Fusobacterium nucleatum Causes Microbial Dysbiosis and Exacerbates Visceral Hypersensitivity in a Colonization-Independent Manner

Campylobacter infection of young children in Colombia and its impact on the gastrointestinal environment

Campylobacter infections are a leading cause of bacterial-derived gastroenteritis worldwide with particularly profound impacts on pediatric patients in low-and-middle income countries. It remains unclear how Campylobacter impacts these hosts, though it is becoming increasingly evident that it is a multifactorial process that depends on the host immune response, the gastrointestinal microbiota, various bacterial factors, and host nutritional status. Since these factors likely vary between adult and pediatric patients in different regions of the world, it is important that studies define these attributes in well characterized clinical cohorts in diverse settings. In this study, we analyzed the fecal microbiota and the metabolomic and micronutrient profiles of asymptomatic and symptomatic pediatric patients in Colombia that were either infected or uninfected with Campylobacter during a case-controlled study on acute diarrheal disease. Here, we report that the microbiome of Campylobacter- infected children only changed in their abundance of Campylobacter spp. despite the inclusion of children with or without diarrhea. In addition to increased Campylobacter, computational models were used to identify fecal metabolites that were associated with Campylobacter infection and found that glucose-6-phosphate and homovanillic acid were the strongest predictors of infection in these pediatric patients, which suggest that colonocyte metabolism are impacted during infection. Despite changes to the fecal metabolome, the concentrations of intestinal minerals and trace elements were not significantly impacted by Campylobacter infection, but were elevated in uninfected children with diarrhea.

Importance

Gastrointestinal infection with pathogenic Campylobacter species has long been recognized as a significant cause of human morbidity. Recently, it has been observed that pediatric populations in low-and-middle income countries are uniquely impacted by these organisms in that infected children can be persistently colonized, develop enteric dysfunction, and exhibit reduced development and growth. While the association of Campylobacter species with these long-term effects continues to emerge, the impact of infection on the gastrointestinal environment of these children remains uncharacterized. To address this knowledge gap, our group leveraged clinical samples collected during a previous study on gastrointestinal infections in pediatric patients to examine the fecal microbiota, metabolome, and micronutrient profiles of those infected with Campylobacter species, and found that the metabolome was impacted in a way that suggests gastrointestinal cell metabolism is affected during infection, which is some of the first data indicating how gastrointestinal health in these patients may be affected.

Gut microbial signatures in clinically stable ulcerative colitis according to the mucosal state and associated symptoms

BACKGROUND AND AIM

The gut microbiome of patients with clinically stable ulcerative colitis (UC) differs from that of healthy individuals depending on the state of the colonic mucosa, especially with or without advanced scarring; however, the underlying mechanism is unclear. Therefore, this study examined the gut microbiome compositional signatures in patients with significant mucosal scarring and UC-related symptoms.

METHODS

Stool samples for gut microbiome analysis were prospectively collected from 57 patients with clinically stable UC between January 1 and December 31, 2022. Data from 57 individuals without inflammatory bowel disease (non-IBD) paired by age and sex were selected from our previous study as the control group. The fecal samples were subjected to 16S rRNA gene sequencing. Associations between gut microbiome profiles and clinical or colonoscopic assessments were examined using diversity and differential abundance analyses.

RESULTS

Gut microbiome compositions between the patients with clinically stable UC and non-IBD controls differed significantly. Furthermore, gut microbiome compositions varied between the preserved and altered mucosa groups identified based on mucosal changes in the UC group. Differential abundance test of patients with UC for symptomatic remission based on stool frequency from the two-item patient-reported outcome identified several overlapping taxa specified as gut microbiome signatures, including the Enterobacteriaceae unknown genera (Enterobacteriaceae_g), Klebsiella, and several Lachnospiraceae spp. both in mucosal and symptom change analyses.

CONCLUSIONS

The gut microbiome can change with mucosal changes, even in clinically stable UC, and some gut microbial signatures may explain the symptom manifestations in patients with UC showing significant mucosal changes.

Tomato-fruit-derived extracellular vesicles inhibit Fusobacterium nucleatum via lipid-mediated mechanism

Nano-sized extracellular vesicles (EV) are essential for cell communication. Studies on EV from natural sources including edible plants are gaining momentum due to the biological implications. In this study, EV from tomato fruit were isolated by ultracentrifugation and their physical and morphological features along with their biocargo profiles were analyzed. We found that tomato EV promote the growth of probiotic Lactobacillus species, while inhibiting growth of the opportunistic intestinal pathogens Clostridioides difficile and Fusobacterium nucleatum. Tomato EV reversed microbiota dysbiosis caused by F. nucleatum in a simulator of the gut microbiota fermentation model. Phospholipid analysis of tomato EV revealed that the anti-bacterial effect of tomato-EV was driven by the presence of specific lipids in the EV, as demonstrated by lipid depletion and reconstitution experiments. The findings suggest the potential of tomato-derived EV for treating gut microbiota dysbiosis and preventing intestinal bacterial infections.

The Influence of PRO-SELF Cancer Pain Control Programme on Patients' Self-Management Ability

Objective

Recently, cancer patients have challenges with self-management. This study aims to improve symptoms of chronic pain, and anxiety and depression associated with cancer by PRO-SELF nursing intervention.

Methods

Sixty-four patients were randomly assigned to an intervention and a control group from Jan 2016 to Dec 2019, 34 usable cases in the intervention group and 30 cases in the control group were collected. The control group received a routine cancer pain nursing intervention, whereas the intervention group received a PRO-SELF based multidisciplinary collaborative cancer pain nursing intervention. After three months of intervention, the Numeric Rating Scale (NRS), Medication Compliance Questionnaire (MCQ), Social Support Rating Scale (SSRS), Self-rating Anxiety Scale (SAS) and Self-Rating Depression Scale (SDS), Quality of Life Scale (FACT-G Chinese version) and Chronic Pain Self-efficacy Scale were resent to compare the differences in the observation indicators included evaluation of patients' social support degree, anxiety and depression score, quality of life scores and self-efficacy scores between two groups. The t-test and rank-sum test were used for statistic analysis.

Results

No significant differences were found between groups for pain and medication compliance (P > 0.05). However, significant differences were found between groups in social support, life quality, chronic pain self-efficacy, and self-rating anxiety and depression index scores (P < 0.001). The intervention group report more social support, pain self-efficacy and less anxiety and depression (P < 0.001).

Conclusion

The PRO-SELF pain symptoms in patients with a cancer pain management programme improved degree of social support, life quality, self-efficacy, anxiety, depression which is worthy of clinical application.

Postinfective bowel dysfunction following Campylobacter enteritis is characterised by reduced microbiota diversity and impaired microbiota recovery

OBJECTIVES

Persistent bowel dysfunction following gastroenteritis (postinfectious (PI)-BD) is well recognised, but the associated changes in microbiota remain unclear. Our aim was to define these changes after gastroenteritis caused by a single organism, Campylobacter jejuni, examining the dynamic changes in the microbiota and the impact of antibiotics.

DESIGN

A single-centre cohort study of 155 patients infected with Campylobacter jejuni. Features of the initial illness as well as current bowel symptoms and the intestinal microbiota composition were recorded soon after infection (visit 1, <40 days) as well as 40-60 days and >80 days later (visits 2 and 3). Microbiota were assessed using 16S rRNA sequencing.

RESULTS

PI-BD was found in 22 of the 99 patients who completed the trial. The cases reported significantly looser stools, with more somatic and gastrointestinal symptoms. Microbiota were assessed in 22 cases who had significantly lower diversity and altered microbiota composition compared with the 44 age-matched and sex-matched controls. Moreover 60 days after infection, cases showed a significantly lower abundance of 23 taxa including phylum Firmicutes, particularly in the order Clostridiales and the family Ruminoccocaceae, increased Proteobacteria abundance and increased levels of Fusobacteria and Gammaproteobacteria. The microbiota changes were linked with diet; higher fibre consumption being associated with lower levels of Gammaproteobacteria.

CONCLUSION

The microbiota of PI-BD patients appeared more disturbed by the initial infection compared with the microbiota of those who recovered. The prebiotic effect of high fibre diets may inhibit some of the disturbances seen in PI-BD.

TRIAL REGISTRATION NUMBER

NCT02040922.

Fusobacterium nucleatum Pyogenic Liver Abscess and the Role of Bacterial Virulence and Gut Microbiota Dysbiosis

In the United States, pyogenic liver abscesses are often due to monomicrobial infection and are rarely documented to be a consequence of Fusobacterium infection, a common cause of Lemierre's syndrome. Recent advances in gut microbial studies have identified Fusobacterium as a commensal gut flora that becomes pathogenic in the setting of dysbiosis resulting from colorectal diseases, such as diverticulitis. While the bacteria's tropism for the liver remains to be elucidated, the virulence pattern of Fusobacterium and the portal venous drainage system have allowed us to understand the bacterium's propensity for causing right hepatic abscesses. In this case report, we detail an immunocompetent man with a history of sigmoid diverticulitis who developed a right hepatic abscess due to Fusobacterium nucleatum, while delineating a review of the literature on the virulent properties of the bacterium and the impact of gut microbiota dysbiosis in its pathogenicity. A descriptive analysis was also performed to identify the characteristics of patients who are at risk in hopes of further improving the clinical diagnostic schema for this condition.

Pyruvate: Ferredoxin oxidoreductase is involved in IgA-related microbiota dysbiosis and intestinal inflammation

Introduction

Inflammatory bowel diseases (IBDs) are associated with both immune abnormalities and dysbiosis, characterized by a loss of Faecalibacterium prausnitzii (F. prausnitzii). However, the reason for F. prausnitzii deficiency remains unclear.

Methods

16S rDNA seque-ncing and IgA enzyme-linked immunosorbent assay (ELISA) were applied to identify bacterial community and IgA changes in ulcerative colitis (UC) patients. Forced immunization with F. prausnitzii in rabbits was conducted. To screen for potential IgA-reactive proteins in F. prausnitzii lysates, we performed western blotting and mass spectrometry analyses. Pyruvate: ferredoxin oxidoreductase (PFOR) was cloned and purified, then the immunoreactivity of PFOR was verified in peripheral blood mononuclear cells (PBMCs) through PCR, ELISpot assay and single-cell sequencing (scRNA-seq). Finally, the UC fecal dysbiosis was re-analyzed in the context of the phylogenetic tree of PFOR.

Results

F. prausnitzii was underrepresented in UC patients with elevated F. prausnitzii-reactive IgA in the fecal supernatant. Forced immunization with F. prausnitzii in rabbits led to high interferon-γ (IFN-γ) transcription in the colon, along with beta diversity disturbance and intestinal inflammation. PFOR was identified as an IgA-binding antigen of F. prausnitzii and the immunoreactivity was validated in PBMCs, which showed elevated expression of inflammatory cytokines. The scRNA-seq revealed enhanced signals in both T regulatory cells (Tregs) and monocytes after PFOR incubation. Furthermore, phylogenetic analysis revealed that PFOR was a common but conserved protein among the gut bacteria.

Discussion

Our results collectively suggest that PFOR is a bioactive protein in the immune system and may contribute to host-microbial crosstalk. Conserved but bioactive microbial proteins, such as PFOR, warrant more attention in future host-microbial interaction studies.

Understanding the characteristics of the host genome and microbiome interaction in oral squamous cell carcinoma: a narrative review

Background

Oral health status is directly associated with microbes present within it. The abundance of microbes at the OSCC site is more than at its control site, representing its possible role in the progression of OSCC development. Dysbiosis of oral microbiota could be a crucial etiological risk factor in the elevation of OSCC. This study aimed to analyze and assess: a) positive regulator microbes of oral cancer and their abundance at the cancer site, b) pathways involved in positive regulator microbes, and c) identification of the most virulent oral oncogenic microbe.

Main body

It is obtained from several studies that microbes belonging to Prevotella, Fusobacterium, Alloprevotella, Capnocytophaga, Porphyromonas, Campylobacter, and Aggregatibacter are detected to be more in number contrast to healthy sites. Fusobacterium nucleatum, Porphyromonas gingivalis, and Candida albicans show molecular pathways linked with OSCC development. Genes encoding for virulent factors like FimA, Gingipains, lipopolysaccharide (P. gingivalis), FadA, Fap2 (F. nucleatum), and zymosan (C. Albicans) are directly involved in elevating oral cancer.

Conclusion

Mostly, the genes that are involved in promoting oral cancer are the genes that generally encode cell wall proteins. The cell wall proteins that is FadA, Fap, and FimA interact with the host's cell and hamper the normal regulation pathway, which leads to activation of cell proliferating pathways, down-regulates apoptotic pathways, cytoskeleton rearrangement, and upregulates the cell cycle checkpoint regulators; as a result, progression of oral cancer occurs.

Y, Efendi D, Razak FA. ACE2 expression in saliva of patients with COVID-19 and its association with Candida albicans and Aggregatibacter actinomycetemcomitans

Background: A relationship between oral microbiota and susceptibility to SARS-CoV-2 infection has been extensively studied. However, the relationship between oral commensal flora and expression of angiotensin-converting enzyme 2 ( ACE2) remains to be established. In this observational study, we collected saliva from patients with COVID-19 and evaluated the relationship between ACE2 expression and Candida albicans as well as with selected gram-negative bacteria ( Aggregatibacter actinomycetemcomitans, Fusobacterium nucleatum, and Veillonella parvula). We investigated how this may be directly or indirectly involved in oral dysbiosis in patients with COVID-19.

Methods: We included 23 hospitalized patients admitted to Universitas Indonesia Hospital with PCR-confirmed COVID-19, with six healthy participants serving as controls. Saliva and tongue surface swabs were collected from patients with diabetes (DG) and without diabetes (NDG) and subject controls. Using quantitative PCR (qPCR) we assessed the mRNA expression of ACE2, the abundance of C. albicans, and the transcription levels of its biofilm-associated genes, agglutinin-like protein 3 ( ALS3), hyphal wall protein 1 ( HWP1), and yeast-form wall protein 1 ( YWP1). We also counted the relative proportion of the three selected gram-negative oral bacteria in saliva. All analyses were performed to determine the relationship between ACE2 expression and C. albicans and gram-negative bacteria.

Results:ACE2 mRNA expression was significantly higher in tongue swab samples than in saliva. However, no significant difference was observed between the patient groups. Conversely, DG patients had a significantly higher abundance of C. albicans in saliva compared to NDG patients and control group patients. The correlation and sensitivity/specificity relationship between ACE2 expression and C. albicans or the selected oral bacteria were also observed.

Conclusions: The data show that ACE2 expression can be detected in saliva of patients with COVID-19 and its association with C. albicans and gram-negative oral bacteria might contribute toward developing an oral dysbiosis based predictor for prognosis of COVID-19 severity.

Pathogenic Mechanisms of Fusobacterium nucleatum on Oral Epithelial Cells

Periodontitis is an oral chronic inflammatory disease and may cause tooth loss in adults. Oral epithelial cells provide a barrier for bacteria and participate in the immune response. Fusobacterium nucleatum (F. nucleatum) is one of the common inhabitants of the oral cavity and has been identified as a potential etiologic bacterial agent of oral diseases, such as periodontitis and oral carcinomas. F. nucleatum has been shown to be of importance in the development of diverse human cancers. In the dental biofilm, it exhibits a structural role as a bridging organism, connecting primary colonizers to the largely anaerobic secondary colonizers. It expresses adhesins and is able to induce host cell responses, including the upregulation of defensins and the release of chemokines and interleukins. Like other microorganisms, its detection is achieved through germline-encoded pattern-recognition receptors (PRRs) and pathogen-associated molecular patterns (PAMPs). By identification of the pathogenic mechanisms of F. nucleatum it will be possible to develop effective methods for the diagnosis, prevention, and treatment of diseases in which a F. nucleatum infection is involved. This review summarizes the recent progress in research targeting F. nucleatum and its impact on oral epithelial cells.

Potential Roles of Enterochromaffin Cells in Early Life Stress-Induced Irritable Bowel Syndrome

Irritable bowel syndrome (IBS) is one of the most common functional gastrointestinal disorders, also known as disorders of the gut–brain interaction; however, the pathophysiology of IBS remains unclear. Early life stress (ELS) is one of the most common risk factors for IBS development. However, the molecular mechanisms by which ELS induces IBS remain unclear. Enterochromaffin cells (ECs), as a prime source of peripheral serotonin (5-HT), play a pivotal role in intestinal motility, secretion, proinflammatory and anti-inflammatory effects, and visceral sensation. ECs can sense various stimuli and microbiota metabolites such as short-chain fatty acids (SCFAs) and secondary bile acids. ECs can sense the luminal environment and transmit signals to the brain via exogenous vagal and spinal nerve afferents. Increasing evidence suggests that an ECs-5-HT signaling imbalance plays a crucial role in the pathogenesis of ELS-induced IBS. A recent study using a maternal separation (MS) animal model mimicking ELS showed that MS induced expansion of intestinal stem cells and their differentiation toward secretory lineages, including ECs, leading to ECs hyperplasia, increased 5-HT production, and visceral hyperalgesia. This suggests that ELS-induced IBS may be associated with increased ECs-5-HT signaling. Furthermore, ECs are closely related to corticotropin-releasing hormone, mast cells, neuron growth factor, bile acids, and SCFAs, all of which contribute to the pathogenesis of IBS. Collectively, ECs may play a role in the pathogenesis of ELS-induced IBS. Therefore, this review summarizes the physiological function of ECs and focuses on their potential role in the pathogenesis of IBS based on clinical and pre-clinical evidence.

Gut microbiome characteristics of comorbid generalized anxiety disorder and functional gastrointestinal disease: Correlation with alexithymia and personality traits

OBJECTIVE

The aim of this study was to investigate the characteristics of intestinal flora in patients with functional gastroenteropathy and generalized anxiety disorder (GAD) and the relationship between intestinal flora and psychological factors.

MATERIALS AND METHODS

From March 2020 to December 2020, a total of 35 patients with functional gastroenteropathy and generalized anxiety disorder, 30 healthy controls, 16 patients with functional gastroenteropathy, and 44 patients with generalized anxiety disorder were selected from the Affiliated Hospital of Guizhou Medical University. Fecal samples were collected from each group, and the related psychophysiological factors scales (Hamilton Anxiety Scale, Hamilton Depression Scale, Neurotic Personality Questionnaire, concept of illness questionnaire, Toronto Alexithymia Scale, Severity of Physical Symptoms Scale, and Cognitive Emotion Regulation Questionnaire) were improved. 16S rRNA high-pass sequencing was used to determine the correlation between intestinal flora changes and functional gastroenteropathy with generalized anxiety disorder. Then, the scale and gut microbiota results were analyzed for correlation to determine the correlation between personality traits and gut microbiota.

RESULTS

We found similar intestinal microbiota in patients with functional gastroenterology, generalized anxiety disorder, and functional gastroenteropathy with generalized anxiety disorder. But the relative abundance of Clostridium was significantly increased in patients with functional gastrointestinal disease (FGID) and generalized anxiety. The relative abundance of Haemophilus influenzae was significantly increased in patients with functional gastrointestinal disease without a generalized anxiety disorder. The intestinal microecological composition was significantly correlated with personality traits.

CONCLUSION

Functional gastrointestinal disease comorbidity GAD may be related to an increase in the relative abundance of Fusobacterium. FGID non-comorbidity GAD may be related to the increased relative abundance of Hemophilus. The increased relative abundance of Fusobacterium and Megamonas is associated with personality traits such as difficulty describing feelings and difficulty identifying feelings, neuroticism, and negative cognition of disease.

Understanding of the Site-Specific Microbial Patterns towards Accurate Identification for Patients with Diarrhea-Predominant Irritable Bowel Syndrome

Fecal microbial community could not fully represent the intestinal microbial community. However, most studies analyzing diarrhea-dominant irritable bowel syndrome (IBS-D) were mainly based on fecal samples. We aimed to characterize the IBS-D microbial community patterns using samples at multiple intestinal sites. This study recruited 74 IBS-D patients and 20 healthy controls (HC). 22.34%, 8.51%, 14.89%, and 54.26% of them contributed to one, two, three, and four sites: duodenal mucosa (DM), duodenal lumen (DL), rectal mucosa (RM), and rectal lumen (RL) of intestinal samples, respectively. Then 16S rRNA gene analysis was performed on these 283 samples. The result showed that IBS-D microbial communities have specific patterns at each intestinal site differing from that of HC. Across hosts and sites, Bacillus, Burkholderia, and Faecalibacterium were the representative genera in duodenum of IBS-D, duodenum of HC, and rectum of HC, respectively. Samples from mucosa and lumen in rectum were highly distinguishable, regardless of IBS-D and HC. Additionally, IBS-D patients have lower microbial co-abundance network connectivity. Moreover, RM site-specific biomarker: Bacteroides used alone or together with Prevotella and Oscillospira in RM showed outstanding performance in IBS-D diagnosis. Furthermore, Bacteroides and Prevotella in RM were strongly related to the severity of abdominal pain, abdominal discomfort, and bloating in IBS-D patients. In summary, this study also confirmed fecal microbial community could not fully characterize intestinal microbial communities. Among these site-specific microbial communities, RM microbial community would be more applicable in the diagnosis of IBS-D.

IMPORTANCE Microbial community varied from one site to another along the gastrointestinal tract, but current studies about intestinal microbial community in IBS-D were mainly based on fecal samples. Based on 283 intestinal samples collected from DM, DL, RM, and RL of HC and IBS-D, we found different intestinal sites had their site-specific microbial patterns in IBS-D. Notably, RM site-specific microbes Bacteroides, Prevotella, and Oscillospira could be used to discriminate IBS-D from HC accurately. Our findings could help clinicians realize the great potential of the intestinal microbial community in RM for better diagnosis of IBS-D patients.

Interplay between gut microbiota and bile acids in diarrhoea-predominant irritable bowel syndrome: a review

Irritable bowel syndrome (IBS) is a common functional gastrointestinal disease that disturbs the physiology and psychology of patients and increases the burden on families, the healthcare system, society, and economic development, affecting more and more people around the world. Despite the multiple factors that account for IBS remaining incompletely studied, emerging evidence demonstrated the abnormal changes in gut microbiota and bile acids (BAs) metabolism closely associated with IBS. Moreover, microbiota drives significant modifications for BAs, consisting of deconjugation, 7α-dehydroxylation, oxidation, epimerization, desulfation, esterification, and so on, while BAs, in turn, affect the microbiota directly or indirectly. In light of the complex connection among gut microbiota, BAs, and IBS, it is urgent to review the latest research progress in this field. In this review, we described the disorders of intestinal microecology and BAs profiles in IBS-D and also highlighted the cross-talk between gut microbiota and BAs in the context of IBS-D. Integrating these, we suggest that new therapeutic strategies targeting the microbiota-BAs axis for IBS-D, even for other related diseases caused by bacteria-bile acid dysbiosis should be expected.

Bacterial variation in the oral microbiota in multiple sclerosis patients

BACKGROUND

Microorganisms in oral cavity are called oral microbiota, while microbiome consists of total genome content of microorganisms in a host. Interaction between host and microorganisms is important in nervous system development and nervous diseases such as Autism, Alzheimer, Parkinson and Multiple Sclerosis (MS). Bacterial infections, as an environmental factor in MS pathogenesis play role in T helper 17(Th17) increase and it enhancing the production of pro-inflammatory cytokines such as Interlukin-21(IL-21), IL-17 and IL -22. Oral microbiota consists diverse populations of cultivable and uncultivable bacterial species. Denaturing gradient gel electrophoresis (DGGE) is an acceptable method for identification of uncultivable bacteria. In this study, we compared the bacterial population diversity in the oral cavity between MS and healthy people.

METHODS

From October to March 2019, samples were taken at Kermanshah University of Medical Sciences' MS patients center. A total of 30 samples were taken from MS patients and another 30 samples were taken from healthy people. Phenotypic tests were used to identify bacteria after pure cultures were obtained. DNA was extracted from 1 mL of saliva, and PCR products produced with primers were electrophoresed on polyacrylamide gels.

RESULTS

The genera Staphylococcus, Actinomyces, Fusobacterium, Bacteroides, Porphyromonas, Prevotella, Veillonella, Propionibacterium and uncultivable bacteria with accession number MW880919-25, JQ477416.1, KF074888.1 and several other un-culturable strains were significantly more abundant in the MS group while Lactobacillus and Peptostreptococcus were more prevalent in the normal healthy group according to logistic regression method.

CONCLUSION

Oral micro-organisms may alleviate or exacerbate inflammatory condition which impact MS disease pathogenesis. It may be assumed that controlling oral infections may result in reduction of MS disease progression.

Fecal microbiota profiling in irritable bowel syndrome and inflammatory bowel disease patients with irritable bowel syndrome-type symptoms

BACKGROUND

The intestinal microbiota is thought to be involved in the occurrence of inflammatory bowel disease in remission with irritable bowel syndrome (IBS)-type symptoms, but the specific distinct profile of these bacteria remains unclear. This cross-sectional study aims to investigate the fecal microbiota profiling in patients with these diseases.

METHODS

Fecal samples from 97 subjects, including Crohn's disease patients in remission with IBS-type symptoms (CDR-IBS+) or without IBS-type symptoms (CDR-IBS-), ulcerative colitis patients in remission with IBS-type symptoms (UCR-IBS+) or without IBS-type symptoms (UCR-IBS-), IBS patients and healthy controls, were collected and applied 16S ribosomal DNA (rDNA) gene sequencing. The V4 hypervariable regions of 16S rDNA gene were amplified and sequenced by the Illumina MiSeq platform. The differences in the sample diversity index in groups were analyzed with R software.

RESULTS

The richness of the intestinal microbiota in the CDR-IBS group was markedly lower than those in the control and IBS groups based on the analysis of observed species and the Chao index (P < 0.05). The observed species index in the CDR-IBS+ group was higher than that in the CDR-IBS- group (median index: 254.8 vs 203, P = 0.036). No difference was found in alpha diversity between UCR patients with IBS-type symptoms and those without related symptoms. At the genus level, the number of Faecalibacterium in CDR patients with IBS-type symptoms increased significantly, while Fusobacterium decreased versus those without such symptoms (mean relative abundance of Faecalibacterium: 20.35% vs 5.18%, P < 0.05; Fusobacterium: 1.51% vs 5.2%, P < 0.05). However, compared with the UCR-IBS- group, the number of Faecalibacterium in the UCR-IBS+ group decreased, while the number of Streptococcus increased, but there was no significant difference in the genus structure. The abundance and composition of the microbiota of IBS patients were not distinct from those of healthy controls.

CONCLUSIONS

The IBS-type symptoms in CD patients in remission may be related to an increase in Faecalibacterium and a decrease in Fusobacterium. The IBS-type symptoms in UC patients in remission cannot be explained by changes in the abundance and structure of the intestinal microbiota.

Crosstalk Between Intestinal Serotonergic System and Pattern Recognition Receptors on the Microbiota-Gut-Brain Axis

Disruption of the microbiota-gut-brain axis results in a wide range of pathologies that are affected, from the brain to the intestine. Gut hormones released by enteroendocrine cells to the gastrointestinal (GI) tract are important signaling molecules within this axis. In the search for the language that allows microbiota to communicate with the gut and the brain, serotonin seems to be the most important mediator. In recent years, serotonin has emerged as a key neurotransmitter in the gut-brain axis because it largely contributes to both GI and brain physiology. In addition, intestinal microbiota are crucial in serotonin signaling, which gives more relevance to the role of the serotonin as an important mediator in microbiota-host interactions. Despite the numerous investigations focused on the gut-brain axis and the pathologies associated, little is known regarding how serotonin can mediate in the microbiota-gut-brain axis. In this review, we will mainly discuss serotonergic system modulation by microbiota as a pathway of communication between intestinal microbes and the body on the microbiota-gut-brain axis, and we explore novel therapeutic approaches for GI diseases and mental disorders.

Porphyromonas gingivalis outer membrane vesicles inhibit the invasion of Fusobacterium nucleatum into oral epithelial cells by downregulating FadA and FomA

Background

Porphyromonas gingivalis (P. gingivalis) and Fusobacterium nucleatum (F. nucleatum) participate in the formation and progression of periodontitis. They can exert virulence by invading into host cells, but the interaction between them and their specific mechanisms remain unclear. The purpose of this study was to study the effect of P. gingivalis outer membrane vesicles (OMVs) on the ability of F. nucleatum to invade oral epithelial cells, and the reasons for the influence.

Methods

The invasion abilities of the two bacteria were detected separately after mixed infection of P. gingivalis and F. nucleatum. Next, P. gingivalis OMVs were extracted with the kit, and their influence on the invasion ability of F. nucleatum was tested. The effects of P. gingivalis OMVs on F. nucleatum were evaluated by assessment of bacterial morphology, growth curves, auto‐aggregation morphology, and the expression of adhesion‐related proteins FadA and FomA.

Results

Our results showed that P. gingivalis inhibited the invasion of F. nucleatum into oral epithelial cells but F. nucleatum promoted the invasion of P. gingivalis. In subsequent experiments, we extracted P. gingivalis OMVs successfully and revealed that proteases in P. gingivalis OMVs inhibited the invasion of F. nucleatum into oral epithelial cells. Furthermore, P. gingivalis OMVs did not affect the morphology and proliferation of F. nucleatum, but proteases inside decreased the auto‐aggregation of F. nucleatum. Additionally, proteases in P. gingivalis OMVs reduced the expression levels of F. nucleatum surface adhesion‐related proteins FadA and FomA.

Conclusion

Our study demonstrated that proteases in P. gingivalis OMVs inhibited the invasion of F. nucleatum into oral epithelial cells by downregulating FadA and FomA.

Looking into key bacterial proteins involved in gut dysbiosis

The gastrointestinal microbiota plays a pivotal role in health and has been linked to many diseases. With the rapid accumulation of pyrosequencing data of the bacterial composition, the causal-effect relationship between specific dysbiosis features and diseases is now being explored. The aim of this review is to describe the key functional bacterial proteins and antigens in the context of dysbiosis related-diseases. We subjectively classify the key functional proteins into two categories: Primary key proteins and secondary key proteins. The primary key proteins mainly act by themselves and include biofilm inhibitors, toxin degraders, oncogene degraders, adipose metabolism modulators, anti-inflammatory peptides, bacteriocins, host cell regulators, adhesion and invasion molecules, and intestinal barrier regulators. The secondary key proteins mainly act by eliciting host immune responses and include flagellin, outer membrane proteins, and other autoantibody-related antigens. Knowledge of key bacterial proteins is limited compared to the rich microbiome data. Understanding and focusing on these key proteins will pave the way for future mechanistic level cause-effect studies of gut dysbiosis and diseases.

[Irritable bowel syndrome: Role of gut microbiota]

Irritable Bowel Syndrome (IBS) is a functional disorder of the gastrointestinal tract with high prevalence. IBS, in particular the diarrheic subtype, is associated with alterations in gut microbiota composition and functionality, called dysbiosis. However, the treatment of this disease mainly relies on the patient's symptoms without considering the gut microbiota perturbations. In this review, we present epidemiological data about IBS-D. Then, we describe the main pathophysiological mechanisms associated with this disease, by focusing on gut microbiota alterations. We end up discussing the current therapies now available.

Comparative Analysis of Milk Microbiomes and Their Association with Bovine Mastitis in Two Farms in Central Russia

Bovine mastitis is a widespread infectious disease. In addition to the economic damages associated with reduced milk yield due to mastitis, the problem of food contamination by microorganism metabolites, in particular toxins, is also a concern. Horizontal transfer of microorganisms from animal populations to humans can also be complicated by antibiotic resistance. Therefore, bovine mastitis is relevant to the study of microbiology and veterinary medicine. In this study, we investigated the microbiome of milk samples from healthy cows and cows with different forms of mastitis from individual quarters of the udder of cows during first and second lactation. Total DNA was extracted from milk samples. The V3-V4 regions of the bacterial 16S rRNA genes from each sample were amplified to generate a library via high-throughput sequencing. We revealed significant dominance of several operational taxonomic units (OTUs) corresponding mostly to groups of Staphylococcus aureus, Aerococcus spp., and Streptococcus spp. In addition, we unexpectedly identified Streptococcus thermophilus in samples with high SCC quantities. We found some infectious agents that characterized summer mastitis. We demonstrated that in Central Russia, mastitis is associated with a wide variety of causal organisms. We observed some differences in the diversity of the two investigated farms. However, we did not find any significant difference among healthy, mastitis and subclinical samples according to their SCC status from either farms by principal component analysis. Linear discriminant analysis effect size (LEfSe) confirmed the presence of several indicator genera in farms from Moscow and the Tula Region. These results confirm the complex bacterial etiology of bovine mastitis.

Oral-Gut Microbiome Axis in Gastrointestinal Disease and Cancer

It is well-known that microbiota dysbiosis is closely associated with numerous diseases in the human body. The oral cavity and gut are the two largest microbial habitats, playing a major role in microbiome-associated diseases. Even though the oral cavity and gut are continuous regions connected through the gastrointestinal tract, the oral and gut microbiome profiles are well-segregated due to the oral-gut barrier. However, the oral microbiota can translocate to the intestinal mucosa in conditions of the oral-gut barrier dysfunction. Inversely, the gut-to-oral microbial transmission occurs as well in inter- and intrapersonal manners. Recently, it has been reported that oral and gut microbiomes interdependently regulate physiological functions and pathological processes. Oral-to-gut and gut-to-oral microbial transmissions can shape and/or reshape the microbial ecosystem in both habitats, eventually modulating pathogenesis of disease. However, the oral-gut microbial interaction in pathogenesis has been underappreciated to date. Here, we will highlight the oral-gut microbiome crosstalk and its implications in the pathogenesis of the gastrointestinal disease and cancer. Better understanding the role of the oral-gut microbiome axis in pathogenesis will be advantageous for precise diagnosis/prognosis and effective treatment.

Oral–Gut Microbiome Axis in Gastrointestinal Disease and Cancer

It is well-known that microbiota dysbiosis is closely associated with numerous diseases in the human body. The oral cavity and gut are the two largest microbial habitats, playing a major role in microbiome-associated diseases. Even though the oral cavity and gut are continuous regions connected through the gastrointestinal tract, the oral and gut microbiome profiles are well-segregated due to the oral–gut barrier. However, the oral microbiota can translocate to the intestinal mucosa in conditions of the oral–gut barrier dysfunction. Inversely, the gut-to-oral microbial transmission occurs as well in inter- and intrapersonal manners. Recently, it has been reported that oral and gut microbiomes interdependently regulate physiological functions and pathological processes. Oral-to-gut and gut-to-oral microbial transmissions can shape and/or reshape the microbial ecosystem in both habitats, eventually modulating pathogenesis of disease. However, the oral–gut microbial interaction in pathogenesis has been underappreciated to date. Here, we will highlight the oral–gut microbiome crosstalk and its implications in the pathogenesis of the gastrointestinal disease and cancer. Better understanding the role of the oral–gut microbiome axis in pathogenesis will be advantageous for precise diagnosis/prognosis and effective treatment.