scholarly journals C. difficile-associated antibiotics prime the host for infection by a microbiome-independent mechanism

2019 ◽  
Author(s):  
Jemila C. Kester ◽  
Douglas K. Brubaker ◽  
Jason Velazquez ◽  
Charles Wright ◽  
Douglas A. Lauffenburger ◽  
...  
Keyword(s):  
Innate Immune ◽  
Mucosal Barrier ◽  
Human Gut ◽  
Germ Free ◽  
Clostridioides Difficile ◽  
Increased Risk ◽  
Independent Mechanism ◽  
Relevant Risk Factor ◽  
Independent Effects

AbstractThe most clinically relevant risk factor for Clostridioides difficile-associated disease (CDAD) is recent antibiotic treatment. Though most broad-spectrum antibiotics significantly disrupt the structure of the gut microbiota, only particular ones increase CDAD risk, suggesting additional factors might increase the risk from certain antibiotics. Here we show that commensal-independent effects of antibiotics collectively prime an in vitro germ-free human gut for CDAD. We found a marked loss of mucosal barrier and immune function with CDAD-associated antibiotic pretreatment distinct from pretreatment with an antibiotic unassociated with CDAD, which did not reduce innate immune or mucosal barrier functions. Importantly, pretreatment with CDAD-associated antibiotics sensitized mucosal barriers to C. difficile toxin activity in primary cell-derived enteroid monolayers. These data implicate commensal-independent host changes in the increased risk of CDAD with specific antibiotics. Our findings are contrary to the previously held belief that antibiotics allow for CDAD solely through disruption of the microbiome. We anticipate this work to suggest potential avenues of research for host-directed treatment and preventive therapies for CDAD, and to impact human tissue culturing protocols.

scholarly journals Clostridioides difficile-Associated Antibiotics Alter Human Mucosal Barrier Functions by Microbiome-Independent Mechanisms

2020 ◽  
Vol 64 (4) ◽  
Author(s):  
Jemila C. Kester ◽  
Douglas K. Brubaker ◽  
Jason Velazquez ◽  
Charles Wright ◽  
Douglas A. Lauffenburger ◽  
...  
Keyword(s):  
Biological Effects ◽  
Human Colon ◽  
Mucosal Barrier ◽  
Barrier Functions ◽  
Content Type ◽  
Epithelial Culture ◽  
Clostridioides Difficile ◽  
Increased Risk

ABSTRACT A clinically relevant risk factor for Clostridioides difficile-associated disease (CDAD) is recent antibiotic treatment. Although broad-spectrum antibiotics have been shown to disrupt the structure of the gut microbiota, some antibiotics appear to increase CDAD risk without being highly active against intestinal anaerobes, suggesting direct nonantimicrobial effects. We examined cell biological effects of antibiotic exposure that may be involved in bacterial pathogenesis using an in vitro germfree human colon epithelial culture model. We found a marked loss of mucosal barrier and immune function with exposure to the CDAD-associated antibiotics clindamycin and ciprofloxacin, distinct from the results of pretreatment with an antibiotic unassociated with CDAD, tigecycline, which did not reduce innate immune or mucosal barrier functions. Importantly, pretreatment with CDAD-associated antibiotics sensitized mucosal barriers to C. difficile toxin activity in primary cell-derived enteroid monolayers. These data implicate commensal-independent gut mucosal barrier changes in the increased risk of CDAD with specific antibiotics and warrant further studies in in vivo systems. We anticipate this work to suggest potential avenues of research for host-directed treatment and preventive therapies for CDAD.

scholarly journals Ursodeoxycholic Acid (UDCA) Mitigates the Host Inflammatory Response during Clostridioides difficile Infection by Altering Gut Bile Acids

2020 ◽  
Vol 88 (6) ◽  
Author(s):  
Jenessa A. Winston ◽  
Alissa J. Rivera ◽  
Jingwei Cai ◽  
Rajani Thanissery ◽  
Stephanie A. Montgomery ◽  
...  
Keyword(s):  
Immune Response ◽  
Bile Acid ◽  
Inflammatory Response ◽  
Innate Immune Response ◽  
Innate Immune ◽  
Colonization Resistance ◽  
Content Type ◽  
Clostridioides Difficile

ABSTRACT Clostridioides difficile infection (CDI) is associated with increasing morbidity and mortality posing an urgent threat to public health. Recurrence of CDI after successful treatment with antibiotics is high, thus necessitating discovery of novel therapeutics against this enteric pathogen. Administration of the secondary bile acid ursodeoxycholic acid (UDCA; ursodiol) inhibits the life cycles of various strains of C. difficile in vitro, suggesting that the FDA-approved formulation of UDCA, known as ursodiol, may be able to restore colonization resistance against C. difficile in vivo. However, the mechanism(s) by which ursodiol is able to restore colonization resistance against C. difficile remains unknown. Here, we confirmed that ursodiol inhibits C. difficile R20291 spore germination and outgrowth, growth, and toxin activity in a dose-dependent manner in vitro. In a murine model of CDI, exogenous administration of ursodiol resulted in significant alterations in the bile acid metabolome with little to no changes in gut microbial community structure. Ursodiol pretreatment resulted in attenuation of CDI pathogenesis early in the course of disease, which coincided with alterations in the cecal and colonic inflammatory transcriptome, bile acid-activated receptors nuclear farnesoid X receptor (FXR) and transmembrane G-protein-coupled membrane receptor 5 (TGR5), which are able to modulate the innate immune response through signaling pathways such as NF-κB. Although ursodiol pretreatment did not result in a consistent decrease in the C. difficile life cycle in vivo, it was able to attenuate an overly robust inflammatory response that is detrimental to the host during CDI. Ursodiol remains a viable nonantibiotic treatment and/or prevention strategy against CDI. Likewise, modulation of the host innate immune response via bile acid-activated receptors FXR and TGR5 represents a new potential treatment strategy for patients with CDI.

scholarly journals Investigation of the effect of the adsorbent DAV131A on the propensity of moxifloxacin to induce simulated Clostridioides (Clostridium) difficile infection (CDI) in an in vitro human gut model

2020 ◽  
Vol 75 (6) ◽  
pp. 1458-1465
Author(s):  
C H Chilton ◽  
G S Crowther ◽  
C Miossec ◽  
J de Gunzburg ◽  
A Andremont ◽  
...  
Keyword(s):  
Limit Of Detection ◽  
Toxin Production ◽  
Human Gut ◽  
Antibiotic Resistant ◽  
Delayed Onset ◽  
Clostridioides Difficile ◽  
Clostridioides Difficile Infection ◽  
Clinical Benefits ◽  
Bacteroides Fragilis Group

Abstract Background Clostridioides difficile infection (CDI) remains a high burden worldwide. DAV131A, a novel adsorbent, reduces residual gut antimicrobial levels, reducing CDI risk in animal models. Objectives We used a validated human gut model to investigate the efficacy of DAV131A in preventing moxifloxacin-induced CDI. Methods C. difficile (CD) spores were inoculated into two models populated with pooled human faeces. Moxifloxacin was instilled (43 mg/L, once daily, 7 days) alongside DAV131A (5 g in 18 mL PBS, three times daily, 14 days, Model A), or PBS (18 mL, three times daily, 14 days, Model B). Selected gut microbiota populations, CD total counts, spore counts, cytotoxin titre and antimicrobial concentrations (HPLC) were monitored daily. We monitored for reduced susceptibility of CD to moxifloxacin. Growth of CD in faecal filtrate and medium in the presence/absence of DAV131A, or in medium pre-treated with DAV131A, was also investigated. Results DAV131A instillation reduced active moxifloxacin levels to below the limit of detection (50 ng/mL), and prevented microbiota disruption, excepting Bacteroides fragilis group populations, which declined by ∼3 log10 cfu/mL. DAV131A delayed onset of simulated CDI by ∼2 weeks, but did not prevent CD germination and toxin production. DAV131A prevented emergence of reduced susceptibility of CD to moxifloxacin. In batch culture, DAV131A had minor effects on CD vegetative growth, but significantly reduced toxin/spores (P < 0.005). Conclusions DAV131A reduced moxifloxacin-induced microbiota disruption and emergence of antibiotic-resistant CD. Delayed onset of CD germination and toxin production indicates further investigations are warranted to understand the clinical benefits of DAV131A in CDI prevention.

scholarly journals Flexible Cobamide Metabolism in Clostridioides (Clostridium) difficile 630 Δerm

2019 ◽  
Vol 202 (2) ◽  
Author(s):  
Amanda N. Shelton ◽  
Xun Lyu ◽  
Michiko E. Taga
Keyword(s):  
De Novo ◽  
Aminolevulinic Acid ◽  
Genomic Analysis ◽  
Opportunistic Pathogen ◽  
Vitamin B ◽  
Uptake System ◽  
Human Gut ◽  
Content Type ◽  
Clostridioides Difficile

ABSTRACT Clostridioides (Clostridium) difficile is an opportunistic pathogen known for its ability to colonize the human gut under conditions of dysbiosis. Several aspects of its carbon and amino acid metabolism have been investigated, but its cobamide (vitamin B12 and related cofactors) metabolism remains largely unexplored. C. difficile has seven predicted cobamide-dependent pathways encoded in its genome in addition to a nearly complete cobamide biosynthesis pathway and a cobamide uptake system. To address the importance of cobamides to C. difficile, we studied C. difficile 630 Δerm and mutant derivatives under cobamide-dependent conditions in vitro. Our results show that C. difficile can use a surprisingly diverse array of cobamides for methionine and deoxyribonucleotide synthesis and can use alternative metabolites or enzymes, respectively, to bypass these cobamide-dependent processes. C. difficile 630 Δerm produces the cobamide pseudocobalamin when provided the early precursor 5-aminolevulinic acid or the late intermediate cobinamide (Cbi) and produces other cobamides if provided an alternative lower ligand. The ability of C. difficile 630 Δerm to take up cobamides and Cbi at micromolar or lower concentrations requires the transporter BtuFCD. Genomic analysis revealed genetic variations in the btuFCD loci of different C. difficile strains, which may result in differences in the ability to take up cobamides and Cbi. These results together demonstrate that, like other aspects of its physiology, cobamide metabolism in C. difficile is versatile. IMPORTANCE The ability of the opportunistic pathogen Clostridioides difficile to cause disease is closely linked to its propensity to adapt to conditions created by dysbiosis of the human gut microbiota. The cobamide (vitamin B12) metabolism of C. difficile has been underexplored, although it has seven metabolic pathways that are predicted to require cobamide-dependent enzymes. Here, we show that C. difficile cobamide metabolism is versatile, as it can use a surprisingly wide variety of cobamides and has alternative functions that can bypass some of its cobamide requirements. Furthermore, C. difficile does not synthesize cobamides de novo but produces them when given cobamide precursors. A better understanding of C. difficile cobamide metabolism may lead to new strategies to treat and prevent C. difficile-associated disease.

Abstract 207: ApoC-II Mimetic Peptide Blunts Post-Prandial Hypertriglyceridemia in Mice

2017 ◽  
Vol 37 (suppl_1) ◽  
Author(s):  
Anna Wolska ◽  
Toshihiro Sakurai ◽  
Denis Sviridov ◽  
Milton Pryor ◽  
Larry Lo ◽  
...  
Keyword(s):  
Challenge Test ◽  
Molar Ratio ◽  
Oral Gavage ◽  
Cvd Risk ◽  
Mimetic Peptide ◽  
Independent Mechanism ◽  
Apoe Ko Mice ◽  
Independent Effects

Post-prandial hypertriglyceridemia is as an important CVD risk factor. We recently described an apoC-II mimetic peptide (18A-CII) that activates LPL and lowers plasma TG in apoC-II-KO mice. To investigate 18A-CII as a therapy for post-prandial hyperTG, we investigated its effect on several mouse models after a fat challenge test. After an oral gavage with vegetable oil (10 μL/gram), plasma TG increased by 3 h in C57BL/6 mice by at least 5-fold but when mice were injected 30 min before gavage with 18A-CII (1 μmoL/kg; IP or SQ), the post-prandial TG rise was almost completely blunted. Similar results were found in apoE-KO mice, indicating that the effect of 18A-CII is independent of apoE. 18A-CII did not appear to work at the level of TG absorption, because it also rapidly accelerated plasma clearance of TG after IP injection of 20% Intralipid. Addition of exogenous LPL to plasma samples collected after IP injection with Intralipid revealed that lipoprotein particles from mice treated with 18A-CII were better substrates for LPL. The rise in plasma TG after IP injection of Intralipid was only partially blocked by about 50% when mice were co-injected with the LPL inhibitor Triton WR1339, indicating that 18A-CII also works by an LPL-independent mechanism. Incubation of human plasma with exogenous 18A-CII at doses comparable to that achieved in vivo in mice showed that 18A-CII binds to all lipoproteins, including HDL and causes the displacement of apoC-I and apoC-III. Furthermore, the in vitro inhibition of LPL from the addition of exogenous apoC-III could be overcome by adding 18A-CII at a molar ratio of at least 1:10 compared to apoC-III. In summary, the18A-CII mimetic peptide at relatively low doses can accelerate the clearance of post-prandial TG after a fat load. It does so in part by activating LPL but also by relieving the inhibition of LPL by apoC-III and possibly by also blocking the other known LPL-independent effects of apoC-III and possibly apoC-I in delaying the post-prandial clearance of TG.

scholarly journals Contribution of gut bacteria to the metabolism of cyanidin 3-glucoside in human microbiota-associated rats

2012 ◽  
Vol 109 (8) ◽  
pp. 1433-1441 ◽  
Author(s):  
Laura Hanske ◽  
Wolfram Engst ◽  
Gunnar Loh ◽  
Silke Sczesny ◽  
Michael Blaut ◽  
...  
Keyword(s):  
Intestinal Bacteria ◽  
Hydroxycinnamic Acid ◽  
Gut Bacteria ◽  
Dihydroxybenzoic Acid ◽  
Human Gut ◽  
Germ Free ◽  
Human Microbiota ◽  
Human Intestinal Bacteria ◽  
The Impact

Cyanidin 3-glucoside (C3G) is one of the major dietary anthocyanins implicated in the prevention of chronic diseases. To evaluate the impact of human intestinal bacteria on the fate of C3G in the host, we studied the metabolism of C3G in human microbiota-associated (HMA) rats in comparison with germ-free (GF) rats. Urine and faeces of the rats were analysed for C3G and its metabolites within 48 h after the application of 92 μmol C3G/kg body weight. In addition, we tested the microbial C3G conversion in vitro by incubating C3G with human faecal slurries and selected human gut bacteria. The HMA rats excreted with faeces a three times higher percentage of unconjugated C3G products and a two times higher percentage of conjugated C3G products than the GF rats. These differences were mainly due to the increased excretion of 3,4-dihydroxybenzoic acid, 2,4,6-trihydroxybenzaldehyde and 2,4,6-trihydroxybenzoic acid. Only the urine of HMA rats contained peonidin and 3-hydroxycinnamic acid and the percentage of conjugated C3G products in the urine was decreased compared with the GF rats. Overall, the presence of intestinal microbiota resulted in a 3·7 % recovery of the C3G dose in HMA rats compared with 1·7 % in GF rats. Human intestinal bacteria rapidly degraded C3G in vitro. Most of the C3G products were also found in the absence of bacteria, but at considerably lower levels. The higher concentrations of phenolic acids observed in the presence of intestinal bacteria may contribute to the proposed beneficial health effects of C3G.

scholarly journals Pilot study: Trehalose-induced remodelling of the human microbiota affects Clostridioides difficile infection outcome in an in vitro colonic model

2021 ◽  
Author(s):  
Anthony M. Buckley ◽  
Ines B. Moura ◽  
Norie Arai ◽  
William Spittal ◽  
Emma Clark ◽  
...  
Keyword(s):  
Metabolic Pathways ◽  
Intestinal Tract ◽  
Enhanced Recovery ◽  
Human Gut ◽  
Human Microbiota ◽  
Clostridioides Difficile ◽  
Clostridioides Difficile Infection ◽  
Saline Ingestion ◽  
Human Intestinal Tract

AbstractWithin the human intestinal tract, dietary, microbial- and host-derived compounds are used as signals by many pathogenic organisms, including Clostridioides difficile. Trehalose has been reported to enhance virulence of certain C. difficile ribotypes; however, such variants are widespread and not correlated with clinical outcomes for patients suffering from C. difficile infection (CDI). Here, we make preliminary observations to how to trehalose supplementation affects the microbiota in an in vitro model and show that trehalose can reduce the outgrowth of C. difficile, preventing simulated CDI. Three clinically reflective human gut models simulated the effects of sugar (trehalose or glucose) or saline ingestion on the microbiota. Models were instilled with sugar or saline and further exposed to C. difficile spores. The recovery of the microbiota following antibiotic treatment and CDI induction was monitored in each model. The human microbiota remodeled to utilise the bioavailable trehalose. Clindamycin induction caused simulated CDI in models supplemented with either glucose or saline; however, trehalose supplementation did not result in CDI, although limited spore germination did occur. The absence of CDI in trehalose model was associated with enhanced abundances of Finegoldia, Faecalibacterium and Oscillospira, and reduced abundances of Klebsiella and Clostridium spp., compared with the other models. Functional analysis of the microbiota in the trehalose model revealed differences in the metabolic pathways, such as amino acid metabolism, which could be attributed to prevention of CDI. Our data show that trehalose supplementation remodelled the microbiota, which prevented simulated CDI, potentially due to enhanced recovery of nutritionally competitive microbiota against C. difficile.

Innate Immune Signaling and Porphyromonas gingivalis-accelerated Atherosclerosis

2006 ◽  
Vol 85 (2) ◽  
pp. 106-121 ◽  
Author(s):  
F.C. Gibson ◽  
H. Yumoto ◽  
Y. Takahashi ◽  
H.-H. Chou ◽  
C.A. Genco
Keyword(s):  
Periodontal Disease ◽  
Soft Tissues ◽  
Periodontal Diseases ◽  
Epidemiological Studies ◽  
Innate Immune ◽  
In Vivo Studies ◽  
Atherosclerotic Cardiovascular Disease ◽  
Systemic Complications ◽  
Increased Risk

Periodontal diseases are a group of diseases that lead to erosion of the hard and soft tissues of the periodontium, which, in severe cases, can result in tooth loss. Anecdotal clinical observations have suggested that poor oral health may be associated with poor systemic health; however, only recently have appropriate epidemiological studies been initiated, with defined clinical endpoints of periodontal disease, to address the association of periodontal disease with increased risk for cardiovascular and cerebrovascular disease. Although conflicting reports exist, these epidemiological studies support this connection. Paralleling these epidemiological studies, emerging basic scientific studies also support that infection may represent a risk factor for atherosclerosis. With P. gingivalis as a model pathogen, in vitro studies support that this organism can activate host innate immune responses associated with atherosclerosis, and in vivo studies demonstrate that this organism can accelerate atheroma deposition in animal models. In this review, we focus primarily on the basic scientific studies performed to date which support that infection with bacteria, most notably P. gingivalis, accelerates atherosclerosis. Furthermore, we attempt to bring together these studies to provide an up-to-date framework of emerging theories into the mechanisms underlying periodontal disease and increased risk for atherosclerosis, as well as identify intervention strategies to reduce the incidence of periodontal disease in humans, in an attempt to decrease risk for systemic complications of periodontal disease such as atherosclerotic cardiovascular disease.

scholarly journals Flexible cobamide metabolism in Clostridioides (Clostridium) difficile 630 Δerm

2019 ◽  
Author(s):  
Amanda N. Shelton ◽  
Xun Lyu ◽  
Michiko E. Taga
Keyword(s):  
Clostridium Difficile ◽  
De Novo ◽  
Genomic Analysis ◽  
Opportunistic Pathogen ◽  
Vitamin B ◽  
Uptake System ◽  
Human Gut ◽  
Clostridioides Difficile ◽  
Lower Ligand

AbstractClostridioides (Clostridium) difficile is an opportunistic pathogen known for its ability to colonize the human gut under conditions of dysbiosis. Several aspects of its carbon and amino acid metabolism have been investigated, but its cobamide (vitamin B12 and related cofactors) metabolism remains largely unexplored. C. difficile has seven predicted cobamide-dependent metabolisms encoded in its genome in addition to a nearly complete cobamide biosynthesis pathway and a cobamide uptake system. To address the importance of cobamides to C. difficile, we studied C. difficile 630 Δerm and mutant derivatives under cobamide-dependent conditions in vitro. Our results show that C. difficile can use a surprisingly diverse array of cobamides for methionine and deoxyribonucleotide synthesis, and can use alternative metabolites or enzymes, respectively, to bypass these cobamide-dependent processes. C. difficile 630 Δerm produces the cobamide pseudocobalamin when provided the early precursor 5-aminolevulinc acid or the late intermediate cobinamide, and produces other cobamides if provided an alternative lower ligand. The ability of C. difficile 630 Δerm to take up cobamides and Cbi at micromolar or lower concentrations requires the transporter BtuFCD. Genomic analysis revealed genetic variations in in the btuFCD locus of different C. difficile strains, which may result in differences in the ability to take up cobamides and Cbi. These results together demonstrate that, like other aspects of its physiology, cobamide metabolism in C. difficile is versatile.ImportanceThe ability of the opportunistic pathogen Clostridioides difficile to cause disease is closely linked to its propensity to adapt to conditions created by dysbiosis of the human gut microbiota. The cobamide (vitamin B12) metabolism of C. difficile has been underexplored, though it has seven metabolic pathways that are predicted to require cobamide-dependent enzymes. Here, we show that C. difficile cobamide metabolism is versatile, as it can use a surprisingly wide variety of cobamides and has alternative functions that can bypass some of its cobamide requirements. Furthermore, C. difficile does not synthesize cobamides de novo, but produces them when given cobamide precursors. Better understanding of C. difficile cobamide metabolism may lead to new strategies to treat and prevent C. difficile-associated disease.

Carrageenan oligosaccharides and their degrading bacteria induce intestinal inflammation in germ-free mouse

2020 ◽  
Author(s):  
Yeshi Yin ◽  
Miaomiao Li ◽  
Weizhong Gu ◽  
Benhua Zeng ◽  
Wei Liu ◽  
...  
Keyword(s):  
Inflammatory Response ◽  
Gut Microbiota ◽  
Fecal Microbiota ◽  
Rna Seq ◽  
Human Gut ◽  
Germ Free ◽  
Esi Ms ◽  
Human Gut Microbiota ◽  
Degrading Bacteria

Abstract Background: Carrageenans (CGNs) are widely used in food and pharmaceutical industries. However, the safety of CGNs is still under debate, because degraded CGNs have been reported to promote an intestinal inflammatory response in animal models. Here, we studied the relationship among CGNs, human gut microbiota, and the host inflammatory response.Methods: TLC was selected for detecting the degradation of KCPs by human gut microbiota in vitro batch fermentation system. PCR-DGGE and real time PCR were used for studying bacterial community. ESI-MS was used for KCPs structure analysis. Hematoxylin-eosin staining (HE), immunohistochemistry (IHC) and RNA-seq were used to evaluated the KCPs on host inflammation response in germ-free mice.Results: Thin-layer chromatography (TLC) data showed that CGNs with a molecular weight (Mw) higher than 100 kDa are not degraded by human fecal microbiota, but low Mw CGNs with an Mw around ~4.5 kDa (KCOs) could be degraded by seven of eight human fecal microbiota samples. KCO degrading B. xylanisolvens was isolated from fecal samples, and PCR-DGGE profiling with band sequencing suggested that B. xylanisolvens was the key KCO degrader in the human gut. Two putative κ-carrageenase genes were identified in the genome sequence of B. xylanisolvens. However, their function on KCO degrading was not verified in vitro. And the sulfate group from KCO is not removed after in vitro degradation by human fecal microbiota, as shown by ESI-MS analysis. The effects of KCO and KCO degrading bacteria on the inflammatory response were investigated in germ-free mice. Increased numbers of P-P38-, CD3a-, and CD79a-positive cells were found in the colon and rectum in mice fed with KCO plus KCO degrading bacteria than in mice fed with only KCO or only B. xylanisolvens and E. coli, as shown by RNA-Seq analysis, HE staining, and IHC. Conclusion: Our data suggested that the presence of KCO degrading bacteria promote the pro-inflammatory effects of CGNs.

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