Relationship Between Dietary Fiber Intake and Short-Chain Fatty Acid-Producing Bacteria During Critical Illness: A Prospective Cohort Study

Quantifying fecal and plasma short-chain fatty acids in healthy Thai individuals

Short-chain fatty acids (SCFAs) are involved in important physiological processes such as gut health and immune response, and changes in SCFA levels can be indicative of disease. Despite the importance of SCFAs in human health and disease, reference values for fecal and plasma SCFA concentrations in healthy individuals are scarce. To address this gap in current knowledge, we developed a simple and reliable derivatization-free GC-TOFMS method for quantifying fecal and plasma SCFAs in healthy individuals. We targeted six linear- and seven branched-SCFAs, obtaining method recoveries of 73-88% and 83-134% in fecal and plasma matrices, respectively. The developed methods are simpler, faster, and more sensitive than previously published methods and are well suited for large-scale studies. Analysis of samples from 157 medically confirmed healthy individuals showed that the total SCFAs in the feces and plasma were 34.1 ± 15.3 µmol/g and 60.0 ± 45.9 µM, respectively. In fecal samples, acetic acid (Ace), propionic acid (Pro), and butanoic acid (But) were all significant, collectively accounting for 89% of the total SCFAs, whereas the only major SCFA in plasma samples was Ace, constituting of 93% of the total plasma SCFAs. There were no statistically significant differences in the total fecal and plasma SCFA concentrations between sexes or among age groups. The data revealed, however, a positive correlation for several nutrients, such as carbohydrate, fat, iron from vegetables, and water, to most of the targeted SCFAs. This is the first large-scale study to report SCFA reference intervals in the plasma and feces of healthy individuals, and thereby delivers valuable data for microbiome, metabolomics, and biomarker research.

Effects of different dietary fiber supplement strategies on incidence of acute gastrointestinal injury in ICU patients: A prospective observational study

OBJECTIVE

This study aimed to explore the effects of dietary fiber (DF) supplement strategies on the incidence of acute gastrointestinal injury (AGI) in critically ill patients.

DESIGN

A prospective observational study.

SETTING

The study was conducted in the First Affiliated Hospital of Soochow University from April 2021 to March 2023.

METHODS

Using a five-day dietary log counted the amount of DF supplement. The best fitting trajectories of DF supplement were determined based on the latent class trajectory modelling (LCTM). The data of AGI were evaluated on the day 5 (D5) and day 7 (D7) after intensive care unit admission.

RESULTS

A total of 179 patients were included in the study. The LCTM yielded a four-trajectories of models, named; Sustained Low - Group, Slowly Rising - Group, Early Supplement & Slowly Rising - Group and Rapidly Rising - Group, respectively. The incidences of AGI on D5 and D7 were 51.4 % and 40.0 %, respectively. There was an increased risk in the grade of AGI in the Sustained Low - Group compared with the Rapidly Rising - Group on D5 [odds ratio (OR), 4.8; 95 % confidence interval (CI), 1.9-12.1] and D7 (OR, 12.0; 95 % CI, 3.9-37.0); and an increased risk in the Slowly Rising - Group on D5 (OR, 3.6; 95 % CI, 1.3-9.9).

CONCLUSION

The supplement of DF in critically ill patients may be insufficient and the incidence of AGI is high. Sustained low and slow rising DF supplement may be associated with an increased risk in the AGI.

IMPLICATIONS FOR CLINICAL PRACTICE

The clinical staff could focus on the supplementation of not only the three macronutrients, but also DF in critically ill patients.

Interactions between Dietary Antioxidants, Dietary Fiber and the Gut Microbiome: Their Putative Role in Inflammation and Cancer

The intricate relationship between the gastrointestinal (GI) microbiome and the progression of chronic non-communicable diseases underscores the significance of developing strategies to modulate the GI microbiota for promoting human health. The administration of probiotics and prebiotics represents a good strategy that enhances the population of beneficial bacteria in the intestinal lumen post-consumption, which has a positive impact on human health. In addition, dietary fibers serve as a significant energy source for bacteria inhabiting the cecum and colon. Research articles and reviews sourced from various global databases were systematically analyzed using specific phrases and keywords to investigate these relationships. There is a clear association between dietary fiber intake and improved colon function, gut motility, and reduced colorectal cancer (CRC) risk. Moreover, the state of health is reflected in the reciprocal and bidirectional relationships among food, dietary antioxidants, inflammation, and body composition. They are known for their antioxidant properties and their ability to inhibit angiogenesis, metastasis, and cell proliferation. Additionally, they promote cell survival, modulate immune and inflammatory responses, and inactivate pro-carcinogens. These actions collectively contribute to their role in cancer prevention. In different investigations, antioxidant supplements containing vitamins have been shown to lower the risk of specific cancer types. In contrast, some evidence suggests that taking antioxidant supplements can increase the risk of developing cancer. Ultimately, collaborative efforts among immunologists, clinicians, nutritionists, and dietitians are imperative for designing well-structured nutritional trials to corroborate the clinical efficacy of dietary therapy in managing inflammation and preventing carcinogenesis. This review seeks to explore the interrelationships among dietary antioxidants, dietary fiber, and the gut microbiome, with a particular focus on their potential implications in inflammation and cancer.

The importance of providing dietary fiber in medical and surgical critical care

The early provision of soluble/insoluble fiber to the patient who is critically ill has been controversial in the past. Especially in the setting of hemodynamic instability, dysmotility, or impaired gastrointestinal transit, fear of inspissation of formula with precipitation of nonocclusive mesenteric ischemia (NOMI)/nonocclusive bowel necrosis (NOBN) limited its utilization by medical and surgical intensivists. The incidence of NOMI/NOBN has been estimated at 0.2%-0.3% for all intensive care unit (ICU) patients receiving enteral nutrition (EN), and the occurrence of inspissated formula is even less. The science supporting a benefit from providing fiber has recently increased exponentially. The fermentation of soluble fibers leading to the production of short chain fatty acids supports gut barrier function, modulates immune responses, and promotes refaunation of commensal organisms. The "butyrate effect" refers to local (gastrointestinal tract) and systemic anti-inflammatory responses mediated by the M2 polarization of macrophages, inhibition of histone deacetylase, and stimulation of ubiquitous G protein receptors. Both soluble and insoluble fiber have been shown to promote intestinal motility, reduce feeding intolerance, and shorten hospital length of stay. The benefit of providing dietary fiber early upon admission to the ICU outweighs its minimal associated risk. The point at which the intensivist determines that is safe to initiate EN, both soluble and insoluble fiber should be included in the enteral formulation.

Unraveling the microbiome-metabolome nexus: a comprehensive study protocol for personalized management of Behçet's disease using explainable artificial intelligence

The presented study protocol outlines a comprehensive investigation into the interplay among the human microbiota, volatilome, and disease biomarkers, with a specific focus on Behçet's disease (BD) using methods based on explainable artificial intelligence. The protocol is structured in three phases. During the initial three-month clinical study, participants will be divided into control and experimental groups. The experimental groups will receive a soluble fiber-based dietary supplement alongside standard therapy. Data collection will encompass oral and fecal microbiota, breath samples, clinical characteristics, laboratory parameters, and dietary habits. The subsequent biological data analysis will involve gas chromatography, mass spectrometry, and metagenetic analysis to examine the volatilome and microbiota composition of salivary and fecal samples. Additionally, chemical characterization of breath samples will be performed. The third phase introduces Explainable Artificial Intelligence (XAI) for the analysis of the collected data. This novel approach aims to evaluate eubiosis and dysbiosis conditions, identify markers associated with BD, dietary habits, and the supplement. Primary objectives include establishing correlations between microbiota, volatilome, phenotypic BD characteristics, and identifying patient groups with shared features. The study aims to identify taxonomic units and metabolic markers predicting clinical outcomes, assess the supplement's impact, and investigate the relationship between dietary habits and patient outcomes. This protocol contributes to understanding the microbiome's role in health and disease and pioneers an XAI-driven approach for personalized BD management. With 70 recruited BD patients, XAI algorithms will analyze multi-modal clinical data, potentially revolutionizing BD management and paving the way for improved patient outcomes.

Association of early dietary fiber intake and mortality in septic patients with mechanical ventilation based on MIMIC IV 2.1 database: a cohort study

BACKGROUND

Whether early dietary fiber intake in septic patients is associated with a better clinical prognosis remains unclear, especially the time and the amount. Therefore, we assessed the association between early dietary fiber intake and clinical outcomes in septic patients by examining an extensive database.

METHODS

We conducted a retrospective cohort study using data from the MIMIC IV 2.1 database, focusing on consecutive septic patients requiring mechanical ventilation in medical or mixed medical-surgical ICUs. We collected patient demographics and nutritional data. Dietary fiber amounts were calculated according to enteral nutrition instructions from manufacturers within the first 72 h after admission. After adjusting for covariates, we employed restricted cubic spline (RCS) regression to investigate the relationship between fiber intake (FI) and 28-day mortality. Patients were categorized into three groups based on their fiber index (FI) within 72 h of admission: low fiber index (LFI) group when FI was < 3 g/(%), medium fiber index (MFI) group when FI ranged from 3 to 35 g(%), and high fiber index (HFI) group when FI ≥ 35 g(%). Univariate and multivariate Cox proportional hazards regression models were utilized to assess the association between early FI and 28-day mortality. We ultimately employed Kaplan-Meier (KM) curves and log-rank test visually represent the association between FI and 90-day mortality. The second outcomes include ICU-acquired infections and the hospital and ICU death, length of hospital and ICU stay, and length of mechanical ventilation.

RESULTS

Among 1057 subjects, 562 (53.2%) were male, with a median age of 64.8 years (IQR 53.4-75.2). We observed a J-shaped relationship between FI and 28-day mortality. The MFI group exhibited the lowest 28-day mortality [adjusted HR 0.64 (0.45-0.91), p = 0.013] and the lowest rate of hospital mortality [adjusted OR 0.60 (0.39-0.93), p = 0.022], with no statistically significant differences noted in the HFI group when compared to the LFI group. Similar patterns were observed for 60-day and 90-day mortality. However, no statistically significant differences were observed in other secondary outcomes after adjusting for covariates.

CONCLUSION

Early medium fiber index intake improved 28-day mortality and lower hospital mortality in septic M/SICU patients on mechanical ventilation.

Pathogenesis and therapeutic opportunities of gut microbiome dysbiosis in critical illness

For many years, it has been hypothesized that pathological changes to the gut microbiome in critical illness is a driver of infections, organ dysfunction, and other adverse outcomes in the intensive care unit (ICU). The advent of contemporary microbiome methodologies and multi-omics tools have allowed researchers to test this hypothesis by dissecting host-microbe interactions in the gut to better define its contribution to critical illness pathogenesis. Observational studies of patients in ICUs have revealed that gut microbial communities are profoundly altered in critical illness, characterized by markedly reduced alpha diversity, loss of commensal taxa, and expansion of potential pathogens. These key features of ICU gut dysbiosis have been associated with adverse outcomes including life-threatening hospital-acquired (nosocomial) infections. Current research strives to define cellular and molecular mechanisms connecting gut dysbiosis with infections and other outcomes, and to identify opportunities for therapeutic modulation of host-microbe interactions. This review synthesizes evidence from studies of critically ill patients that have informed our understanding of intestinal dysbiosis in the ICU, mechanisms linking dysbiosis to infections and other adverse outcomes, as well as clinical trials of microbiota-modifying therapies. Additionally, we discuss novel avenues for precision microbial therapeutics to combat nosocomial infections and other life-threatening complications of critical illness.

Diet-driven microbiome changes and physical activity in cancer patients

Exploring the role of the gut microbiome in oncology is gaining more attention, mainly due to its ability to shape the immune system in cancer patients. A well-balanced microbial composition forms a symbiotic relationship with the host organism. Mounting evidence supports the potential of modifiable lifestyle factors, such as diet and physical activity, in restoring intestinal dysbiosis related to cancer development and treatment. In this Minireview, we describe the host-microbiome interplay following different dietary patterns, including a high-fat diet, fiber-rich diet, diet rich in rice and beans, Mediterranean diet, ketogenic diet, and physical activity in preclinical findings and clinical settings. According to the results, nutrition is a critical factor influencing the composition of gut microbial communities. Therefore, knowledge about the patient's nutritional status in pre-treatment and treatment becomes crucial for further management. A combination of individualized dietary habits and professional training plans might help to maintain gut homeostasis, potentially improving the response to anti-cancer therapy and the quality of life in cancer survivors. However, a deep understanding of underlying mechanisms and large clinical trials are needed to uncover clinically relevant correlations for personalized treatment approaches leading to better outcomes for cancer patients.

Gut Microbiome-Based Therapeutics in Critically Ill Adult Patients-A Narrative Review

The gut microbiota plays a crucial role in the human microenvironment. Dysbiosis of the gut microbiota is a common pathophysiological phenomenon in critically ill patients. Therefore, utilizing intestinal microbiota to prevent complications and improve the prognosis of critically ill patients is a possible therapeutic direction. The gut microbiome-based therapeutics approach focuses on improving intestinal microbiota homeostasis by modulating its diversity, or treating critical illness by altering the metabolites of intestinal microbiota. There is growing evidence that fecal microbiota transplantation (FMT), selective digestive decontamination (SDD), and microbiota-derived therapies are all effective treatments for critical illness. However, different treatments are appropriate for different conditions, and more evidence is needed to support the selection of optimal gut microbiota-related treatments for different diseases. This narrative review summarizes the curative effects and limitations of microbiome-based therapeutics in different critically ill adult patients, aiming to provide possible directions for gut microbiome-based therapeutics for critically ill patients such as ventilator-associated pneumonia, sepsis, acute respiratory distress syndrome, and COVID-19, etc.

Impact of Dietary Fiber on Inflammation and Insulin Resistance in Older Patients: A Narrative Review

The beneficial impact of dietary fiber on the prevention and management of several chronic conditions associated with aging, including diabetes, neurodegenerative, cardiovascular diseases, and cancer, is well-known. High fiber intake has been associated with reduced inflammatory mediators counteracting the low-grade chronic inflammation typical of older age. In addition, dietary fiber improves postprandial glucose response and insulin resistance. In contrast, during acute diseases, its effects on insulin resistance and modulation of immune response are unclear. The aim of this narrative is to summarize the evidence for the potential impact of dietary fiber on inflammation and insulin resistance in older adults, with a particular focus on those acutely ill. Available evidence suggests that dietary fiber has the potential to counteract acute inflammation and to improve metabolic health. In addition, modulation of gut microbiota composition may contribute to improved immune function, particularly in the setting of aging-associated dysbiosis. This phenomenon has relevant implications in those acutely ill, in whom dysbiosis can be exacerbated. Our review leads to the conclusion that dietary interventions based on fiber manipulation could exploit its beneficial effects on inflammation and insulin resistance, if conducted from a precision nutrition perspective. This could also be true for the acutely ill patient, even though strong evidence is lacking.

Enteral nutrition product formulations: A review of available products and indications for use

When oral nutrition is not feasible, enteral nutrition (EN) therapy is often considered the preferred route of nutrition support to meet the nutrient needs of individuals with a functional gastrointestinal tract across multiple levels of care (critical care, acute care, and home care). Enteral formulations have progressively evolved over the last 50 years from the simple blending of hospital food thin enough to run through a feeding tube, to the development of commercial standard formulas, followed by specialized formulas with immune-modulating and disease-specific qualities, to the most recent shift to food-based or blenderized EN composed of natural, whole foods with perceived health benefits. With the vast number of enteral formulations on the market, clinicians may be overwhelmed trying to determine proven vs theoretical benefits. This review is intended to explore differences in enteral formulations, identify implications for clinical practice, and review evidenced-based clinical guidelines to assist clinicians in enteral formula selection.

Impact of Intensive Care Unit Nutrition on the Microbiome and Patient Outcomes

The bipartite relationship between nutrition and the intestinal microbiome represents an exciting frontier in critical care medicine. In this review, the authors first address these topics independently, leading with a summary of recent clinical studies assessing intensive care unit nutritional strategies, followed by an exploration of the microbiome in the context of perioperative and intensive care, including recent clinical data implicating microbial dysbiosis as a key driver of clinical outcomes. Finally, the authors address the intersection of nutrition and the microbiome, exploring the use of supplemental pre-, pro-, and synbiotics to influence microbial composition and improve outcomes in critically ill and postsurgical patients.

Effects of dietary fibre on enteral feeding intolerance and clinical outcomes in critically ill patients: A meta-analysis

BACKGROUND

Although some studies have explored the relationships between dietary fibre and enteral feeding intolerance in critically ill patients, the results are equivocal.

OBJECTIVE

This study aimed to explore the effects of dietary fibre on enteral feeding intolerance and clinical outcomes in critically ill patients.

METHODS

We searched five databases from inception to July 12, 2021. Data were expressed as mean difference or odds ratio with 95% confidence interval.

RESULTS

Thirteen studies enrolled 709 critically ill patients included in the study. The results showed the dietary fibre group had a significantly decreased risk of diarrhea (OR: 0.46, 95% CI: 0.30,0.69, P < 0.001), regurgitation (OR: 0.28, 95%CI: 0.13, 0.60, P < 0.05), vomiting (OR: 0.40, 95%CI: 0.17, 0.92, P < 0.05), constipation (OR: 0.21, 95%CI: 0.09, 0.47, P < 0.001) and mortality (OR:0.34; 95%CI:-0.13, 0.91; P < 0.05) compared with the fibre free group. Besides, there was a significant decrease on time to reach full enteral nutrition (MD:-2.08; 95%CI:-4.05, -0.12; P < 0.05), the duration of the intensive care unit stay (MD:-4.62; 95%CI:-6.60, -2.64; P < 0.001) and hospital stay (MD:-6.42; 95%CI:-9.49, -3.36; P < 0.001) in the dietary fibre group.

CONCLUSIONS

Dietary fibre supplementation may significantly reduce the risk of enteral feeding intolerance and improve the clinical outcomes.

Obesity and critical care nutrition: current practice gaps and directions for future research

Background

This review has been developed following a panel discussion with an international group of experts in the care of patients with obesity in the critical care setting and focuses on current best practices in malnutrition screening and assessment, estimation of energy needs for patients with obesity, the risks and management of sarcopenic obesity, the value of tailored nutrition recommendations, and the emerging role of immunonutrition. Patients admitted to the intensive care unit (ICU) increasingly present with overweight and obesity that require individualized nutrition considerations due to underlying comorbidities, immunological factors such as inflammation, and changes in energy expenditure and other aspects of metabolism. While research continues to accumulate, important knowledge gaps persist in recognizing and managing the complex nutritional needs in ICU patients with obesity. Available malnutrition screening and assessment tools are limited in patients with obesity due to a lack of validation and heterogeneous factors impacting nutrition status in this population. Estimations of energy and protein demands are also complex in patients with obesity and may include estimations based upon ideal, actual, or adjusted body weight. Evidence is still sparse on the role of immunonutrition in patients with obesity, but the presence of inflammation that impacts immune function may suggest a role for these nutrients in hemodynamically stable ICU patients. Educational efforts are needed for all clinicians who care for complex cases of critically ill patients with obesity, with a focus on strategies for optimal nutrition and the consideration of issues such as weight stigma and bias impacting the delivery of care.

Conclusions

Current nutritional strategies for these patients should be undertaken with a focus on individualized care that considers the whole person, including the possibility of preexisting comorbidities, altered metabolism, and chronic stigma, which may impact the provision of nutritional care. Additional research should focus on the applicability of current guidelines and evidence for nutrition therapy in populations with obesity, especially in the setting of critical illness.

The effects of dietary fiber on common complications in critically ill patients; with a special focus on viral infections; a systematic reveiw

Background

Viral infections are mostly highly contagious and may cause widespread health problems. Some studies reported that the dietary fiber (DF) may be effective in reducing the complications of viral infections in intensive care unit (ICU) patients. The present review study aimed to investigate the effect of DF on common complications in critically ill patients with viral infections.

Methods

A literature review was conducted for the published papers in English from January 2001 to July 2021 using related keywords. Studies with clinical trial or case‐control design described the effects of fiber intake on the complications of viral infections in patients admitted to the ICU were collected.

Results

DF may reduce the mortality rate of viral infections through modulating inflammatory processes. A higher intake of DF intake may improve hyperglycemia and impaired glucose tolerance in patients with viral infections. A high‐fiber formula in enteral nutrition was reported to reduce the risk of diarrhea in patients with viral infections.

Conclusion

DF may reduce the complications of viral infections such as inflammation, diarrhea, hyperglycemia, and mortality in critically ill patients. Future longitudinal studies on the amount and type of DF are warranted.

The Impact of the Microbiome on Resistance to Cancer Treatment with Chemotherapeutic Agents and Immunotherapy

Understanding the mechanisms of resistance to therapy in human cancer cells has become a multifaceted limiting factor to achieving optimal cures in cancer patients. Besides genetic and epigenetic alterations, enhanced DNA damage repair activity, deregulation of cell death, overexpression of transmembrane transporters, and complex interactions within the tumor microenvironment, other mechanisms of cancer treatment resistance have been recently proposed. In this review, we will summarize the preclinical and clinical studies highlighting the critical role of the microbiome in the efficacy of cancer treatment, concerning mainly chemotherapy and immunotherapy with immune checkpoint inhibitors. In addition to involvement in drug metabolism and immune surveillance, the production of microbiota-derived metabolites might represent the link between gut/intratumoral bacteria and response to anticancer therapies. Importantly, an emerging trend of using microbiota modulation by probiotics and fecal microbiota transplantation (FMT) to overcome cancer treatment resistance will be also discussed.

The effect of dietary fiber on gut barrier function, gut microbiota, short-chain fatty acids, inflammation and clinical outcomes in critically ill patients: A systematic review and meta-analysis

BACKGROUND

Although some studies have explored the relationships between dietary fiber (DF) supplement and gut barrier function, changes of gut microbiota and other clinical outcomes in critically ill patients, the results from different studies were not consistent.

OBJECTIVE

The purpose of this study was to explore the effect of dietary fiber on gut barrier function, gut microbiota, short-chain fatty acids (SCFAs), inflammation and clinical outcomes in critically ill patients.

METHODS

A search was performed through PubMed, Embase, the Cochrane Central Register of Clinical Trials, Web of Science and EBSCO-host that includes Health Sciences Research from inception to July 12, 2021. Data were pooled using fixed effects model for low heterogeneity and random effects model for high heterogeneity. Data were expressed as mean difference (MD) or odds ratio (OR) with confidence interval.

RESULTS

A total of 21 studies involving 2084 critically ill patients were included. The results showed that there was a significant reduction in intestinal permeability demonstrated by lactulose/rhamnose ratio (MD:-0.04; 95%CI:-0.08, -0.00; P = 0.03) on day 8 in DF supplement group. Three studies reported the relative abundance (RA) of gut microbiota and the results showed the RA of some SCFAs producers increased higher in DF supplement group. There was a significant decrease in C-reactive protein on day 14 (MD:-36.66; 95%CI:-44.40, -28.93; P<0.001) and the duration of hospital stay (MD:-3.16; 95%CI:-5.82, -0.49; P<0.05) after DF supplement. There were no significant differences on SCFAs levels, the duration of mechanical ventilation and mortality between the two groups. However, in subgroup analysis, the results indicated there was a significant reduction on the duration of mechanical ventilation in fiber combined probiotic group (MD:-13; 95%CI:-19.69, -6.31; P<0.001). Besides, significant decreases in the duration of hospital stay and risk of mortality were seen in the subgroups with fiber supplementary dose ≥20 g/d (MD:-5.62; 95%CI: -8.04, -3.21; P<0.0001; OR: 0.18, 95%CI: 0.06, 0.57, P = 0.004), as well as in medical ICU (MD:-4.77; 95%CI: -7.48, -2.07; P<0.01; OR: 0.13; 95%CI: 0.03, 0.65; P<0.05).

CONCLUSIONS

Dietary fiber may improve the gut barrier function, modulate the intestinal microbiota, decrease systemic inflammatory response and may advance the clinical outcomes in critically ill patients. This article is protected by copyright. All rights reserved.

Re-examining chemically defined liquid diets through the lens of the microbiome

Trends in nutritional science are rapidly shifting as information regarding the value of eating unprocessed foods and its salutary effect on the human microbiome emerge. Unravelling the evolution and ecology by which humans have harboured a microbiome that participates in every facet of health and disease is daunting. Most strikingly, the host habitat has sought out naturally occurring foodstuff that can fulfil its own metabolic needs and also the needs of its microbiota, each of which remain inexorably connected to one another. With the introduction of modern medicine and complexities of critical care, came the assumption that the best way to feed a critically ill patient is by delivering fibre-free chemically defined sterile liquid foods (that is, total enteral nutrition). In this Perspective, we uncover the potential flaws in this assumption and discuss how emerging technology in microbiome sciences might inform the best method of feeding malnourished and critically ill patients.

Long-term changes in the gut microbiota after triple therapy, sequential therapy, bismuth quadruple therapy and concomitant therapy for Helicobacter pylori eradication in Chinese children

BACKGROUND

We previously reported that the administration of 14-day standard triple therapy (TT), sequential therapy (ST), bismuth-based quadruple therapy (BT), and concomitant therapy (CT) as the first-line therapy for Helicobacter pylori infection in Chinese children achieved eradication rates of 74.1%, 69.5%, 89.8%, and 84.6%, respectively. In this follow-up study, we further evaluated the short- and long-term effects of the four regimens on the gut microbiota in these children.

METHODS

We prospectively recruited treatment-naïve children with H. pylori infection. Fecal samples were collected at week 0, 2, 6, and 52, and alterations in the gut microbiota were analyzed by 16S rRNA gene sequencing.

RESULTS

Sixty-three patients participated in this study (16 with TT, 15 with ST, 16 with BT and 16 with CT). At week 2, the alpha diversity (Shannon and Chao 1 index) was significantly reduced in the TT (p = 0.008, p < 0.001), ST (p < 0.001, p < 0.001), BT (p < 0.001, p < 0.001) and CT groups (p < 0.001, p < 0.001). Some changes persisted in the ST, BT, and CT groups at week 6, and all were restored (expect p = 0.02 with Chao 1 index in the CT group) at week 52. The beta diversity was significantly changed in the BT (p = 0.001) and CT groups (p = 0.001) 2 weeks post-eradication and restored 1 year after therapy. Immediately after therapy, the relative abundance of Proteobacteria was strikingly increased in the ST (p = 0.005), BT (p < 0.001) and CT groups (p < 0.001), and the genus-level analysis showed that the abundances of 23.1%, 43.3%, 78.6%, and 78% of the bacterial genera in the TT, ST, BT, and CT groups were significantly changed. All these changes returned to almost the pre-eradication level 1 year post-eradication.

CONCLUSION

Eradication of H. pylori infection can lead to transient dysbiosis of gut microbiota, and these changes almost recovered 1 year post-eradication, which indicates the long-term safety of H. pylori therapy.

Safety of Using Enteral Nutrition Formulations Containing Dietary Fiber in Hospitalized Critical Care Patients: A Systematic Review and Meta-Analysis

Enteral nutrition (EN) is the preferred route of nutrition support for patients with critical illness undergoing intensive care. Experts in the field caution against using fiber during EN because of perceived adverse patient outcomes; however, a comprehensive assessment of this topic is not evident to date. In this systematic review and meta-analysis, we searched four databases from inception to April 20, 2020, for studies on adverse events or health outcomes associated with using EN formulations containing fiber in hospitalized adults with critical illness. Nineteen articles were included. Random-effects meta-analysis models showed significantly lower diarrhea scores for fiber groups compared with nonfiber groups (pooled mean difference: -2.78; 95% CI, -4.10 to -1.47) but mixed results for risk of diarrhea between groups, depending on measures used for diarrhea (Hart and Dobb scale, pooled risk ratio [RR]: 0.68; 95% CI, 0.45-1.02; other diarrhea scales, pooled RR: 0.42; 95% CI, 0.20-0.89). Models showed 39% lower risk of gastrointestinal (GI) complications overall for fiber compared with nonfiber groups (pooled RR: 0.61; 95% CI, 0.47-0.79) but no group differences for individual GI complications, mortality, and intensive care unit or hospital length of stay. Analyses stratified by soluble- or mixed-fiber interventions reduced heterogeneity in models but showed identical conclusions. EN formulas with fiber may help reduce incidence and severity of diarrhea and GI complications overall in critically ill patients, without increased risk of other adverse events. Bias among specific GI measures indicates more high-quality studies are needed to verify these conclusions.

Nutritional Status and the Critically Ill Patient: Gut Microbiota and Immuno-Nutrition in I.C.U. at the Time of SARS-COV 2 Pandemic

Background: Gut microbiota is a complex ecosystem of bacteria, viruses, archaea, protozoa and yeasts in our intestine. It has several functions, including maintaining human body equilibrium. Microbial “dysbiosis” can be responsible for outbreak of local and systemic infections, especially in critically ill patients. Methods: to build a narrative review, we performed a Pubmed, Medline and EMBASE search for English language papers, reviews, meta-analyses, case series and randomized controlled trials (RCTs) by keywords and their associations: critically ill patient; nutrition; gut microbiota; probiotics; gut virome; SARS-COV 2. Results: Over the antibiotic-based “selective decontamination”, potentially responsible for drug-resistant microorganisms development, there is growing interest of scientists and the pharmaceutical industry for pre-, probiotics and their associations as safe and reliable remedies restoring gut microbial “eubiosis”. Very first encouraging evidences link different gut microbiota profiles with SARS-COV 2 disease stage and gravity. Thus, there is frame for a probiotic therapeutic approach of COVID-19. Conclusions: gut microbiota remodulation seems to be a promising and safe therapeutic approach to prevent local and systemic multi-resistant bug infections in the intensive care unit (ICU) patients. This approach deserves more and more attention at the time of SARS-COV 2 pandemic.

Gut-liver crosstalk in sepsis-induced liver injury

Sepsis is characterized by a dysregulated immune response to infection leading to life-threatening organ dysfunction. Sepsis-induced liver injury is recognized as a powerful independent predictor of mortality in the intensive care unit. During systemic infections, the liver regulates immune defenses via bacterial clearance, production of acute-phase proteins (APPs) and cytokines, and metabolic adaptation to inflammation. Increased levels of inflammatory cytokines and impaired bacterial clearance and disrupted metabolic products can cause gut microbiota dysbiosis and disruption of the intestinal mucosal barrier. Changes in the gut microbiota play crucial roles in liver injury during sepsis. Bacterial translocation and resulting intestinal inflammation lead to a systemic inflammatory response and acute liver injury. The gut-liver crosstalk is a potential target for therapeutic interventions. This review analyzes the underlying mechanisms for the gut-liver crosstalk in sepsis-induced liver injury.

Long-term changes in the gut microbiota after 14-day bismuth quadruple therapy in penicillin-allergic children

BACKGROUND

Penicillin-allergic children who are infected with Helicobacter pylori constitute a relatively common subgroup. We aimed to study the short-term and long-term effects of bismuth quadruple therapy on gut microbiota in penicillin-allergic children.

METHODS

We prospectively recruited treatment-naive children with H pylori infection and H pylori-negative asymptomatic children as healthy controls. Patients received 14-day bismuth quadruple therapy consisting of omeprazole, clarithromycin, metronidazole, and bismuth. Fecal samples were collected at weeks 0, 2, 6, and 52. Alterations in the gut microbiota were analyzed by 16S rRNA gene sequencing.

RESULTS

Twenty-two subjects (14 gastritis patients, 8 duodenal ulcer patients) and 23 controls participated in this study. At week 2, alpha diversity was reduced in both gastritis (P < .05) and ulcer (except P = .16 with Chao 1 index) patients compared with baseline. Some changes persisted at week 6, and all were restored at week 52. Beta diversity was significantly altered 2 weeks after treatment in the gastritis and duodenal ulcer groups (P = .001, P = .002, respectively) and restored at weeks 6 and 52. The mean relative abundance of Bacteroidetes (P < .001, P = .005, respectively) decreased and that of Proteobacteria increased (P < .001, P = .03, respectively). All alterations recovered at week 6 and 52. In both the gastritis and ulcer groups at week 2, some beneficial bacteria were decreased including Bacteroides (P < .001 and P = .003), Faecalibacterium (P < .001 and P = .02), Phascolarctobacterium (P = .002 and P = .004), Roseburia ( P < .001 and P = .13), Bifidobacterium (P = .08 and P = .04), and Blautia (P < .001 and P = .002). Some detrimental bacteria were increased including Escherichia-Shigella (P < .001 and P = .19), Klebsiella (P < .001, and P = .09), Enterococcus (P < .001 and P = .007), and Streptococcus (P = .002 and P = .004). The changes returned to almost the pre-eradication level 1 year after therapy.

CONCLUSION

Bismuth quadruple therapy causes short-term dysbiosis of the gut microbiota. Most changes recovered 1-year post-eradication, indicating the long-term safety of H pylori therapy.

Gut Microbiota Dysbiosis as a Target for Improved Post-Surgical Outcomes and Improved Patient Care: A Review of Current Literature

ABSTRACT

Critical illness results in significant changes in the human gut microbiota, leading to the breakdown of the intestinal barrier function, which plays a role in the pathogenesis of multiple organ dysfunction. Patients with sepsis/acute respiratory distress syndrome (ARDS) have a profoundly distorted intestinal microbiota rhythm, which plays a considerable role in the development of gut-derived infections and intestinal dysbiosis. Despite recent medical developments, postsurgical complications are associated with a high morbidity and mortality rate. Bacterial translocation, which is the movement of bacteria and bacterial products across the intestinal barrier, was shown to be a mechanism behind sepsis. Current research is focusing on a solution by addressing significant factors that contribute to intestinal dysbiosis, which subsequently leads to multiple organ failure and, thus, mortality. It may, however, be challenging to manipulate the microbiota in critically ill patients for enhanced therapeutic gain. Probiotic manipulation is advantageous for maintaining the gut-barrier defense and for modulating the immune response. Based on available published research, this review aims to address the application of potential strategies in the intensive care unit, supplemented with current therapeutics by the administration of probiotics, prebiotics, and fecal microbiota transplant, to reduce post-surgical complications of sepsis/ARDS in critically ill patients.

Impact of microbiome-based interventions on gastrointestinal pathogen colonization in the intensive care unit

In the intensive care unit (ICU), colonization of the gastrointestinal tract by potentially pathogenic bacteria is common and often precedes clinical infection. Though effective in the short term, traditional antibiotic-based decolonization methods may contribute to rising resistance in the long term. Novel therapies instead focus on restoring gut microbiome equilibrium to achieve pathogen colonization resistance. This review summarizes the existing data regarding microbiome-based approaches to gastrointestinal pathogen colonization in ICU patients with a focus on prebiotics, probiotics, and synbiotics.

Impact of Fiber-Based Enteral Nutrition on the Gut Microbiome of ICU Patients Receiving Broad-Spectrum Antibiotics: A Randomized Pilot Trial

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Objectives:

Dietary fiber increases the abundance of bacteria that metabolize fiber into short-chain fatty acids and confers resistance against gut colonization with multidrug-resistant bacteria. This pilot trial estimated the effect of fiber on gut short-chain fatty acid–producing bacteria in the ICU.

Design:

Randomized, controlled, open label trial.

Setting:

Medical ICU.

Patients:

Twenty ICU adults receiving broad-spectrum IV antibiotics for sepsis.

Intervention:

1:1 randomization to enteral nutrition with mixed soy- and oat-derived fiber (14.3 g fiber/L) versus calorie- and micronutrient-identical enteral nutrition with 0 g/L fiber.

Measurements:

Rectal swabs and whole stools were collected at baseline and on study Days 3, 7, 14, and 30. The primary outcome was within-individual change in the cumulative relative abundance of short-chain fatty acid–producing taxa from baseline to Day 3 based on 16S sequencing of rectal swabs. The secondary outcome was Day 3 cumulative short-chain fatty acid levels based on mass spectrometry of whole stools. Analyses were all intent to treat.

Main Results:

By Day 3, the fiber group received a median of 32.1 g fiber cumulatively (interquartile range, 17.6–54.6) versus 0 g fiber (interquartile range, 0–4.0) in the no fiber group. The median within-individual change in short-chain fatty acid producer relative abundance from baseline to Day 3 was +61% (interquartile range −51 to +1,688) in the fiber group versus −46% (interquartile range, −78 to +13) in the no fiber group (p = 0.28). Whole stool short-chain fatty acid levels on Day 3 were a median of 707 μg short-chain fatty acids/g stool (interquartile range, 190–7,265) in the fiber group versus 118 μg short-chain fatty acids/g stool (interquartile range, 22–1,195) in the no fiber group (p = 0.16).

Conclusions:

Enteral fiber was associated with nonsignificant trends toward increased relative abundance of short-chain fatty acid–producing bacteria and increased short-chain fatty acid levels among ICU patients receiving broad-spectrum IV antibiotics. Larger studies should be undertaken and our results can be used for effect size estimates.

Faecal diversion system usage in an adult intensive care unit

OBJECTIVE

To determine the frequency, indications and complications associated with the use of faecal diversion systems (rectal tubes) in critically ill patients.

DESIGN

A single centre observational study over 15 months.

SETTING

Intensive care unit (ICU).

PARTICIPANTS

Patients admitted during this period.

MAIN OUTCOME MEASURES

Frequency of rectal tubes utilisation in ICU, as well as associated adverse events, with major events defined as lower gastrointestinal bleeding associated with defined blood transfusion of two or more units of red cells or endoscopy or surgical intervention.

RESULTS

Of 3418 admission episodes, there were 111 episodes of rectal tubes inserted in 99 patients. Rectal tubes remained indwelling for a median of 5 days (range, 1-23) for a total of 641 patient-days. The most frequent indication for insertion was excessive bowel motions. A major adverse event was observed in three patients (3%; 0.5 events per 100 device days). Two patients underwent laparotomy and one patient sigmoidoscopy. These patients received between two and 23 units of packed red blood cells. Patients who had a rectal tube inserted had a substantially greater duration of ICU admission (mean, 14 days [SD, 14] v 2.8 days [SD, 3.7]) and hospital mortality (15% v 7.7%; risk ratio, 2.0; 95% CI, 1.2-3.4) as well as an overall higher Australian and New Zealand Risk of Death (ANZROD) score (mean, 27 [SD, 22] v 12.6 [SD, 20]).

CONCLUSION

Rectal tubes appear to be frequently inserted and can lead to major adverse events in critically ill patients.

The Importance of the Microbiome in Critically Ill Patients: Role of Nutrition

Critically ill patients have an alteration in the microbiome in which it becomes a disease-promoting pathobiome. It is characterized by lower bacterial diversity, loss of commensal phyla, like Firmicutes and Bacteroidetes, and a domination of pathogens belonging to the Proteobacteria phylum. Although these alterations are multicausal, many of the treatments administered to these patients, like antibiotics, play a significant role. Critically ill patients also have a hyperpermeable gut barrier and dysregulation of the inflammatory response that favor the development of the pathobiome, translocation of pathogens, and facilitate the emergence of sepsis. In order to restore the homeostasis of the microbiome, several nutritional strategies have been evaluated with the aim to improve the management of critically ill patients. Importantly, enteral nutrition has proven to be more efficient in promoting the homeostasis of the gut microbiome compared to parenteral nutrition. Several nutritional therapies, including prebiotics, probiotics, synbiotics, and fecal microbiota transplantation, are currently being used, showing variable results, possibly due to the unevenness of clinical trial conditions and the fact that the beneficial effects of probiotics are specific to particular species or even strains. Thus, it is of great importance to better understand the mechanisms by which nutrition and supplement therapies can heal the microbiome in critically ill patients in order to finally implement them in clinical practice with optimal safety and efficacy.