Clostridioides difficile infection in patients with nonalcoholic fatty liver disease-current status

Nonalcoholic fatty liver disease(NAFLD)is the most common chronic liver disease,leading to fibrosis,cirrhosis and hepatocellular carcinoma and also associated with increased cardiovascular disease mortality.The pathogenesis of NAFLD is not fully understood,although NAFLD is thought to be a hepatic form of metabolic syndrome.There is an increasing understanding of the role of microbiota disturbances in NAFLD pathogenesis,and as with many other conditions affecting the microbiota,NAFLD may be a novel risk factor for Clostridioides difficile(C.difficile)colonization(CDC)and C.difficile infection(CDI).CDI is an emerging nosocomial disease,and community-acquired cases of infection are growing,probably due to an increase in CDC rates.The association of NAFLD with CDI has been shown in only 4 studies to date,three of which included less than 1000 patients,although the frequency of NAFLD in these studies was observed in almost 20%of the total patient cohort.These data revealed that NAFLD is a risk factor for CDI development and,moreover,is a risk factor for intestinal complications of CDI.More studies are needed to investigate this association and move forward CDC and CDI screening efforts for this group of patients.

Novel,non-colonizing,single-strain live biotherapeutic product ADS024 protects against Clostridioides difficile infection challenge in vivo

BACKGROUND The Centers for Disease Control and Prevention estimate that Clostridioides difficile(C.difficile)causes half a million infections(CDI)annually and is a major cause of total infectious disease death in the United States,causing inflammation of the colon and potentially deadly diarrhea.We recently reported the isolation of ADS024,a Bacillus velezensis(B.velezensis)strain,which demonstrated direct in vitro bactericidal activity against C.difficile,with minimal collateral impact on other members of the gut microbiota.In this study,we hypothesized that in vitro activities of ADS024 will translate in vivo to protect against CDI challenge in mouse models.AIM To investigate the in vivo efficacy of B.velezensis ADS024 in protecting against CDI challenge in mouse models.METHODS To mimic disruption of the gut microbiota,the mice were exposed to vancomycin prior to dosing with ADS024.For the mouse single-dose study,the recovery of ADS024 was assessed via microbiological analysis of intestinal and fecal samples at 4 h,8 h,and 24 h after a single oral dose of 5×108 colony-forming units(CFU)/mouse of freshly grown ADS024.The single-dose study in miniature swine included groups that had been pre-dosed with vancomycin and that had been exposed to a dose range of ADS024,and a group that was not pre-dosed with vancomycin and received a single dose of ADS024.The ADS024 colonies[assessed by quantitative polymerase chain reaction(qPCR)using ADS024-specific primers]were counted on agar plates.For the 28-d miniature swine study,qPCR was used to measure ADS024 levels from fecal samples after oral administration of ADS024 capsules containing 5×109 CFU for 28 consecutive days,followed by MiSeq compositional sequencing and bioinformatic analyses to measure the impact of ADS024 on microbiota.Two studies were performed to determine the efficacy of ADS024 in a mouse model of CDI:Study 1 to determine the effects of fresh ADS024 culture and ADS024 spore preparations on the clinical manifestations of CDI in mice,and Study 2 to compare the efficacy of single daily doses vs dosing 3 times per day with fresh ADS024.C.difficile challenge was performed 24 h after the start of ADS024 exposure.To model the human distal colon,an anerobic fecal fermentation system was used.MiSeq compositional sequencing and bioinformatic analyses were performed to measure microbiota diversity changes following ADS024 treatment.To assess the potential of ADS024 to be a source of antibiotic resistance,its susceptibility to 18 different antibiotics was tested.RESULTS In a mouse model of CDI challenge,single daily doses of ADS024 were as efficacious as multiple daily doses in protecting against subsequent challenge by C.difficile pathogen-induced disease.ADS024 showed no evidence of colonization based on the observation that the ADS024 colonies were not recovered 24 h after single doses in mice or 72 h after single doses in miniature swine.In a 28-d repeat-dose study in miniature swine,ADS024 was not detected in fecal samples using plating and qPCR methods.Phylogenetic analysis performed in the human distal colon model showed that ADS024 had a selective impact on the healthy human colonic microbiota,similarly to the in vivo studies performed in miniature swine.Safety assessments indicated that ADS024 was susceptible to all the antibiotics tested,while in silico testing revealed a low potential for off-target activity or virulence and antibioticresistance mechanisms.CONCLUSION Our findings,demonstrating in vivo efficacy of ADS024 in protecting against CDI challenge in mouse models,support the use of ADS024 in preventing recurrent CDI following standard antibiotic treatment.

Cytotoxic synergism of Clostridioides difficile toxin B with proinflammatory cytokines in subjects with inflammatory bowel diseases

Clostridioides difficile(C.difficile)is progressively colonizing humans and animals living with humans.During this process,hypervirulent strains and mutated toxin A and B of C.difficile(TcdA and TcdB)are originating and developing.While in healthy subjects colonization by C.difficile becomes a risk after the use of antibiotics that alter the microbiome,other categories of people are more susceptible to infection and at risk of relapse,such as those with inflammatory bowel disease(IBD).Recent in vitro studies suggest that this increased susceptibility could be due to the strong cytotoxic synergism between TcdB and proinflammatory cytokines the tumor necrosis factor-alpha and interferon-gamma(CKs).Therefore,in subjects with IBD the presence of an inflammatory state in the colon could be the driver that increases the susceptibility to C.difficile infection and its progression and relapses.TcdB is internalized in the cell via three receptors:chondroitin sulphate proteoglycan 4;poliovirus receptor-like 3;and Wnt receptor frizzled family.Chondroitin sulphate proteoglycan 4 and Wnt receptor frizzled family are involved in cell death by apoptosis or necrosis depending on the concentration of TcdB and cell types,while poliovirus receptor-like 3 induces only necrosis.It is possible that cytokines could also induce a greater expression of receptors for TcdB that are more involved in necrosis than in apoptosis.Therefore,in subjects with IBD there are the conditions:(1)For greater susceptibility to C.difficile infection,such as the inflammatory state,and abnormalities of the microbiome and of the immune system;(2)for the enhancement of the cytotoxic activity of TcdB+Cks;and(3)for a greater expression of TcdB receptors stimulated by cytokines that induce cell death by necrosis rather than apoptosis.The only therapeutic approach currently possible in IBD patients is monitoring of C.difficile colonization for interventions aimed at reducing tumor necrosis factor-alpha and interferon-gamma levels when the infection begins.The future perspective is to generate bacteriophages against C.difficile for targeted therapy.

Overview of current detection methods and microRNA potential in Clostridioides difficile infection screening

Clostridioides difficile(formerly called Clostridium difficile,C.difficile)infection(CDI)is listed as an urgent threat on the 2019 antibiotic resistance threats report in the United States by the Centers for Disease Control and Prevention.Early detection and appropriate disease management appear to be essential.Meanwhile,although the majority of cases are hospital-acquired CDI,community-acquired CDI cases are also on the rise,and this vulnerability is not limited to immunocompromised patients.Gastrointestinal treatments and/or gastrointestinal tract surgeries may be required for patients diagnosed with digestive diseases.Such treatments could suppress or interfere with the patient’s immune system and disrupt gut flora homeostasis,creating a suitable microecosystem for C.difficile overgrowth.Currently,stool-based non-invasive screening is the first-line approach to CDI diagnosis,but the accuracy is varied due to different clinical microbiology detection methods;therefore,improving reliability is clearly required.In this review,we briefly summarised the life cycle and toxicity of C.difficile,and we examined existing diagnostic approaches with an emphasis on novel biomarkers such as microRNAs.These biomarkers can be easily detected through noninvasive liquid biopsy and can yield crucial information about ongoing pathological phenomena,particularly in CDI.

Coexisting cytomegalovirus colitis in an immunocompetent patient with Clostridioides difficile colitis:A case report

BACKGROUND Clostridioides difficile(C.difficile)colitis is one of the most common infections in hospitalized patients,characterized by fever and diarrhea.It usually improves after appropriate antibiotic treatment;if not,comorbidities should be considered.Cytomegalovirus(CMV)colitis is a possible co-existing diagnosis in patients with C.difficile infection with poor treatment response.However,compared with immunocompromised patients,CMV colitis in immunocompetent patients is not well studied.CASE SUMMARY We present an unusual case of co-existing CMV colitis in an immunocompetent patient with C.difficile infection.An 80-year-old female patient was referred to the infectious disease department due to diarrhea,abdominal discomfort,and fever for 1 wk during her hospitalization for surgery.C.difficile toxin B polymerase chain reaction on stool samples was positive.After C.difficile infection was diagnosed,oral vancomycin treatment was administered.Her symptoms including diarrhea,fever and abdominal discomfort improved for ten days.Unfortunately,the symptoms worsened again with bloody diarrhea and fever.Therefore,a sigmoidoscopy was performed for evaluation,showing a longitudinal ulcer on the sigmoid colon.Endoscopic biopsy confirmed CMV colitis,and the clinical symptoms improved after using ganciclovir.CONCLUSION Co-existing CMV colitis should be considered in patients with aggravated C.difficile infection on appropriate treatment,even in immunocompetent hosts.

Fecal microbiota transplantation as potential first-line treatment for patients with Clostridioides difficile infection and prior appendectomy

Clostridioides difficile infection(CDI)is a global health problem.The association of appendectomy on the severity and prognosis of CDI has been reported in many literatures,but there are still contradictions.In a retrospective study entitled“Patients with Closterium diffuse infection and prior appendectomy may be prone to word outcomes”published in World J Gastrointest Surg 2021,the author found that prior appendectomy affects the severity of CDI.Appendectomy may be a risk factor for increasing the severity of CDI.Therefore,it is necessary to seek alternative treatment for patients with prior appendectomy when they are more likely to have severe or fulminant CDI.

P2X7 receptor blockade decreases inflammation,apoptosis,and enteric neuron loss during Clostridioides difficile toxin A-induced ileitis in mice

Clostridioides difficile(C.difficile)is the most common pathogen causing health care-associated infections.C.difficile TcdA and TcdB have been shown to activate enteric neurons;however,what population of these cells is more profoundly influenced and the mechanism underlying these effects remain unknown.AIM To characterize a specific population of TcdA-affected myenteric neurons and investigate the role of the P2X7 receptor in TcdA-induced ileal inflammation,cell death,and the changes in the enteric nervous system in mice.METHODS Swiss mice were used to model TcdA-induced ileitis in ileal loops exposed to TcdA(50μg/Loop)for 4 h.To investigate the role of the P2X7 receptor,Brilliant Blue G(50 mg/kg,i.p.),which is a nonspecific P2X7 receptor antagonist,or A438079(0.7μg/mouse,i.p.),which is a competitive P2X7 receptor antagonist,were injected one hour prior to TcdA challenge.Ileal samples were collected to analyze the expression of the P2X7 receptor(by quantitative real-time polymerase chain reaction and immunohistochemistry),the population of myenteric enteric neurons(immunofluorescence),histological damage,intestinal inflammation,cell death(terminal deoxynucleotidyltransferasemediated dUTP-biotin nick end labeling),neuronal loss,and S100B synthesis(immunohistochemistry).RESULTS TcdA upregulated(P<0.05)the expression of the P2X7 receptor gene in the ileal tissues,increasing the level of this receptor in myenteric neurons compared to that in control mice.Comparison with the control mice indicated that TcdA promoted(P<0.05)the loss of myenteric calretinin+(Calr)and choline acetyltransferase+neurons and increased the number of nitrergic+and Calr+neurons expressing the P2X7 receptor.Blockade of the P2X7 receptor decreased TcdAinduced intestinal damage,cytokine release[interleukin(IL)-1β,IL-6,IL-8,and tumor necrosis factor-α],cell death,enteric neuron loss,and S100B synthesis in the mouse ileum.CONCLUSION Our findings demonstrated that TcdA induced the upregulation of the P2X7 receptor,which promoted enteric neuron loss,S100B synthesis,tissue damage,inflammation,and cell death in the mouse ileum.These findings contribute to the future directions in understanding the mechanism involved in intestinal dysfunction reported in patients after C.difficile infection.

Frontiers in antibiotic alternatives for Clostridioides difficile infection

Clostridioides difficile(C.difficile)is a gram-positive,anaerobic spore-forming bacterium and a major cause of antibiotic-associated diarrhea.Humans are naturally resistant to C.difficile infection(CDI)owing to the protection provided by healthy gut microbiota.When the gut microbiota is disturbed,C.difficile can colonize,produce toxins,and manifest clinical symptoms,ranging from asymptomatic diarrhea and colitis to death.Despite the steady-if not risingprevalence of CDI,it will certainly become more problematic in a world of antibiotic overuse and the post-antibiotic era.C.difficile is naturally resistant to most of the currently used antibiotics as it uses multiple resistance mechanisms.Therefore,current CDI treatment regimens are extremely limited to only a few antibiotics,which include vancomycin,fidaxomicin,and metronidazole.Therefore,one of the main challenges experienced by the scientific community is the development of alternative approaches to control and treat CDI.In this Frontier article,we collectively summarize recent advances in alternative treatment approaches for CDI.Over the past few years,several studies have reported on natural product-derived compounds,drug repurposing,highthroughput library screening,phage therapy,and fecal microbiota transplantation.We also include an update on vaccine development,pre-and probiotics for CDI,and toxin antidote approaches.These measures tackle CDI at every stage of disease pathology via multiple mechanisms.We also discuss the gaps and concerns in these developments.The next epidemic of CDI is not a matter of if but a matter of when.Therefore,being well-equipped with a collection of alternative therapeutics is necessary and should be prioritized.

Immunological mechanisms of fecal microbiota transplantation in recurrent Clostridioides difficile infection

Fecal microbiota transplantation(FMT)is a successful method for treating recurrent Clostridioides difficile(C.difficile)infection(rCDI)with around 90%efficacy.Due to the relative simplicity of this approach,it is being widely used and currently,thousands of patients have been treated with FMT worldwide.Nonetheless,the mechanisms underlying its effects are just beginning to be understood.Data indicate that FMT effectiveness is due to a combination of microbiological direct mechanisms against C.difficile,but also through indirect mechanisms including the production of microbiota-derived metabolites as secondary bile acids and short chain fatty acids.Moreover,the modulation of the strong inflammatory response triggered by C.difficile after FMT seems to rely on a pivotal role of regulatory T cells,which would be responsible for the reduction of several cells and soluble inflammatory mediators,ensuing normalization of the intestinal mucosal immune system.In this minireview,we analyze recent advances in these immunological aspects associated with the efficacy of FMT.

Nonalcoholic fatty liver disease is associated with worse intestinal complications in patients hospitalized for Clostridioides difficile infection

BACKGROUND Nonalcoholic fatty liver disease(NAFLD)has become the leading cause of chronic liver disease with increasing prevalence worldwide.Clostridioides difficile infection(CDI)remains the most common cause of nosocomial diarrhea in developed countries.AIM To assess the impact of NAFLD on the outcomes of hospitalized patients with CDI.METHODS This study was a retrospective cohort study.The Nationwide Inpatient Sample database was used to identify a total of 7239 adults admitted as inpatients with a primary diagnosis of CDI and coexisting NAFLD diagnosis from 2010 to 2014 using ICD-9 codes.Patients with CDI and coexisting NAFLD were compared to those with CDI and coexisting alcoholic liver disease(ALD)and viral liver disease(VLD),individually.Primary outcomes included mortality,length of stay,and total hospitalization charges.Secondary outcomes were in-hospital complications.Multivariate regression was used for outcome analysis after adjusting for possible confounders.RESULTS CDI with NAFLD was independently associated with lower rates of acute respiratory failure(2.7%vs 4.2%,P<0.01;2.7%vs 4.2%,P<0.05),shorter length of stay(days)(5.75±0.16 vs 6.77±0.15,P<0.001;5.75±0.16 vs 6.84±0.23,P<0.001),and lower hospitalization charges(dollars)(38150.34±1757.01 vs 46326.72±1809.82,P<0.001;38150.34±1757.01 vs 44641.74±1660.66,P<0.001)when compared to CDI with VLD and CDI with ALD,respectively.CDI with NAFLD was associated with a lower rate of acute kidney injury(13.0%vs 17.2%,P<0.01),but a higher rate of intestinal perforation(P<0.01)when compared to VLD.A lower rate of mortality(0.8%vs 2.7%,P<0.05)but a higher rate of intestinal obstruction(4.6%vs 2.2%,P=0.001)was also observed when comparing CDI with NAFLD to ALD.CONCLUSION Hospitalized CDI patients with NAFLD had more intestinal complications compared to CDI patients with VLD and ALD.Gut microbiota dysbiosis may contribute to the pathogenesis of intestinal complications.

Risk factors for Clostridioides difficile infection in children and adolescents with inflammatory bowel disease: a systematic review and meta-analysis

Background Risk factors and consequences associated with Clostridioides difficile infection(CDI)in children and adolescents with inflammatory bowel disease(IBD)are still uncertain.We conduct a systematic review and meta-analysis to assess risk factors and outcomes associated with CDI in children and adolescents with IBD.Methods PubMed,EMBASE and Cochrane Library databases were searched from inception to 24th February,2021.Studies investigating risk factors,bowel surgery rate in pediatric IBD patients with and without CDI were included.Random-effects model was used for calculating summary estimates.Newcastle–Ottawa scale(NOS)was used for quality assessment.Results Fourteen studies,comprising 17,114 patients,were included.There was a significant association between 5-aminosalicylic acid(5-ASA)use and CDI[odds ratio(OR)=1.95,95%confidence interval(CI)1.26–3.03],with minimal heterogeneity(I^(2)=0.00%).Increased risk of active disease(OR=4.66,95%CI 2.16–10.07)were associated with CDI in those studies performed in high quality score(NOS>6)and significantly higher CDI rates in studies conducted outside USA(OR=2.94,95%CI 1.57–5.58).The bowel surgery rate in IBD with CDI was 3.8–57.1%,compared to that in IBD without CDI(0–21.3%).All studies were of moderate to high quality.Conclusions 5-ASA use and active disease might be risk factors associated with CDI in children and adolescents with IBD.Bowel surgery rates associated with CDI in IBD patients varied greatly.Large-scale clinical studies on CDI in children and adolescents with IBD are still needed to verify risk factors and outcomes.

Therapies to modulate gut microbiota:Past,present and future

The human gut microbiota comprises of a complex and diverse array of microorganisms,and over the years the interaction between human diseases and the gut microbiota has become a subject of growing interest.Disturbed microbial milieu in the gastrointestinal tract is central to the pathogenesis of several diseases including antibiotic-associated diarrhea and Clostridioides difficile infection(CDI).Manipulation of this microbial milieu to restore balance by microbial replacement therapies has proven to be a safe and effective treatment for recurrent CDI.There is considerable heterogeneity in various aspects of stool processing and administration for fecal microbiota transplantation(FMT)across different centers globally,and standardized microbioal replacement therapies offer an attractive alternative.The adverse effects associated with FMT are usually mild.However,there is paucity of data on long term safety of FMT and there is a need for further studies in this regard.With our increasing understanding of the host-microbiome interaction,there is immense potential for microbial replacement therapies to emerge as a treatment option for several diseases.The role of microbioal replacement therapies in diseases other than CDI is being extensively studied in ongoing clinical trials and it may be a potential treatment option for inflammatory bowel disease,irritable bowel syndrome,obesity,multidrug resistant infections,and neuropsychiatric illnesses.Fecal microbiota transplantation for non-CDI disease states should currently be limited only to research settings.

Update on gut microbiota in gastrointestinal diseases

The human gut is a complex microbial ecosystem comprising approximately 100 trillion microbes collectively known as the“gut microbiota”.At a rough estimate,the human gut microbiome contains almost 3.3 million genes,which are about 150 times more than the total human genes present in the human genome.The vast amount of genetic information produces various enzymes and physiologically active substances.Thus,the gut microbiota contributes to the maintenance of host health;however,when healthy microbial composition is perturbed,a condition termed“dysbiosis”,the altered gut microbiota can trigger the development of various gastrointestinal diseases.The gut microbiota has consequently become an extremely important research area in gastroenterology.It is also expected that the results of research into the gut microbiota will be applied to the prevention and treatment of human gastrointestinal diseases.A randomized controlled trial conducted by a Dutch research group in 2013 showed the positive effect of fecal microbiota transplantation(FMT)on recurrent Clostridioides difficile infection(CDI).These findings have led to the development of treatments targeting the gut microbiota,such as probiotics and FMT for inflammatory bowel diseases(IBD)and other diseases.This review focuses on the association of the gut microbiota with human gastrointestinal diseases,including CDI,IBD,and irritable bowel syndrome.We also summarize the therapeutic options for targeting the altered gut microbiota,such as probiotics and FMT.

Low-density lipoprotein receptor-related protein 1 is a CROPs-associated receptor for Clostridioides infection toxin B

As the leading cause of worldwide hospital-acquired infection,Clostridioides difficile(C.difficile)infection has caused heavy economic and hospitalized burden,while its pathogenesis is not fully understood.Toxin B(Tcd B)is one of the major virulent factors of C.difficile.Recently,CSPG4 and FZD2 were reported to be the receptors that mediate Tcd B cellular entry.However,genetic ablation of genes encoding these receptors failed to completely block Tcd B entry,implicating the existence of alternative receptor(s)for this toxin.Here,by employing the CRISPR-Cas9 screen in CSPG4-deficient He La cells,we identified LDL receptor-related protein-1(LRP1)as a novel receptor for Tcd B.Knockout of LRP1 in both CSPG4-deficient He La cells and colonic epithelium Caco2 cells conferred cells with increased Tcd B resistance,while LRP1 overexpression sensitized cells to Tcd B at a low concentration.Co-immunoprecipitation assay showed that LRP1 interacts with full-length Tcd B.Moreover,CROPs domain,which is dispensable for Tcd B’s interaction with CSPG4 and FZD2,is sufficient for binding to LRP1.As such,our study provided evidence for a novel mechanism of Tcd B entry and suggested potential therapeutic targets for treating C.difficile infection.

Encyclopedia of fecal microbiota transplantation: a review of effectiveness in the treatment of 85 diseases

Fecal microbiota transplantation(FMT)has been used as a core therapy for treating dysbiosis-related diseases by remodeling gut microbiota.The methodology and technology for improving FMT are stepping forward,mainly including washed microbiota transplantation(WMT),colonic transendoscopic enteral tubing(TET)for microbiota delivery,and purified Firmicutes spores from fecal matter.To improve the understanding of the clinical applications of FMT,we performed a systematic literature review on FMT published from 2011 to 2021.Here,we provided an overview of the reported clinical benefits of FMT,the methodology of processing FMT,the strategy of using FMT,and the regulations on FMT from a global perspective.A total of 782 studies were included for the final analysis.The present review profiled the effectiveness from all clinical FMT uses in 85 specific diseases as eight categories,including infections,gut diseases,microbiotagut-liver axis,microbiotagut-brain axis,metabolic diseases,oncology,hematological diseases,and other diseases.Although many further controlled trials will be needed,the dramatic increasing reports have shown the promising future of FMT for dysbiosis-related diseases in the gut or beyond the gut.