Lactobacillus rhamnosus GG and Bifidobacterium longum attenuate lung injury and inflammatory response in experimental sepsis

Efficacy of probiotic treatment as post-exposure prophylaxis for COVID-19: A double-blind, Placebo-Controlled Randomized trial

BACKGROUND & AIMS

The COVID-19 pandemic continues to pose unprecedented challenges to worldwide health. While vaccines are effective, additional strategies to mitigate the spread/severity of COVID-19 continue to be needed. Emerging evidence suggests susceptibility to respiratory tract infections in healthy subjects can be reduced by probiotic interventions; thus, probiotics may be a low-risk, low-cost, and easily implementable modality to reduce risk of COVID-19.

METHODS

In this initial study, we conducted a randomized, double-blind, placebo-controlled trial across the United States testing probiotic Lacticaseibacillus rhamnosus GG (LGG) as postexposure prophylaxis for COVID-19 in 182 participants who had household exposure to someone with confirmed COVID-19 diagnosed within ≤7 days. Participants were randomized to receive oral LGG or placebo for 28 days. The primary outcome was development of illness symptoms within 28 days of COVID-19 exposure. Stool was collected to evaluate microbiome changes.

RESULTS

Intention-to-treat analysis showed LGG treatment led to a lower likelihood of developing illness symptoms versus placebo (26.4 % vs. 42.9 %, p = 0.02). Further, LGG was associated with a statistically significant reduction in COVID-19 diagnosis (log rank, p = 0.049) via time-to-event analysis. Overall incidence of COVID-19 diagnosis did not significantly differ between LGG and placebo groups (8.8 % vs. 15.4 %, p = 0.17).

CONCLUSIONS

This data suggests LGG is associated with prolonged time to COVID-19 infection, reduced incidence of illness symptoms, and gut microbiome changes when used as prophylaxis ≤7 days post-COVID-19 exposure, but not overall incidence. This initial work may inform future COVID-19 prevention studies worldwide, particularly in developing nations where Lacticaseibacillus probiotics have previously been utilized to reduce other non-COVID infectious-morbidity.

TRIAL REGISTRATION

ClinicalTrials.gov, NCT04399252, Date: 22/05/2020. https://clinicaltrials.gov/ct2/show/NCT04399252.

Lactobacillus rhamnosus Restores Antiviral Signaling and Attenuates Cytokines Secretion from Human Bronchial Epithelial Cells Exposed to Cigarette Smoke and Infected with SARS-CoV-2

Individuals with chronic obstructive pulmonary disease (COPD) are more susceptible to exacerbation crisis triggered by secondary lung infections due to the dysfunction of antiviral signaling, principally via suppression of IFN-γ. Although the probiotic is known for controlling pulmonary inflammation in COPD, the influence of the Lactobacillus rhamnosus (Lr) on antiviral signaling in bronchial epithelium exposed to cigarette smoke extract (CSE) and viruses, remains unknown. Thus, the present study investigated the Lr effect on the antiviral signaling and the secretion of inflammatory mediators from bronchial epithelial cells (16HBE cells) exposed to CSE and SARS-CoV-2. The 16HBE cells were cultured, treated with Lr, stimulated with CSE, and infected with SARS-CoV-2. The cellular viability was evaluated using the MTT assay and cytotoxicity measured by lactate dehydrogenase (LDH) activity. The viral load, TLR2, TLR3, TLR4, TLR7, TLR8, MAVS, MyD88, and TRIF were quantified using specific PCR. The pro-inflammatory mediators were measured by a multiplex biometric immunoassay, and angiotensin converting enzyme 2 (ACE2) activity, NF-κB, RIG-I, MAD5, and IRF3 were measured using specific ELISA kits. Lr decreased viral load, ACE2, pro-inflammatory mediators, TLR2, TLR4, NF-κB, TLR3, TLR7, and TLR8 as well as TRIF and MyD88 expression in CSE and SARS-CoV-2 -exposed 16HBE cells. Otherwise, RIG-I, MAD5, IRF3, IFN-γ, and the MAVS expression were restored in 16HBE cells exposed to CSE and SARS-CoV-2 and treated with Lr. Lr induces antiviral signaling associated to IFN-γ secreting viral sensors and attenuates cytokine storm associated to NF-κB in bronchial epithelial cells, supporting its emerging role in prevention of COPD exacerbation.

Host tracheal and intestinal microbiomes inhibit Coccidioides growth in vitro

Coccidioidomycosis, also known as Valley fever, is a disease caused by the fungal pathogen Coccidioides. Unfortunately, patients are often misdiagnosed with bacterial pneumonia leading to inappropriate antibiotic treatment. Soil bacteria B. subtilis-like species exhibits antagonistic properties against Coccidioides in vitro; however, the antagonistic capabilities of host microbiota against Coccidioides are unexplored. We sought to examine the potential of the tracheal and intestinal microbiomes to inhibit the growth of Coccidioides in vitro. We hypothesized that an uninterrupted lawn of microbiota obtained from antibiotic-free mice would inhibit the growth of Coccidioides while partial in vitro depletion through antibiotic disk diffusion assays would allow a niche for fungal growth. We observed that the microbiota grown on 2xGYE (GYE) and CNA w/ 5% sheep's blood agar (5%SB-CNA) inhibited the growth of Coccidioides, but that grown on chocolate agar does not. Partial depletion of the microbiota through antibiotic disk diffusion revealed that microbiota depletion leads to diminished inhibition and comparable growth of Coccidioides growth to controls. To characterize the bacteria grown and narrow down potential candidates contributing to the inhibition of Coccidioides, 16s rRNA sequencing of tracheal and intestinal agar cultures and murine lung extracts was performed. The identity of host bacteria that may be responsible for this inhibition was revealed. The results of this study demonstrate the potential of the host microbiota to inhibit the growth of Coccidioides in vitro and suggest that an altered microbiome through antibiotic treatment could negatively impact effective fungal clearance and allow a niche for fungal growth in vivo.

The role of the gut microbiota in multiple sclerosis

During the past decade, research has revealed that the vast community of micro-organisms that inhabit the gut - known as the gut microbiota - is intricately linked to human health and disease, partly as a result of its influence on systemic immune responses. Accumulating evidence demonstrates that these effects on immune function are important in neuroinflammatory diseases, such as multiple sclerosis (MS), and that modulation of the microbiome could be therapeutically beneficial in these conditions. In this Review, we examine the influence that the gut microbiota have on immune function via modulation of serotonin production in the gut and through complex interactions with components of the immune system, such as T cells and B cells. We then present evidence from studies in mice and humans that these effects of the gut microbiota on the immune system are important in the development and course of MS. We also consider how strategies for manipulating the composition of the gut microbiota could be used to influence disease-related immune dysfunction and form the basis of a new class of therapeutics. The strategies discussed include the use of probiotics, supplementation with bacterial metabolites, transplantation of faecal matter or defined microbial communities, and dietary intervention. Carefully designed studies with large human cohorts will be required to gain a full understanding of the microbiome changes involved in MS and to develop therapeutic strategies that target these changes.

Probiotics in Critical Illness: A Systematic Review and Meta-Analysis of Randomized Controlled Trials

OBJECTIVES

To determine the safety and efficacy of probiotics or synbiotics on morbidity and mortality in critically ill adults and children.

DATA SOURCES

We searched MEDLINE, EMBASE, CENTRAL, and unpublished sources from inception to May 4, 2021.

STUDY SELECTION

We performed a systematic search for randomized controlled trials (RCTs) that compared enteral probiotics or synbiotics to placebo or no treatment in critically ill patients. We screened studies independently and in duplicate.

DATA EXTRACTION

Independent reviewers extracted data in duplicate. A random-effects model was used to pool data. We assessed the overall certainty of evidence for each outcome using the Grading Recommendations Assessment, Development, and Evaluation approach.

DATA SYNTHESIS

Sixty-five RCTs enrolled 8,483 patients. Probiotics may reduce ventilator-associated pneumonia (VAP) (relative risk [RR], 0.72; 95% CI, 0.59 to 0.89 and risk difference [RD], 6.9% reduction; 95% CI, 2.7-10.2% fewer; low certainty), healthcare-associated pneumonia (HAP) (RR, 0.70; 95% CI, 0.55-0.89; RD, 5.5% reduction; 95% CI, 8.2-2.0% fewer; low certainty), ICU length of stay (LOS) (mean difference [MD], 1.38 days fewer; 95% CI, 0.57-2.19 d fewer; low certainty), hospital LOS (MD, 2.21 d fewer; 95% CI, 1.18-3.24 d fewer; low certainty), and duration of invasive mechanical ventilation (MD, 2.53 d fewer; 95% CI, 1.31-3.74 d fewer; low certainty). Probiotics probably have no effect on mortality (RR, 0.95; 95% CI, 0.87-1.04 and RD, 1.1% reduction; 95% CI, 2.8% reduction to 0.8% increase; moderate certainty). Post hoc sensitivity analyses without high risk of bias studies negated the effect of probiotics on VAP, HAP, and hospital LOS.

CONCLUSIONS

Low certainty RCT evidence suggests that probiotics or synbiotics during critical illness may reduce VAP, HAP, ICU and hospital LOS but probably have no effect on mortality.

Probiotic Saccharomyces boulardii attenuates cardiopulmonary bypass-induced acute lung injury by inhibiting ferroptosis

OBJECTIVE

Acute lung injury (ALI) is one of the most common and fatal complications of cardiopulmonary bypass (CPB). Probiotics treatment has been shown to reduce lung injury in different experimental models. However, the effect of probiotics on CPB-induced ALI is still poorly understood. This study aimed to investigate whether probiotic Saccharomyces boulardii CNCM I-745 treatment protects against lung injury in a rat model of CPB.

METHODS

Rats were orally gavaged with Saccharomyces boulardii CNCM I-745 once a day for 5 days before being subjected to CPB. Rats were euthanized post-CPB, and samples of lung tissue were processed for later investigation. The levels of inflammatory cytokines were measured by ELISA. The expression levels of ferroptosis markers in lungs were assessed by western blot. The microbes in feces and proximal colon of rats were analyzed by using 16S rDNA amplicon sequencing method. The ratio and maturity of conventional dendritic cells (cDCs) were determined by flow-cytometry.

RESULTS

Saccharomyces boulardii CNCM I-745 treatment improved lung function, attenuated pathologic lung changes and decelerated the exacerbation of inflammatory cytokine level after experimental CPB. Saccharomyces boulardii CNCM I-745 treatment also inhibited CPB-induced ferroptosis, as evidenced by the changes of main markers of ferroptosis, namely, the increase of Glutathione peroxidase 4 (GPX4) and the decrease of Acyl-CoA synthetase long chain family member 4 (ACSL4). In addition, after Saccharomyces boulardii CNCM I-745 treatment, the ratio and maturity of conventional dendritic cells (cDCs) in the guts of rats with CPB were significantly up-regulated.

CONCLUSION

Our findings suggest that probiotic Saccharomyces boulardii CNCM I-745 reduces CPB-induced lung injury through suppression of the ferroptosis in lung and up-regulation of the ratio and maturity of cDCs in gut.

Probiotics in the Intensive Care Unit

The understanding of the gut microbiome in health and disease has shown tremendous progress in the last decade. Shaped and balanced throughout life, the gut microbiome is intricately related to the local and systemic immune system and a multitude of mechanisms through which the gut microbiome contributes to the host’s defense against pathogens have been revealed. Similarly, a plethora of negative consequences, such as superinfections and an increased rate of hospital re-admissions, have been identified when the gut microbiome is disturbed by disease or by the iatrogenic effects of antibiotic treatment and other interventions. In this review, we describe the role that probiotics may play in the intensive care unit (ICU). We discuss what is known about the gut microbiome of the critically ill, and the concept of probiotic intervention to positively modulate the gut microbiome. We summarize the evidence derived from randomized clinical trials in this context, with a focus on the prevention of ventilator-associated pneumonia. Finally, we consider what lessons we can learn in terms of the current challenges, efficacy and safety of probiotics in the ICU and what we may expect from the future. Throughout the review, we highlight studies that have provided conceptual advances to the field or have revealed a specific mechanism; this narrative review is not intended as a comprehensive summary of the literature.

The role of the microbiota in the management of intensive care patients

The composition of the gut microbiota is highly dynamic and changes according to various conditions. The gut microbiota mainly includes difficult-to-cultivate anaerobic bacteria, hence knowledge about its composition has significantly arisen from culture-independent methods based on next-generation sequencing (NGS) such as 16S profiling and shotgun metagenomics. The gut microbiota of patients hospitalized in intensive care units (ICU) undergoes many alterations because of critical illness, antibiotics, and other ICU-specific medications. It is then characterized by lower richness and diversity, and dominated by opportunistic pathogens such as Clostridioides difficile and multidrug-resistant bacteria. These alterations are associated with an increased risk of infectious complications or death. Specifically, at the time of writing, it appears possible to identify distinct microbiota patterns associated with severity or infectivity in COVID-19 patients, paving the way for the potential use of dysbiosis markers to predict patient outcomes. Correcting the microbiota disturbances to avoid their consequences is now possible. Fecal microbiota transplantation is recommended in recurrent C. difficile infections and microbiota-protecting treatments such as antibiotic inactivators are currently being developed. The growing interest in the microbiota and microbiota-associated therapies suggests that the control of the dysbiosis could be a key factor in the management of critically ill patients. The present narrative review aims to provide a synthetic overview of microbiota, from healthy individuals to critically ill patients. After an introduction to the different techniques used for studying the microbiota, we review the determinants involved in the alteration of the microbiota in ICU patients and the latter's consequences. Last, we assess the means to prevent or correct microbiota alteration.

Pharmacological Effects of Marine-Derived Enterococcus faecium EA9 against Acute Lung Injury and Inflammation in Cecal Ligated and Punctured Septic Rats

Microorganisms obtained from the marine environment may represent a potential therapeutic value for multiple diseases. This study explored the possible protective role of marine-derived potential probiotic Enterococcus faecium EA9 (E. faecium) against pulmonary inflammation and oxidative stress using the cecal ligation and puncture (CLP) model of sepsis in Wistar rats. Animals were pretreated with E. faecium for 10 days before either sham or CLP surgeries. Animals were sacrificed 72 hours following the surgical intervention. The histological architecture of lung tissues was evaluated as indicated by the lung injury score. In addition, the extend of pulmonary edema was determined as wet/dry weight ratio. The inflammatory cytokines were estimated in lung tissues, including tumor necrosis factor-alpha (TNF-α), interleukin-6 (IL-6), and interleukin-1 beta (IL-1β) using the enzyme-linked-immunosorbent-assay (ELISA) technique. Moreover, markers for lipid peroxidation such as thiobarbituric acid reaction substances (TBARs), and endogenous antioxidants, including reduced glutathione (GSH) were determined in lung tissues. Finally, the enzymatic activities of antioxidant enzymes such as catalase (CAT), superoxide dismutase (SOD), glutathione peroxidase (GPx), and glutathione reductase (GR) were assayed in the lungs. Pretreatment with E. faecium markedly attenuated CLP-induced lung injury and pulmonary edema. Markers for inflammation, including TNF-α, IL-6, and IL-1β were augmented in the lung tissues of CLP animals, while E. faecium ameliorated their augmented levels. E. faecium pretreatment also restored the elevated TBARS levels and the prohibited CAT, SOD, and GPx enzymatic activities in CLP animals. GSH levels were corrected by E. faecium in CLP animals. The inflammatory and lipid peroxidation mediators were positively correlated, while antioxidant enzymatic activities were negatively correlated with CLP-induced lung injury and pulmonary edema. Collectively, marine-derived Enterococcus faecium EA9 might be considered as a prospective therapeutic tool for the management of pulmonary dysfunction associated with sepsis.

Lactobacillus rhamnosus GG as dietary supplement improved survival from lipopolysaccharides-induced sepsis in mice

Sepsis is a state of host immune response triggered by virus or bacterial infection, in which the extent of regional and systemic inflammation and companion counter-inflammatory reactions determines disease outcomes. Probiotics are known for the immunomodulatory effect on allergic disorders, but it is not clear whether the beneficiary effect extends to sepsis and increases survival. In this mouse model, we injected intraperitoneally lipopolysaccharides (LPS) to induce sepsis, and investigated whether the pretreatment of Lactobacillus rhamnosus GG (LGG) contributed to host survival and examined the alteration of the gut microbiota and blood cytokines/chemokines profile before sepsis induction. Four-week-old male BALB/c mice were divided into two groups: one group were fed daily with LGG as a dietary supplement for fourteen days, whereas the other group with sterile water. Before sepsis induction, some mice from each group were killed to collect stool in the intestine and blood for microbial metagenomic and cytokine/chemokine analyses, respectively, and the rest were monitored afterward for mortality. The relative abundance of several families in the gut microbiota after LGG treatment was altered as well as the ratio of Firmicutes/Bacteroidetes. In addition, several pro-inflammatory cytokines such as G-CSF, IL7, IL15, and MCP1 were lower in the LGG group than in the control group. The survival rate following LPS-induced sepsis improved with LGG treatment. Our results indicated that dietary supplement of probiotic LGG improved survival from LPS-induced sepsis, most likely through pre-septic changes in the gut microbial constituents by LGG with reciprocal alteration of host immune system to a less reactive state to incoming pathogens.

Nutritional and Health Potential of Probiotics: A Review

Several products consist of probiotics that are available in markets, and their potential uses are growing day by day, mainly because some strains of probiotics promote the health of gut microbiota, especially Furmicutes and Bacteroidetes, and may prevent certain gastrointestinal tract (GIT) problems. Some common diseases are inversely linked with the consumption of probiotics, i.e., obesity, type 2 diabetes, autism, osteoporosis, and some immunological disorders, for which the disease progression gets delayed. In addition to disease mitigating properties, these microbes also improve oral, nutritional, and intestinal health, followed by a robust defensive mechanism against particular gut pathogens, specifically by antimicrobial substances and peptides producing probiotics (AMPs). All these positive attributes of probiotics depend upon the type of microbial strains dispensed. Lactic acid bacteria (LAB) and Bifidobacteria are the most common microbes used, but many other microbes are available, and their use depends upon origin and health-promoting properties. This review article focuses on the most common probiotics, their health benefits, and the alleviating mechanisms against chronic kidney diseases (CKD), type 1 diabetes (T1D), type 2 diabetes (T2D), gestational diabetes mellitus (GDM), and obesity.

Cross-talk between immune system and microbiota in COVID-19

INTRODUCTION

Human gut microbiota plays a crucial role in providing protective responses against pathogens, particularly by regulating immune system homeostasis. There is a reciprocal interaction between the gut and lung microbiota, called the gut-lung axis (GLA). Any alteration in the gut microbiota or their metabolites can cause immune dysregulation, which can impair the antiviral activity of the immune system against respiratory viruses such as severe acute respiratory syndrome coronavirus (SARS-CoV) and SARS-CoV-2.

AREAS COVERED

This narrative review mainly outlines emerging data on the mechanisms underlying the interactions between the immune system and intestinal microbial dysbiosis, which is caused by an imbalance in the levels of essential metabolites. The authors will also discuss the role of probiotics in restoring the balance of the gut microbiota and modulation of cytokine storm.

EXPERT OPINION

Microbiota-derived signals regulate the immune system and protect different tissues during severe viral respiratory infections. The GLA's equilibration could help manage the mortality and morbidity rates associated with SARS-CoV-2 infection.

Priming with intranasal lactobacilli prevents Pseudomonas aeruginosa acute pneumonia in mice

Background

Increasing resistance to antibiotics of Pseudomonas aeruginosa leads to therapeutic deadlock and alternative therapies are needed. We aimed to evaluate the effects of Lactobacillus clinical isolates in vivo, through intranasal administration on a murine model of Pseudomonas aeruginosa pneumonia.

Results

We screened in vitro 50 pulmonary clinical isolates of Lactobacillus for their ability to decrease the synthesis of two QS dependent-virulence factors (elastase and pyocyanin) produced by Pseudomonas aeruginosa strain PAO1.

Two blends of three Lactobacillus isolates were then tested in vivo: one with highly effective anti-PAO1 virulence factors properties (blend named L.rff for L. rhamnosus, two L. fermentum strains), and the second with no properties (blend named L.psb, for L. paracasei, L. salivarius and L. brevis). Each blend was administered intranasally to mice 18 h prior to PAO1 pulmonary infection. Animal survival, bacterial loads, cytological analysis, and cytokines secretion in the lungs were evaluated at 6 or 24 h post infection with PAO1.

Intranasal priming with both lactobacilli blends significantly improved 7-day mice survival from 12% for the control PAO1 group to 71 and 100% for the two groups receiving L.rff and L.psb respectively. No mortality was observed for both control groups receiving either L.rff or L.psb. Additionally, the PAO1 lung clearance was significantly enhanced at 24 h. A 2-log and 4-log reduction was observed in the L.rff + PAO1 and L.psb + PAO1 groups respectively, compared to the control PAO1 group. Significant reductions in neutrophil recruitment and proinflammatory cytokine and chemokine secretion were observed after lactobacilli administration compared to saline solution, whereas IL-10 production was increased.

Conclusions

These results demonstrate that intranasal priming with lactobacilli acts as a prophylaxis, and avoids fatal complications caused by Pseudomonas aeruginosa pneumonia in mice. These results were independent of in vitro anti-Pseudomonas aeruginosa activity on QS-dependent virulence factors. Further experiments are required to identify the immune mechanism before initiating clinical trials.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12866-021-02254-7.

MYD88, NFKB1, and IL6 transcripts overexpression are associated with poor outcomes and short survival in neonatal sepsis

Toll-like receptor (TLR) family signature has been implicated in sepsis etiopathology. We aimed to evaluate the genetic profile of TLR pathway-related key genes; the myeloid differentiation protein 88 (MYD88), IL1 receptor-associated kinase 1 (IRAK1), the nuclear factor kappa-B1 (NFKB1), and interleukin 6 (IL6) in the blood of neonates with sepsis at the time of admission and post-treatment for the available paired-samples. This case–control study included 124 infants with sepsis admitted to the neonatal intensive care unit and 17 controls. The relative gene expressions were quantified by TaqMan Real-Time qPCR and correlated to the clinic-laboratory data. MYD88, NFKB1, and IL6 relative expressions were significantly higher in sepsis cases than controls. Higher levels of MYD88 and IL6 were found in male neonates and contributed to the sex-based separation of the cases by the principal component analysis. ROC analysis revealed MYD88 and NFKB1 transcripts to be good biomarkers for sepsis. Furthermore, patients with high circulatory MYD88 levels were associated with poor survival, as revealed by Kaplan–Meier curves analysis. MYD88, NFKB1, and IL6 transcripts showed association with different poor-outcome manifestations. Clustering analysis split the patient cohort into three distinct groups according to their transcriptomic signature and CRP levels. In conclusion, the study TLR pathway-related transcripts have a gender-specific signature, diagnostic, and prognostic clinical utility in neonatal sepsis.

Probiotics for the Management of Sepsis: Advances in Animal Models and Intensive Care Unit Environments

Sepsis frequently leads to multiple organ failure and is a major cause of morbidity and mortality in critically ill patients. Although intensive care protocols and antibiotic therapy have improved sepsis treatment, specific management is lacking with respect to efficient protection from tissue damage and long-term outcomes. Probiotics are live microbes that modulate the immune system and inflammation and colonize the gut. In this narrative review, we have traced the evolution of the administration of probiotics in an animal model of sepsis and treatment alternatives in the intensive care unit setting. First, probiotics are categorized by species before describing their modulation of the microbiota, repair of tissue-specific damage, immune response, and molecular pathways to prevent complications. The impact on therapy for infant and adult patients is also addressed. Finally, we have emphasized the challenges and gaps in current studies as well as future perspectives for further investigation. The present review can open up avenues for new strategies that employ promising probiotic strains for the treatment of sepsis and discusses their ability to prevent disease-associated long-term complications.

The Surviving Sepsis Campaign: Basic/Translational Science Research Priorities

Objectives:

Expound upon priorities for basic/translational science identified in a recent paper by a group of experts assigned by the Society of Critical Care Medicine and the European Society of Intensive Care Medicine.

Data Sources:

Original paper, search of the literature.

Study Selection:

By several members of the original task force with specific expertise in basic/translational science.

Data Extraction:

None.

Data Synthesis:

None.

Conclusions:

In the first of a series of follow-up reports to the original paper, several members of the original task force with specific expertise provided a more in-depth analysis of the five identified priorities directly related to basic/translational science. This analysis expounds on what is known about the question and what was identified as priorities for ongoing research. It is hoped that this analysis will aid the development of future research initiatives.

Randomised, double-blind, placebo-controlled trial of Probiotics To Eliminate COVID-19 Transmission in Exposed Household Contacts (PROTECT-EHC): a clinical trial protocol

INTRODUCTION

The COVID-19 pandemic has proven to be an unprecedented challenge to worldwide health, and strategies to mitigate the spread and severity of COVID-19 infection are urgently needed. Emerging evidence suggests that the composition of the gut microbiome and modification of microbial ecology via probiotics can affect susceptibility to a wide range of infections, including respiratory tract infections. In this study, we aim to evaluate the effects of the probiotic Lactobacillus rhamnosus GG (LGG) versus placebo on COVID-19 infection status and the gut microbiome in subjects with a household contact who has tested positive for COVID-19.

METHODS AND ANALYSIS

In this double-blinded, randomised, placebo-controlled trial, we will randomise 1132 subjects having a household contact who has recently (≤7 days) tested positive for COVID-19 to daily oral LGG or placebo for 28 days. We hypothesise that taking LGG as a probiotic will protect against COVID-19 infection and reduce the severity of disease in those who become infected (primary endpoint: decreased symptoms), and will be associated with beneficial changes in the composition of the gut microbiome. Stool samples and nasal swabs will be collected to evaluate the microbiome by 16S rRNA sequencing and the presence of SARS-CoV-2 by PCR, respectively. We will also conduct multivariate analysis of demographic, behavioural, temporal, and other variables that may predict development of symptoms and other outcomes.

ETHICS AND DISSEMINATION

This trial is conducted under a Food and Drug Administration Investigational New Drug for LGG, has received ethics approval by the institutional review board of Duke University and enrolment has begun. We plan to disseminate the results in peer-reviewed journals and at national and international conferences.

TRIAL REGISTRATION NUMBER

NCT04399252.

Effects of the Administration of Bifidobacterium longum subsp. infantis CECT 7210 and Lactobacillus rhamnosus HN001 and Their Synbiotic Combination With Galacto-Oligosaccharides Against Enterotoxigenic Escherichia coli F4 in an Early Weaned Piglet Model

We evaluated the potential of multi-strain probiotic (Bifidobacterium longum subsp. infantis CECT 7210 and Lactobacillus rhamnosus HN001) with or without galacto-oligosaccharides against enterotoxigenic Escherichia coli (ETEC) F4 infection in post-weaning pigs. Ninety-six piglets were distributed into 32 pens assigned to five treatments: one non-challenged (CTR+) and four challenged: control diet (CTR-), with probiotics (>3 × 10¹⁰ CFU/kg body weight each, PRO), prebiotic (5%, PRE), or their combination (SYN). After 1 week, animals were orally inoculated with ETEC F4. Feed intake, weight, and clinical signs were recorded. On days 4 and 8 post-inoculation (PI), one animal per pen was euthanized and samples from blood, digesta, and tissues collected. Microbiological counts, ETEC F4 real-time PCR (qPCR) quantification, fermentation products, serum biomarkers, ileal histomorphometry, and genotype for mucin 4 (MUC4) polymorphism were determined. Animals in the PRO group had similar enterobacteria and coliform numbers to the CTR+ group, and the ETEC F4 prevalence, the number of mitotic cells at day 4 PI, and villus height at day 8 PI were between that observed in the CTR+ and CTR- groups. The PRO group exhibited reduced pig major acute-phase protein (Pig-MAP) levels on day 4 PI. The PRE diet group presented similar reductions in ETEC F4 and Pig-MAP, but there was no effect on microbial groups. The SYN group showed reduced fecal enterobacteria and coliform counts after the adaptation week but, after the inoculation, the SYN group showed lower performance and more animals with high ETEC F4 counts at day 8 PI. SYN treatment modified the colonic fermentation differently depending on the MUC4 polymorphism. These results confirm the potential of the probiotic strains and the prebiotic to fight ETEC F4, but do not show any synergy when administered together, at least in this animal model.

Gut-Lung Axis in COVID-19

COVID-19 is a pandemic infection of the respiratory system caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). The viral ribonucleic acid (RNA) was found in many parts of the COVID-19 patients including the stool, suggesting a potential interaction with the host's gut microbiome. The gut microbiome also plays major roles in immunity and inflammation. It also impacts pulmonary functions through the gut-lung axis. There have been recent reports of the importance of the host microbiome in infection and pathogenicity. The understanding of the gut and lung microbiomes would open the gate to new therapeutic approaches.

SARS-CoV-2 microbiome dysbiosis linked disorders and possible probiotics role

In December 2019, a pneumonia outbreak of unknown etiology was reported which caused panic in Wuhan city of central China, which was later identified as Coronavirus disease (COVID-19) caused by a novel coronavirus, Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) by the Chinese Centre for Disease Control and Prevention (CDC) and WHO. To date, the SARS-CoV-2 spread has already become a global pandemic with a considerable death toll. The associated symptoms of the COVID-19 infection varied with increased inflammation as an everyday pathological basis. Among various other symptoms such as fever, cough, lethargy, gastrointestinal (GI) symptoms included diarrhea and IBD with colitis, have been reported. Currently, there is no sole cure for COVID-19, and researchers are actively engaged to search out appropriate treatment and develop a vaccine for its prevention. Antiviral for controlling viral load and corticosteroid therapy for reducing inflammation seems to be inadequate to control the fatality rate. Based on the available related literature, which documented GI symptoms with diarrhea, inflammatory bowel diseases (IBD) with colitis, and increased deaths in the intensive care unit (ICU), conclude that dysbiosis occurs during SARS-COV-2 infection as the gut-lung axis cannot be ignored. As probiotics play a therapeutic role for GI, IBD, colitis, and even in viral infection. So, we assume that the inclusion of studies to investigate gut microbiome and subsequent therapies such as probiotics might help decrease the inflammatory response of viral pathogenesis and respiratory symptoms by strengthening the host immune system, amelioration of gut microbiome, and improvement of gut barrier function.

Preventive Effect of Probiotics on Ventilator-Associated Pneumonia: A Meta-analysis of 2428 Patients

BACKGROUND

Researchers had contradictory conclusions about the role of probiotics in preventing ventilator-associated pneumonia (VAP), which has led to the controversial use of probiotics in mechanically ventilated patients.

OBJECTIVE

To explore the efficacy and safety of probiotics in preventing VAP.

METHODS

A literature search was conducted in 7 medical databases. Two investigators assessed literature quality independently and collected data. The primary outcome was the incidence of VAP. Secondary outcomes included 16 measures. Sensitivity analysis and subgroup and meta-regression analyses were performed to analyze the source of heterogeneity. P values <0.05 were considered statistically significant, and CIs were set at 95%. A random-effects model was set when I² <50%, otherwise a fixed-effects model was used.

RESULTS

A total of 20 randomized controlled studies with a total of 2428 patients were analyzed. Pooled results showed positive effects of probiotics on the reduction of VAP incidence (risk ratio [RR] = 0.672; P < 0.001; I² = 11.3%), length of ICU stay (WMD = -1.417; P = 0.012; I² = 90.7%), oropharyngeal (RR = 0.866; P = 0.031; I² = 12.4%) and gastric (RR = 0.645; P < 0.001; I² = 30.2%) colonization.

CONCLUSIONS AND RELEVANCE

Probiotics can reduce the incidence of VAP and reduce oropharyngeal and gastric bacterial colonization. The results also suggest that probiotics do not cause adverse effects.

Nrf2-interacting nutrients and COVID-19: time for research to develop adaptation strategies

There are large between- and within-country variations in COVID-19 death rates. Some very low death rate settings such as Eastern Asia, Central Europe, the Balkans and Africa have a common feature of eating large quantities of fermented foods whose intake is associated with the activation of the Nrf2 (Nuclear factor (erythroid-derived 2)-like 2) anti-oxidant transcription factor. There are many Nrf2-interacting nutrients (berberine, curcumin, epigallocatechin gallate, genistein, quercetin, resveratrol, sulforaphane) that all act similarly to reduce insulin resistance, endothelial damage, lung injury and cytokine storm. They also act on the same mechanisms (mTOR: Mammalian target of rapamycin, PPARγ:Peroxisome proliferator-activated receptor, NFκB: Nuclear factor kappa B, ERK: Extracellular signal-regulated kinases and eIF2α:Elongation initiation factor 2α). They may as a result be important in mitigating the severity of COVID-19, acting through the endoplasmic reticulum stress or ACE-Angiotensin-II-AT₁R axis (AT₁R) pathway. Many Nrf2-interacting nutrients are also interacting with TRPA1 and/or TRPV1. Interestingly, geographical areas with very low COVID-19 mortality are those with the lowest prevalence of obesity (Sub-Saharan Africa and Asia). It is tempting to propose that Nrf2-interacting foods and nutrients can re-balance insulin resistance and have a significant effect on COVID-19 severity. It is therefore possible that the intake of these foods may restore an optimal natural balance for the Nrf2 pathway and may be of interest in the mitigation of COVID-19 severity.

Randomized Clinical Trial Examining the Impact of Lactobacillus rhamnosus GG Probiotic Supplementation on Cognitive Functioning in Middle-aged and Older Adults

PURPOSE

The gut microbiome has been linked to cognitive function and appears to worsen with aging. Probiotic supplementation has been found to improve the health of the gut microbiome. As such, it is possible that probiotic supplementation may protect the aging brain. The current study examined the cognitive benefits of probiotic supplementation (Lactobacillus rhamnosus GG) in healthy middle-aged and older adults.

MATERIALS AND METHODS

The study was a double-blind, placebo-controlled, randomized clinical trial. Two hundred community-dwelling adults aged 52-75 were enrolled (mean age=64.3, SD=5.52). A three-month intervention involved daily consumption of probiotic or placebo. Independent sample t-tests, chi-squared tests, and repeated measure ANOVAs compared groups and examined changes over time. Primary outcome was change in NIH Toolbox Total Cognition Score from baseline to follow-up.

RESULTS

A total of 145 participants were examined in primary analyses (probiotic=77, placebo=68) and excluded persons due to discontinuation, low adherence, missing data, or outlier values. Established criteria (ie ≥1 subtest t-scores ≤35; n=19, n=23) were used to operationally define cognitive impairment. Repeated measures ANOVAs revealed that persons with cognitive impairment who consumed probiotics exhibited a greater total cognition score improvement than persons with cognitive impairment in the placebo group and cognitively intact persons in probiotic or placebo groups.

CONCLUSION

Lactobacillus rhamnosus GG probiotic supplementation was associated with improved cognitive performance in middle-aged and older adults with cognitive impairment. Probiotic supplementation may be a novel method for protecting cognitive health in aging.

Probiotics and Coronavirus disease 2019: think about the link

The pandemic of Coronavirus disease 2019 (COVID-19) is rapidly progressing, causing significant morbidity and mortality. Various antiviral drugs, anti-inflammatory drugs and immunomodulators have been tried without substantial clinical benefits. The severe and critical cases of COVID-19 disease are characterised by gut microbiome dysbiosis, immune dysregulation, hyper-inflammation and hypercytokinaemia (cytokine storm). Therefore, the strategies which target these pathophysiological processes may be beneficial. Probiotics are one such strategy that exerts beneficial effects by manipulation of the gut microbiota, suppression of opportunistic pathogens in the gut, decreasing translocation of opportunistic organisms, activation of mucosal immunity and modulation of the innate and adaptive immune response. Probiotics are the potential candidates to be tested in moderate and severe cases of COVID-19 due to several beneficial effects, including easy availability, easy to administer, safe and economical to use.

The surviving sepsis campaign: basic/translational science research priorities

Objectives

Expound upon priorities for basic/translational science identified in a recent paper by a group of experts assigned by the Society of Critical Care Medicine and the European Society of Intensive Care Medicine.

Data sources

Original paper, search of the literature.

Study selection

This study is selected by several members of the original task force with specific expertise in basic/translational science. Data extraction and data synthesis are not available.

Conclusions

In the first of a series of follow-up reports to the original paper, several members of the original task force with specific expertise provided a more in-depth analysis of the five identified priorities directly related to basic/translational science. This analysis expounds on what is known about the question and what was identified as priorities for ongoing research. It is hoped that this analysis will aid the development of future research initiatives.

Bio-functional properties of probiotic Lactobacillus: current applications and research perspectives

Lactic acid bacteria as a starter culture are very important component in the fermentation process of dairy and food industry. Application of lactic acid bacteria as probiotic bacteria adds more functionality to the developed product. Gut colonizing bacteria have attractive benefits related to human health. Bio-functional properties such as antimicrobial activity, anti-inflammatory, ACE-inhibitory, antioxidant, antidiarrheal, antiviral, immunomodulatory, hypocholesterolemic, anti-diabetic and anti-cancer activities are the most applicable research areas of lactic acid bacteria. Different strains of Lactobacillus are generally consumed as probiotics and colonize the gastrointestinal tract. Sometimes these bacteria may possess antimicrobial activity and may positively influence the effect of antibiotics. Use of Lactobacillus spp. for the development of functional foods is one of the promising areas of current research and applications. Individual bacterial species have unique biological activity, which may vary from strains to strains and identification of this uniqueness could be helpful in the development of functional and therapeutic food products.

Human microbiome and homeostasis: insights into the key role of prebiotics, probiotics, and symbiotics

The interest in the study of the gut microbiome has grown exponentially. Indeed, its impact on health and disease has been increasingly reported, and the importance of keeping gut microbiome homeostasis clearly highlighted. However, and despite many advances, there are still some gaps, as well as the real discernment on the contribution of some species falls far short of what is needed. Anyway, it is already more than a solid fact of its importance in maintaining health and preventing disease, as well as in the treatment of some pathologies. In this sense, and given the existence of some ambiguous opinions, the present review aims to discuss the importance of gut microbiome in homeostasis maintenance, and even the role of probiotics, prebiotics, and symbiotics in both health promotion and disease prevention.

The microbiome and nutrition in critical illness

PURPOSE OF REVIEW

The present review aims to describe the relationship between nutrition and the gut microbiome in critical illness.

RECENT FINDINGS

Critical illness disrupts not only cells of human origin but also the intestinal microbiome, with a decrease in bacterial diversity and transformation into a pathobiome. Under basal conditions, nutrition profoundly alters microbial composition with significant salutatory effects on human health. In critical illness, enteral nutrition is recommended and has theoretical (but not proven) advantages towards improved inner microbial health and diminution of bacterial translocation. Dietary supplements such as probiotics and fiber have been shown to improve microbial derangements in health. However, their impact on the microbiome in critical illness is unclear and although they may have some beneficial effects on patient-centric outcomes, they do not alter mortality. The precise mechanisms of how nutrition and dietary supplements modulate the gut microbiome remain to be determined.

SUMMARY

Nutrition and supplements such as probiotics appear to play a significant role in modulating the microbiome in health, yet the relationship in critical illness is unclear. Further investigation is required to determine the mechanistic determinants of the impact of nutrition on the microbiome in critical illness and the potential clinical implications of this.

Effects of Bifidobacterium longum BB536 and Lactobacillus rhamnosus HN001 in IBS patients

BACKGROUND

Irritable bowel syndrome (IBS) is a common gastrointestinal disorder, which still lacks effective therapy. We aimed to investigate the effects of a novel formulation of Bifidobacterium longum BB536 and Lactobacillus rhamnosus HN001 with vitamin B6 (LBB) on symptoms, intestinal permeability, cultivable bacteria and metabolome in IBS subjects.

MATERIALS AND METHODS

Twenty-five IBS patients (Rome IV criteria) (M:F = 8:17; age 48 years ± 11 SD) were randomized to treatment (LBB) or placebo (one month each) in a crossover randomized double-blind controlled trial. Symptoms, intestinal habits, disease severity, intestinal permeability and intestinal microbiota were analysed at 0, 30, 45 and 60 days.

RESULTS

Percentage decrease from baseline of abdominal pain (-48.8% vs -3.5%), bloating (-36.35% vs +7.35%) and severity of disease (-30.1% vs -0.4%) was significantly (P < .0001) greater with LBB than placebo, respectively. In IBS-D patients, the improvement from baseline of Bristol score was more consistent with LBB (from 6 ± 0.4 to 4.3 ± 1.1, P < .00001) than placebo (from 6.2 ± 0.7 to 5.3 ± 1.1, P = .04). In IBS-C patients, Bristol score tended to improve from baseline after LBB (2.6 ± 1.1 vs 3.2 ± 0.5, P = .06). LBB significantly improved the percentage of sucralose recovery (colonic permeability) (1.86 ± 0.1 vs 1.1 ± 0.2, P = .01). During treatment, presumptive lactic acid bacteria and bifidobacteria, relative abundance of propanoic, butanoic, pentanoic acids and hydrocarbons increased, while phenol decreased.

CONCLUSIONS

The novel formulation of B. longum BB536 and L. rhamnosus HN001 with B6 vitamin improves symptoms and severity of disease, restores intestinal permeability and gut microbiota in IBS patients.

Lactobacillus rhamnosus GG Ameliorates Liver Injury and Hypoxic Hepatitis in Rat Model of CLP-Induced Sepsis

BACKGROUND

Probiotic use to prevent gastrointestinal infections in critical care has shown great promise in recent clinical trials. Although well-documented benefits of probiotic use in intestinal disorders, the potential for probiotic treatment to ameliorate liver injury and hypoxic hepatitis following sepsis has not been well explored.

METHODS

In order to evaluate, if Lactobacillus rhamnosus GG (LGG) treatment in septic rats will protect against liver injury, this study used 20-22-week-old Sprague-Dawley rats which were subjected to cecal ligation and puncture to establish sepsis model and examine mRNA and protein levels of IL-1β, NLRP3, IL-6, TNF-a, VEGF, MCP1, NF-kB and HIF-1α in the liver via real-time PCR, Elisa and Western blot.

RESULTS

This study showed that LGG treatment significantly ameliorated liver injury following experimental infection and sepsis. Liver mRNA and protein levels of IL-1β, NLRP3, IL-6, TNF-a, VEGF, MCP1, NF-kB and HIF-1α were significantly reduced in rats receiving LGG.

CONCLUSIONS

Thus, our study demonstrated that LGG treatment can reduce liver injury following experimental infection and sepsis and is associated with improved hypoxic hepatitis. Probiotic therapy may be a promising intervention to ameliorate clinical liver injury and hypoxic hepatitis following systemic infection and sepsis.

The influence of the microbiome on respiratory health

The revolution in microbiota research over the past decade has provided invaluable knowledge about the function of the microbial species that inhabit the human body. It has become widely accepted that these microorganisms, collectively called 'the microbiota', engage in networks of interactions with each other and with the host that aim to benefit both the microbial members and the mammalian members of this unique ecosystem. The lungs, previously thought to be sterile, are now known to harbor a unique microbiota and, additionally, to be influenced by microbial signals from distal body sites, such as the intestine. Here we review the role of the lung and gut microbiotas in respiratory health and disease and highlight the main pathways of communication that underlie the gut-lung axis.

Diet Supplemented with Antioxidant and Anti-Inflammatory Probiotics Improves Sperm Quality after Only One Spermatogenic Cycle in Zebrafish Model

Infertility is a medical concern worldwide and could also have economic consequences in farmed animals. Developing an efficient diet supplement with immediate effects on sperm quality is a promising tool for human reproduction and for domesticated animal species. This study aims at elucidating the effect of a short-time probiotic supplementation consisting of a mixture of two probiotic bacteria with proven antioxidant and anti-inflammatory activities on zebrafish sperm quality and male behavior. For this purpose, three homogeneous groups of males in terms of motility (<60%) were established. The control group was fed with a normal standard diet. The other received supplements: One group (vehicle control) was fed with maltodextrin and the other received a probiotic preparation based on a mixture (1:1) of Lactobacillus rhamnosus CECT8361 and Bifidobacterium longum CECT7347. The feeding regime was 21 days corresponding with a single spermatogenesis in zebrafish. The preparation did not modify animal weight, positively affected the number of fluent males, increased sperm concentration, total motility, progressive motility, and fast spermatozoa subpopulations. Moreover, the animals fed with the supplement showed different behavior patterns compared to control groups. Our results suggest a diet-related modulation on the exploration activity indicating a lower stress-like conduct. The studied formulation described here should be considered as advantageous in male reproductive biotechnology.

Microbial communities in swine lungs and their association with lung lesions

Under natural farming, environmental pathogenic microorganisms may invade and affect swine lungs, further resulting in lung lesions. However, few studies on swine lung microbiota and their potential relationship with lung lesions were reported. Here, we sampled 20 pigs from a hybrid herd raised under natural conditions; we recorded a lung‐lesion phenotype and investigated lung microbial communities by sequencing the V3‐V4 region of 16S rRNA gene for each individual. We found reduced microbial diversity but more biomass in the severe‐lesion lungs. Methylotenera, Prevotella, Sphingobium and Lactobacillus were the prominent bacteria in the healthy lungs, while Mycoplasma, Ureaplasma, Sphingobium, Haemophilus and Phyllobacterium were the most abundant microbes in the severe‐lesion lungs. Notably, we identified 64 lung‐lesion‐associated OTUs, of which two classified to Mycoplasma were positively associated with lung lesions and 62 showed negative association including thirteen classified to Prevotella and six to Ruminococcus. Cross‐validation analysis showed that lung microbiota explained 23.7% phenotypic variance of lung lesions, suggesting that lung microbiota had large effects on promoting lung healthy. Furthermore, 22 KEGG pathways correlated with lung lesions were predicted. Altogether, our findings improve the knowledge about swine lung microbial communities and give insights into the relationship between lung microbiota and lung lesions.

Probiotics for the airways: Potential to improve epithelial and immune homeostasis

Probiotics are live microorganisms that, when administered in adequate amounts, confer health benefit on the host. The therapeutic effects of probiotics have been mostly studied in the gastrointestinal tract, but recent evidence points toward the potential of these bacteria to prevent and/or treat chronic airway diseases. In this review, possible mechanisms of action of probiotics in the airways are described, with a particular focus on their capacity to modulate the epithelial barrier function and their mode of interaction with the immune system. Indeed, probiotic bacteria, mostly lactobacilli, can promote the expression and regulation of tight junctions and adherence junctions, resulting in the restoration of a defective epithelial barrier. These bacteria interact with the epithelial barrier and immune cells through pattern recognition receptors, such as Toll-like receptors, which upon activation can stimulate or suppress various immune responses. Finally, the clinical potential of probiotics to treat inflammatory diseases of the upper and lower respiratory tract, and the difference between their mode of application (eg, oral or nasal) are discussed here.

Probiotic and synbiotic therapy in the critically ill: State of the art

Recent medical history has largely viewed our bacterial symbionts as pathogens to be eradicated rather than as essential partners in optimal health. However, one of the most exciting scientific advances in recent years has been the realization that commensal microorganisms (our microbiome) play vital roles in human physiology in nutrition, vitamin synthesis, drug metabolism, protection against infection, and recovery from illness. Recent data show that loss of "health-promoting" microbes and overgrowth of pathogenic bacteria (dysbiosis) in patients in the intensive care unit (ICU) appears to contribute to nosocomial infections, sepsis, and poor outcomes. Dysbiosis results from many factors, including ubiquitous antibiotic use and altered nutrition delivery in illness. Despite modern antibiotic therapy, infections and mortality from often multidrug-resistant organisms are increasing. This raises the question of whether restoration of a healthy microbiome via probiotics or synbiotics (probiotic and prebiotic combinations) to intervene on ubiquitous ICU dysbiosis would be an optimal intervention in critical illness to prevent infection and to improve recovery. This review will discuss recent innovative experimental data illuminating mechanistic pathways by which probiotics and synbiotics may provide clinical benefit. Furthermore, a review of recent clinical data demonstrating that probiotics and synbiotics can reduce complications in ICU and other populations will be undertaken. Overall, growing data for probiotic and symbiotic therapy reveal a need for definitive clinical trials of these therapies, as recently performed in healthy neonates. Future studies should target administration of probiotics and synbiotics with known mechanistic benefits to improve patient outcomes. Optimally, future probiotic and symbiotic studies will be conducted using microbiome signatures to characterize actual ICU dysbiosis and determine, and perhaps even personalize, ideal probiotic and symbiotic therapies.

Role of the microbiome, probiotics, and 'dysbiosis therapy' in critical illness

PURPOSE OF REVIEW

Loss of 'health-promoting' microbes and overgrowth of pathogenic bacteria (dysbiosis) in ICU is believed to contribute to nosocomial infections, sepsis, and organ failure (multiple organ dysfunction syndrome). This review discusses new understanding of ICU dysbiosis, new data for probiotics and fecal transplantation in ICU, and new data characterizing the ICU microbiome.

RECENT FINDINGS

ICU dysbiosis results from many factors, including ubiquitous antibiotic use and overuse. Despite advances in antibiotic therapy, infections and mortality from often multidrug-resistant organisms (i.e., Clostridium difficile) are increasing. This raises the question of whether restoration of a healthy microbiome via probiotics or other 'dysbiosis therapies' would be an optimal alternative, or parallel treatment option, to antibiotics. Recent clinical data demonstrate probiotics can reduce ICU infections and probiotics or fecal microbial transplant (FMT) can treat Clostridium difficile. This contributes to recommendations that probiotics should be considered to prevent infection in ICU. Unfortunately, significant clinical variability limits the strength of current recommendations and further large clinical trials of probiotics and FMT are needed. Before larger trials of 'dysbiosis therapy' can be thoughtfully undertaken, further characterization of ICU dysbiosis is needed. To addressing this, we conducted an initial analysis demonstrating a rapid and marked change from a 'healthy' microbiome to an often pathogen-dominant microbiota (dysbiosis) in a broad ICU population.

SUMMARY

A growing body of evidence suggests critical illness and ubiquitous antibiotic use leads to ICU dysbiosis that is associated with increased ICU infection, sepsis, and multiple organ dysfunction syndrome. Probiotics and FMT show promise as ICU therapies for infection. We hope future-targeted therapies using microbiome signatures can be developed to correct 'illness-promoting' dysbiosis to restore a healthy microbiome post-ICU to improve patient outcomes.

Lactobacillus rhamnosus L34 Attenuates Gut Translocation-Induced Bacterial Sepsis in Murine Models of Leaky Gut

Gastrointestinal (GI) bacterial translocation in sepsis is well known, but the role of Lactobacillus species probiotics is still controversial. We evaluated the therapeutic effects of Lactobacillus rhamnosus L34 in a new sepsis model of oral administration of pathogenic bacteria with GI leakage induced by either an antibiotic cocktail (ATB) and/or dextran sulfate sodium (DSS). GI leakage with ATB, DSS, and DSS plus ATB (DSS+ATB) was demonstrated by fluorescein isothiocyanate (FITC)-dextran translocation to the circulation. The administration of pathogenic bacteria, either Klebsiella pneumoniae or Salmonella enterica serovar Typhimurium, enhanced translocation. Bacteremia was demonstrated within 24 h in 50 to 88% of mice with GI leakage plus the administration of pathogenic bacteria but not with GI leakage induction alone or bacterial gavage alone. Salmonella bacteremia was found in only 16 to 29% and 0% of mice with Salmonella and Klebsiella administrations, respectively. Klebsiella bacteremia was demonstrated in 25 to 33% and 10 to 16% of mice with Klebsiella and Salmonella administrations, respectively. Lactobacillus rhamnosus L34 attenuated GI leakage in these models, as shown by the reductions of FITC-dextran gut translocation, serum interleukin-6 (IL-6) levels, bacteremia, and sepsis mortality. The reduction in the amount of fecal Salmonella bacteria with Lactobacillus treatment was demonstrated. In addition, an anti-inflammatory effect of the conditioned medium from Lactobacillus rhamnosus L34 was also demonstrated by the attenuation of cytokine production in colonic epithelial cells in vitro In conclusion, Lactobacillus rhamnosus L34 attenuated the severity of symptoms in a murine sepsis model induced by GI leakage and the administration of pathogenic bacteria.

Effect of Lactobacillus rhamnosus HN001 and Bifidobacterium longum BB536 on the healthy gut microbiota composition at phyla and species level: A preliminary study

AIM

To evaluate the ability of Lactobacillus rhamnosus HN001 and Bifidobacterium longum BB536 to colonize the intestinal environment of healthy subjects and modify the gut microbiota composition.

METHODS

Twenty healthy Italian volunteers, eight males and twelve females, participated in the study. Ten subjects took a sachet containing 4 × 10⁹ colony-forming units (CFU) of Bifidobacterium longum BB536 and 10⁹ CFU of Lactobacillus rhamnosus HN001, 30 min before breakfast (pre-prandial administration), while ten subjects took a sachet of probiotic product 30 min after breakfast (post-prandial administration). The ability of Lactobacillus rhamnosus HN001 and Bifidobacterium longum BB536 to colonize human gut microbiota was assessed by means of quantitative real-time PCR, while changes in gut microbiota composition were detected by using Ion Torrent Personal Genome Machine.

RESULTS

Immediately after 1-mo of probiotic administration, B. longum BB536 and L. rhamnosus HN001 load was increased in the majority of subjects in both pre-prandial and post-prandial groups. This increase was found also 1 mo after the end of probiotic oral intake in both groups, if compared to samples collected before probiotic consumption. At phyla level a significant decrease in Firmicutes abundance was detected immediately after 1-mo of B. longum BB536 and L. rhamnosus HN001 oral intake. This reduction persisted up to 1 mo after the end of probiotic oral intake together with a significant decrease of Proteobacteria abundance if compared to samples collected before probiotic administration. Whereas, at species level, a higher abundance of Blautia producta, Blautia wexlerae and Haemophilus ducrey was observed, together with a reduction of Holdemania filiformis, Escherichia vulneris, Gemmiger formicilis and Streptococcus sinensis abundance. In addition, during follow-up period we observed a further reduction in Escherichia vulneris and Gemmiger formicilis, together with a decrease in Roseburia faecis and Ruminococcus gnavus abundance. Conversely, the abundance of Akkermansia muciniphila was increased if compared to samples collected at the beginning of the experimental time course

CONCLUSION

B. longum BB536 and L. rhamnosus HN001 showed the ability to modulate the gut microbiota composition, leading to a significant reduction of potentially harmful bacteria and an increase of beneficial ones. Further studies are needed to better understand the specific mechanisms involved in gut microbiota modulation.

Lactobacillus rhamnosus GG supernatant enhance neonatal resistance to systemic Escherichia coli K1 infection by accelerating development of intestinal defense

The objective of this study was to determine whether Lactobacillus rhamnosus GG culture supernatant (LCS) has a preventive effect against gut-derived systemic neonatal Escherichia coli (E. coli) K1 infection. The preventive effects were evaluated in human colonic carcinoma cell line Caco-2 and neonatal rat models. Our in vitro results showed that LCS could block adhesion, invasion and translocation of E. coli K1 to Caco-2 monolayer via up-regulating mucin production and maintaining intestinal integrity. In vivo experiments revealed that pre-treatment with LCS significantly decrease susceptibility of neonatal rats to oral E. coli K1 infection as reflected by reduced bacterial intestinal colonization, translocation, dissemination and systemic infections. Further, we found that LCS treated neonatal rats have higher intestinal expressions of Ki67, MUC2, ZO-1, IgA, mucin and lower barrier permeability than those in untreated rats. These results indicated that LCS could enhance neonatal resistance to systemic E. coli K1 infection via promoting maturation of neonatal intestinal defense. In conclusions, our findings suggested that LCS has a prophylactic effect against systemic E. coli K1 infection in neonates. Future studies aimed at identifying the specific active ingredients in LCS will be helpful in developing effective pharmacological strategies for preventing neonatal E. coli K1 infection.

Lactobacillus rhamnosus induced epithelial cell apoptosis, ameliorates inflammation and prevents colon cancer development in an animal model

BACKGROUND/AIM

Probiotics have been suggested as prophylactic measure in colon carcinogenesis. This study aimed at determining the potential prophylactic activity of Lactobacillus rhamnosus GG CGMCC 1.2134 (LGG) strain on colorectal carcinogenesis via measuring its effect on Nuclear factor kappa B (NFκB) inflammatory pathway and apoptosis.

MATERIALS AND METHODS

64 Sprague Dawley rats were grouped into four as follows; Group 1 (Healthy control), Group 2 (LGG), Group 3 (cancer control Dimethyl hydrazine (DMH)) and Group 4 (LGG+DMH). LGG was administered orally to LGG and LGG+DMH groups. Colon carcinogenesis was chemically induced in LGG+DMH and DMH groups by weekly injection of 40mg/kg DMH. Animals were sacrificed after 25 weeks of experiment and tumor characteristics assessed. The change in expression of NFκB-p65, COX-2, TNFα, Bcl-2, Bax, iNOS, VEGFα, β-catenin, Casp3 and p53 were evaluated by western blotting and qRT-PCR.

RESULTS

LGG treatment significantly reduced tumor incidence, multiplicity and volume in LGG+DMH treatment group compared to DMH cancer control group. Also, LGG treatment reduced the expression of β-catenin and the inflammatory proteins NFκB-p65, COX-2 and TNFα; the anti-apoptotic protein Bcl-2, but increased the expression of the pro-apoptotic proteins Bax, casp3 and p53 compared with DMH group.

CONCLUSION

LGG have a potential protection effect against colon carcinogenesis; inducing apoptosis and ameliorating inflammation, and may hold a promise as bio-therapeutic dietary agent.

Reduced Levels of D-dimer and Changes in Gut Microbiota Composition After Probiotic Intervention in HIV-Infected Individuals on Stable ART

BACKGROUND

Microbial translocation and chronic inflammation may contribute to non-AIDS morbidity in patients with HIV. This study assessed the impact of probiotic intervention on microbial translocation and inflammation in patients on antiretroviral therapy with viral suppression and subnormal CD4 count.

METHODS

Thirty-two patients receiving antiretroviral therapy (CD4 <500 cells/μL) were randomized in a double-blind fashion to multistrain daily probiotics (n = 15), placebo (n = 9), or controls (n = 8) for 8 weeks. Soluble inflammation markers, D-dimer, lipopolysaccharide (LPS), sCD14, T-cell activation, tryptophan metabolites, and gut microbiota composition were analyzed at baseline and end of study. Nonparametric statistics were applied.

RESULTS

Twenty-four participants completed the study and were included in as-treated analyses. In patients receiving probiotics, there was a significant reduction in D-dimer levels (median change 33%, P = 0.03) and a tendency to reduced levels of C-reactive protein (CRP) (P = 0.05) and interleukin (IL)-6 (P = 0.06). The changes in CRP and IL-6 were highly correlated (r = 0.95, P < 0.01), whereas changes in D-dimer did not correlate with changes in CRP or IL-6. Increases in Bifidobacteria (P = 0.04) and Lactobacilli (P = 0.06) were observed in the probiotic group, whereas the relative abundance of Bacteroides decreased (P ≤ 0.01). No significant changes were seen in markers of microbial translocation or T-cell activation. However, the expansion of Bifidobacteria correlated negatively with differences in LPS (r = -0.77, P = 0.01), whereas the reduction in Bacteroides correlated positively with changes in LPS during the study period (r = 0.72, P = 0.02).

CONCLUSIONS

Probiotic intervention seemed to reduce markers of coagulation and inflammation without overt changes in microbial translocation. These findings warrant further studies in larger cohorts with long-term follow-up.

Inflammatory mediators in intra-abdominal sepsis or injury - a scoping review

Introduction

Inflammatory and protein mediators (cytokine, chemokine, acute phase proteins) play an important, but still not completely understood, role in the morbidity and mortality of intra-abdominal sepsis/injury. We therefore systematically reviewed preclinical and clinical studies of mediators in intra-abdominal sepsis/injury in order to evaluate their ability to: (1) function as diagnostic/prognostic biomarkers; (2) serve as therapeutic targets; and (3) illuminate the pathogenesis mechanisms of sepsis or injury-related organ dysfunction.

Methods

We searched MEDLINE, PubMed, EMBASE and the Cochrane Library. Two investigators independently reviewed all identified abstracts and selected articles for full-text review. We included original studies assessing mediators in intra-abdominal sepsis/injury.

Results

Among 2437 citations, we selected 182 studies in the scoping review, including 79 preclinical and 103 clinical studies. Serum procalcitonin and C-reactive protein appear to be useful to rule out infection or monitor therapy; however, the diagnostic and prognostic value of mediators for complications/outcomes of sepsis or injury remains to be established. Peritoneal mediator levels are substantially higher than systemic levels after intra-abdominal infection/trauma. Common limitations of current studies included small sample sizes and lack of uniformity in study design and outcome measures. To date, targeted therapies against mediators remain experimental.

Conclusions

Whereas preclinical data suggests mediators play a critical role in intra-abdominal sepsis or injury, there is no consensus on the clinical use of mediators in diagnosing or managing intra-abdominal sepsis or injury. Measurement of peritoneal mediators should be further investigated as a more sensitive determinant of intra-abdominal inflammatory response. High-quality clinical trials are needed to better understand the role of inflammatory mediators.

Electronic supplementary material

The online version of this article (doi:10.1186/s13054-015-1093-4) contains supplementary material, which is available to authorized users.

The Role of Intestinal Microbiota in Acute Graft-versus-Host Disease

The mammalian intestinal microbiota is a complex ecosystem that plays an important role in host immune responses. Recent studies have demonstrated that alterations in intestinal microbiota composition are linked to multiple inflammatory diseases in humans, including acute graft-versus-host disease (aGVHD). aGVHD is one of the major obstacles in allogeneic hematopoietic stem cell transplantation (allo-HSCT), characterized by tissue damage in the gastrointestinal (GI) tract, liver, lung, and skin. Here, we review the current understanding of the role of intestinal microbiota in the control of immune responses during aGVHD. Additionally, the possibility of using probiotic strains for potential treatment or prevention of aGVHD will be discussed.