constipation by increasing the abundances of Actinobacteria, Deferribacteres, and Lachnospiraceae UCG-006 (which were positively correlated with SCFAs) and decreasing the abundances of Cyanobateria and Rikenellaceae_RC9_gut group (which were negatively correlated with SCFAs) and the levels of Ruminococcaceae UGC-014 and Alistipes. In this study, the effects of probiotics in the form of spore or vegetative cell were compared, and the optimal preparation form was determined, providing a theoretical basis for the application of probiotics of B. coagulans to relieve constipation.

Examining the Effects of 4He Exposure on the Gut-Brain Axis

Beyond low-Earth orbit, space radiation poses significant risks to astronaut health. Previous studies have shown that the microbial composition of the gastrointestinal (GI) microbiome changes upon exposure to high-linear energy transfer radiation. Interestingly, radiation-induced shifts in GI microbiota composition are linked to various neuropsychological disorders. Herein, we aimed to study changes in GI microbiota and behaviors of rats exposed to whole-body radiation (0, 5 or 25 cGy 4He, 250 MeV/n) at approximately 6 months of age. Fecal samples were collected 24 h prior to 4He irradiation and 24 h and 7 days postirradiation for quantitative PCR analyses to assess fecal levels of spore-forming bacteria (SFB), Bifidobacterium, Lactobacillus and Akkermansia. Rats were also tested in the social odor recognition memory (SORM) test at day 7 after 4He exposure. A subset of rats was euthanized 90 min after completion of the SORM test, and GI tissue from small intestine to colon were prepared for examining overall histological changes and immunohistochemical staining for serotonin (5-HT). No notable pathological changes were observed in GI tissues. Akkermansia spp. and SFB were significantly decreased in the 25 cGy group at 24 h and 7 days postirradiation compared to pre-exposure, respectively. Bifidobacterium and Lactobacillus spp. showed no significant changes. 5-HT production was significantly higher in the proximal small intestine and the cecum in the 25 cGy group compared to the sham group. The 25 cGy group exhibited deficits in recognition in SORM testing at day 7 postirradiation. Taken together, these results suggest a connection between GI microbiome composition, serotonin production, and neurobehavioral performance, and that this connection may be disrupted upon exposure to 25 cGy of 4He ions.

Investigating the Efficiency of Recombinant FliC-Loaded Bacillus subtilis Spores in Mice Immunization against Salmonella enterica Serovar Typhi

Background:

Bacterial spores are among the most efficient vaccine delivery vehicles. Because of their safety and efficacy, Bacillus subtilis spores are increasingly used in this regard. The negatively charged surfaces of the spores allow antigens to be adsorbed onto these structures. In this study, a candidate vaccine against Salmonella enterica serovar Typhi was adsorbed onto B. subtilis spores and the immunogenicity of the formulation was investigated in BALB/c mice.

Methods:

This work was performed during 2018–2019 in Islamic Azad University of Lahijan. FliC protein was recombinantly expressed in E. coli BL21 (DE3) cells and purified by affinity chromatography. On the other hand, B. subtilis strain PY79 (ATCC1609) was cultured in DSM medium and after the sporulation, FliC protein was adsorbed onto the spores in three different pH values (4, 7 and 10) and the adsorption was verified using dot-blot assay. FliC-adsorbed spores were then administered to BALB/c mice through the subcutaneous route. Mice immunization was evaluated by serum IgG assessment and challenge study.

Results:

FliC protein was successfully expressed and purified. Sporulation was controlled by phase-contrast microscopy. Serum IgG assay showed significant stimulation of the mice’s humoral immune system. Immunized mice were able to resist bacterial infection.

Conclusion:

The results showed the efficiency of spores as natural adjuvants for the stimulation of mice immune system. The formulation can be exploited for the delivery of recombinant vaccines against bacterial pathogens.

Presence and Germination of the Probiotic Bacillus subtilis DE111® in the Human Small Intestinal Tract: A Randomized, Crossover, Double-Blind, and Placebo-Controlled Study

Spore-based probiotics offer important advantages over other probiotics as they can survive the harsh gastric conditions of the stomach and bile salts in the small intestine, ultimately germinating in the digestive tract. A novel clinical trial in 11 ileostomy participants was conducted to directly investigate the presence and germination of the probiotic strain Bacillus subtilis DE111^® in the small intestine. Three hours following ingestion of DE111^®, B. subtilis spores (6.4 × 10⁴ ± 1.3 × 10⁵ CFU/g effluent dry weight) and vegetative cells (4.7 × 10⁴ ± 1.1 × 10⁵ CFU/g effluent dry weight) began to appear in the ileum effluent. Six hours after ingestion, spore concentration increased to 9.7 × 10⁷ ± 8.1 × 10⁷ CFU/g and remained constant to the final time point of 8 h. Vegetative cells reached a concentration of 7.3 × 10⁷ ± 1.4 × 10⁸ CFU/g at 7 h following ingestion. These results reveal orally ingested B. subtilis DE111^® spores are able to remain viable during transit through the stomach and germinate in the small intestine of humans within 3 h of ingestion.

Effects of Bacillus subtilis and Bacillus licheniformis on growth performance, immunity, short chain fatty acid production, antioxidant capacity, and cecal microflora in broilers

This study investigated the effects of dietary supplementation with Bacillus subtilis (B. subtilis) or Bacillus licheniformis (B. licheniformis) on growth performance, immunity, antioxidant capacity, short chain fatty acid (SCFA) production, and the cecal microflora in broiler chickens. In total, 360 male, 1-day-old Cobb 500 birds were randomly divided into 3 groups: the control group was fed a basal diet; the B. subtilis group was fed a basal diet supplemented with 1.5 × 10⁹ CFU/kg B. subtilis; the B. licheniformis group was fed a basal diet supplemented with 1.5 × 10⁹ CFU/kg B. licheniformis. Results showed that chickens supplemented with either B. subtilis or B. licheniformis had comparatively higher (P < 0.05) body weight and average daily gain, whereas no difference (P > 0.05) was observed in feed efficiency. Concentrations of serum IgA, IgY, and IgM, as well as anti-inflammatory IL-10 were significantly increased (P < 0.05), and proinflammatory IL-1β and IL-6 were significantly decreased (P < 0.05) by B. subtilis or B. licheniformis supplementation. Moreover, chickens fed with diets supplemented by either B. subtilis or B. licheniformis had greater antioxidant capacity, indicated by the notable increases (P < 0.05) in glutathione peroxidase, superoxide dismutase, and catalase, along with decrease (P < 0.05) in malondialdehyde. Compared to the control group, levels of SCFA, excluding acetic and propionic acid, in cecal content had improved (P < 0.05) by adding B. licheniformis, and significant increase (P < 0.05) in acetic and butyric acid was observed with B. subtilis supplementation. Microbial analysis showed that both B. subtilis or B. licheniformis supplementation could increase butyrate-producing bacteria such as Alistipes and Butyricicoccus, and decrease pathogenic bacteria such as the Synergistetes and Gammaproteobacteria. In summary, dietary supplemented with B. subtilis or B. licheniformis improved growth performance, immune status, and antioxidant capacity, increased SCFA production, and modulated cecal microbiota in chickens. Moreover, B. licheniformis was more effective than B. subtilis with the same supplemental amount.

Effects of the Use of a Combination of Two Bacillus Species on Performance, Egg Quality, Small Intestinal Mucosal Morphology, and Cecal Microbiota Profile in Aging Laying Hens

Sixty-week-old Hy-Line brown laying hens were randomly divided into five groups and fed different diets over a period of 84 days. Experimental treatments included a basal diet (control); the basal diet supplemented with 1.0 × 10⁶B. licheniformis yb-214245; the basal diet supplemented with 1.0 × 10⁶B. subtilis yb-114246; a combination of both strains in a 2:1 ratio (6.6 × 10⁵:3.3 × 10⁵B. licheniformis yb-214245:B. subtilis yb-114246); and the latter, added with 5 mg/kg flavomycin. Basal diet supplementation with the combined Bacillus species improved egg-laying performance in aging hens significantly (P < 0.05). Eggshell strength improved significantly with this treatment, compared to the control or the antibiotic-supplemented groups (P < 0.05). The levels of total cholesterol, triglycerides, and very low-density lipoprotein cholesterol in egg yolk declined significantly more in the Bacillus-treated group than in the control or the antibiotic-supplemented groups (P < 0.01). Small intestinal morphology was better in the hens treated with the Bacillus combination than in the hens in the control group (P < 0.05). The total number of aerobic bacteria (Bacillus, Lactobacillus, and Bifidobacterium) in the cecum was significantly higher in all the Bacillus-supplemented hens than either in the control or the antibiotic-supplemented hens (P < 0.01); additionally, the number of E. coli and Salmonella was significantly lower than in the control group (P < 0.01). In conclusion, diet supplementation with the combination of Bacillus species used here for aging laying hens improved their growth performance, cecal bacterial composition, egg quality, and small intestine morphology.

Molecular identification and antibiotic resistance pattern of actinomycetes isolates among immunocompromised patients in Iran, emerging of new infections

Recent advancements in DNA-based approaches have led to the identification of uncommon and rare bacterial pathogens. In this study, by utilizing a DNA-based approach, a total of 1043 clinical specimens were processed for the identification of actinobacteria targeting the 16S rRNA and gyrB genes. Drug susceptibility testing was also conducted using micro-broth dilution and PCR. Two isolates of Nocardia flavorosea and Rhodococcus erythropolis were reported for the first time in Iran. Also, Nocardiopsis dassonvillei, Streptomyces olivaceus, and Streptomyces griseus were reported for the first time in Asia. Infections caused by Nocardia caishijiensis and Prauserella muralis have also been reported in this study. The first Asian case of pulmonary infection caused by Nocardia ignorata and the first global case of brain abscess caused by Nocardia ninae and Nocardia neocaledoniensis have been reported in this study. Overall 30 isolates belonging to 6 genera (Nocardia, Streptomyces, Rodoccoccus, Nocardiopsis, Rothia, and Prauserella) were detected in 30 patients. All 30 isolates were susceptible to amikacin and linezolid. Three isolates including Nocardia otitidiscaviarum (n = 2) and Nocardia flavorosea (n = 1) were resistant to trimethoprim-sulfamethoxazole which were the first trimethoprim-sulfamethoxazole resistant clinical actinomycetes in Iran. Isolation of rare species of actinomycetes particularly Nocardia spp. requires urgent action before they spread clinically particularly among immunocompromised patients.

Characterization of Bacillus Species from Market Foods in Beijing, China

Foodborne diseases have been witnessing a constant rising trend worldwide, mainly caused by pathogenic microorganisms, such as Bacillus spp., posing a direct threat to public health. The purpose of this study was to evaluate the biological risk of foodborne and probiotic Bacillus spp. in Beijing markets. A total of 55 Bacillus isolates, including 29 B. cereus, 9 B. licheniformis and 7 B. subtilis, mostly found in dairy products (32.7%), were recovered from 106 samples and identified by matrix-assisted laser desorption/ionization mass spectrometry and polymerase chain reaction methods. The susceptibility towards 16 antibiotics was determined using a broth microdilution method. Bacillus showed a high level of resistance to florfenicol (100%), lincomycin (100%), tiamulin (78.2%) and ampicillin (67.3%), while they were all susceptible or intermediate to vancomycin and rifampin. Additionally, we obtained the whole genome of 19 Bacillus strains using high-throughput sequencing, and the rates of resistance genes van, fosB, erm and tet were 57.9%, 57.9%, 21.1% and 26.3%, respectively. Moreover, 100%, 9.1%, 45.5% and 100% of these isolates carried virulence genes nhe, hbl, cytK and entFM, respectively. Lastly, 60% Bacillus strains were positive in hemolysis tests, and 3 B. licheniformis strains displayed an inhibitory activity on the growth of S. aureus ATCC 29213 using agar overlay technique. Our study outlines the characteristics of foodborne Bacillus spp. and provides information for the monitoring of food safety.

Bacillus Subtilis 29784 as a Feed Additive for Broilers Shifts the Intestinal Microbial Composition and Supports the Production of Hypoxanthine and Nicotinic Acid

The probiotic Bacillus subtilis strain 29784 (Bs29784) has been shown to improve performance in broilers. In this study, we used a metabolomic and 16S rRNA gene sequencing approach to evaluate effects of Bs29874 in the broiler intestine. Nicotinic acid and hypoxanthine were key metabolites that were produced by the strain in vitro and were also found in vivo to be increased in small intestinal content of broilers fed Bs29784 as dietary additive. Both metabolites have well-described anti-inflammatory effects in the intestine. Furthermore, Bs29784 supplementation to the feed significantly altered the ileal microbiome of 13-day-old broilers, thereby increasing the abundance of genus Bacillus, while decreasing genera and OTUs belonging to the Lactobacillaceae and Enterobacteriacae families. Moreover, Bs29784 did not change the cecal microbial community structure, but specifically enriched members of the family Clostridiales VadinBB60, as well as the butyrate-producing families Ruminococcaceae and Lachnospiraceae. The abundance of various OTUs and genera belonging to these families was significantly associated with nicotinic acid levels in the cecum, suggesting a possible cross-feeding between B. subtilis strain 29784 and these beneficial microbes. Taken together, the data indicate that Bs29784 exerts its described probiotic effects through a combined action of its metabolites on both the host and its microbiome.

Bacillus subtilis natto as a potential probiotic in animal nutrition

The growing global demand for animal products and processed meat has created a challenge for the livestock sector to enhance animal productivity without compromising product quality. The restriction of antibiotics in animal feeds as growth promoters makes the use of probiotics a natural and safe alternative to obtain functional foods that provide animal health and quality and to maintain food safety for consumers. To incorporate these additives into the diet, detailed studies are required, in which in vitro and in vivo assays are used to prove the efficacy and to ensure the safety of probiotic candidate strains. Studies on the use of Bacillus subtilis natto as a spore-forming probiotic bacterium in animal nutrition have shown no hazardous effects and have demonstrated the effectiveness of its use as a probiotic, mainly due to its proven antimicrobial, anti-inflammatory, antioxidant, enzymatic, and immunomodulatory activity. This review summarizes the recent scientific background on the probiotic effects of B. subtilis natto in animal nutrition. It focuses on its safety assessment, host-associated efficacy, and industrial requirements.

Quantifying the impact of eight unit operations on the survival of eight Bacillus strains with claimed probiotic properties

This study assessed the impact of eight unit operations [slow pasteurization, high-temperature short time (HTST) pasteurization, cooking, baking, drying, fermentation, supercritical carbon dioxide (CO₂), irradiation and extrusion] in different food matrices (milk, orange juice, meatballs, bread, crystallized pineapple, yogurt, orange juice, ground black pepper, snacks, and spaghetti) on the resistance of eight (Bacillus flexus Hk1 Bacillus subtilis Bn1, Bacillus licheniformis Me1, Bacillus mojavensis KJS3, Bacillus subtilis PXN21, Bacillus subtilis PB6, Bacillus coagulans MTCC 5856 and Bacillus coagulans GBI-30, 6086) Bacillus strains with claimed probiotic properties (PB). The number of decimal reductions (γ) caused by the unit operations varied (p < 0.05) amongst the PB. Most of the unit operations caused ≤ 2 γ of PB in the food matrices evaluated. Irradiation caused up to 4.9 γ (p < 0.05) amongst the PB tested. B. subtilis Bn1, B. mojavensis KJS3, B. licheniformis Me1, and B. coagulans GBI-30 showed higher resistance to most of the tested unit operations. These results indicate that the choice of PB for application in foods should also be based on their resistance to unit operations employed during processing. Finally, the high resistance of PB to the unit operations tested comprise valuable data for the development and diversification of probiotic foods with sporeforming strains with claimed probiotic properties.

Probiotic Bacillus Spores Together with Amino Acids and Immunoglobulins Exert Protective Effects on a Rat Model of Ulcerative Colitis

In inflammatory bowel disease (IBD), experimental models have proven to be important tools for evaluating potential therapeutic agents and for investigating the mechanisms of pathogenesis. Oxidative stress and the immune response have been associated with acetic acid (AA)-induced ulcerative colitis (UC). Our study aimed to evaluate, for the first time, the ability of a spore-based probiotic and an amino acid and immunoglobulin supplement in reducing tissue damage and inflammatory responses in an experimental animal model of UC. Forty-two Wistar rats were divided into six groups, receiving 1% carboxymethylcellulose, 4% AA, MegaSporeBiotic™ (MSB; 1 × 10⁹ colony forming units/day) and MegaMucosa™ (MM; 70 mg/100 g/day). Pretreatment with MSB or MM alone and in combination significantly lowered inflammation and reduced damage to the colonic mucosa. Pretreatment with these agents resulted in levels of proinflammatory cytokines, vascular tight junction proteins, and measures of oxidative stress similar to those reported for methylprednisolone, one of the first-line therapies for moderate to severe activity of UC. The protection was further confirmed by histologic analysis of the colon tissue. In conclusion, pretreatment with probiotic spore-forming Bacillus strains and a supplement of amino acids in combination with immunoglobulins exhibited anti-inflammatory and antioxidant effects in an AA-induced rat model of UC.

Diffraction pattern of Bacillus subtilis CotY spore coat protein 2D crystals

Bacillus subtilis spore coat is a bacterial proteinaceous structure with amazing characteristics of self-organization, unique resiliency, toughness and flexibility in the same time. The spore coat represents a complex multilayered protein structure which is composed of over 80 coat proteins. Some of these proteins form two dimensional crystal structures who's low resolution ternary structure as was determined by electron microscopy. However, there are no 3D structure of these proteins known, due to a problem of preparing 3D crystals which could be analyzed by synchrotron X-ray sources. In the present study, Grazing-Incidence Wide-Angle X-ray Scattering (GIWAXS) was applied to investigate a diffraction pattern of CotY 2D crystals formed on Langmuir monolayer films. We observed two distinct diffraction rings and their position corresponds to a structure with the lattice spacing of 10.6 Å and 5.0 Å, respectively. Obtaining diffractions of 2D crystals pave the way to determination of 3D structure of coat proteins by using strong X-ray sources.

Combined Use of Bacillus subtilis yb-114,246 and Bacillus licheniformis yb-214,245 Improves Body Growth Performance of Chinese Huainan Partridge Shank Chickens by Enhancing Intestinal Digestive Profiles

The aim of our study was to unveil the promoting function of compound Bacillus sp. in improving chicken digestion-induced higher body growth performance. Strains of Bacillus subtilis and B. licheniformis were jointly supplemented to the chick diet. Digestive enzyme activities in the digesta improved, development of intestinal villus enhanced, and duodenum and ileum villous height increased, while their crypt depth declined, and the cecum's bacterial composition optimized after 56 days of supplementation. Bacterial composition at the phylum level changed significantly, more Firmicutes, Proteobacteria, Epsilonbacteraeota, and Tenericutes, but fewer Bacteroidetes were detected in cecum digesta in the compound Bacillus supplemented group. Bacterial composition diversity, which improves the abundances of metabolic genes through KEGG pathway classification, became more abundant. Results indicated that the Ruminococcaceae UCG-005, unclassified Ruminococcaceae, and unclassified Lachnospiraceae species are actively correlated with body growth, promoting higher final body weight. In conclusion, owing to digestive enzyme secretion, the development of intestinal villus was stimulated and gastrointestinal bacterial composition optimized, and two combined Bacillus sp. improved chicken body growth. Our findings show the promoting action of Bacillus subtilis and B. licheniformis on digestion, which can be an alternative to antibiotics.

Effects of two probiotic spores of Bacillus species on hematological, biochemical, and inflammatory parameters in Salmonella Typhimurium infected rats

Salmonella infections have become a major health concern in recent decades. This pathogen has evolved to become resistant to antibiotics, which has caused problems in its treatment. As such, finding a novel preventive method is important in the treatment and management of this infection. In recent years, uses of probiotics, especially spore-former genera such as Bacillus spp. has become increasingly popular. In this study spores of two probiotic bacteria, Bacillus subtilis and Bacillus coagulans were fed to rats for three weeks through their daily water intake after which Salmonella Typhimurium was gavaged to the rats. On days 1, 3, 5 and 7 after gavaging, the number of Salmonella was counted in liver, spleen, mesenteric lymph nodes, feces and content of ileum and cecum. Hematological and biochemical parameters, inflammatory mediators, total antioxidant capacity and malondialdehyde were also measured. The results showed that B. subtilis and B. coagulans caused delation in infiltration of Salmonella into the lymph nodes, spleen and liver, reduction of the inflammatory mediators, and decreases in oxidative stress, hematological and biochemical changes. The overall count of Salmonella in the above mentioned parameters has also decreased and a faster return to normal base were also witnessed. The results showed that the use of B. subtilis and B. coagulans can potentially help boost the body’s immune system, to combat the effects of exposure to the Salmonella pathogen.

Autochthonous Acid-Producing Bacteria from Catfish (Clarias sp.) with Antibacterial Activity against Selected Fish Pathogens: A Preliminary Study

In this study, the application of an autochthonous microorganism as probiotic on catfish (Clarias sp.) was scarcely reported. This study aimed to obtain probiotic candidates from the digestive tract (intestinal and gastric) of catfish. A total of nine isolates were successfully isolated from the catfish. Almost all bacterial colonies were morphologically round, had flat edges, were yellow, and produced clear zones as a sign of producing acid during culture. The analysis showed that the three isolates had the best activity in inhibiting fish pathogen isolates. Furthermore, molecular analysis revealed that those three isolates were Bacillus velezensis UB-C1, Bacillus amyloliquifaciens UB-C5, and Bacillus cereus UB-C8. Interestingly, those three bacteria were non-lactic acid bacteria.

Method of preparation, visualization and ultrastructural analysis of a formulation of probiotic Bacillus subtilis KATMIRA1933 produced by solid-phase fermentation

Probiotic preparations are used in medical treatment and in agricultural practice. They modulate numerous activities in eukaryotic hosts, such as: inhibition of pathogenic microbiota; stimulation of immunological responses; and production of antioxidants, anti-mutagens, and DNA protectors. Also, probiotic bacteria are used as a preventive measure to prevent bacterial diseases of the gastrointestinal tract. Solid-phase fermentation is reported as being used in the production of probiotic formulations where a solid substratum, such as soy and oil meal, is utilized for the growth of beneficial microorganisms. However, there are insufficient reports in the literature related to methodological approaches enabling evaluation of the final products of solid-phase fermentation. We suggest a novel method enabling evaluation of probiotic solid-state fermentation dry powders and observation of their morphology, ultrastructure, and elucidation of the quantitative distribution of probiotic microorganisms in solid substrates using electron microscopy. •The method is intended for ultrastructure microphotography of dry substances - for example, ultrastructure of solid-phase fermentation products.•The method allows preserving the ultrastructure of substrates that are damaged when soaking.•The method does not require additional equipment and reagents and can be used in all laboratories using electron microscopy.

Selection of carbohydrate-active probiotics from the gut of carnivorous fish fed plant-based diets

The gastrointestinal microbiota plays a critical role on host health and metabolism. This is particularly important in teleost nutrition, because fish do not possess some of the necessary enzymes to cope with the dietary challenges of aquaculture production. A main difficulty within fish nutrition is its dependence on fish meal, an unsustainable commodity and a source of organic pollutants. The most obvious sustainable alternatives to fish meal are plant feedstuffs, but their nutritive value is limited by the presence of high levels of non-starch polysaccharides (NSP), which are not metabolized by fish. The composition of fish-gut microbial communities have been demonstrated to adapt when the host is fed different ingredients. Thus, we hypothesized that a selective pressure of plant-based diets on fish gut microbiota, could be a beneficial strategy for an enrichment of bacteria with a secretome able to mobilize dietary NSP. By targeting bacterial sporulating isolates with diverse carbohydrase activities from the gut of European sea bass, we have obtained isolates with high probiotic potential. By inferring the adaptive fitness to the fish gut and the amenability to industrial processing, we identified the best two candidates to become industrially valuable probiotics. This potential was confirmed in vivo, since one of the select isolates lead to a better growth and feed utilization efficiency in fish fed probiotic-supplemented plant-based diets, thus contributing for sustainable and more cost-effective aquaculture practices.

Effects of selenium-enriched Bacillus sp. compounds on growth performance, antioxidant status, and lipid parameters breast meat quality of Chinese Huainan partridge chicks in winter cold stress

BACKGROUND

Both selenium (Se) and probiotic Bacillus regulate the metabolism to help defense clod stress and improve the meat quality in breeding chicks. The purpose of this study was to evaluate the effect of supplemental Se and Bacillus in the form of Se-enriched Bacillus (SECB) on the growth performance, lipid parameters, breast Se and antibiotic levels, and breast meat quality of chicken in winter cold stress.

METHODS

Five hundred 1-d-old chickens were divided into five groups randomly: Control, inorganic Se, compound Bacillus, SECB, and antibiotic. The feed duration was 56 d.

RESULTS

After 28 d of treatment, chicks feed SECB or compound Bacillus had higher body weights than the control, and after 56 d, chicks given either SECB or compound Bacillus had higher body weights than the control chicks or those given inorganic Se. Adding SECB to feed significantly increased the lightness, redness, and yellowness of breast meat, improved the water-holding capacity, and reduced the shear force and cooking loss. The concentration of Se in the breast muscle very significantly increased after SECB and inorganic Se supplementation, which was opposite to the concentration of flavomycin in antibiotic supplemented chicks. The antioxidative status of plasma and breast meat was significantly improved with added compound Bacillus and SECB: the total antioxidant capacity, total superoxide dismutase, and glutathione peroxidase ability in the breast muscle significantly improved, and the malondialdehyde concentration in plasma decreased. The levels of total cholesterol plasma triglyceride and very-low-density lipoprotein cholesterol in the plasma and breast muscle was decreased compared to that of the control, while the plasma high-density lipoprotein cholesterol concentration increased.

CONCLUSIONS

In conclusion, SECB supplementation promoted the body growth, antioxidative status, and Se concentrations in the plasma and breast meat, and also improved the breast meat quality.

Spores of Bacillus coagulans GBI-30, 6086 show high germination, survival and enzyme activity in a dynamic, computer-controlled in vitro model of the gastrointestinal tract

The aim of this study was to assess the germination, survival and metabolic activity of the probiotic Bacillus coagulans GBI-30, 6086 [GanedenBC³⁰] (BC30) in a dynamic, computer controlled in vitro model of the gastrointestinal (GI) tract, simulating human adults. Experiments were performed in the presence of a meal to maximise germination, due to the presence of germination-triggers. Both an upper GI tract (stomach and small intestine; TIM-1) and a colon model (TIM-2) were used, where material exiting TIM-1 was added to TIM-2. Spores of BC30 were introduced in the gastric compartment of TIM-1 and samples were taken immediately after the pylorus. Moreover, for 6 h, every hour the ileal efflux was collected and a subsample was plated for viable counts (spores and germinated cells). The remainder of the sample was fed to TIM-2, and after 24 h another sample was taken and tested for viable counts. In addition, samples were taken from the dialysates of the model and analysed using LC-MS/MS to determine bacterial metabolites and digestion products. Survival after transit through the gastric compartment was high (97%) and most cells were still in the spore form (76%). Survival after transit through TIM-1 was on average 51%, meaning that on average half of the orally provided spores was found back as cfu on the agar plates. Of these on average 93% were germinated cells and only 7% were spores. 24 h after the start of the experiments germination had increased in TIM-2 to 97% vegetative cells, and only 3% spores. No further loss of viability was observed in TIM-2. In terms of metabolic activity, increased levels of amino acids, dipeptides and citric acid cycle metabolites were found compared to experiments in the absence of BC30. In conclusion, BC30 spores germinate to a large extent (>90%) in the presence of germination triggers in the small intestine in a model that closely mimics the physiological conditions of human adults. Of the oral dose, as much as half of the cells survived transit through the upper GI tract, and based on the metabolite profile, these cells were metabolically active. Either these cells or the enzymes released from the dead cells aided in digestion of the meal. These insights help explain some of the observations in previous experiments, and support the understanding of the mechanism of action of the probiotic BC30.

Microbial-derived products as potential new antimicrobials

Due to the continuing global concerns involving antibiotic resistance, there is a need for scientific forums to assess advancements in the development of antimicrobials and their alternatives that might reduce development and spread of antibiotic resistance among bacterial pathogens. The objectives of the 2nd International Symposium on Alternatives to Antibiotics were to highlight promising research results and novel technologies that can provide alternatives to antibiotics for use in animal health and production, assess challenges associated with their authorization and commercialization for use, and provide actionable strategies to support their development. The session on microbial-derived products was directed at presenting novel technologies that included exploiting CRISPR-Cas nucleases to produce sequence-specific antimicrobials, probiotics development via fecal microbiome transplants among monogastric production animals such as chickens and mining microbial sources such as bacteria or yeast to identify new antimicrobial compounds. Other research has included continuing development of antimicrobial peptides such as newly discovered bacteriocins as alternatives to antibiotics, use of bacteriophages accompanied by development of unique lytic proteins with specific cell-wall binding domains and novel approaches such as microbial-ecology guided discovery of anti-biofilm compounds discovered in marine environments. The symposium was held at the Headquarters of the World Organisation for Animal Health (OIE) in Paris, France during 12-15 December 2016.

Caecibacterium sporoformans gen. nov., sp. nov., an anaerobic, butyrate-producing, spore-forming bacterium isolated from chicken caecum

Strains of a Gram-stain-negative, rod-shaped and immotile bacterium were isolated from broiler chicken caecal content. The isolates required strict anaerobic conditions for growth, formed spores, were catalase-positive and oxidase-negative. They produced butyrate as the major metabolic end product in reinforced clostridial medium broth. The genomic DNA G+C content of the isolated strains was 32.5-34.6 mol%. The major cellular fatty acids were C16 : 0 FAME, C14 : 0 FAME, C19 : 0CYC 9,10DMA and C16 : 0DMA. The fatty acid composition of the cell wall showed no similarity to any strain in the midi database. 16S rRNA gene sequence analysis showed that the nearest phylogenetic neighbours were Anaerostipes hadrus and Clostridium populeti (92 % sequence similarity) within Clostridium cluster XIVa of the phylum Firmicutes. Therefore, a novel genus is proposed, with the name Caecibacterium sporoformans gen. nov., sp. nov. The type strain of Caecibacterium sporoformans is LMG 27730^T=DSM 26959^T.

Bacillus As Potential Probiotics: Status, Concerns, and Future Perspectives

Spore-forming bacilli are being explored for the production and preservation of food for many centuries. The inherent ability of production of large number of secretory proteins, enzymes, antimicrobial compounds, vitamins, and carotenoids specifies the importance of bacilli in food chain. Additionally, Bacillus spp. are gaining interest in human health related functional food research coupled with their enhanced tolerance and survivability under hostile environment of gastrointestinal tract. Besides, bacilli are more stable during processing and storage of food and pharmaceutical preparations, making them more suitable candidate for health promoting formulations. Further, Bacillus strains also possess biotherapeutic potential which is connected with their ability to interact with the internal milieu of the host by producing variety of antimicrobial peptides and small extracellular effector molecules. Nonetheless, with proposed scientific evidences, commercial probiotic supplements, and functional foods comprising of Bacillus spp. had not gained much credential in general population, since the debate over probiotic vs pathogen tag of Bacillus in the research and production terrains is confusing consumers. Hence, it’s important to clearly understand the phenotypic and genotypic characteristics of selective beneficial Bacillus spp. and their substantiation with those having GRAS status, to reach a consensus over the same. This review highlights the probiotic candidature of spore forming Bacillus spp. and presents an overview of the proposed health benefits, including application in food and pharmaceutical industry. Moreover, the growing need to evaluate the safety of individual Bacillus strains as well as species on a case by case basis and necessity of more profound analysis for the selection and identification of Bacillus probiotic candidates are also taken into consideration.

Possible correlation between levansucrase production and probiotic activity of Bacillus sp. isolated from honey and honey bee

Five bacterial isolates from honey and bee gut were selected based on their high levansucrase activity and levan yield which were strongly positively correlated. All isolates showed good tolerance to temperature up to 70 °C, to NaCl up to 3 M and to 0.1% H₂O₂. They maintained over 59 and 64% survival at pH 9.0 and 2.0 respectively, but showed varying tolerance to 0.1% bile salts and pancreatic enzymes. Most isolates were susceptible to widely used antibiotics, but demonstrated diverse antimicrobial activity. Non hemolytic isolates were identified on the basis of 16S rRNA sequencing as Bacillus subtilis HMNig-2 and B. subtilis MENO2 with 97% homology. They exhibited promising probiotic characteristics and achieved highest levansucrase activity of 94.1 and 81.5 U/mL respectively. Both exhibited highest biofilm formation ability in static microtiter plate assay. Also, they achieved 34 and 26% adhesion respectively to Caco-2cells and had highest free radical scavenging activity of 30.8 and 26.2% respectively. The levans of the two isolates showed good antimicrobial activity against some pathogens and exhibited positive prebiotic effect (prebiotic index >1) with Lactobacillus casei and Lactobacillus reuteri. Results suggest a correlation between levansucrase production, levan yield and pre-probiotic activities of the studied strains.

Effect of oral administration of Bacillus coagulans B37 and Bacillus pumilus B9 strains on fecal coliforms, Lactobacillus and Bacillus spp. in rat animal model

Aim:

To investigate the effect of oral administration of two Bacillus strains on fecal coliforms, Lactobacillus and Bacillus spp. in rat animal model.

Materials and Methods:

An in vivo experiment was conducted for 49-day period on 36 adult male albino Wister rats divided equally into to four groups. After 7-day adaptation period, one group (T1) was fed on sterile skim milk along with basal diet for the next 28 days. Second (T2) and (T3) groups received spore biomass of Bacillus coagulans B37 and Bacillus pumilus B9, respectively, suspended in sterilized skim milk at 8-9 log colony-forming units/ml plus basal diet for 28 days, while control group (T4) was supplied with clean water along with basal diet. There was a 14-day post-treatment period. A total of 288 fecal samples (8 fecal collections per rat) were collected at every 7-day interval starting from 0 to 49 days and subjected to the enumeration of the counts of coliforms and lactobacilli and Bacillus spores using respective agar media. In vitro acid and bile tolerance tests on both the strains were performed.

Results:

The rats those (T2 and T3) received either B. coagulans B37 or B. pumilus B9 spore along with non-fermented skim milk showed decrease (p<0.01) in fecal coliform counts and increase (p<0.05) in both fecal lactobacilli and Bacillus spore counts as compared to the control group (T4) and the group fed only skim milk (T1). In vitro study indicated that both the strains were found to survive at pH 2.0 and 3.0 even up to 3 h and tolerate bile up to 2.0% concentration even after 12 h of exposure.

Conclusions:

This study revealed that oral administration of either B. coagulans B37 or B. pumilus B9 strains might be useful in reducing coliform counts accompanied by concurrent increase in lactobacilli counts in the intestinal flora in rats.

Spore Resistance Properties

Spores of various Bacillus and Clostridium species are among the most resistant life forms known. Since the spores of some species are causative agents of much food spoilage, food poisoning, and human disease, and the spores of Bacillus anthracis are a major bioweapon, there is much interest in the mechanisms of spore resistance and how these spores can be killed. This article will discuss the factors involved in spore resistance to agents such as wet and dry heat, desiccation, UV and γ-radiation, enzymes that hydrolyze bacterial cell walls, and a variety of toxic chemicals, including genotoxic agents, oxidizing agents, aldehydes, acid, and alkali. These resistance factors include the outer layers of the spore, such as the thick proteinaceous coat that detoxifies reactive chemicals; the relatively impermeable inner spore membrane that restricts access of toxic chemicals to the spore core containing the spore's DNA and most enzymes; the low water content and high level of dipicolinic acid in the spore core that protect core macromolecules from the effects of heat and desiccation; the saturation of spore DNA with a novel group of proteins that protect the DNA against heat, genotoxic chemicals, and radiation; and the repair of radiation damage to DNA when spores germinate and return to life. Despite their extreme resistance, spores can be killed, including by damage to DNA, crucial spore proteins, the spore's inner membrane, and one or more components of the spore germination apparatus.

DNA-protection and antioxidant properties of fermentates from Bacillus amyloliquefaciens B-1895 and Bacillus subtilis KATMIRA1933

DNA protective and antioxidant activity of Bacillus amyloliquefaciens B-1895 and Bacillus subtilis KATMIRA1933 were evaluated by Escherichia coli-based Lux biosensors. Two biosensor strains of E. coli, MG1655 (pColD-lux) and MG1655 (pSoxS-lux), which react on DNA damage and superoxide-anion radical activity, were used. SOS-response and Sox-response were stimulated by addition of dioxidine (2,3-Quinoxalinedimethanol,1,4-dioxide) and paraquat (N,N'-dimethyl-4,4'-bipyridinium dichloride) respectively. Preparations of both Bacillus fermentates demonstrated DNA protective and antioxidant (superoxide scavenging) activity (up to 60·19%). The strain К1933 is, in general, characterized by higher DNA protective activity (28·85%), with parameters of antioxidant activity of both bacilli strains being statistically not significantly different. Sporogenous potential probiotic micro-organisms with antioxidant and DNA protective activities can become an effective tool for compensation of various negative oxidative stress processes in humans.

SIGNIFICANCE AND IMPACT OF THE STUDY

In humans, oxidative stress is a cause or an important component of many serious diseases, as well as being one of the age influencing factors. Environmental stresses lead to the increase in levels of reactive oxygen species (ROS). Oxidative DNA damage is a side effect of nonspecific inflammation. These human health challenging factors trigger the search for health-promoting bacteria capable of production of antioxidants and DNA-protectors. In this study, two Bacillus strains of interest were shown to produce noticeable DNA protective and antioxidant activities.

Oral administration of a select mixture of Bacillus probiotics generates Tr1 cells in weaned F4ab/acR- pigs challenged with an F4+ ETEC/VTEC/EPEC strain

Although breeding of F4 receptor − negative (F4R⁻) pigs may prevent post-weaning diarrhea, the underlying immunity is poorly understood. Here, various doses of a Bacillus licheniformis and Bacillus subtilis mixture (BLS-mix) were orally administered to F4ab/acR⁻ pigs for 1 week before F4 (K88) − positive ETEC/VTEC/EPEC challenge. Administration of BLS-mix increased the percentage of Foxp3⁻IL-10⁺ T cells but not of Foxp3⁺IL-10⁺ regulatory T (Treg) cells among peripheral blood CD4⁺ T cells. A low dose of BLS-mix feeding resulted in increased the expression of IL-6, TNF-α, IL-10, and the transcription factors Foxp3 and T-bet mRNAs in the jejunum. Administration of either a low or high dose BLS-mix also led to an increase in the percentage of CD4⁺Foxp3⁺ Treg cells among intraepithelial lymphocytes and CD4⁺IL-10⁺ T cells in the small intestinal Peyer’s patches and the lamina propria of F4ab/acR⁻ pigs following F4⁺ ETEC/VTEC/EPEC challenge. The increased number of IL-10–producing CD4⁺ T cells was attributed to an increase in the proportion of Foxp3⁻IL-10⁺ Treg cells rather than Foxp3⁺IL-10⁺ Treg cells. Our data indicate that oral administration of BLS-mix to newly weaned F4ab/acR⁻ pigs ameliorates enteritis in an F4⁺ ETEC/VTEC/EPEC model; however, induction of IL-10–producing Foxp3⁻ Treg cells by BLS-mix administration cannot account for the protection of newly weaned F4ab/acR⁻ pigs from F4⁺ ETEC/VTEC/EPEC infection, and that excessive generation of CD4⁺IL-10⁺ T cells following consumption of BLS-mix during episodes of intestinal inflammation that is caused by enteric pathogens might prohibit clearance of the pathogen. Select probiotic mixtures may allow for tailoring strategies to prevent infectious diseases.

A highly acid-resistant novel strain of Lactobacillus johnsonii No. 1088 has antibacterial activity, including that against Helicobacter pylori, and inhibits gastrin-mediated acid production in mice

A novel strain of Lactobacillus johnsonii No. 1088 was isolated from the gastric juice of a healthy Japanese male volunteer, and characterized for its effectiveness in the stomach environment. Lactobacillus johnsonii No. 1088 was found to have the strongest acid resistance among several lactobacilli examined (>10% of cells survived at pH 1.0 after 2 h), and such a high acid resistance property was a specific characteristic of this strain of L. johnsonii. When cultured with various virulent bacteria, L. johnsonii No. 1088 inhibited the growth of Helicobacter pylori,Escherichia coli O-157, Salmonella Typhimurium, and Clostridium difficile, in which case its effectiveness was more potent than that of a type strain of L. johnsonii,JCM2012. In addition to its effect in vitro, L. johnsonii No. 1088 inhibited the growth of H. pylori in human intestinal microbiota-associated mice in both its live and lyophilized forms. Moreover, L. johnsonii No. 1088 suppressed gastric acid secretion in mice via decreasing the number of gastrin-positive cells in the stomach. These results taken together suggest that L. johnsonii No. 1088 is a unique lactobacillus having properties beneficial for supporting H. pylori eradication by triple therapy including the use of a proton pump inhibitor (PPI) and also for prophylaxis of gastroesophageal reflux disease possibly caused after H. pylori eradication as a side effect of PPI.

Physiology and Sporulation in Clostridium

Clostridia are Gram-positive, anaerobic, endospore-forming bacteria, incapable of dissimilatory sulfate reduction. Comprising approximately 180 species, the genus Clostridium is one of the largest bacterial genera. Physiology is mostly devoted to acid production. Numerous pathways are known, such as the homoacetate fermentation by acetogens, the propionate fermentation by Clostridium propionicum , and the butyrate/butanol fermentation by C. acetobutylicum , a well-known solvent producer. Clostridia degrade sugars, alcohols, amino acids, purines, pyrimidines, and polymers such as starch and cellulose. Energy conservation can be performed by substrate-level phosphorylation as well as by the generation of ion gradients. Endospore formation resembles the mechanism elucidated in Bacillus . Morphology, contents, and properties of spores are very similar to bacilli endospores. Sporulating clostridia usually form swollen mother cells and accumulate the storage substance granulose. However, clostridial sporulation differs by not employing the so-called phosphorelay. Initiation starts by direct phosphorylation of the master regulator Spo0A. The cascade of sporulation-specific sigma factors is again identical to what is known from Bacillus . The onset of sporulation is coupled in some species to either solvent (acetone, butanol) or toxin (e.g., C. perfringens enterotoxin) formation. The germination of spores is often induced by various amino acids, often in combination with phosphate and sodium ions. In medical applications, C. butyricum spores are used as a C. difficile prophylaxis and as treatment against diarrhea. Recombinant spores are currently under investigation and testing as antitumor agents, because they germinate only in hypoxic tissues (i.e., tumor tissue), allowing precise targeting and direct killing of tumor cells.