Microbiota-based Therapies Clostridioides difficile infection that is refractory to antibiotic therapy

Clostridioides difficile infection (CDI) has had a devastating impact worldwide with significant rates of mortality, especially among the elderly. Despite effective antibiotics, the incidence of recurrent CDI (rCDI) is increasing and more difficult to treat with antibiotics alone. Fecal Microbiota Transplantation (FMT) has emerged as a consistently effective treatment for rCDI. Mechanisms for FMT are not entirely understood, but remain an area of active investigation. There have been recent safety reports with the use of FMT regarding transmission of pathogens in a few patients that have led to serious illness. With appropriate screening, FMT can be safely administered and continue to have a significant impact on eradication of rCDI and improve the lives of patients suffering from this disease. In this review, we summarize current treatments for CDI with a focus on microbiota-based therapies used for antibiotic refractory disease.

Transethnic analysis of the human leukocyte antigen region for ulcerative colitis reveals not only shared but also ethnicity-specific disease associations

Inflammatory bowel disease (IBD) is a chronic inflammatory disease of the gut. Genetic association studies have identified the highly variable human leukocyte antigen (HLA) region as the strongest susceptibility locus for IBD and specifically DRB1*01:03 as a determining factor for ulcerative colitis (UC). However, for most of the association signal such as delineation could not be made because of tight structures of linkage disequilibrium within the HLA. The aim of this study was therefore to further characterize the HLA signal using a transethnic approach. We performed a comprehensive fine mapping of single HLA alleles in UC in a cohort of 9272 individuals with African American, East Asian, Puerto Rican, Indian and Iranian descent and 40 691 previously analyzed Caucasians, additionally analyzing whole HLA haplotypes. We computationally characterized the binding of associated HLA alleles to human self-peptides and analyzed the physicochemical properties of the HLA proteins and predicted self-peptidomes. Highlighting alleles of the HLA-DRB1*15 group and their correlated HLA-DQ-DR haplotypes, we not only identified consistent associations (regarding effects directions/magnitudes) across different ethnicities but also identified population-specific signals (regarding differences in allele frequencies). We observed that DRB1*01:03 is mostly present in individuals of Western European descent and hardly present in non-Caucasian individuals. We found peptides predicted to bind to risk HLA alleles to be rich in positively charged amino acids. We conclude that the HLA plays an important role for UC susceptibility across different ethnicities. This research further implicates specific features of peptides that are predicted to bind risk and protective HLA proteins.

Microbiota as Drivers and as Therapeutic Targets in Ocular and Tissue Specific Autoimmunity

Autoimmune uveitis is a major cause of blindness in humans. Activation of retina-specific autoreactive T cells by commensal microbiota has been shown to trigger uveitis in mice. Although a culprit microbe and/or its immunogenic antigen remains to be identified, studies from inducible and spontaneous mouse models suggest the potential of microbiota-modulating therapies for treating ocular autoimmune disease. In this review, we summarize recent findings on the contribution of microbiota to T cell-driven, tissue-specific autoimmunity, with an emphasis on autoimmune uveitis, and analyze microbiota-altering interventions, including antibiotics, probiotics, and microbiota-derived metabolites (e.g., short-chain fatty acids), which have been shown to be effective in other autoimmune diseases. We also discuss the need to explore more translational animal models as well as to integrate various datasets (microbiomic, transcriptomic, proteomic, metabolomic, and other cellular measurements) to gain a better understanding of how microbiota can directly or indirectly modulate the immune system and contribute to the onset of disease. It is hoped that deeper understanding of these interactions may lead to more effective treatment interventions.

Understanding the host-microbe interactions using metabolic modeling

The human gut harbors an enormous number of symbiotic microbes, which is vital for human health. However, interactions within the complex microbiota community and between the microbiota and its host are challenging to elucidate, limiting development in the treatment for a variety of diseases associated with microbiota dysbiosis. Using in silico simulation methods based on flux balance analysis, those interactions can be better investigated. Flux balance analysis uses an annotated genome-scale reconstruction of a metabolic network to determine the distribution of metabolic fluxes that represent the complete metabolism of a bacterium in a certain metabolic environment such as the gut. Simulation of a set of bacterial species in a shared metabolic environment can enable the study of the effect of numerous perturbations, such as dietary changes or addition of a probiotic species in a personalized manner. This review aims to introduce to experimental biologists the possible applications of flux balance analysis in the host-microbiota interaction field and discusses its potential use to improve human health. Video abstract.

Bacteriotherapy for inflammatory bowel disease

The number of patients with inflammatory bowel disease is rapidly increasing in developed countries. The main cause of this increase is thought not to be genetic, but secondary to rapidly modernized environmental change. Changes in the environment have been detrimental to enteric probiotics useful for fermentation, inducing an increase in pathobionts that survive by means other than fermentation. This dysregulated microbiota composition, the so-called dysbiosis, is believed to have increased the incidence of inflammatory bowel disease. Bacteriotherapy, a treatment that prophylactically and therapeutically corrects the composition of disturbed intestinal microbiota, is a promising recent development. In fact, fecal microbiome transplantation for recurrent Clostridioides difficile infection in 2013 was a significant contribution for bacteriotherapy. In this paper, we comprehensively review bacteriotherapy in an easy-to-understand format.

Dietary Factors Modulating Colorectal Carcinogenesis

The development of colorectal cancer, responsible for 9% of cancer-related deaths, is favored by a combination of genetic and environmental factors. The modification of diet and lifestyle may modify the risk of colorectal cancer (CRC) and prevent neoplasia in up to 50% of cases. The Western diet, characterized by a high intake of fat, red meat and processed meat has emerged as an important contributor. Conversely, a high intake of dietary fiber partially counteracts the unfavorable effects of meat through multiple mechanisms, including reduced intestinal transit time and dilution of carcinogenic compounds. Providing antioxidants (e.g., vitamins C and E) and leading to increased intraluminal production of protective fermentation products, like butyrate, represent other beneficial and useful effects of a fiber-rich diet. Protective effects on the risk of developing colorectal cancer have been also advocated for some specific micronutrients like vitamin D, selenium, and calcium. Diet-induced modifications of the gut microbiota modulate colonic epithelial cell homeostasis and carcinogenesis. This can have, under different conditions, opposite effects on the risk of CRC, through the production of mutagenic and carcinogenic agents or, conversely, of protective compounds. The aim of this review is to summarize the most recent evidence on the role of diet as a potential risk factor for the development of colorectal malignancies, as well as providing possible prevention dietary strategies.

Role of gut microbiota in epigenetic regulation of colorectal Cancer

Colorectal cancer (CRC) remains one of the most commonly diagnosed cancers and a leading cause of cancer-related deaths worldwide. The stepwise accumulation of epigenetic alterations in the normal colorectal epithelium has been reported to act as a driving force for the initiation and promotion of tumorigenesis in CRC. From a mechanistic standpoint, emerging evidence indicates that within the colorectal epithelium, the diverse gut microbiota can interact with host cells to regulate multiple physiological processes. In fact, recent studies have found that the gut microbiota represents a potential cause of carcinogenesis, invasion, and metastasis via DNA methylation, histone modifications, and non-coding RNAs - providing an epigenetic perspective for the connection between the gut microbiota and CRC. Herein, we comprehensively review the recent research that provides a comprehensive yet succinct evidence connecting the gut microbiota to CRC at an epigenetic level, including carcinogenic mechanisms of cancer-related microbiota, and the potential for utilizing the gut microbiota as CRC biomarkers. These scientific findings highlight a promising future for manipulating the gut microbiota to improve clinical outcomes in patients suffering from CRC.

The role of the intestinal microbiota in allogeneic HCT: clinical associations and preclinical mechanisms

Allogeneic hematopoietic cell transplantation (allo-HCT) is a curative-intent therapy for patients with hematological malignancies, but despite advances in the field in recent years, there is still a significant risk of post-transplant mortality. In addition to relapse of the underlying malignancy, the key contributors to this high mortality are graft-versus-host disease (GVHD) and infection. The intestinal microbiota is the collective term describing the community of bacteria, fungi, viruses and protozoa that resides in the human gastrointestinal tract. Bacterial communities have been studied most comprehensively, and disruption of these communities has been associated with the development of a variety of medical conditions in large clinical associative studies. Preclinical studies suggest a mechanistic role for the intestinal microbiota in the instruction and maintenance of both intestinal and systemic immune cell function. This review outlines our current understanding of the relationship between gut bacteria and allo-HCT outcomes, including infection, immune reconstitution, GVHD and relapse, drawing on evidence from both clinical associative studies and preclinical mechanistic studies.

Can the FUT2 Non-secretor Phenotype Associated With Gut Microbiota Increase the Children Susceptibility for Type 1 Diabetes? A Mini Review

The global toll of type 1 diabetes (T1D) has steadily increased over the last decades. It is now widely acknowledged that T1D pathophysiology is more complex than expected. Indeed, a multifaceted interplay between genetic, metabolic, inflammatory and environmental factors exists that leads to heterogeneous clinical manifestations across individuals. Children with non-secretor phenotype and those affected by T1D share low abundance of bifidobacteria, low content of short-chain fatty acids, intestinal phosphatase alkaline and a high incidence of inflammatory bowel diseases. In this context, host-gut microbiota dyad may represent a relevant contributor to T1D development and progression due to its crucial role in shaping host immunity and susceptibility to autoimmune conditions. The FUT2 gene is responsible for the composition and functional properties of glycans in mucosal tissues and bodily secretions, including human milk. FUT2 polymorphisms may profoundly influence gut microbiota composition and host susceptibility to viral infections and chronic inflammatory disease. In this minireview, the possible interplay between mothers' phenotype, host FUT2 genetic background and gut microbiota composition will be discussed in perspective of the T1D onset. The study of FUT2-gut microbiota interaction may add a new piece on the puzzling T1D etiology and unveil novel targets of intervention to contrast T1D development and progression. Dietary interventions, including the intake of α-(1, 2)-fucosyl oligosaccharides in formula milk and the use of specific prebiotics and probiotics, could be hypothesized.

Gut Microbiota and Colorectal Cancer Development: A Closer Look to the Adenoma-Carcinoma Sequence

There is wide evidence that CRC could be prevented by regular physical activity, keeping a healthy body weight, and following a healthy and balanced diet. Many sporadic CRCs develop via the traditional adenoma-carcinoma pathway, starting as premalignant lesions represented by conventional, tubular or tubulovillous adenomas. The gut bacteria play a crucial role in regulating the host metabolism and also contribute to preserve intestinal barrier function and an effective immune response against pathogen colonization. The microbiota composition is different among people, and is conditioned by many environmental factors, such as diet, chemical exposure, and the use of antibiotic or other medication. The gut microbiota could be directly involved in the development of colorectal adenomas and the subsequent progression to CRC. Specific gut bacteria, such as Fusobacterium nucleatum, Escherichia coli, and enterotoxigenic Bacteroides fragilis, could be involved in colorectal carcinogenesis. Potential mechanisms of CRC progression may include DNA damage, promotion of chronic inflammation, and release of bioactive carcinogenic metabolites. The aim of this review was to summarize the current knowledge on the role of the gut microbiota in the development of CRC, and discuss major mechanisms of microbiota-related progression of the adenoma-carcinoma sequence.

Growth rate alterations of human colorectal cancer cells by 157 gut bacteria

Several bacteria in the human gut microbiome have been associated with colorectal cancer (CRC) by high-throughput screens. In some cases, molecular mechanisms have been elucidated that drive tumorigenesis, including bacterial membrane proteins or secreted molecules that interact with the human cancer cells. For most gut bacteria, however, it remains unknown if they enhance or inhibit cancer cell growth. Here, we screened bacteria-free supernatants (secretomes) and inactivated cells of over 150 cultured bacterial strains for their effects on cell growth. We observed family-level and strain-level effects that often differed between bacterial cells and secretomes, suggesting that different molecular mechanisms are at play. Secretomes of Bacteroidaceae, Enterobacteriaceae, and Erysipelotrichaceae bacteria enhanced cell growth, while most Fusobacteriaceae cells and secretomes inhibited growth, contrasting prior findings. In some bacteria, the presence of specific functional genes was associated with cell growth rates, including the virulence genes TcdA, TcdB in Clostridiales and FadA in Fusobacteriaceae, which both inhibited growth. Bacteroidaceae cells that enhanced growth were enriched for genes of the cobalamin synthesis pathway, while Fusobacteriaceae cells that inhibit growth were enriched for genes of the ethanolamine utilization pathway. Together, our results reveal how different gut bacteria have wide-ranging effects on cell growth, contribute a better understanding of the effects of the gut microbiome on host cells, and provide a valuable resource for identifying candidate target genes for potential microbiome-based diagnostics and treatment strategies.

Catching a glimpse of the bacterial gut community of companion animals: a canine and feline perspective

Dogs and cats have gained a special position in human society by becoming our principal companion animals. In this context, efforts to ensure their health and welfare have increased exponentially, with in recent times a growing interest in assessing the impact of the gut microbiota on canine and feline health. Recent technological advances have generated new tools to not only examine the intestinal microbial composition of dogs and cats, but also to scrutinize the genetic repertoire and associated metabolic functions of this microbial community. The application of high-throughput sequencing techniques to canine and feline faecal samples revealed similarities in their bacterial composition, with Fusobacteria, Firmicutes and Bacteroidetes as the most prevalent and abundant phyla, followed by Proteobacteria and Actinobacteria. Although key bacterial members were consistently present in their gut microbiota, the taxonomic composition and the metabolic repertoire of the intestinal microbial population may be influenced by several factors, including diet, age and anthropogenic aspects, as well as intestinal dysbiosis. The current review aims to provide a comprehensive overview of the multitude of factors which play a role in the modulation of the canine and feline gut microbiota and that of their human owners with whom they share the same environment.

MHC Class I related chain A (MICA), Human Leukocyte Antigen (HLA)-DRB1, HLA-DQB1 genotypes in Turkish patients with ulcerative colitis

Objectives

We aimed to determine Human Leukocyte Antigen (HLA)-DRB1, DQB1, and MHC Class I related chain A (MICA) genotypes in patients with ulcerative colitis.

Methods

HLA-DRB1, HLA-DQB1, MICA genotyping of patient (n:85) and controls (n:100) were performed by PCR-SSO Luminex (One Lambda genotyping kit).

Results

We found significantly higher DRB1*01 (p:0.022, OR:0.23, CI:0.06–0.8) and MICA*0002/20/55 (p:0.03, OR:0.53, CI:0.29–0.93) alleles in control group whereas DRB1*14 (p:0.04, OR:2.25, CI:1–5.08), DRB1*15 (p:<0.0001, OR:4.54, CI:2.09–9.88) and MICA*0004 (p:0.01, OR:2.84, CI:1.2–6.7) alleles were higher in patient group.

Conclusions

The present study will inform the MICA and HLA genotypes about the protective (DRB1*01, MICA*0002/20/55) or susceptible (DRB1*14, DRB1*15, MICA*0004) alleles of the disease and helps the literature on Turkish patients with ulcerative colitis.

Opportunities and challenges in the management of celiac disease in Asia

Although once considered uncommon, there is increasing recognition of celiac disease (CeD) in Asia. It is now clear that CeD is a disorder as frequent in certain Asian countries as that in western countries, although it often remains undiagnosed. With increasing awareness and diagnosis, the absolute numbers of celiac patients are expected to increase markedly in Asia. Asia, with 60% of the population of the world, is probably the major "reservoir" of undiagnosed CeD in the world. As Asia has a huge landscape along with highly heterogenous genetic, social, cultural, and nutritional practices, similar heterogeneity is seen in the epidemiology, diagnostic, and therapeutic facilities for CeD in Asia. In this article, we have reviewed the changes in the epidemiology, diagnostics, and management of CeD in Asia and summarized the challenges and opportunities for its emergence in Asia.

FadA promotes DNA damage and progression of Fusobacterium nucleatum-induced colorectal cancer through up-regulation of chk2

Background

Globally, colorectal cancer (CRC) affects more than 1 million people each year. In addition to non-modifiable and other environmental risk factors, Fusobacterium nucleatum infection has been linked to CRC recently. In this study, we explored mechanisms underlying the role of Fusobacterium nucleatum infection in the progression of CRC in a mouse model.

Methods

C57BL/6 J-Adenomatous polyposis coli (APC) Min/J mice [APC (Min/+)] were treated with Fusobacterium nucleatum (10⁹ cfu/mL, 0.2 mL/time/day, i.g., 12 weeks), saline, or FadA knockout (FadA−/−) Fusobacterium nucleatum. The number, size, and weight of CRC tumors were determined in isolated tumor masses. The human CRC cell lines HCT29 and HT116 were treated with lentiviral vectors overexpressing chk2 or silencing β-catenin. DNA damage was determined by Comet assay and γH2AX immunofluorescence assay and flow cytometry. The mRNA expression of chk2 was determined by RT-qPCR. Protein expression of FadA, E-cadherin, β-catenin, and chk2 were determined by Western blot analysis.

Results

Fusobacterium nucleatum treatment promoted DNA damage in CRC in APC (Min/+) mice. Fusobacterium nucleatum also increased the number of CRC cells that were in the S phase of the cell cycle. FadA−/− reduced tumor number, size, and burden in vivo. FadA−/− also reduced DNA damage, cell proliferation, expression of E-cadherin and chk2, and cells in the S phase. Chk2 overexpression elevated DNA damage and tumor growth in APC (Min/+) mice.

Conclusions

In conclusion, this study provided evidence that Fusobacterium nucleatum induced DNA damage and cell growth in CRC through FadA-dependent activation of the E-cadherin/β-catenin pathway, leading to up-regulation of chk2.

Fucosylation in the intestinal mucosa and inflammatory bowel disease

Inflammatory bowel disease (IBD) is an unexplained, abnormal immune mediated chronic and recurrent inflammatory disorder of the intestine. Fucosylation in the intestinal mucosal is the process of transferring fucose to intestinal mucosal protein side chains under the control of fucosyltransferases to form fucosyl bonds. The mechanism of fucosylation in the intestinal mucosa in IBD has not been fully proved. In this paper, we will review the progress in understanding the relationship between fucosylation in the intestinal mucosa and IBD.

Fecal Microbiota Transplantation for Ulcerative Colitis: An Evolving Therapy

Background

Fecal microbiota transplantation (FMT) is currently an approved treatment for recurrent and refractory Clostridioides difficile infection. However, its use in ulcerative colitis is at an early stage and significant gaps remain in our understanding of the mechanisms and logistics of its practical application.

Methods and results

This article aims to look into specific issues which remain unsettled for use of FMT in ulcerative colitis including donor and recipient selection, route of administration, and duration of therapy. We also discuss optimal ways to assess response to FMT and the current state of FMT regulations. In addition, we postulate the impact of diet on the microbiome profile of the donor and recipient. We also suggest a change in the nomenclature from FMT to fecal microbiome transfer.

Conclusion

FMT is an evolving therapy. There are several considerations for its use in UC but its use and role should be directed by further clinical trials.

Two-day enema antibiotic therapy for parasite eradication and resolution of symptoms

BACKGROUND

Blastocystis hominis (B. hominis) and Dientamoeba fragilis (D. fragilis) are two protozoan parasites of human bowel that are found throughout the world. There is still debate about the pathogenicity of these protozoans, despite them being commonly associated with gastrointestinal symptoms and can cause health issue in both children and adults. These parasites are usually transmitted through faecal-oral contact particularly under poor hygiene conditions or food/water contamination. Once a person is infected, the parasites live in the large intestine and are passed in the faeces.

AIM

To investigate the effect of triple antibiotic therapy using enema infusion in the treatment of B. hominis and D. fragilis infections.

METHODS

This retrospective longitudinal study was conducted in a single medical centre, which included fifty-four patients (≥ 18 years) who were positive for D. fragilis, B. hominis or both between 2017 and 2018. The treatment consisted of triple antibiotics that were infused over two consecutive days through rectal enema. Faecal samples were collected from participants pre- and post-treatment and were tested for parasites using microscopy and polymerase chain reaction. Patients’ symptoms were recorded prior and after the treatment as well as patient demographic data.

RESULTS

Patients (n = 54), were either positive for B. hominis (37%), D. fragilis (35%) or both (28%). All patients completed the two-day treatment and no serious adverse effect was reported. The most common side effect experienced by the patients during the treatment was urine discolouration which was cleared by six weeks of follow-up. Common symptoms reported prior to treatment were diarrhoea, abdominal pain, constipation and fatigue. Other symptoms included abdominal discomfort, dizziness and blood in the stool. Eighty-nine percent of patients completed a final stool test post-treatment. At six weeks post-treatment, 79% of patients cleared the parasites from their faeces. Symptoms such as abdominal discomfort, dizziness and blood in the stool decreased significantly at both seven days and six weeks post-treatment (P < 0.040). The enema retention time, bowel preparation, previous antibiotic treatment or previous gastrointestinal problems had no significant effect on parasite eradication.

CONCLUSION

Overall, eradication of parasites and improvement of clinical outcomes were observed in treated patients, showing the efficacy of this combination to eradicate the parasites and provide positive clinical outcome.

The phenomenon of intestinal permeability and its association with cardiovascular disease. Current status

Changes in the intestinal permeability in various pathologies are widely discussed in the scientific community. There is still no consensus on whether high intestinal permeability can lead to chronic noncommunicable diseases, but there is much evidence that increased permeability can aggravate some of them. The article discusses a modern vision of the intestinal permeability including its potential contribution to the development of cardiovascular pathologies, which are the number one mortality cause both in Russia and around the world.

Gut microbiome transfer-Finding the perfect fit

Gut microbiome transfer (GMT; also referred to as faecal microbiota transplantation or FMT) has been propelled from fringe therapy to mainstream science as a highly effective treatment for recurrent Clostridioides difficile infection. As a result, there has been great interest in the potential efficacy and safety of GMT in treating other medical conditions, for example inflammatory bowel disease, and more recently as a novel therapy for obesity and metabolic diseases. For these chronic conditions, the results from clinical trials have been mixed. Further, specifically in obesity and metabolic diseases, there are limited available data, with only a few published studies with a small number of participants and short duration of follow-up. Therefore, this review aims to explore the human, microbial and formulation factors that may affect the success of GMT. This includes various aspects in the preparation and administration of GMT, such as stool processing, modes of delivery, pretreatment with antibiotics and/or bowel lavage, frequency of GMT and possible use of precision bacteriotherapy. In addition, we examine the potential use of GMT in obesity, type 2 diabetes and metabolic diseases based on current available literature, highlighting some recent advances in GMT research in this area, as well as potential adverse effects after GMT therapy.

Proton pump inhibitor in upper gastrointestinal fecal microbiota transplant: A systematic review and analysis

BACKGROUND AND AIMS

Fecal microbiota transplantation (FMT) is used in recurrent Clostridioides difficile infections. However, protocols are facility dependent, and one variable is whether pre-procedural proton pump inhibitors (PPIs) are given. In theory, PPIs reduce acidity and protect the transplanted microbiome for the most potent dose. We conducted a systematic review to study the effect of PPIs on FMT delivered by upper gastrointestinal (GI) routes.

METHODS

We searched Pubmed/Medline, Cochrane Library, Embase, Scopus, and Web of Science through December 16, 2018 using variations of keywords "fecal microbiota transplant" and "Clostridium difficile infection." Two authors independently reviewed 4210 results and found 11 qualifying studies with data on upper GI FMT, use of PPIs, and the rate of treatment failure at follow-up.

RESULTS

Of 233 included patients, treatment failure occurred in 20.6% of those with use of PPIs versus 22.6% in the group without (relative risk 0.91; confidence interval 0.56-1.50). Limitations include the lack of studies directly comparing outcomes based on use of PPIs and inability to control for possible confounders such as chronic PPI use, amount of stool transplanted, and pre-FMT antibiotics.

CONCLUSIONS

We did not find evidence supporting a clinically significant benefit from routine use of PPIs in FMT protocol. It is possible that the theoretical benefit from improved survival of transplanted microbiota is offset by negative effects on the microbiome. We suggest that routine use of PPIs in upper GI FMT be reconsidered. Further investigation is needed to optimize protocols for safety and efficacy.

Fecal microbiota transplantation ameliorates active ulcerative colitis

Ulcerative colitis (UC) is a complex chronic pathological condition of the gut in which microbiota targeted treatment, such as fecal microbiota transplantation (FMT), has shown an encouraging effect. The aim of the present study was to investigate the efficacy and safety of FMT in patients with mild or moderate UC. A single-center, open-label study was designed, including 47 patients with mild or moderate active UC who received three treatments of fresh FMT via colonic transendoscopic enteral tubing within 1 week. The inflammatory bowel disease questionnaire, partial Mayo scores, colonoscopy, erythrocyte sedimentation rate, C-reactive protein level and procalcitoin values were used to assess the efficacy of FMT and alteration in gut microbiota was detected by 16S ribosomal RNA-sequencing. Before FMT, microbiota Faecalibacterium prausnitzii (F. prausnitzii) levels were significantly decreased in patients with UC compared with healthy donors (P<0.01). At 4 weeks post-FMT, F. prausnitzii levels were significantly increased (P<0.05), and the Mayo score was significantly decreased (1.91±1.07 at baseline vs. 4.02±1.47 at week 4; P<0.001) in patients with UC compared with healthy donors. Steroid-free clinical responses were reported in 37 patients (84.1%), and steroid-free clinical remission was achieved in 31 patients (70.5%) at week 4 post-FMT, however, steroid-free remission was not achieved in any patient. No adverse events were reported in 41 (93.2%) patients after FMT or during the 12-week follow-up. Shannon's diversity index and Chao1 estimator were also improved in patients with UC receiving FMT. In conclusion, the results of the present study suggested that FMT resulted in clinical remission in patients with mild to moderate UC, and that the remission may be associated with significant alterations to the intestinal microbiota of patients with UC. Furthermore, F. prausnitzii may serve as a diagnostic and therapeutic biomarker for the use of FMT in UC.

Management of difficult-to-treat Clostridioides difficile in a patient with chronic osteomyelitis

A 61-year-old male patient being treated with intravenous antibiotics for left foot osteomyelitis presented to the hospital septic, with several days of worsening abdominal pain, bloating and watery bowel movements. Investigation revealed that the patient had severe, treatment-resistant Clostridioides difficile colitis. He was initially treated with oral vancomycin and intravenous metronidazole, which was switched to oral fidaxomicin. After no improvement in the patient's symptoms, he was treated with two faecal microbiota transplants. He was offered a third faecal microbiota transplant but declined. The patient was placed back on oral fidaxomicin and saw ultimate resolution of his symptoms. This case provides an example of a treatment pathway for refractory C. difficile infection.

Altering Routine Intensive Care Unit Practices to Support Commensalism

The gastrointestinal (GI) tract consists of trillions of organisms that support multiple functions in the body, from immunity, digestion, and absorption to drug metabolism. These microbes form an overall collection of microorganisms that form the body's microbiome. In critical illness, many of these functions are aberrant, and the microbiome is altered, leading to untoward effects. Some of the most common medications received by patients include antibiotics and proton pump inhibitors, which affect particular changes in the microbiome. In addition, patients receiving prolonged enteral and parenteral nutrition experience changes in the microbiological composition and diversity of their GI tracts. Research is ongoing to characterize the crosstalk between the microbiome and immune function as targets for drug and nutrition therapy.

Treatment of Clostridioides (Clostridium) difficile infection

Clostridioides (formerly: Clostridium) difficile infection (CDI) is a major cause of diarrhoea for inpatients as well as outpatients. Usually, CDI is healthcare-associated but the number of community-acquired infections is increasing. CDI is generally associated with changes in the normal intestinal microbiota caused by administration of antibiotics. Elderly and immunocompromised patients are at greater risk for CDI and CDI recurrence. Recently, the treatment options of CDI have undergone major changes: current recommendations speak against using metronidazole for primary CDI, fidaxomicin and bezlotoxumab have been added to the treatment armamentarium and microbial replacement therapies have emerged. Several other therapies are undergoing clinical trials. In this article, we review current treatment guidelines, present the most recent data on the options to treat CDI and glance towards future developments.KEY MESSAGESThe cornerstones for the treatment of CDI are vancomycin and fidaxomicin. Metronidazole should be used only in mild-to-moderate disease in younger patients who have no or only few risk factors for recurrence.In recurrent CDI, bezlotoxumab infusion (a monoclonal antibody against C. difficile toxin B) may be considered as an adjunctive therapeutic strategy in addition to the standard care provided to patients with several risk factors for recurrence.Faecal microbiota transplantation (FMT) should be offered to patients with frequently recurring CDI.

A survey of Fusobacterium nucleatum genes modulated by host cell infection

Here, we report comprehensive transcriptomic profiles from Fusobacterium nucleatum under conditions that mimic the first stages of bacterial infection in a highly differentiated adenocarcinoma epithelial cell line. Our transcriptomic in vitro adenocarcinoma approach allows us to measure the expression dynamics and regulation of bacterial virulence and response factors in real time, and is a novel strategy for clarifying the role of F. nucleatum infection in colorectal cancer (CRC) progression. Our data show that: (i) infection alters metabolic and functional pathways in F. nucleatum, allowing the bacterium to adapt to the host-imposed milieu; (ii) infection also stimulates the expression of genes required to help induce and promote a hypoxic and inflammatory microenvironment in the host; and (iii) F. nucleatum invasion occurs by a haematogenous route of infection. Our study identifies novel gene targets from F. nucleatum that are activated during invasion and which may aid in determining how this species invades and promotes disease within the human gastrointestinal tract. These invasion-specific genes may be useful as biomarkers for CRC progression in a host and could also assist in the development of new diagnostic tools and treatments (such as vaccines or small molecule drug targets), which will be able to combat infection and inflammation in the host while circumventing the potential problem of F. nucleatum tolerization.

Insights into the Role of Human Gut Microbiota in Clostridioides difficile Infection

Clostridioides difficile infection (CDI) has emerged as a major health problem worldwide. A major risk factor for disease development is prior antibiotic use, which disrupts the normal gut microbiota by altering its composition and the gut’s metabolic functions, leading to the loss of colonization resistance and subsequent CDI. Data from human studies have shown that the presence of C. difficile, either as a colonizer or as a pathogen, is associated with a decreased level of gut microbiota diversity. The investigation of the gut’s microbial communities, in both healthy subjects and patients with CDI, elucidate the role of microbiota and improve the current biotherapeutics for patients with CDI. Fecal microbiota transplantation has a major role in managing CDI, aiming at re-establishing colonization resistance in the host gastrointestinal tract by replenishing the gut microbiota. New techniques, such as post-genomics, proteomics and metabolomics analyses, can possibly determine in the future the way in which C. difficile eradicates colonization resistance, paving the way for the development of new, more successful treatments and prevention. The aim of the present review is to present recent data concerning the human gut microbiota with a focus on its important role in health and disease.

Potential Use of Biotherapeutic Bacteria to Target Colorectal Cancer-Associated Taxa

The role of the gut microbiome in human health and disease is the focus of much attention. It has been widely agreed upon that our gut bacteria play a role in host immunity, nutrient absorption, digestion, metabolism, and other key drivers of health. Furthermore, certain microbial signatures and specific taxa have also been associated with the development of diseases, such as obesity; inflammatory bowel disease; and, indeed, colorectal cancer (CRC), which is the focus of this review. By extension, such taxa represent potential therapeutic targets. In particular, the emerging human pathogen Fusobacterium nucleatum represents an important agent in CRC development and its control within the gastrointestinal tract is desirable. This paper reviews the principal bacterial pathogens that have been associated with CRC to date and discusses the in vitro and human studies that have shown the potential use of biotherapeutic strains as a means of targeting CRC-associated bacteria.

Clinical Management of Infectious Diarrhea

BACKGROUND

Infectious diarrhea is the most common cause of diarrhea worldwide and is responsible for more deaths than other gastrointestinal tract diseases such as gastrointestinal cancers, peptic ulcer disease or inflammatory bowel disease. Diarrheal disease still represents the 8th leading cause of death worldwide, with more than 1,6 million attributed fatalities in 2016 alone. The majority of cases can be divided into three principal clinical presentations: acute watery diarrhea lasting 5-10 days and normally self-limiting, bloody diarrhea (dysentery), and persistent diarrhea with or without intestinal malabsorption.

METHODS

We performed an electronic search on PUBMED of the scientific literature concerning infectious diarrhea and its clinical management.

AIM

In this review article, we analyze the most important causes of infectious diarrhea and their constellation of signs and symptoms, providing an update on the diagnostic tools available in today's practice and on the different treatment options.

CONCLUSION

Even though the majority of intestinal infections are self-limiting in immunocompetent individuals, specific diagnosis and identification of the causative agent remain crucial from public health and epidemiological perspectives. Specific diagnostic investigation can be reserved for patients with severe dehydration, more severe illness, persistent fever, bloody stools, immunosuppression, and for cases of suspected nosocomial infection or outbreak and it includes complete blood count, creatinine and electrolytes evaluation, determination of leukocytes and lactoferrin presence in the stools, stool culture, together with C. difficile testing, PCR, ova and parasites' search, endoscopy and abdominal imaging. Since acute diarrhea is most often self-limited and caused by viruses, routine antibiotic use is not recommended for most adults with mild, watery diarrhea. However, when used appropriately, antibiotics are effective against shigellosis, campylobacteriosis, C. difficile colitis, traveler's diarrhea, and protozoal infections. Furthermore, antibiotics use should be considered in patients who are older than 65 years, immunocompromised, severely ill, or septic.

South African Society of Clinical Microbiology Clostridioides difficile infection diagnosis, management and infection prevention and control guideline

Clostridioides difficile infection (CDI) is a problem in both developed and developing countries and is a common hospital-acquired infection. This guideline provides evidence-based practical recommendations for South Africa and other developing countries. The scope of the guideline includes CDI diagnostic approaches; adult, paediatric and special populations treatment options; and surveillance and infection prevention and control recommendations.

Fucosyltransferase Gene Polymorphisms and Lewisb-Negative Status Are Frequent in Swedish Newborns, With Implications for Infectious Disease Susceptibility and Personalized Medicine

BACKGROUND

Single-nucleotide polymorphisms (SNPs) in the fucosyltransferase genes FUT2 and FUT3 have been associated with susceptibility to various infectious and inflammatory disorders. FUT variations influence the expression of human histo-blood group antigens (HBGAs) (H-type 1 and Lewis), which are highly expressed in the gut and play an important role in microbial attachment, metabolism, colonization, and shaping of the microbiome. In particular, FUT polymorphisms confer susceptibility to specific rotavirus and norovirus genotypes, which has important global health implications.

METHODS

We designed a genotyping method using a nested polymerase chain reaction approach to determine the frequency of SNPs in FUT2 and FUT3, thereby inferring the prevalence of Lewisb-positive, Lewisb-negative, secretor, and nonsecretor phenotypes in 520 Swedish newborns.

RESULTS

There was an increased frequency of homozygotes for the minor allele for 1 SNP in FUT2 and 4 SNPs in FUT3. Overall, 37.3% of newborns were found to have Lewis b negative phenotypes (Le (a+b-) or Le (a-b-). Using our new, sensitive genotyping method, we were able to genetically define the Le (a-b-) individuals based on their secretor status and found that the frequency of Lewis b negative newborns in our cohort was 28%.

CONCLUSIONS

Given the high frequency of fucosyltransferase polymorphisms observed in our newborn cohort and the implications for disease susceptibility, FUT genotyping might play a future role in personalized health care, including recommendations for disease screening, therapy, and vaccination.

The E-Cadherin Cleavage Associated to Pathogenic Bacteria Infections Can Favor Bacterial Invasion and Transmigration, Dysregulation of the Immune Response and Cancer Induction in Humans

Once bound to the epithelium, pathogenic bacteria have to cross epithelial barriers to invade their human host. In order to achieve this goal, they have to destroy the adherens junctions insured by cell adhesion molecules (CAM), such as E-cadherin (E-cad). The invasive bacteria use more or less sophisticated mechanisms aimed to deregulate CAM genes expression or to modulate the cell-surface expression of CAM proteins, which are otherwise rigorously regulated by a molecular crosstalk essential for homeostasis. Apart from the repression of CAM genes, a drastic decrease in adhesion molecules on human epithelial cells can be obtained by induction of eukaryotic endoproteases named sheddases or through synthesis of their own (prokaryotic) sheddases. Cleavage of CAM by sheddases results in the release of soluble forms of CAM. The overexpression of soluble CAM in body fluids can trigger inflammation and pro-carcinogenic programming leading to tumor induction and metastasis. In addition, the reduction of the surface expression of E-cad on epithelia could be accompanied by an alteration of the anti-bacterial and anti-tumoral immune responses. This immune response dysfunction is likely to occur through the deregulation of immune cells homing, which is controlled at the level of E-cad interaction by surface molecules α_E integrin (CD103) and lectin receptor KLRG1. In this review, we highlight the central role of CAM cell-surface expression during pathogenic microbial invasion, with a particular focus on bacterial-induced cleavage of E-cad. We revisit herein the rapidly growing body of evidence indicating that high levels of soluble E-cad (sE-cad) in patients’ sera could serve as biomarker of bacterial-induced diseases.

Cooperative and Escaping Mechanisms between Circulating Tumor Cells and Blood Constituents

Metastasis is the leading cause of cancer-related deaths and despite measurable progress in the field, underlying mechanisms are still not fully understood. Circulating tumor cells (CTCs) disseminate within the bloodstream, where most of them die due to the attack of the immune system. On the other hand, recent evidence shows active interactions between CTCs and platelets, myeloid cells, macrophages, neutrophils, and other hematopoietic cells that secrete immunosuppressive cytokines, which aid CTCs to evade the immune system and enable metastasis. Platelets, for instance, regulate inflammation, recruit neutrophils, and cause fibrin clots, which may protect CTCs from the attack of Natural Killer cells or macrophages and facilitate extravasation. Recently, a correlation between the commensal microbiota and the inflammatory/immune tone of the organism has been stablished. Thus, the microbiota may affect the development of cancer-promoting conditions. Furthermore, CTCs may suffer phenotypic changes, as those caused by the epithelial–mesenchymal transition, that also contribute to the immune escape and resistance to immunotherapy. In this review, we discuss the findings regarding the collaborative biological events among CTCs, immune cells, and microbiome associated to immune escape and metastatic progression.

Recoding the metagenome: microbiome engineering in situ

Synthetic biology has enabled a new generation of tools for engineering the microbiome, including targeted antibiotics, protein delivery, living biosensors and diagnostics, and metabolic factories. Here, we discuss opportunities and limitations in microbiome engineering, focusing on a new generation of tools for in situ genetic modification of a microbiome that hold particular promise in circumventing these limitations.

Fecal microbiota transplantation in irritable bowel syndrome: A systematic review and meta-analysis

Background

Modulating gut microbiota is a potential treatment for irritable bowel syndrome (IBS). This meta-analysis explored whether fecal microbiota transplantation (FMT) is successful in treating IBS.

Methods

A systematic review was performed to find trials on FMT in IBS. Ratios and relative ratios (RR) of improvement for single-arm trials (SATs) and randomized controlled trials (RCTs) were calculated, respectively. Changes in IBS Severity Scoring System (IBS-SSS) and IBS Quality of Life (IBS-QOL) instrument compared to baseline in FMT versus placebo groups were pooled.

Results

In SATs, 59.5% (95% confidence interval (CI) 49.1-69.3) of IBS patients showed significant improvement. In RCTs, there were no differences between FMT and control in improvement (RR=0.93 (95% CI 0.50-1.75)) or changes in the IBS-SSS and IBS-QOL.

Conclusions

FMT was not effective in IBS. Variations in FMT methods and patient factors may contribute to the heterogeneous results of the trials.

Impact of Fecal Microbiota Transplantation on Obesity and Metabolic Syndrome-A Systematic Review

Fecal microbiota transplantation (FMT) is a gut microbial-modulation strategy that has been investigated for the treatment of a variety of human diseases, including obesity-associated metabolic disorders. This study appraises current literature and provides an overview of the effectiveness and limitations of FMT as a potential therapeutic strategy for obesity and metabolic syndrome (MS). Five electronic databases and two gray literature sources were searched up to 10 December 2018. All interventional and observational studies that contained information on the relevant population (adult patients with obesity and MS), intervention (receiving allogeneic FMT) and outcomes (metabolic parameters) were eligible. From 1096 unique citations, three randomized placebo-controlled studies (76 patients with obesity and MS, body mass index = 34.8 ± 4.1 kg/m², fasting plasma glucose = 5.8 ± 0.7 mmol/L) were included for review. Studies reported mixed results with regards to improvement in metabolic parameters. Two studies reported improved peripheral insulin sensitivity (rate of glucose disappearance, RD) at 6 weeks in patients receiving donor FMT versus patients receiving the placebo control. In addition, one study observed lower HbA1c levels in FMT patients at 6 weeks. No differences in fasting plasma glucose, hepatic insulin sensitivity, body mass index (BMI), or cholesterol markers were observed between two groups across all included studies. While promising, the influence of FMT on long-term clinical endpoints needs to be further explored. Future studies are also required to better understand the mechanisms through which changes in gut microbial ecology and engraftment of microbiota affect metabolic outcomes for patients with obesity and MS. In addition, further research is needed to better define the optimal fecal microbial preparation, dosing, and method of delivery.

Microbiota, Microbial Metabolites, and Barrier Function in A Patient with Anorexia Nervosa after Fecal Microbiota Transplantation

The change in the gut microbiome and microbial metabolites in a patient suffering from severe and enduring anorexia nervosa (AN) and diagnosed with small intestinal bacterial overgrowth syndrome (SIBO) was investigated. Microbial gut dysbiosis is associated with both AN and SIBO, and therefore gut microbiome changes by serial fecal microbiota transplantation (FMT) is a possible therapeutic modality. This study assessed the effects of FMT on gut barrier function, microbiota composition, and the levels of bacterial metabolic products. The patient treatment with FMT led to the improvement of gut barrier function, which was altered prior to FMT. Very low bacterial alpha diversity, a lack of beneficial bacteria, together with a great abundance of fungal species were observed in the patient stool sample before FMT. After FMT, both bacterial species richness and gut microbiome evenness increased in the patient, while the fungal alpha diversity decreased. The total short-chain fatty acids (SCFAs) levels (molecules presenting an important source of energy for epithelial gut cells) gradually increased after FMT. Contrarily, one of the most abundant intestinal neurotransmitters, serotonin, tended to decrease throughout the observation period. Overall, gut microbial dysbiosis improvement after FMT was considered. However, there were no signs of patient clinical improvement. The need for an in-depth analysis of the donor´s stool and correct selection pre-FMT is evident.

Fecal microbiota transplantation (FMT) for C. difficile infection, just say 'No'

Despite lack of regulatory approval, fecal microbiota transplantation (FMT) is widely performed to manage C. difficile infection (CDI), particularly recurrent CDI. Herein, we critically review the available randomized controlled trials of FMT and address the following questions: Is FMT better than drug management of recurrent CDI?; Is FMT treatment per se or adjunctive treatment to antibiotics for CDI?; and, Is FMT safe? Finally, we elaborate non-FMT options for the management of recurrent CDI. Although promising, FMT should be reserved for patients who have failed appropriate antibiotic management of recurrent CDI.

Clostridioides difficile: diagnosis and treatments

Clostridioides difficile (formerly Clostridium) is a major cause of healthcare associated diarrhea, and is increasingly present in the community. Historically, C difficile infection was considered easy to diagnose and treat. Over the past two decades, however, diagnostic techniques have changed in line with a greater understanding of the physiopathology of C difficile infection and the use of new therapeutic molecules. The evolution of diagnosis showed there was an important under- and misdiagnosis of C difficile infection, emphasizing the importance of algorithms recommended by European and North American infectious diseases societies to obtain a reliable diagnosis. Previously, metronidazole was considered the reference drug to treat C difficile infection, but more recently vancomycin and other newer drugs are shown to have higher cure rates. Recurrence of infection represents a key parameter in the evaluation of new drugs, and the challenge is to target the right population with the adapted therapeutic molecule. In multiple recurrences, fecal microbiota transplantation is recommended. New approaches, including antibodies, vaccines, and new molecules are already available or in the pipeline, but more data are needed to support the inclusion of these in practice guidelines. This review aims to provide a baseline for clinicians to understand and stratify their choice in the diagnosis and treatment of C difficile infection based on the most recent data available.

Real-world efficacy of bezlotoxumab for prevention of recurrent Clostridium difficile infection: a retrospective study of 46 patients in five university hospitals in Finland

Reports on real-world experience on efficacy of bezlotoxumab (BEZ) has been lacking thus far. We retrospectively studied the efficacy and safety of BEZ in preventing the recurrence of Clostridium difficile infection (CDI) in five university hospitals in Finland. Seventy-three percent of our 46 patients remained free of recurrence in the following 3 months and the performance remained as 71% effective also among immunocompromised patients. In severe CDI, BEZ prevented recurrence in 63% of cases. From our study patients, 78% had three or more known risk factors for recurrence of CDI. Eight of our patients were waiting for fecal microbiota transplantation but after stopping the antibiotics that were continued to prevent recurrence of CDI and after receiving BEZ, all remained free of recurrence and did not need the procedure. Success with BEZ as an adjunctive treatment in preventing recurrence of CDI in high-risk patients may be rated as high. Among a subgroup of our patients, those already evaluated to be in need of fecal microbiota transplantation, BEZ seems to be an alternative option.

The Molecular Hallmarks of the Serrated Pathway in Colorectal Cancer

Colorectal cancer (CRC) is a leading cause of cancer death worldwide. It includes different subtypes that differ in their clinical and prognostic features. In the past decade, in addition to the conventional adenoma-carcinoma model, an alternative multistep mechanism of carcinogenesis, namely the “serrated pathway”, has been described. Approximately, 15 to 30% of all CRCs arise from neoplastic serrated polyps, a heterogeneous group of lesions that are histologically classified into three morphologic categories: hyperplastic polyps, sessile serrated adenomas/polyps, and the traditional serrated adenomas/polyps. Serrated polyps are characterized by genetic (BRAF or KRAS mutations) and epigenetic (CpG island methylator phenotype (CIMP)) alterations that cooperate to initiate and drive malignant transformation from normal colon mucosa to polyps, and then to CRC. The high heterogeneity of the serrated lesions renders their diagnostic and pathological interpretation difficult. Hence, novel genetic and epigenetic biomarkers are required for better classification and management of CRCs. To date, several molecular alterations have been associated with the serrated polyp-CRC sequence. In addition, the gut microbiota is emerging as a contributor to/modulator of the serrated pathway. This review summarizes the state of the art of the genetic, epigenetic and microbiota signatures associated with serrated CRCs, together with their clinical implications.

Faecal microbiota transplantation for diarrhoea-predominant irritable bowel syndrome: a double-blind, randomised, placebo-controlled trial

BACKGROUND

Faecal microbiota transplantation (FMT) has shown promise in alleviating the symptoms of irritable bowel syndrome (IBS); however, controlled data on this technique are scarce. The aim of this clinical trial was to assess the efficacy of FMT in alleviating diarrhoea-predominant IBS (IBS-D).

METHODS

We did a double-blind, randomised, placebo-controlled crossover trial in patients aged 18-65 years with moderate-to-severe IBS-D defined by an IBS-Symptom Severity Score (IBS-SSS) of more than 175, recruited from three US centres. Patients were randomly assigned (1:1) in blocks of four with a computer-generated randomisation sequence to receive FMT capsules followed by identical-appearing placebo capsules, or placebo capsules followed by FMT capsules. All participants and study team members were masked to randomisation. An independent staff member assigned the treatments according to consecutive numbers. Patients received either 75 FMT capsules (each capsule contained approximately 0·38 g of minimally processed donor stool) or 75 placebo capsules over 3 days (25 capsules per day). All patients crossed over to the alternate treatment at 12 weeks. The primary outcome was difference in IBS-SSS between the groups at 12 weeks. Intention-to-treat analyses were done and all patients who received study drug were included in an adverse events analysis. The trial was terminated during recruitment because results from an interim analysis revealed futility. The study is registered with ClinicalTrials.gov, number NCT02328547.

FINDINGS

From May 28, 2015, to April 21, 2017, 48 patients were randomly assigned to receive FMT first (n=25) or placebo first (n=23). Three participants were lost to follow-up in the FMT group. IBS-SSS did not differ between FMT recipients (mean 221 [SD 105]) and placebo recipients (236 [95]) at 12 weeks (p=0·65), after adjustment for baseline scores. The most common drug-related adverse events included abdominal pain (five [10%] of the 48 participants while receiving FMT capsules vs four [8%] while receiving placebo), nausea (four [8%] vs two [4%]), and exacerbation of diarrhoea (three [6%] vs eight [17%]). One serious adverse event that was unrelated to study drug (acute cholecystitis) was reported in a patient while receiving placebo capsules.

INTERPRETATION

FMT was safe, but did not induce symptom relief at 12 weeks compared with placebo. Additional studies are needed to determine the efficacy of FMT for IBS-D.

FUNDING

National Institutes of Health.

Fecal microbiota transplantation as a new therapy: from Clostridioides difficile infection to inflammatory bowel disease, irritable bowel syndrome, and colon cancer

Fecal microbiota transplantation (FMT) represents the most effective means of therapeutically manipulating the gastrointestinal microbiome. Originally employed as a treatment of last-resort in patients with life-threatening Clostridioides difficile infection (CDI), FMT gained widespread acceptance during the CDI epidemic, where it achieved resolution rates approaching 100%. Following our newfound appreciation for the role of the gut microbiome in both health and disease and owing to FMT's unique mechanism/s of action, FMT is rapidly advancing as an effective treatment for a number of conditions in which the gastrointestinal microbiome is thought to play a role. We review the role of FMT from its beginnings in CDI to its expansion into inflammatory bowel disease, irritable bowel syndrome, and colon cancer.

Novel Strategies for the Management of Vancomycin-Resistant Enterococcal Infections

PURPOSE OF REVIEW

Vancomycin-resistant enterococci (VRE) are important nosocomial pathogens that commonly affect critically ill patients. VRE have a remarkable genetic plasticity allowing them to acquire genes associated with antimicrobial resistance. Therefore, the treatment of deep-seated infections due to VRE has become a challenge for the clinician. The purpose of this review is to assess the current and future strategies for the management of recalcitrant deep-seated VRE infections and efforts for infection control in the hospital setting.

RECENT FINDINGS

Preventing colonization and decolonization of multidrug-resistant bacteria are becoming the most promising novel strategies to control and eradicate VRE from the hospital environment. Fecal microbiota transplantation (FMT) has shown remarkable results on treating colonization and infection due to Clostridiodes difficille and VRE, as well as to recover the integrity of the gut microbiota under antibiotic pressure. Initial reports have shown the efficacy of FMT on reestablishing patient microbiota diversity in the gut and reducing the dominance of VRE in the gastrointestinal tract. In addition, the use of bacteriophages may be a promising strategy in eradicating VRE from the gut of patients. Until these strategies become widely available in the hospital setting, the implementation of infection control measures and stewardship programs are paramount for the control of this pathogen and each program should provide recommendations for the proper use of antibiotics and develop strategies that help to detect populations at risk of VRE colonization, prevent and control nosocomial transmission of VRE, and develop educational programs for all healthcare workers addressing the epidemiology of VRE and the potential impact of these pathogens on the cost and outcomes of patients. In terms of antibiotic strategies, daptomycin has become the standard of care for the management of deep-seated infections due to VRE. However, recent evidence indicates that the efficacy of this antibiotic is limited, and higher (10-12 mg/kg) doses and/or combination with β-lactams is needed for therapeutic success. Clinical data to support the best use of daptomycin against VRE are urgently needed. This review provides an overview of recent developments regarding the prevention, treatment, control, and eradication of VRE in the hospital setting. We aim to provide an update of the most recent therapeutic strategies to treat deep-seated infections due to VRE.

Detection of Fusobacterium nucleatum in stool and colonic tissues from Norwegian colorectal cancer patients

Norway has one of the world's highest incidences of colorectal cancer (CRC). Accumulating research suggests that the intestinal microbiota may have an important role in initiation and progression of colorectal cancer. In order to evaluate microbiome-based biomarkers for non-invasive detection of CRC, the levels of Fusobacterium nucleatum and selected Escherichia coli toxin genes in stool and mucosa from a small cohort of Norwegian patients were investigated. The study cohort included 72 patients scheduled for colonoscopy. The patients were divided into three groups upon their examinations: cancer, polyp, and control groups. Levels of F. nucleatum in stool samples were significantly higher in the cancer group compared with the control group and the polyp group. High levels of F. nucleatum in stool reflected detection of F. nucleatum in the tumor tissues of colorectal cancer patients. However, no difference in the levels of E. coli toxin genes in neither stool nor biopsy samples between the patient groups was observed. This study suggests that a quantitative PCR assay targeting F. nucleatum in stool samples has the potential to be included in a larger panel of biomarkers for non-invasive testing for colorectal cancer.

Chronic Inflammation as a Link between Periodontitis and Carcinogenesis

Periodontitis is characterized by a chronic inflammation produced in response to a disease-associated multispecies bacterial community in the subgingival region. Although the inflammatory processes occur locally in the oral cavity, several studies have determined that inflammatory mediators produced during periodontitis, as well as subgingival species and bacterial components, can disseminate from the oral cavity, contributing therefore, to various extraoral diseases like cancer. Interestingly, carcinogenesis associated with periodontal species has been observed in both the oral cavity and in extra oral sites. In this review, several studies were summarized showing a strong association between orodigestive cancers and poor oral health, presence of periodontitis-associated bacteria, tooth loss, and clinical signs of periodontitis. Proinflammatory pathways were also summarized. Such pathways are activated either by mono- or polymicrobial infections, resulting in an increase in the expression of proinflammatory molecules such as IL-6, IL-8, IL-1β, and TNF-α. In addition, it has been shown that several periodontitis-associated species induce the expression of genes related to cell proliferation, cell cycle, apoptosis, transport, and immune and inflammatory responses. Intriguingly, many of these pathways are linked to carcinogenesis. Among them, the activation of Toll-like receptors (TLRs) and antiapoptotic pathways (such as the PI3K/Akt, JAK/STAT, and MAPK pathways), the reduction of proapoptotic protein expression, the increase in cell migration and invasion, and the enhancement in metastasis are addressed. Considering that periodontitis is a polymicrobial disease, it is likely that mixed species promote carcinogenesis both in the oral cavity and in extra oral tissues and probably—as observed in periodontitis—synergistic and/or antagonistic interactions occur between microbes in the community. To date, a good amount of studies has allowed us to understand how monospecies infections activate pathways involved in tumorigenesis; however, more studies are needed to determine the combined effect of oral species in carcinogenesis.