Inhibition of the cytotoxic effect of Clostridium difficile in vitro by Clostridium butyricum MIYAIRI 588 strain

A rapid genome-proteome approach to identify rate-limiting steps in the butyrate production pathway in probiotic Clostridium butyricum, CBM588

OBJECTIVES

Clostridium butyricum ferments non-digested dietary fibre in the colon to produce butyric acid. Butyrate is a four-carbon, short-chain fatty acid (SCFA) which has multiple health benefits. Many microbial products of pharmaceutical or industrial interest, such as butyrate, are produced in low quantities due to rate-limiting steps in their metabolic pathway, including low abundance or low activity of one or more enzymes in the pathway. By identifying the former, appropriate enzymes can be over-expressed to increase product yields, however, methods to determine these enzymes are laborious. To improve butyrate production in C. butyricum probiotic strain, CBM588, a novel rapid genome-proteome approach was deployed.

METHODS

First, whole genome sequencing was performed and the 8 genes involved in butyrate production identified on the chromosome. Second, the relative abundance of these enzymes was investigated by liquid chromatography-mass spectrometry (LC-MS) analysis of total cytosolic proteins from early stationary phase cultures.

RESULTS

Phosphotransbutyrylase (Ptb), butyrate kinase (Buk) and crotonase (Crt) were found to be the least abundant. Over-expression episomally of the corresponding genes individually or of the ptb-buk bicistron led to significant increases in butyrate titre per density of culture from 10 to 24 h, compared to the wild type.

CONCLUSIONS

Our findings pave the way for over-expressing these genes chromosomally to generate a recombinant probiotic with improved butyrate production and potentially enhanced gut health properties.

The effect of Miya on skeletal muscle changes by regulating gut microbiota in rats with osteoarthritis through AMPK pathway

BACKGROUND

The study aimed to explore whether Miya (MY), a kind of Clostridium butyricum, regulated osteoarthritis (OA) progression through adenosine 5'-monophosphate-activated protein kinase (AMPK) pathway.

METHODS

The OA rats were orally given MY daily for 4 weeks and were intramuscularly injected with AMPK inhibitor once a week for 4 weeks. Hematoxylin eosin (HE) staining was used to observe the histological morphology of the knee joint. The levels of succinate dehydrogenase (SDH) and muscle glycogen (MG) in the tibia muscle of rats were detected by the corresponding kits, as well as the expression of related genes/proteins were assessed by real-time quantitative PCR (RT-qPCR) and western blot.

RESULTS

HE staining suggested that MY suppressed the symptoms of OA, which was abolished by AMPK inhibitor. Furthermore, the SDH and MG contents in the OA + MY + AMPK inhibitor group were lower than in the OA + MY group. At last, the levels of AMPK, PI3K, AKT1, Ldh, Myod, Chrna1, and Chrnd were notably decreased after AMPK inhibitor treatment, while the levels of Lcad and Mcad were up-regulated by AMPK inhibitor. Furthermore, their protein expression levels detected by western blot were consistent with those from RT-qPCR.

CONCLUSION

MY may partially regulate skeletal muscle changes and prevente OA development through the AMPK pathway.

Recombinant Lactococcus lactis Expressing Human LL-37 Prevents Deaths from Viral Infections in Piglets and Chicken

Novel antibiotic substitutes are increasingly in demand in the animal husbandry industry. An oral recombinant Lactococcus lactis (L. lactis) expressing human LL-37 (oral LL-37) was developed and its safety and antiviral effectiveness in vivo was tested. In addition to impairing liposome integrity, LL-37 polypeptide from recombinant L. lactis could prevent the host cell infection by a variety of viruses, including recombinant SARS, SARS-CoV-2, Ebola virus, and vesicular stomatitis virus G. Subchronic toxicity studies performed on Sprague-Dawley rats showed that no cumulative toxicity was found during short-term intervention. Oral LL-37 treatment after the onset of fever could reduce mortality in piglets infected with porcine reproductive and respiratory syndrome virus. Moreover, body weight gain of piglets receiving treatment was progressively restored, and nucleic acid positive rebound was not undetected after discontinuation. Oral LL-37 consistently increased the lifespan of chickens infected with Newcastle viruses. These findings suggested a potential use of recombinantly modified microorganisms in veterinary medicine.

Heterologous Expression of the Antiviral Lectin Griffithsin in Probiotic Saccharomyces boulardii and In Vitro Characterization of Its Properties

In this study, the probiotic yeast Saccharomyces boulardii was engineered to secrete the antiviral lectin griffithsin. Twelve genetic tools with the griffithsin gene were cloned into the vector pSF-TEF1-URA3 and introduced into S. boulardii. In the recombinant strains, a 16.9 kDa band was detected using SDS-PAGE and further recognized by griffithsin antibody with Western blotting. S. boulardii strains FM, FT, HC, and HE with a high yield of griffithsin were acquired for property characterization in vitro. The four recombinant strains displayed a similar growth pattern to that of the control strains, while their morphological characteristics had changed according to scanning electron microscopy. In simulated gastrointestinal digestive fluids, the survival rates of S. boulardii FM, FT, and HC were significantly decreased (86.32 ± 1.49% to 95.36 ± 1.94%) compared with those of the control strains, with survival rates between 95.88 ± 0.00% and 98.74 ± 1.97%. The hydrophobicity of S. boulardii FM, the strain with the highest griffithsin production, was significantly increased to 21.89 ± 1.07%, and it exhibited a reduced auto-aggregation rate (57.64 ± 2.61%). Finally, Vero cells infected with porcine epidemic diarrhea virus (PEDV) were used to evaluate the strains' antiviral activity, and the rate at which S. boulardii FM inhibited PEDV reached 131.36 ± 1.06%, which was significantly higher than that of the control group.

The Potential of Clostridium butyricum to Preserve Gut Health, and to Mitigate Non-AIDS Comorbidities in People Living with HIV

A dramatic reduction in mortality among people living with HIV (PLWH) has been achieved during the modern antiretroviral therapy (ART) era. However, ART does not restore gut barrier function even after long-term viral suppression, allowing microbial products to enter the systemic blood circulation and induce chronic immune activation. In PLWH, a chronic state of systemic inflammation exists and persists, which increases the risk of development of inflammation-associated non-AIDS comorbidities such as metabolic disorders, cardiovascular diseases, and cancer. Clostridium butyricum is a human butyrate-producing symbiont present in the gut microbiome. Convergent evidence has demonstrated favorable effects of C. butyricum for gastrointestinal health, including maintenance of the structural and functional integrity of the gut barrier, inhibition of pathogenic bacteria within the intestine, and reduction of microbial translocation. Moreover, C. butyricum supplementation has been observed to have a positive effect on various inflammation-related diseases such as diabetes, ulcerative colitis, and cancer, which are also recognized as non-AIDS comorbidities associated with epithelial gut damage. There is currently scant published research in the literature, focusing on the influence of C. butyricum in the gut of PLWH. In this hypothesis review, we speculate the use of C. butyricum as a probiotic oral supplementation may well emerge as a potential future synergistic adjunctive strategy in PLWH, in tandem with ART, to restore and consolidate intestinal barrier integrity, repair the leaky gut, prevent microbial translocation from the gut, and reduce both gut and systemic inflammation, with the ultimate objective of decreasing the risk for development of non-AIDS comorbidities in PLWH.

The metagenomic and metabolomic profile of the gut microbes in Chinese full-term and late preterm infants treated with Clostridium butyricum

The present study investigated the composition, abundance, and diversity of gut microbes in full-term and late-preterm infants from a medical center in eastern China. A total of 144 genomes of stool samples were captured for 16S rRNA metagenomic analyses. A high abundance of commensal intestinal bacteria was detected in these samples such as Phocaeicola vulgatus, Escherichia coli, and Faecalibacterium prausnitzii, indicating a relatively consistent diversity of gut microbes in the present full-term infants aged 38-40 weeks. However, late preterm infants (n = 50) with mandatory antimicrobials feeding exhibited lower diversity but a higher composition of opportunistic pathogens such as Enterococcus species. Centralized on the situation, we explored the regulatory effect of Clostridium butyricum as probiotics on these late preterm infants. The consumption of C. butyricum did not restore the composition of gut microbes altered by antimicrobials to normal levels, although several opportunistic pathogens decreased significantly after probiotic therapy including Staphylococcus aureus, Sphingomonas echinoides, and Pseudomonas putida. We also compared the effects of day-fed versus night-fed probiotics. Intriguingly, the nighttime feeding showed a higher proportion of C. butyricum compared with probiotic day-feeding. Finally, fecal metabolome and metabolites were analyzed in late preterm infants with (n = 20) or without probiotic therapy (n = 20). The KEGG enrichment analysis demonstrated that vitamin digestion and absorption, synaptic vesicle cycle, and biotin metabolism were significantly increased in the probiotic-treated group, while MSEA indicated that a series of metabolism were significantly enriched in probiotic-treated infants including glycerolipid, biotin, and lysine, indicating the complex effects of probiotic therapy on glutathione metabolism and nutrients digestion and absorption in late preterm infants. Overall, this study provided metagenomic and metabolomic profile of the gut microbes in full-term newborns and late preterm infants in eastern China. Further studies are needed to support and elucidate the role of probiotic feeding in late preterm infants with mandatory antimicrobial treatment.

Prescribed probiotic usage to prevent Clostridioides difficile infection among older patients receiving antibiotics: A retrospective cohort study

OBJECTIVES

Clostridioides difficile infection (CDI) is a leading cause of antimicrobial-associated colitis and is a global clinical concern. Probiotics are considered a CDI-preventive measure; however, highly inconsistent data have been previously reported. Thus, we evaluated the CDI-preventive effect of prescribed probiotics in high-risk older patients receiving antibiotics.

METHODS

Older patients (aged ≥65 years) admitted to the emergency department who received antibiotics between 2014 and 2017 were enrolled in this single-center retrospective cohort study. Propensity score-matched analysis was used to compare the CDI incidence in patients who took the prescribed probiotics within 2 days of receiving antibiotics for at least 7 days with those who did not. The rates of severe CDI and associated hospital mortality were also evaluated.

RESULTS

Among 6148 eligible patients, 221 were included in the prescribed probiotic group. A propensity score-matched (221 matched pairs) well-balanced for patient characteristics was obtained. The incidence of primary nosocomial CDI did not differ significantly between the prescribed and non-prescribed probiotic groups (0% [0/221] vs. 1.0% [2/221], p = 0.156). Of the 6148 eligible patients, 0.5% (30/6148) developed CDI, with a severe CDI rate of 33.3% (10/30). Furthermore, no CDI-associated in-hospital mortality was observed in the study cohort.

CONCLUSIONS

The evidence from this study does not support recommendations for the routine use of prescribed probiotics to prevent primary CDI in older patients receiving antibiotics in situations where the CDI is infrequent.

Probiotics: insights and new opportunities for Clostridioides difficile intervention

Clostridioides difficile infection (CDI) is a life-threatening disease caused by the Gram-positive, opportunistic intestinal pathogen C. difficile. Despite the availability of antimicrobial drugs to treat CDI, such as vancomycin, metronidazole, and fidaxomicin, recurrence of infection remains a significant clinical challenge. The use of live commensal microorganisms, or probiotics, is one of the most investigated non-antibiotic therapeutic options to balance gastrointestinal (GI) microbiota and subsequently tackle dysbiosis. In this review, we will discuss major commensal probiotic strains that have the potential to prevent and/or treat CDI and its recurrence, reassess the efficacy of probiotics supplementation as a CDI intervention, delve into lessons learned from probiotic modulation of the immune system, explore avenues like genome-scale metabolic network reconstructions, genome sequencing, and multi-omics to identify novel strains and understand their functionality, and discuss the current regulatory framework, challenges, and future directions.

Comparison of clinical severity, genotype and toxin gene expression of binary toxin-producing Clostridioides difficile clinical isolates in Japan

The emerging Clostridioides difficile strain BI/NAP1/027 has been reported to be associated with more severe clinical symptoms and higher mortality rates, thought in part due to production of a novel binary toxin alongside conventional A and B toxins. However, recent studies suggest that this may not always be the case. Therefore, the purpose of this report was to investigate the correlation between clinical severity and microbiological characteristics of CDT-producing C. difficile isolates in Japan. Eight Japanese isolates of CDT producing C. difficile were investigated using genotyping, cytotoxic activity assays and toxin gene expression. Correlation with clinical severity was performed retrospectively using the patient record. Three of eight patients were assessed as having severe C. difficile infection (CDI). PCR ribotyping resolved six ribotypes including ribotype 027. No specific genes were identified determining severe compared with non-severe cases. Positive correlation of expression levels of tcdA, tcdB and cdtB were observed although these expression levels were not correlated with cytotoxicity. CDI severity index neither correlated with toxin gene expression level nor cytotoxicity. These data indicate that the possession of the CDT gene and toxin gene expression levels may not relate to C. difficile cytotoxicity or clinical severity.

Probiotics as Alternatives to Antibiotics for the Prevention and Control of Necrotic Enteritis in Chickens

Necrotic enteritis (NE) in poultry is an economically important disease caused by Clostridium perfringens type A bacteria. A global trend on restricting the use of antibiotics as feed supplements in food animal production has caused a spike in the NE incidences in chickens, particularly in broiler populations. Amongst several non-antibiotic strategies for NE control tried so far, probiotics seem to offer promising avenues. The current review focuses on studies that have evaluated probiotic effects on C. perfringens growth and NE development. Several probiotic species, including Lactobacillus, Enterococcus, Bacillus, and Bacteroides bacteria as well as some yeast species have been tested in chickens against C. perfringens and NE development. These findings have shown to improve bird performance, reduce C. perfringens colonization and NE-associated pathology. The underlying probiotic mechanisms of NE control suggest that probiotics can help maintain a healthy gut microbial balance by modifying its composition, improve mucosal integrity by upregulating expression of tight-junction proteins, and modulate immune responses by downregulating expression of inflammatory cytokines. Collectively, these studies indicate that probiotics can offer a promising platform for NE control and that more investigations are needed to study whether these experimental probiotics can effectively prevent NE in commercial poultry operational settings.

Association between Nutrition Protocol with Clostridium butyricum MIYAIRI 588 and Reduced Incidence of Clostridioides difficile Infection in Critically Ill Patients: A Single-Center, Before-and-After Study

Background: Clostridioides difficile infection (CDI) is associated with high mortality. Clostridium butyricum MIYAIRI 588 (CBM) is a probiotic that suppresses Clostridioides difficile proliferation. We assessed the effect of a prophylactic nutritional protocol with CBM on reducing CDI incidence in critically ill patients. Patients and Methods: Adult critically ill patients admitted to the intensive care unit (ICU) between 2008 and 2012 were enrolled in this single-center observational study. The original nutritional protocol was introduced in 2010. Patients admitted between 2011 and 2012 (nutrition protocol group) were compared with those admitted between 2008 and 2009 (control group). The primary outcome was CDI incidence during ICU stay. Results: There were 755 and 1,047 patients in the control and nutrition protocol groups, respectively. The median (interquartile range) age of the control and nutrition protocol groups was 61 (43-75) and 63 (47-76) years, respectively (p = 0.05). The Acute Physiology and Health Evaluation II (APACHE II) and Sequential Organ Failure Assessment (SOFA) scores of the control and nutrition protocol groups were 14 (9-23) and 15 (10-22) points (p = 0.73), and four (2-7) and four (2-7) points (p = 0.48), respectively. There were 14 (1.9%) patients with CDI in the control group and one (0.1%) patient in the protocol group (p < 0.01). As a secondary outcome, there were five (0.7%) patients with recurrent CDI in the control group and zero patients in the protocol group (p = 0.01). The length of ICU stay was seven (4-14) days and six (4-13) days in the control and protocol groups (p = 0.01), respectively. Univariable analyses of the relative risk for CDI showed that the nutrition protocol reduced the risk of CDI (0.05 [0.01-0.39]; p < 0.01). Conclusions: The nutritional protocol using Clostridioides butyricum may reduce CDI in critically ill patients.

Miya Improves Osteoarthritis Characteristics via the Gut-Muscle-Joint Axis According to Multi-Omics Analyses

Background: The gut microbiota is associated with osteoarthritis (OA) progression. Miya (MY) is a product made from Clostridium butyricum, a member of gut microbiota. This study was conducted to investigate the effects of MY on OA and its underlying mechanisms.

Methods: An OA rat model was established, and MY was used to treat the rats for 4 weeks. Knee joint samples from the rats were stained with hematoxylin-eosin, and fecal samples from the OA and OA+MY groups were subjected to 16S rDNA sequencing and metabolomic analysis. The contents of succinate dehydrogenase and muscle glycogen in the tibia muscle were determined, and related genes and proteins were detected using quantitative reverse transcription polymerase chain reaction and western blotting.

Results: Hematoxylin and eosin staining showed that treatment with MY alleviated the symptoms of OA. According to the sequencing results, MY significantly increased the Chao1, Shannon, and Pielou evenness values compared to those in the untreated group. At the genus level, the abundances of Prevotella, Ruminococcus, Desulfovibrio, Shigella, Helicobacter, and Streptococcus were higher in the OA group, whereas Lactobacillus, Oscillospira, Clostridium, and Coprococcus were enriched after MY treatment. Metabolomic analysis revealed 395 differentially expressed metabolites. Additionally, MY treatment significantly increased the succinate dehydrogenase and muscle glycogen contents in the muscle caused by OA (p > 0.05). Finally, AMPK, Tfam, Myod, Ldh, Chrna1, Chrnd, Rapsyn, and Agrin were significantly downregulated in the muscles of OA mice, whereas Lcad, Mcad, and IL-1β were upregulated; MY significantly reversed these trends induced by OA.

Conclusions: MY may promote the repair of joint damage and protect against OA via the gut-muscle-joint axis.

Effect of Clostridium butyricum on Gastrointestinal Infections

Clostridium butyricum is a human commensal bacterium with beneficial effects including butyrate production, spore formation, increasing levels of beneficial bacteria, and inhibition of pathogenic bacteria. Owing to its preventive and ameliorative effects on gastrointestinal infections, C. butyricum MIYAIRI 588 (CBM 588) has been used as a probiotic in clinical and veterinary medicine for decades. This review summarizes the effects of C. butyricum, including CBM 588, on bacterial gastrointestinal infections. Further, the characteristics of the causative bacteria, examples of clinical and veterinary use, and mechanisms exploited in basic research are presented. C. butyricum is widely effective against Clostoridioides difficile, the causative pathogen of nosocomial infections; Helicobacter pylori, the causative pathogen of gastric cancer; and antibiotic-resistant Escherichia coli. Accordingly, its mechanism is gradually being elucidated. As C. butyricum is effective against gastrointestinal infections caused by antibiotics-induced dysbiosis, it can inhibit the transmission of antibiotic-resistant genes and maintain homeostasis of the gut microbiome. Altogether, C. butyricum is expected to be one of the antimicrobial-resistance (AMR) countermeasures for the One-health approach.

Butyrate-producing human gut symbiont, Clostridium butyricum, and its role in health and disease

Clostridium butyricum is a butyrate-producing human gut symbiont that has been safely used as a probiotic for decades. C. butyricum strains have been investigated for potential protective or ameliorative effects in a wide range of human diseases, including gut-acquired infection, intestinal injury, irritable bowel syndrome, inflammatory bowel disease, neurodegenerative disease, metabolic disease, and colorectal cancer. In this review we summarize the studies on C. butyricum supplementation with special attention to proposed mechanisms for the associated health benefits and the supporting experimental evidence. These mechanisms center on molecular signals (especially butyrate) as well as immunological signals in the digestive system that cascade well beyond the gut to the liver, adipose tissue, brain, and more. The safety of probiotic C. butyricum strains appears well-established. We identify areas where additional human randomized controlled trials would provide valuable further data related to the strains' utility as an intervention.

Fermented rice bran supplementation ameliorates obesity via gut microbiota and metabolism modification in female mice

We investigated the effects of fermented rice bran (FRB) administration in two groups of C57BL/6J mice. The first group was fed with a high-fat diet, and the second group was fed with a high-fat diet supplemented with the FRB for 8 weeks. FRB supplementation suppressed the high-fat-induced weight gain and considerable alterations in the intestinal microbiota profile in the second group. Among 27 bacterial genera detected in the FRB, only Enterococcus, Lactobacillus, Bacteroides, Prevotella, and the unclassified family Peptostreptococcaceae were detected in mice feces. Their abundances were not particularly increased by FRB supplementation. The abundances of Enterococcus and the unclassified family Peptostreptococcaceae were even suppressed in the second group, suggesting that FRB supplementation didn’t cause an addition of beneficial microbiome but inhibit the proliferation of specific bacteria. Fecal succinic acid concentration was significantly decreased in the second group and highly correlated with the relative abundances of Turicibacter, Enterococcus, and the unclassified family Peptostreptococcaceae. A significant increase in fumaric acid and a decrease in xylitol, sorbitol, uracil, glutamic acid, and malic acid levels were observed in the peripheral blood of the second group. FRB supplementation counteracted the high-fat-induced obesity in mice by modulating the gut microbiota and the host metabolism.

Clostridium butyricum enhances colonization resistance against Clostridioides difficile by metabolic and immune modulation

Clostridioides difficile infection (CDI) represents the leading cause of nosocomial diarrhea worldwide and is associated with gut dysbiosis and intestinal damage. Clostridium butyricum MIYAIRI 588 (CBM 588) contributes significantly to reduce epithelial damage. However, the impacts of CBM 588 on antibacterial therapy for CDI are not clear. Here we show that CBM 588 enhanced the antibacterial activity of fidaxomicin against C. difficile and negatively modulated gut succinate levels to prevent C. difficile proliferation and downregulate tumor necrosis factor-α (TNF-α) producing macrophages in the colon lumina propria (cLP), resulting in a significant decrease in colon epithelial damage. Additionally, CBM 588 upregulated T cell-dependent pathogen specific immunoglobulin A (IgA) via interleukin (IL)-17A producing CD4⁺ cells and plasma B cells in the cLP, and Th17 cells in the cLP enhanced the gut epithelial barrier function. IL-17A and succinic acid modulations with CBM 588 enhance gut colonization resistance to C. difficile and protect the colon tissue from CDI.

Dietary Supplementation With Xylo-oligosaccharides Modifies the Intestinal Epithelial Morphology, Barrier Function and the Fecal Microbiota Composition and Activity in Weaned Piglets

The present study determined the effects of dietary xylo-oligosaccharides (XOS) supplementation on the morphology of jejunum and ileum epithelium, fecal microbiota composition, metabolic activity, and expression of genes related to colon barrier function. A total of 150 piglets were randomly assigned to one of five groups: a blank control group (receiving a basal diet), three XOS groups (receiving the basal diet supplemented with 100, 250, and 500 g/t XOS, respectively), as well as a positive control group, used as a matter of comparison, that received the basal diet supplemented with 0.04 kg/t virginiamycin, 0.2 kg/t colistin, and 3,000 mg/kg ZnO. The trial was carried out for 56 days. The results showed that the lowest dose tested (100 g/t XOS) increased (P < 0.05) the ileal villus height, the relative amount of Lactobacillus and Bifidobacterium spp., and the concentration of acetic acid and short-chain fatty acid in feces when compared with the blank control group. In conclusion, dietary 100 g/t XOS supplementation modifies the intestinal ecosystem in weaned piglets in an apparently overall beneficial way.

Short-chain fatty acids-producing probiotics: A novel source of psychobiotics

Psychobiotics-live microorganisms with potential mental health benefits, which can modulate the microbiota-gut-brain-axis via immune, humoral, neural, and metabolic pathways-are emerging as novel therapeutic options for the effective treatment of psychiatric disorders Recently, microbiome studies have identified numerous putative psychobiotic strains, of which short-chain fatty acids (SCFAs) producing bacteria have attracted special attention from neurobiologists. Recent studies have highlighted that SCFAs-producing bacteria such as Lactobacillus, Bifidobacterium and Clostridium have a very specific function in various psychiatric disorders, suggesting that these bacteria can be potential novel psychobiotics. SCFAs, potential mediators of microbiota-gut-brain axis, might modulate function of neurological processes. While the specific roles and mechanisms of SCFAs-producing bacteria of microbiota-targeted interventions on neuropsychiatric disease are largely unknown. This Review summarizes existing knowledge on the neuroprotective effects of the SCFAs-producing bacteria in neurological disorders via modulating microbiota-gut-brain axis and illustrate their possible mechanisms by which SCFAs-producing bacteria may act on these disorders, which will shed light on the SCFAs-producing bacteria as a promising novel source of psychobiotics.

Next-generation probiotics: a promising approach towards designing personalized medicine

Second brain, forgotten organ, individual's identity card, and host's fingerprint are the few collective terms that are often used to describe the gut microbiome because of its variability, accountability, and its role in deciding the host's health. Also, the understanding of this host health-gut microbiota relationship can create an opportunity to control an individual's health by manipulating the gut microbiota composition. Several approaches like administration of probiotic, prebiotics, synbiotics, faecal microbiota transplantation have been tried to mitigate the dysbiosis originated ill effects. But the effects of these approaches are highly generic and non-specific. This creates the necessity to design personalized medicine that focuses on treatment of specific disease considering the individual specific gut microbiome. The health promoting commensals could be the new promising prophylactic and therapeutic agents for designing personalized medicine. These commensals are designated as next-generation probiotics (NGPs) and their unusual characteristics, unknown identity and special growth requirements have presented difficulties for researcher, industrial exploitation, and regulatory agencies. In this perspective, this review discusses the concept of NGPs, NGP candidates as tool for designing personalized medicine, designer probiotics as NGPs, required regulatory framework, and propose a road map to develop the NGP based product.

Systematic Evaluation of Parameters Important for Production of Native Toxin A and Toxin B from Clostridioides difficile

In the attempt to improve the purification yield of native toxin A (TcdA) and toxin B (TcdB) from Clostridioides difficile (C. difficile), we systematically evaluated culture parameters for their influence on toxin production. In this study, we showed that culturing C. difficile in a tryptone-yeast extract medium buffered in PBS (pH 7.5) that contained 5 mM ZnCl₂ and 10 mM glucose supported the highest TcdB production, measured by the sandwich ELISA. These culture conditions were scalable into 5 L and 15 L dialysis tube cultures, and we were able to reach a TcdB concentration of 29.5 µg/mL of culture. Furthermore, we established a purification protocol for TcdA and TcdB using FPLC column chromatography, reaching purities of >99% for both toxins with a yield around 25% relative to the starting material. Finally, by screening the melting temperatures of TcdA and TcdB in various buffer conditions using differential scanning fluorimetry, we found optimal conditions for improving the protein stability during storage. The results of this study present a complete protocol for obtaining high amounts of highly purified native TcdA and TcdB from C. difficile.

The Butyrate-Producing Bacterium Clostridium butyricum Suppresses Clostridioides difficile Infection via Neutrophil- and Antimicrobial Cytokine-Dependent but GPR43/109a-Independent Mechanisms

Short-chain fatty acids, such as butyrate, are major gut microbial metabolites that are beneficial for gastrointestinal health. Clostridium butyricum MIYAIRI588 (CBM588) is a bacterium that produces a robust amount of butyrate and therefore has been used as a live biotherapeutic probiotic in clinical settings. Clostridioides difficile causes life-threatening diarrhea and colitis. The gut resident microbiota plays a critical role in the prevention of C. difficile infection (CDI), as the disruption of the healthy microbiota by antibiotics greatly increases the risk for CDI. We report that CBM588 treatment in mice significantly improved clinical symptoms associated with CDI and increased the number of neutrophils and Th1 and Th17 cells in the colonic lamina propria in the early phase of CDI. The protective effect of CBM588 was abolished when neutrophils, IFN-γ, or IL-17A were depleted, suggesting that induction of the immune reactants is required to elicit the protective effect of the probiotic. The administration of tributyrin, which elevates the concentration of butyrate in the colon, also increased the number of neutrophils in the colonic lamina propria, indicating that butyrate is a potent booster of neutrophil activity during infection. However, GPR43 and GPR109a, two G protein-coupled receptors activated by butyrate, were dispensable for the protective effect of CBM588. These results indicate that CBM588 and butyrate suppress CDI, in part by boosting antimicrobial innate and cytokine-mediated immunity.

Effects of Dietary Supplementation with Clostridium butyricum on Growth Performance, Serum Immunity, Intestinal Morphology, and Microbiota as an Antibiotic Alternative in Weaned Piglets

This study investigated the effects of Clostridium butyricum (C. butyricum) use on growth performance, serum immunity, intestinal morphology, and microbiota as an antibiotic alternative in weaned piglets. Over the course of 28 days, 120 piglets were allocated to four treatments with six replicates of five piglets each. The treatments were: CON (basal diet); AGP (basal diet supplemented with 0.075 g/kg chlortetracycline, 0.055 g/kg kitasamycin, and 0.01 g/kg virginiamycin); CBN (basal diet supplemented with normal dosage of 2.5 × 10⁸ CFU/kg C. butyricum); and CBH (basal diet supplemented with high dosage of 2.5 × 10⁹ CFU/kg C. butyricum). Body weight (BW) and feed consumption were recorded at the beginning and on days 14 and 28 of the experiment, and representative feed samples and fresh feces were collected from each pen between days 26 and 28. Average fecal score of diarrhea was visually assessed each morning during the experimental period. On the morning of days 14 and 28, blood samples were collected to prepare serum for immune and antioxidant parameters measurement. One male piglet close to the average group BW was selected from each replicate and was slaughtered on day 21 of the experiment. Intestinal crypt villi, and colonic microbiota and its metabolites short-chain fatty acids were measured. Compared to the CON group, the CBN and AGP groups significantly decreased (p < 0.05) the ratio of feed to weight gain by 8.86% and 8.37% between days 1 and 14, 3.96% and 13.36% between days 15 and 28, 5.47% and 11.44% between days 1 and 28. Dietary treatment with C. butyricum and AGPs significantly decreased the average fecal score during the experimental period (p < 0.05). The apparent total tract digestibility of dry matter, organic matter, and total carbohydrates in the CBH group were higher respectively at 3.27%, 2.90%, and 2.97%, than those in the CON or AGP groups (p < 0.05). Compared to the CON group, the CBH group significantly increased short-chain fatty acids in colon and villus height in the jejunum (p < 0.05). The CBN group had higher serum levels of immunoglobulins, interleukin 2 (IL-2), and glutathione peroxidase (GSH-PX) activity, but lower serum levels of IL-1β and IL-6, and a lower aspartate aminotransferase (AST), alkaline phosphatase (ALP), and gamma-glutamyl transpeptidase (γ-GT) activity (p < 0.05), while compared to the CON group. Dietary treatment with C. butyricum significantly increased the relative abundance of Streptococcus and Bifidobacterium (p < 0.05). In summary, diet with C. butyricum increased the growth performance and benefited the health of weaned piglets.

Rapid in Vitro Assessment of Clostridioides difficile Inhibition by Probiotics Using Dielectrophoresis to Quantify Cell Structure Alterations

Clostridioides difficile (C. difficile) infection (CDI) is the primary cause of nosocomial antibiotic-associated diarrhea, with high recurrence rates following initial antibiotic treatment regimens. Restoration of the host gut microbiome through probiotic therapy is under investigation to reduce recurrence. Current in vitro methods to assess C. difficile deactivation by probiotic microorganisms are based on C. difficile growth inhibition, but the cumbersome and time-consuming nature of the assay limits the number of assessed permutations. Phenotypic alterations to the C. difficile cellular structure upon interaction with probiotics can potentially enable rapid assessment of the inhibition without the need for extended culture. Because supernatants from cultures of commensal microbiota reflect the complex metabolite milieu that deactivates C. difficile, we explore coculture of C. difficile with an optimal dose of supernatants from probiotic culture to speed growth inhibition assays and enable correlation with alterations to its prolate ellipsoidal structure. Based on sensitivity of electrical polarizability to C. difficile cell shape and subcellular structure, we show that the inhibitory effect of Lactobacillus spp. supernatants on C. difficile can be determined based on the positive dielectrophoresis level within just 1 h of culture using a highly toxigenic strain and a clinical isolate, whereas optical and growth inhibition measurements require far greater culture time. We envision application of this in vitro coculture model, in conjunction with dielectrophoresis, to rapidly screen for potential probiotic combinations for the treatment of recurrent CDI.

Bacteria producing antimicrobials against Clostridium difficile isolated from human stool

Clostridium difficile infection (CDI) is a common cause of morbidity and mortality in hospitalized patients worldwide. The major problem facing current treatment is multiple recurrences, prompting the need for alternative therapies. In this study we isolated bacterial species, from Egyptian individuals' stool, with antimicrobial activity against clinical isolates of C. difficile and tried to examine the nature of the produced antimicrobials. In vitro antibacterial activity against C. difficile was initially screened in 123 fecal samples cultures using an agar overlay method. The isolates with antimicrobial activity against C. difficile in addition to Clostridium isolates were identified using partial 16S rDNA gene sequencing analysis. The isolates acting against C. difficile belonged to Lactobacillus, Enterococcus and Clostridium genera. The concentrated cell-free supernatants (CFSs) from these bacterial isolates were examined for antimicrobial activity against C. difficile growth by broth dilution method. 10 x concentrated CFSs of five isolates showed inhibition for C. difficile growth which was significantly different (p < 0.001) from control. Lactobacillus agilis T99A and Clostridium butyricum T58A isolates were selected for further evaluation of the produced antimicrobials. The antimicrobial activity of 10x CFSs of the two isolates was stable after enzymatic treatment with proteinase K or heating treatments up to 90 °C or neutralizing pH. The spectrum of activity of the two isolates was evaluated using different gram-positive and gram-negative bacterial species and did not show antimicrobial activity against these species. Our results showed two unconventional bacterial isolates: L. agilis T99A and C. butyricum T58A producing extracellular thermo stable antimicrobial agents against C. difficile clinical isolates.

The gut microbiome diversity of Clostridioides difficile-inoculated mice treated with vancomycin and fidaxomicin

OBJECTIVE

To investigate the effect of vancomycin and fidaxomicin on the diversity of intestinal microbiota in a mouse model of Clostridioides difficile infection.

METHODS

Mice were divided into 11 models (4 mice per model): 6 uninoculated models and 5 models inoculated with C. difficile BI/NAP1/027. Inoculated models were prepared using intraperitoneal clindamycin followed by inoculation with C. difficile BI/NAP1/027. Uninoculated and C. difficile-inoculated mice received 2 or 7 days' vancomycin or fidaxomicin. Clostridium butyricum MIYAIRI 588 probiotic and lactoferrin prebiotic were administered for 10 days to uninoculated mice. Intestinal microbiome composition was investigated by sequence analyses of bacterial 16S rRNA genes from faeces, and microbiota diversity estimated.

RESULTS

In uninoculated, untreated ('normal') mice, Clostridia (57.8%) and Bacteroidia (32.4%) accounted for the largest proportions of gut microbiota. The proportion of Clostridia was numerically reduced in C. difficile-inoculated versus normal mice. Administration of vancomycin to C. difficile-inoculated mice reduced the proportions of Bacteroidia and Clostridia, and increased that of Proteobacteria. Administration of fidaxomicin to C. difficile-inoculated mice reduced the proportion of Clostridia to a lesser extent, but increased that of Bacteroidia. Microbiota diversity was lower in C. difficile-inoculated versus normal mice (164.5 versus 349.1 operational taxonomic units (OTUs), respectively); treatment of C. difficile-inoculated mice with 7 days' vancomycin reduced diversity to a greater extent than did 7 days' fidaxomicin treatment (26.2 versus 134.2 OTUs, respectively).

CONCLUSIONS

Both C. difficile inoculation and treatment with vancomycin or fidaxomicin reduced microbiota diversity; however, dysbiosis associated with fidaxomicin was milder than with vancomycin.

Recent Advancements in the Development of Modern Probiotics for Restoring Human Gut Microbiome Dysbiosis

A healthy gut is predominantly occupied by bacteria which play a vital role in nutrition and health. Any change in normal gut homeostasis imposes gut dysbiosis. So far, efforts have been made to mitigate the gastrointestinal symptoms using modern day probiotics. The majority of the probiotics strains used currently belong to the genera Lactobacillus, Clostridium, Bifidobacterium and Streptococcus. Recent advancements in culturomics by implementing newer techniques coupled with the use of gnotobiotic animal models provide a subtle ground to develop novel host specific probiotics therapies. In this review article, the recent advances in the development of microbe-based therapies which can now be implemented to treat a wide spectrum of diseases have been discussed. However, these probiotics are not classified as drugs and there is a lack of stringent law enforcement to protect the end users against the pseudo-probiotic products. While modern probiotics hold strong promise for the future, more rigorous regulations are needed to develop genuine probiotic products and characterize novel probiotics using the latest research and technology. This article also highlights the possibility of reducing antibiotic usage by utilizing probiotics developed using the latest concepts of syn and ecobiotics.

Optimization of pH conditions to improve the spore production of Clostridium butyricum NN-2 during fermentation process

Clostridium butyricum, an anaerobic spore-forming bacillus, is a common human and animal gut commensal bacterium. Spore is an important structure for C. butyricum to tolerate environmental stress. However, it is not easy to form in common fermentation process of C. butyricum. In this study, the parameters for optimizing the spore formation of C. butyricum NN-2 were defined. The results showed that the pH value was a crucial factor that significantly affected the spore formation of C. butyricum NN-2. Down-regulation steps of pH value from 6.5 to 5.5 over time during the cultural process significantly (p < 0.05) promoted spore formation of C. butyricum NN-2, allowing for the sporulation rate of > 90%. In addition, the duration of pH regulation also had significant effects on the spore formation of C. butyricum NN-2. The results revealed a highly effective strategy for enhancing the spore production of C. butyricum.

The Impact of pH on Clostridioides difficile Sporulation and Physiology

Clostridioides difficile is a pathogenic bacterium that infects the human colon to cause diarrheal disease. Growth of the bacterium is known to be dependent on certain bile acids, oxygen levels, and nutrient availability in the intestine, but how the environmental pH can influence C. difficile is mostly unknown. Previous studies indicated that C. difficile modulates the intestinal pH, and prospective cohort studies have found a strong association between a more alkaline fecal pH and C. difficile infection. Based on these data, we hypothesized that C. difficile physiology can be affected by various pH conditions. In this study, we investigated the impact of a range of pH conditions on C. difficile to assess potential effects on growth, sporulation, motility, and toxin production in the strains 630Δerm and R20291. We observed pH-dependent differences in sporulation rate, spore morphology, and viability. Sporulation frequency was lowest under acidic conditions, and differences in cell morphology were apparent at low pH. In alkaline environments, C. difficile sporulation was greater for strain 630Δerm, whereas R20291 produced relatively high levels of spores in a broad range of pH conditions. Rapid changes in pH during exponential growth impacted sporulation similarly among the strains. Furthermore, we observed an increase in C. difficile motility with increases in pH, and strain-dependent differences in toxin production under acidic conditions. The data demonstrate that pH is an important parameter that affects C. difficile physiology and may reveal relevant insights into the growth and dissemination of this pathogen.IMPORTANCE Clostridioides difficile is an anaerobic bacterium that causes gastrointestinal disease. C. difficile forms dormant spores which can survive harsh environmental conditions, allowing their spread to new hosts. In this study, we determine how intestinally relevant pH conditions impact C. difficile physiology in the two divergent strains, 630Δerm and R20291. Our data demonstrate that low pH conditions reduce C. difficile growth, sporulation, and motility. However, toxin production and spore morphology were differentially impacted in the two strains at low pH. In addition, we observed that alkaline environments reduce C. difficile growth, but increase cell motility. When pH was adjusted rapidly during growth, we observed similar impacts on both strains. This study provides new insights into the phenotypic diversity of C. difficile grown under diverse pH conditions present in the intestinal tract, and demonstrates similarities and differences in the pH responses of different C. difficile isolates.

The effect of preoperative synbiotic treatment to prevent surgical-site infection in hepatic resection

We aimed to clarify the influence of preoperative synbiotic therapy on surgical-site infections (SSIs) after hepatic resection. Between January 2011 and December 2017, 284 patients who underwent hepatic resection without biliary tract reconstruction and resection of other organs were included. We prospectively administered Clostridium butyricum and partially hydrolyzed guar gum before hepatic resection between April 2016 and December 2017 (synbiotic group). One-hundred-fifteen patients of the synbiotic group and 169 patients (conventional group) treated between January 2011 and the end of March 2016 were compared using propensity score matching. The frequency of laparoscopic resection was significantly larger in the synbiotic group (conventional group; 28% vs synbiotic group; 55%, p<0.001) and the amount of intraoperative bleeding was significantly smaller in the synbiotic group (median; conventional group, 700 ml vs synbiotic group, 200 ml; p<0.001). The postoperative SSI was significantly lower in the synbiotic group of six patients (5.2%) than in the conventional group of 30 patients (17.8%) (p = 0.002). Sixty patients in each group remained after propensity score matching. There was no significant difference in the incidence of SSI between the groups (conventional group, 15% vs synbiotic group, 6.7%; p = 0.239). In conclusion, preoperative synbiotic treatment did not reduce SSIs after hepatic resection.

Antimicrobial production by strictly anaerobic Clostridium spp

Antimicrobial resistance continues to rise on a global scale, affecting the environment, humans, animals and food systems. Use of natural antimicrobials has been favoured over synthetic molecules in food preservation owing to concerns over the adverse health effects of synthetic chemicals. The continuing need for novel natural antimicrobial compounds has spurred research to investigate natural sources, such as bacteria, for antimicrobials. The antimicrobial-producing potential of bacteria has been investigated in numerous studies. However, the discovery of antimicrobials has been biased towards aerobes and facultative anaerobes, and strict anaerobes such as Clostridium spp. have been largely neglected. In recent years, genomic studies have indicated the genetic potential of strict anaerobes to produce putative bioactive molecules and this has encouraged the exploration of Clostridium spp. for their antimicrobial production. So far, only a limited number of antimicrobial compounds have been isolated, identified and characterised from the genus Clostridium. This review discusses our current knowledge and understanding of clostridial antimicrobial compounds as well as recent genome mining studies of Clostridium spp. focused at identification of putative gene clusters encoding bacterial secondary metabolite groups and peptides reported to possess antimicrobial properties. Furthermore, opportunities and challenges in the identification of antimicrobials from Clostridium spp. using genomic-guided approaches are discussed. The limited studies conducted so far have identified the genus Clostridium as a viable source of antimicrobial compounds for future investigations.

Adult Intestinal Toxemia Botulism

Intoxication with botulinum neurotoxin can occur through various routes. Foodborne botulism results after consumption of food in which botulinum neurotoxin-producing clostridia (i.e., Clostridium botulinum or strains of Clostridiumbutyricum type E or Clostridiumbaratii type F) have replicated and produced botulinum neurotoxin. Infection of a wound with C. botulinum and in situ production of botulinum neurotoxin leads to wound botulism. Colonization of the intestine by neurotoxigenic clostridia, with consequent production of botulinum toxin in the intestine, leads to intestinal toxemia botulism. When this occurs in an infant, it is referred to as infant botulism, whereas in adults or children over 1 year of age, it is intestinal colonization botulism. Predisposing factors for intestinal colonization in children or adults include previous bowel or gastric surgery, anatomical bowel abnormalities, Crohn's disease, inflammatory bowel disease, antimicrobial therapy, or foodborne botulism. Intestinal colonization botulism is confirmed by detection of botulinum toxin in serum and/or stool, or isolation of neurotoxigenic clostridia from the stool, without finding a toxic food. Shedding of neurotoxigenic clostridia in the stool may occur for a period of several weeks. Adult intestinal botulism occurs as isolated cases, and may go undiagnosed, contributing to the low reported incidence of this rare disease.

Integrated Counts of Carbohydrate-Active Protein Domains as Metabolic Readouts to Distinguish Probiotic Biology and Human Fecal Metagenomes

Bowel microbiota is a "metaorgan" of metabolisms on which quantitative readouts must be performed before interventions can be introduced and evaluated. The study of the effects of probiotic Clostridium butyricum MIYAIRI 588 (CBM588) on intestine transplantees indicated an increased percentage of the "other glycan degradation" pathway in 16S-rRNA-inferred metagenomes. To verify the prediction, a scoring system of carbohydrate metabolisms derived from shotgun metagenomes was developed using hidden Markov models. A significant correlation (R = 0.9, p < 0.015) between both modalities was demonstrated. An independent validation revealed a strong complementarity (R = -0.97, p < 0.002) between the scores and the abundance of "glycogen degradation" in bacteria communities. On applying the system to bacteria genomes, CBM588 had only 1 match and ranked higher than the other 8 bacteria evaluated. The gram-stain properties were significantly correlated to the scores (p < 5 × 10^-4). The distributions of the scored protein domains indicated that CBM588 had a considerably higher (p < 10^-5) proportion of carbohydrate-binding modules than other bacteria, which suggested the superior ability of CBM588 to access carbohydrates as a metabolic driver to the bowel microbiome. These results demonstrated the use of integrated counts of protein domains as a feasible readout for metabolic potential within bacteria genomes and human metagenomes.

The effect of gut microbiota and probiotic organisms on the properties of extended spectrum beta-lactamase producing and carbapenem resistant Enterobacteriaceae including growth, beta-lactamase activity and gene transmissibility

The gut microbiota may play a pivotal role in controlling the antimicrobial resistant (AMR) organisms although the evidences are limited. We investigated the effects of gut microbiota on the growth of AMR organisms, β-lactamases activity and transmissibility of antimicrobial resistant properties of the extended spectrum β-lactamase (ESBL)-producing Escherichia coli and carbapenem-resistant Enterobacteriaceae. CTX-M-15-positive, ESBL-producing E. coli and carbapenem resistant Enterobacteriaceae, Bacteroides fragilis, Bifidobacterium longum, Clostridium butyricum, Clostridioides difficile, Clostridium perfringens, Enterococcus faecium, Lactobacillus plantarum and probiotic strain of C. butyricum MIYAIRI 588 were used in this study. The growth of AMR organisms was suppressed by the supernatant of C. butyricum, C. difficile, C. perfringens, E. faecium and L. plantarum in a dose dependent manner but not by that of B. fragilis and B. longum. The β-lactamase activity produced by E. coli was reduced by the presence of culture supernatant of certain gut microbiota during stationary phase of E. coli. Importantly, C. butyricum MIYAIRI 588 culture supernatant suppressed the transcription of bla_CTX-M gene during growth phase of E. coli. The conjugation assay showed the reduction of transmissibility of antibiotic resistant gene by gut microbiota. These findings suggest that certain gut microbiota affect the antibiotic resistant activities of AMR organisms. Further studies are needed to identify the specific mechanism(s) of these actions between AMR organisms and gut microbiota.

Editing the microbiome the CRISPR way

Our bodies are colonized by a complex ecosystem of bacteria, unicellular eukaryotes and their viruses that together play a major role in our health. Over the past few years tools derived from the prokaryotic immune system known as CRISPR-Cas have empowered researchers to modify and study organisms with unprecedented ease and efficiency. Here we discuss how various types of CRISPR-Cas systems can be used to modify the genome of gut microorganisms and bacteriophages. CRISPR-Cas systems can also be delivered to bacterial population and programmed to specifically eliminate members of the microbiome. Finally, engineered CRISPR-Cas systems can be used to control gene expression and modulate the production of metabolites and proteins. Together these tools provide exciting opportunities to investigate the complex interplay between members of the microbiome and our bodies, and present new avenues for the development of drugs that target the microbiome. This article is part of a discussion meeting issue 'The ecology and evolution of prokaryotic CRISPR-Cas adaptive immune systems'.

Effects of dietary supplementation with Clostridium butyricum on laying performance, egg quality, serum parameters, and cecal microflora of laying hens in the late phase of production

This experiment was conducted to evaluate the effects of dietary supplementation with Clostridium butyricum on laying performance, egg quality, serum parameters, and cecal microflora of laying hens in the late phase of production. Jinghong-1 strain laying hens (n = 960; 48 wk of age) were randomly allocated to 5 treatment groups with 6 replicates of 32 hens. Hens were fed with basal diet (control) and basal diet supplemented with 2.5 × 104 (CB1), 5 × 104 (CB2), 1 × 105 (CB3), and 2 × 105 (CB4) cfu/g C. butyricum for 10 wk. The results showed that egg production, egg mass, and eggshell strength increased quadratically as supplemental C. butyricum increased, and these responses were maximized in the CB2 group (P < 0.05). Compared with the control group, the addition of C. butyricum resulted in quadratic effects on serum total protein, uric acid, calcium, complement component C3 and catalase concentrations, and these responses were maximized or minimized in the CB2 group (P < 0.05). Linear and quadratic increases were observed in serum IgM, total superoxide dismutase, and glutathione peroxidase concentrations, and these responses were maximized in CB2 or CB3 group (P < 0.05). The addition of C. butyricum in the CB2 group resulted in linearly increasing levels of serum IgG concentration as compared with the control group (P < 0.05). Spleen index increased (P < 0.05) in the CB2 group. Hens fed with C. butyricum reduced (P > 0.05) the population of E. coli, while Bifidobacterium counts increased quadratically and maximized in the CB2 group (P < 0.05). In conclusion, the results indicated that dietary supplementation with C. butyricum (5 × 104 or 1 × 105 cfu/g) could improve laying performance and egg quality by promoting immune function, enhancing antioxidative capacity, and benefiting the cecal microflora of laying hens in the late phase of production.

Clostridium butyricum MIYAIRI 588 Increases the Lifespan and Multiple-Stress Resistance of Caenorhabditis elegans

Clostridium butyricum MIYAIRI 588 (CBM 588), one of the probiotic bacterial strains used for humans and domestic animals, has been reported to exert a variety of beneficial health effects. The effect of this probiotic on lifespan, however, is unknown. In the present study, we investigated the effect of CBM 588 on lifespan and multiple-stress resistance using Caenorhabditis elegans as a model animal. When adult C. elegans were fed a standard diet of Escherichia coli OP50 or CBM 588, the lifespan of the animals fed CBM 588 was significantly longer than that of animals fed OP50. In addition, the animals fed CBM588 exhibited higher locomotion at every age tested. Moreover, the worms fed CBM 588 were more resistant to certain stressors, including infections with pathogenic bacteria, UV irradiation, and the metal stressor Cu²⁺. CBM 588 failed to extend the lifespan of the daf-2/insulin-like receptor, daf-16/FOXO and skn-1/Nrf2 mutants. In conclusion, CBM 588 extends the lifespan of C. elegans probably through regulation of the insulin/IGF-1 signaling (IIS) pathway and the Nrf2 transcription factor, and CBM 588 improves resistance to several stressors in C. elegans.

Association between Clostridioides difficile ribotypes, restriction endonuclease analysis types, and toxin gene expression

OBJECTIVES

Clostridioides difficile strains cause severe infection. Previous studies suggested that the virulence of C. difficile is dependent on ribotype; however, this hypothesis is still controversial. We aim to investigate the relationship between ribotypes, restriction endonuclease analysis (REA) types, and toxin gene expression in C. difficile strains.

METHODS

We utilized 53 clinical C. difficile strains. All strains were assigned a molecular strain type using PCR ribotyping and REA typing and classified into 17 ribotypes and six REA types. The expression of toxin genes (tcdA, tcdB, and cdtB) in C. difficile strains were quantified by real-time PCR using each specific primer set, and expression was normalized to that of the housekeeping gene rpoA.

RESULTS

All 53 strains expressed tcdB and four strains expressed cdtB. Five strains did not express tcdA. Most ribotype and REA type strains expressed tcdA and tcdB similar to the BAA-1870 strain. In cdtB-positive strains, the cdtB expression levels were similar to those in the BAA-1870 strain. tcdA and tcdB expression levels were similar in the cdtB-positive and cdtB-negative strains.

CONCLUSION

Toxin gene expression was not associated with the ribotype. Production of binary toxin C. difficile transferase was not related to tcdA and tcdB expression levels.

Establishment of an Endogenous Clostridium difficile Rat Infection Model and Evaluation of the Effects of Clostridium butyricum MIYAIRI 588 Probiotic Strain

Clostridium difficile is well known as an agent responsible for pseudomembranous colitis and antibiotic-associated diarrhea. The hamster model utilizing an oral route for infection of C. difficile has been considered to be the standard model for analysis of C. difficile infection (CDI) but this model exhibits differences to human CDI, most notably as most hamsters die without exhibiting diarrhea. Therefore, we attempted to develop a new non-lethal and diarrheal rat CDI model caused by endogenous C. difficile using metronidazole (MNZ) and egg white. In addition, the effects of probiotic strain Clostridium butyricum MIYAIRI 588 (CBM) on CDI were examined using this model. Syrian Golden hamsters received clindamycin phosphate orally at 30 mg/kg on 5 days before challenge with either C. difficile VPI10463 (hypertoxigenic strain) or KY34 (low toxigenic clinical isolate). Mortality and the presence of diarrhea were observed twice a day for the duration of the experiment. Wistar rats received 10% egg white dissolved in drinking water for 1 week ad libitum following intramuscular administration of 200 mg/kg MNZ twice a day for 3 days. Diarrhea score was determined for each day and fecal water content, biotin concentration, and cytotoxin titer in feces were examined. More than 70% of hamsters orally infected with C. difficile died without exhibiting diarrhea regardless of toxigenicity of strain. The rats receiving egg white after MNZ administration developed diarrhea due to overgrowth of endogenous C. difficile. This CDI model is non-lethal and diarrheal, and some rats in this model were spontaneously cured. The incidence of diarrhea was significantly decreased in C. butyricum treated rats. These results indicate that the CDI model using egg white and MNZ has potentially better similarity to human CDI, and implies that treatment with C. butyricum may reduce the risk of CDI.

Necrotizing enterocolitis associated with Clostridium butyricum in a Japanese man

Case

Necrotizing enterocolitis (NEC) caused by Clostridium butyricum is common in neonates; however, a case of NEC in adults has not been previously reported. An 84‐year‐old Japanese man developed C. butyricum‐related NEC during hospitalization for treatment of stab wounds to the left side of the neck and lower abdomen, without organ damage, and concomitant pneumonia.

Outcome

The patient developed acute onset of emesis accompanied by shock during his admission; partial resection of the small intestine was carried out due to necrosis. Pathologic findings showed mucosal necrosis and extensive vacuolation with gram‐positive rods in the necrotic small intestine. Blood culture tests revealed C. butyricum infection. The patient's condition improved after the surgery. He was moved to a rehabilitation hospital on day 66.

Conclusion

This study suggests that hospitalized adult patients who receive antibiotic treatment are at risk for NEC.

Hospital-acquired Clostridium difficile infection in Mainland China: A seven-year (2009-2016) retrospective study in a large university hospital

Clostridium difficile infection (CDI) is associated with risk for severe disease and high mortality. Little is known about the extent of hospital-acquired CDI in Mainland China. In this study, we aimed to investigate the annual CDI incidence, bacterial genotypes, risk factors for severe CDI and survival over a 7-year period. A total of 307 hospital-acquired CDI patients were enrolled, and 70.7% of these cases were male. CDI incidence was 3.4 per 10,000 admissions. Thirty-three different sequence types (STs) were identified, among which ST-54 (18.2%), ST-35 (16.6%) and ST-37 (12.1%) were the most prevalent. During the follow-up period, 66 (21.5%) patients developed severe CDI and 32 (10.4%) patients died in 30 days. Multivariate analysis revealed that bloodstream infection, pulmonary infection and C-reactive protein were significantly associated with severe CDI. After adjustment for potential confounders, old age, bloodstream infection, fever, mechanical ventilation, connective tissue disease, macrolide use and hypoalbuminaemia were independently associated with 30-day mortality in patients with CDI. The CDI prevalence has been low and stable in our center, and STs of Clostridium difficile were different from dominant STs in Western countries. Our data emphasize the need of continued education and surveillance of CDI to reduce the CDI burden in China.

Next-generation probiotics: the spectrum from probiotics to live biotherapeutics

The leading probiotics currently available to consumers are generally drawn from a narrow range of organisms. Knowledge of the gut microbiota and its constituent actors is changing this paradigm, particularly given the phylogenetic range and relatively unknown characteristics of the organisms under investigation as novel therapeutics. For this reason, and because their development is likely to be more amenable to a pharmaceutical than a food delivery route, these organisms are often operationally referred to as next-generation probiotics, a concept that overlaps with the emerging concept of live biotherapeutic products. The latter is a class of organisms developed exclusively for pharmaceutical application. In this Perspective, we discuss what lessons have been learned from working with traditional probiotics, explore the kinds of organisms that are likely to be used as novel microbial therapeutics, discuss the regulatory framework required, and propose how scientists may meet this challenge.

Three New Lactobacillus plantarum Strains in the Probiotic Toolbox against Gut Pathogen Salmonella enterica Serotype Typhimurium

The benefits of probiotic bacteria have been widely explored. However, fermented foods and digestive system of humans and animals are an inexhaustible source of new potentially probiotic microorganisms. In this study we present three new Lactobacillus plantarum strains isolated from different dairy products: cow's cheese, sheep's cheese and whey. In order to determine the antibacterial activity of yet unexplored L. plantarum strains against Salmonella enterica serotype Typhimurium, in vitro competition and co-culture tests were done. Furthermore, adhesion of these strains to Caco-2 cells and their influence on the adhesion of Salmonella were tested. Results showed the potential probiotic activity of isolated strains. L. plantarum strains survived in the presence of 1% bile salts, they possessed acidification ability, antibacterial activity and significantly attenuated the growth of S. Typhimurium in brain heart infusion broth. All tested L. plantarum strains were able to adhere to Caco-2 cells and significantly impair the adhesion of S. Typhimurium. All three L. plantarum strains exhibited significant probiotic potential and anti-Salmonella activity; therefore, further testing on in vivo models should follow.

Tracking Inhibitory Alterations during Interstrain Clostridium difficile Interactions by Monitoring Cell Envelope Capacitance

Global threats arising from the increasing use of antibiotics coupled with the high recurrence rates of Clostridium difficile (C. difficile) infections (CDI) after standard antibiotic treatments highlight the role of commensal probiotic microorganisms, including nontoxigenic C. difficile (NTCD) strains in preventing CDI due to highly toxigenic C. difficile (HTCD) strains. However, optimization of the inhibitory permutations due to commensal interactions in the microbiota requires probes capable of monitoring phenotypic alterations to C. difficile cells. Herein, by monitoring the field screening behavior of the C. difficile cell envelope with respect to cytoplasmic polarization, we demonstrate that inhibition of the host-cell colonization ability of HTCD due to the S-layer alterations occurring after its co-culture with NTCD can be quantitatively tracked on the basis of the capacitance of the cell envelope of co-cultured HTCD. Furthermore, it is shown that effective inhibition requires the dynamic contact of HTCD cells with freshly secreted extracellular factors from NTCD because contact with the cell-free supernatant causes only mild inhibition. We envision a rapid method for screening the inhibitory permutations to arrest C. difficile colonization by routinely probing alterations in the HTCD dielectrophoretic frequency response due to variations in the capacitance of its cell envelope.