Probiotic, prebiotic, and synbiotic use in critically ill patients. Curr Opin Crit Care. 2012;18:186-191. [PMID: 22343306 DOI: 10.1097/MCC.0b013e3283514b17]

Synbiotics and Surgery: Can Prebiotics and Probiotics Affect Inflammatory Surgical Outcomes?

PURPOSE OF REVIEW

Prebiotics, probiotics, and synbiotics have received increasing attention over the years for their beneficial impact on the gut microbiome and for their systemic anti-inflammatory effects. They have also been shown to improve surgical outcomes. Here, we review the inflammatory effects of surgery as well as the data which suggests a benefit of prebiotics, probiotics, and synbiotics taken in the perioperative period.

RECENT FINDINGS

Synbiotics and fermented foods may have an even greater anti-inflammatory effect than probiotics or prebiotics alone. Recent data suggest that the anti-inflammatory effects and microbiome changes brought on by prebiotics, probiotics, and synbiotics have the potential to improve surgical outcomes. We highlight the potential to alter systemic inflammation, surgical and hospital-acquired infections, colorectal cancer formation, recurrence, and anastomotic leak. Synbiotics could also impact metabolic syndrome. Prebiotics, probiotics, and especially synbiotics may be extremely beneficial when taken in the perioperative period. Even short-term gut microbiome pre-habilitation could alter surgical outcomes significantly.

Drugging the microbiome and bacterial live biotherapeutic consortium production

Research leading to characterization, quantification, and functional attribution of the microbes throughout the human body has led to many drug-development programs. These programs aim to manipulate a patient's microbiome through the addition of new strains or functions, the subtraction of deleterious microbes, or the rebalancing of the existing population through various drug modalities. Here, we present a general overview of those modalities with a specific focus on bacterial live biotherapeutic products (LBPs). The bacterial LBP modality has unique concerns to ensure product quality, thus, topics related to manufacturing, quality control, and regulation are addressed.

Effect of probiotics, prebiotics and synbiotics for chronic bronchitis or chronic obstructive pulmonary disease: A protocol for systematic review and meta-analysis

BACKGROUND

Probiotics, prebiotics and synbiotics have been widely used in the treatment of respiratory diseases, but their clinical efficacy for treating chronic bronchitis (CB) or chronic obstructive pulmonary disease (COPD) has not been well studied.

METHODS

The following electronic databases will be searched for eligible randomized controlled trials: the Cochrane Library, EMBASE, MEDLINE, PubMed, Scopus, the Web of Science, the China National Knowledge Infrastructure, the Wanfang database, and the China Science and Technology Journal database (VIP Information Network). We will search these electronic databases weekly and extract relevant data from their inception dates until September 30, 2020. Risk of publication bias will be evaluated by the Cochrane Handbook for Systematic Reviews of Interventions. Data synthesis will be conducted using Review Manager (RevMan) version 5.3 software. Sensitivity and quality of evidence analyses will be conducted.

RESULTS

This systematic review and meta-analysis will provide a high-quality synthesis from existing evidence for estimating the efficacy and safety of probiotics, prebiotics and synbiotics in the treatment of CB or COPD.

CONCLUSION

This systematic review and meta-analysis will provide reliable and accurate evidence to guide the use of probiotics, prebiotics and synbiotics in the treatment of CB or COPD.

REGISTRATION OSF REGISTRATION NUMBER

DOI 10.17605/OSF.IO/SP35M.

In Vitro Evaluation of Probiotic Potential of Lactic Acid Bacteria Isolated from Yunnan De'ang Pickled Tea

This study aimed to investigate the probiotic potential of lactic acid bacteria (LAB) strains isolated from De'ang pickled tea, a traditional food consumed by the De'ang nationality of Yunnan, China. Twenty-six LAB strains isolated from De'ang pickled tea were subjected to identification based on 16S rRNA gene sequence analysis. Twenty-four belonged to Lactobacillus plantarum, one belonged to Enterococcus casseliflavus, and one belonged to Lactobacillus acidophilus. Eighteen out of 26 LAB strains which showed a higher capability to tolerate simulated gastrointestinal juices were chosen to further evaluate their probiotic properties. Varied adhesive abilities and auto-aggregative capacities of selected LAB strains were dependent on species and even strains. All tested LAB strains were resistant to kanamycin, streptomycin, gentamycin, and vancomycin and sensitive to tetracycline and chloramphenicol. Ten out of the 18 strains are resistant to ampicillin, and the remaining strains are sensitive to ampicillin; 4 out of the 18 strains showed resistance to erythromycin. Compared to reference strain Lactobacillus rhamnosus strain GG, these LAB strains had a greater or comparative antimicrobial activity against Salmonella typhimurium or Escherichia coli. In contrast, eight out of the 18 strains suppressed growth of Shigella flexneri. Two L. plantarum strains, ST and STDA10, not only exhibited good probiotic properties but also showed a good ability of scavenging DPPH and ABTS⁺. This study suggests that L. plantarum ST and STDA10 could be used as potential probiotics applied in functional foods.

Probiotics, mechanisms of action, and clinical perspectives for diarrhea management in children

Infectious diarrhea is the second most common cause of morbidity and mortality in children under 5 years of age in the underdeveloped areas of the world. Conventional treatment consists of rehydration, which may be coupled with antimicrobial agents in more severe bacterial infections or with antiprotozoal agents. In the last few decades, research on the use of probiotic strains, such as Lactobacillus rhamnosus GG ATCC 53013 (LGG), Lactobacillus reuteri DSM 17938 and Saccharomyces boulardii, has gained much attention to prevent and treat diarrheal diseases. However, they are rarely used in the clinical routine, perhaps because there are still gaps in the knowledge about the effective benefit to the patient in terms of the reduction of the duration of diarrhea and its prevention. Furthermore, only a few probiotic strains are safely indicated for usage in pediatric practice. This review summarizes the current knowledge on the antimicrobial mechanisms of probiotics on distinct enteropathogens and their role in stimulating host defense mechanisms against intestinal infections. In addition, we highlight the potential of probiotics for the treatment and prevention of diarrhea in children. We conclude that the use of probiotics is beneficial for both the treatment and prevention of diarrhea in children and that the identification of other candidate probiotics might represent an important advance to a greater reduction in hospital stays and to prevent infectious diarrhea in a larger portion of this population.

A Comparative Review on Microbiota Manipulation: Lessons From Fish, Plants, Livestock, and Human Research

During recent years the impact of microbial communities on the health of their host (being plants, fish, and terrestrial animals including humans) has received increasing attention. The microbiota provides the host with nutrients, induces host immune development and metabolism, and protects the host against invading pathogens (1-6). Through millions of years of co-evolution bacteria and hosts have developed intimate relationships. Microbial colonization shapes the host immune system that in turn can shape the microbial composition (7-9). However, with the large scale use of antibiotics in agriculture and human medicine over the last decades an increase of diseases associated with so-called dysbiosis has emerged. Dysbiosis refers to either a disturbed microbial composition (outgrowth of possible pathogenic species) or a disturbed interaction between bacteria and the host (10). Instead of using more antibiotics to treat dysbiosis there is a need to develop alternative strategies to combat disturbed microbial control. To this end, we can learn from nature itself. For example, the plant root (or "rhizosphere") microbiome of sugar beet contains several bacterial species that suppress the fungal root pathogen Rhizoctonia solani, an economically important fungal pathogen of this crop (11). Likewise, commensal bacteria present on healthy human skin produce antimicrobial molecules that selectively kill skin pathogen Staphylococcus aureus. Interestingly, patients with atopic dermatitis (inflammation of the skin) lacked antimicrobial peptide secreting commensal skin bacteria (12). In this review, we will give an overview of microbial manipulation in fish, plants, and terrestrial animals including humans to uncover conserved mechanisms and learn how we might restore microbial balance increasing the resilience of the host species.

Increases in Phenolic, Fatty Acid, and Phytosterol Contents and Anticancer Activities of Sweet Potato after Fermentation by Lactobacillus acidophilus

Phenolic, fatty acid, and phytosterol contents in sweet potato (SP) fermented by Lactobacillus acidophilus were evaluated and compared with those of raw and boiled SPs. The differences in the profiles and levels of phenolics between the raw and boiled SPs were not as significant as the differences between those and the fermented SP. The levels of caffeic acid and 3,5-dicaffeoylquinic acid in fermented SP were more than 4 times higher than those in raw and boiled SPs. Two phenolics, p-coumaric acid and ferulic acid, which were not detected in either raw or boiled SP, were found in fermented SP. The level of each fatty acid or phytosterol increased in fermented SP and decreased in boiled SP. Among the hydrophilic and lipophilic extracts obtained from raw and fermented SPs, the hydrophilic extract of fermented SP exhibited the highest capability of inhibiting cancer-cell PC-12 proliferation. However, each of the extracts had very low cytotoxicities to normal-monkey-kidney-cell growth. The results indicated that SP fermented by L. acidophilus significantly increased free antioxidant-rich phenolics and inhibited cancer-cell-proliferation activity without cytotoxicity to normal cells.

Sporulated Bacillus as alternative treatment for diarrhea of hospitalized adult patients under enteral nutrition: A pilot randomized controlled study

BACKGROUND & AIMS

Among hospitalized patients receiving enteral nutrition (EN), malnutrition and antibiotic use are some of the most common causes of diarrhea. Prebiotics and probiotics agents have been used for treatment of diarrhea in such patients. The aim of this study was to assess the efficacy of a sporulated Bacillus strain (Bacillus cereus A 05), compared to a control group using a prebiotic (soluble fiber), in reducing diarrhea in patients receiving EN and antibiotic therapy.

METHODS

Patients with diarrhea receiving EN were randomized to receive either B. cereus (study group) or soluble fiber (control group) for five days. The group treated with B. cereus received 4 vials with 5 mL × 10⁶ every 6 h. The control group treated with fiber received 10 g of soluble fiber every 8 h. Data assessed were serum albumin, nutrition status through Subjective Global Assessment (SGA), antibiotic use and osmolality (normal or hyperosmolar) of the tube feeding diets.

RESULTS

Twenty-nine patients were treated in each group. There was no significant difference between the groups regarding age, serum albumin, SGA score, dietary osmolality and antibiotic use. There was no significant difference between groups in ceasing diarrhea. However, the group treated with B. cereus took fewer days to cease diarrhea (2.5 ± 1.3 versus 3.7 ± 1.1 days, p = 0.011). Specifically, in the group treated with B. cereus A 05, malnourished patients did better than non-malnourished patients regarding diarrhea cessation (100% versus 25%, p < 0.001).

CONCLUSIONS

B. cereus A 05 was more effective than fiber in reducing diarrhea among patients under EN and antibiotic therapy and was more effective among malnourished patients.

The modulation of enzyme indoleamine 2,3-dioxygenase from dendritic cells for the treatment of type 1 diabetes mellitus

Diabetes mellitus type 1 (DM1) is an autoimmune disease in which β-cells of the pancreas islet are destroyed by T lymphocytes. Specific T cells are activated by antigen-presenting cells, mainly dendritic cells (DCs). It is already known that the regulation of tryptophan pathway in DC can be a mechanism of immunomodulation. The enzyme indoleamine 2,3-dioxygenase (IDO) is present in many cells, including DC, and participates in the metabolism of the amino acid tryptophan. Recent studies suggest the involvement of IDO in the modulation of immune response, which became more evident after the in vitro demonstration of IDO production by DC and of the ability of these cells to inhibit lymphocyte function through the control of tryptophan metabolism. Current studies on immunotherapies describe the use of DC and IDO to control the progression of the immune response that triggers DM1. The initial results obtained are promising and indicate the possibility of developing therapies for the treatment or prevention of the DM1. Clinical trials using these cells in DM1 patients represent an interesting alternative treatment. However, clinical trials are still in the initial phase and a robust group of assays is necessary.

The Shift of an Intestinal "Microbiome" to a "Pathobiome" Governs the Course and Outcome of Sepsis Following Surgical Injury

Sepsis following surgical injury remains a growing and worrisome problem following both emergent and elective surgery. Although early resuscitation efforts and prompt antibiotic therapy have improved outcomes in the first 24 to 48  h, late onset sepsis is now the most common cause of death in modern intensive care units. This time shift may be, in part, a result of prolonged exposure of the host to the stressors of critical illness which, over time, erode the health promoting intestinal microbiota and allow for virulent pathogens to predominate. Colonizing pathogens can then subvert the immune system and contribute to the deterioration of the host response. Here, we posit that novel approaches integrating the molecular, ecological, and evolutionary dynamics of the evolving gut microbiome/pathobiome during critical illness are needed to understand and prevent the late onset sepsis that develops following prolonged critical illness.

Probiotics in Human Immunodeficiency Virus Infection: A Systematic Review and Evidence Synthesis of Benefits and Risks

The risk of sepsis is low. The best probiotic to optimize outcomes has not yet been identified. Potential benefit for CD4 count, recurrence or management of bacterial vaginosis and diarrhea. Uncertain effect on translocation, BV treatment.

People living with human immunodeficiency virus frequently use dietary supplements, including probiotics, but concern exists about ingesting live organisms. We performed a systematic review of the benefits of probiotics and a meta-analysis of sepsis risk. We undertook a protocol-driven, comprehensive review to identify all relevant studies, assess their quality, and summarize the evidence. Of 2068 references, 27 were analyzed. The data suggest possible benefits for CD4 count, recurrence or management of bacterial vaginosis, and diarrhea management. We examined randomized, controlled studies explicitly assessing sepsis in any patient population, and we found zero cases of supplement-associated bacteremia or fungemia in 39 randomized controlled trials comprising 9402 subjects. The estimated number needed to harm is 7369 in Bayesian approach (95% credible interval: 1689, ∞), which should reassure clinicians. No or mild adverse effects were reported. Longer duration studies investigating different individual and mixed strains for plausible indications are needed to establish best practices.

The administration of probiotics and synbiotics in immune compromised adults: is it safe?

This study aimed to systematically evaluate safety of probiotics and synbiotics in immune compromised adults (≥18 years). Safety was analysed using the Common Terminology Clinical Adverse Events (CTCAE version 4.0) classification, thereby providing an update on previous reports using the most recent available clinical data (2008-2013). Safety aspects are represented and related to number of participants per probiotic strain/culture, study duration, dosage, clinical condition and selected afflictions. Analysis of 57 clinical studies indicates that probiotic and/or synbiotic administration in immune compromised adults is safe with regard to the current evaluated probiotic strains, dosages and duration. Individuals were considered immune compromised if HIV-infected, critically ill, underwent surgery or had an organ- or an autoimmune disease. There were no major safety concerns in the study, as none of the serious adverse events (AE)s were related, or suspected to be related, to the probiotic or synbiotic product and the study products were well tolerated. Overall, AEs occurred less frequent in immune compromised subjects receiving probiotics and/or synbiotics compared to the control group. In addition, the results demonstrated a flaw in precise reporting and classification of AE in most studies. Furthermore, generalisability of conclusions are greatly limited by the inconsistent, imprecise and potentially incomplete reporting as well as the variation in probiotic strains, dosages, administration regimes, study populations and reported outcomes. We argue that standardised reporting on adverse events (CTCAE) in 'food' studies should be obligatory, thereby improving reliability of data and re-enforcing the safety profile of probiotics.

The involvement of gut microbiota in inflammatory bowel disease pathogenesis: potential for therapy

Over the past recent years, a great number of studies have been directed toward the evaluation of the human host-gut microbiota interaction, with the goal to progress the understanding of the etiology of several complex diseases. Alterations in the intestinal microbiota associated with inflammatory bowel disease are well supported by literature data and have been widely accepted by the research community. The concomitant implementation of high-throughput sequencing techniques to analyze and characterize the composition of the intestinal microbiota has reinforced the view that inflammatory bowel disease results from altered interactions between gut microbes and the mucosal immune system and has raised the possibility that some form of modulation of the intestinal microbiota may constitute a potential therapeutic basis for the disease. The aim of this review is to describe the changes of gut microbiota in inflammatory bowel disease, focusing the attention on its involvement in the pathogenesis of the disease, and to review and discuss the therapeutic potential to modify the intestinal microbial population with antibiotics, probiotics, prebiotics, synbiotics and fecal microbiota transplantation.

Probiotics in treatment of severe acute pancreatitis

Severe acute pancreatitis (SAP) is a life-threatening condition characterized by high mortality, with infection and bacteremia being major causes of death. Prophylactic antibiotic administration failed to show any favorable effect on the incidence of infectious complications in SAP patients. Consequently, microorganism intervention is recommend by World Health Organization (WHO). Probiotics improve the prognosis of SAP patients by promoting gastrointestinal peristalsis, modulating the content of gut microbiota, maintaining the integrity of the gut barrier, modulating the immune response by the gut-associated immune system and reducing the damage to the pancreas, lung and liver. It has been demonstrated that probiotics in combination with immunonutrition could improve the prognosis of SAP patients. However, the use of probiotics in SAP remains controversial currently.

Effect of commensals and probiotics on visceral sensitivity and pain in irritable bowel syndrome

The last ten years' wide progress in the gut microbiota phylogenetic and functional characterization has been made evidencing dysbiosis in several gastrointestinal diseases including inflammatory bowel diseases and irritable bowel syndrome (IBS). IBS is a functional gut disease with high prevalence and negative impact on patient's quality of life characterized mainly by visceral pain and/or discomfort, representing a good paradigm of chronic gut hypersensitivity. The IBS features are strongly regulated by bidirectional gut-brain interactions and there is increasing evidence for the involvement of gut bacteria and/or their metabolites in these features, including visceral pain. Further, gut microbiota modulation by antibiotics or probiotics has been promising in IBS. Mechanistic data provided mainly by animal studies highlight that commensals or probiotics may exert a direct action through bacterial metabolites on sensitive nerve endings in the gut mucosa, or indirect pathways targeting the intestinal epithelial barrier, the mucosal and/or systemic immune activation, and subsequent neuronal sensitization and/or activation.

Effect of emodin on endoplasmic reticulum stress in rats with severe acute pancreatitis

This study aimed to investigate the protective effect of emodin on endoplasmic reticulum (ER) stress in rats with severe acute pancreatitis (SAP) and the underlying molecular mechanism. Sprague-Dawley male rats were randomly divided into sham operation group, SAP model group, and emodin treatment group. SAP was constructed through injecting sodium taurocholate into pancreatic and biliary duct in rats. Half an hour before establishing the animal model, emodin or sodium carboxymethylcellulose was intragastrically administrated to the rats in respective group. Rats were killed at 3, 6, and 12 h postdisease induction. The amylase, tumor necrosis factor-alpha (TNF-α) and interleukin-6 (IL-6) levels in serum, pancreatic histopathology, acinar ER ultrastructure, protein expression of Bip, IRE1α,TRAF2, ASK1, p-JNK, and p-p38 MAPK in pancreas were examined. Sodium taurocholate induced pancreatic injury and ER lumen dilated in exocrine pancreas in rats at 3-, 6-, and 12-h time points. ER stress transducers Bip, IRE1α, and their downstream molecules TRAF2, ASK1 in pancreatitis were upregulated. Furthermore, phosphorylation of JNK and p38MAPK in pancreas was increased, which induced high expression level of inflammatory cytokines such as TNF-α and IL-6. Treatment with emodin obviously ameliorated pancreatic injury and decreased the release of amylase and inflammatory cytokines. Further studies showed that emodin significantly decreased the expression of Bip, IRE1α, TRAF2, and ASK1, inhibited phosphorylation of JNK and p38 MAPK in pancreas in rats at all time points. Emodin could reduce pancreatic injury and restrain inflammatory reaction in SAP rats partly via inhibiting ER stress transducers IRE1α and its downstream molecules.

[The influence of symbiotics in multi-organ failure: randomised trial]

BACKGROUND AND OBJECTIVE

To assess whether the administration of symbiotic preparations in patients with multi-organ failure (MOF) diminishes the evolution of the failure, the inflammatory response generated, the colonization pattern and the Intensive Care Unit (ICU) infectious illness.

PATIENTS AND METHOD

Randomized and controlled trial. All patients with MOF were included. Neutropenia and acute pancreatitis patients were excluded. A symbiotic (Simbiotic Drink) was administered via enteral feeding during the first 7 days. Variables of interest were: Sequential Organ Failure Assessment (SOFA) score evolution, systemic concentrations of lactate, fibrinogen and D-dimer; skin and mucosa colonization and infectious disease register.

RESULTS

Eighty-nine patients were included; 46 in the symbiotic group (SG) and 43 in the control group (CG). There were 68.5% males, with a median age of 69 years. There were no significant differences in the patients' fundamental characteristics (medical history, age, reason for admission, severity scores), nor in the length of ICU stay or in mortality. Comparing the SG with the CG, there were lower lactate levels on the second day, more fibrinogen levels on the days 5 and 7, and lower D-dimer levels on the day 7. Eight hundred and ninety-five cultures were performed for colonization assessment, with isolation of 528 microorganisms. No differences in microbiological resistance were found; there were more colonization in the SG by Candida in mucous membranes after the third day; this situation resolved after stopping symbiotic administration. Twenty-two patients suffered an infectious disease in ICU, 14 in SG (42.4%) and 19 in CG (57.6%). Although no differences were found in the microbiological pattern, there was a predominance of Candida spp. over other microorganisms (4 vs. 0 cases).

CONCLUSIONS

The symbiotic preparation Simbiotic Drink, administered in MOF, results in differences to improve the early lactate levels and late fibrinogen/D-dimer levels as well as mucosa colonization by Candida. There were no differences in the ICU evolution.

Bugs or drugs: are probiotics safe for use in the critically ill?

Probiotics are living microorganisms which have demonstrated many benefits in prevention, mitigation, and treatment of various disease states in critically ill populations. These diseases include antibiotic-associated diarrhea, Clostridium difficile diarrhea, ventilator-associated pneumonia, clearance of vancomycin-resistant enterococci from the GI tract, pancreatitis, liver transplant, major abdominal surgery, and trauma. However, their use has been severely limited due to a variety of factors including a general naïveté within the physician community, lack of regulation, and safety concerns. This article focuses on uses for probiotics in prevention and treatment, addresses current concerns regarding their use as well as proposing a protocol for safe use of probiotics in the critically ill patient.

Regulatory roles of the PI3K/Akt signaling pathway in rats with severe acute pancreatitis

The phosphatidylinositol 3-kinase(PI3K)/protein kinase B (Akt) pathway plays a key role in inflammation. However, the regulatory roles of PI3K/Akt in severe acute pancreatitis (SAP) have not been elucidated. The aim of this study was to investigate the impact of wortmannin, a PI3K/Akt inhibitor, on SAP rats through exposure to sodium taurocholate (STC) after 3 h and 6 h. The SAP group was found to have a significant increase in pancreas Akt expression, along with the activation of serum amylase, TNF-α, IL-1β, and IL-6, and pancreas histological aggravation. The administration of wortmannin in SAP rats reduced Akt expression, attenuated the level of serum amylase and inflammation factor, and alleviated the damage of pancreatic tissue. Furthermore, the administration of wortmannin led to an obvious reduction in NF-κB and p38MAPK expression in SAP rats. These findings showed that the PI3K/Akt inhibitor wortmannin decreases inflammatory cytokines in SAP rats and suggests its regulatory mechanisms may occur through the suppression on NF-κB and p38MAPK activity.

Diarrhea in enterally fed patients: blame the diet?

PURPOSE OF REVIEW

Diarrhea has great impact on enteral nutrition. The purpose of this review is to identify the factors leading to diarrhea during enteral nutrition and to provide the published updates on diarrhea prevention through nutritional intervention.

RECENT FINDINGS

Diarrhea in enteral fed patients is attributed to multiple factors, including medications (major contributor), infections, bacterial contamination, underlying disease, and enteral feeding. Diet management can alleviate diarrhea in enteral feeding. High content of fermentable oligosaccharides, disaccharides, and monosaccharides and polyols (FODMAPs) in enteral formula is postulated to induce diarrhea and lower FODMAPs formula may reduce the likelihood of diarrhea in enterally fed patients. Fiber-enriched formula can reduce the incidence of diarrhea and produce short-chain fatty acids for colonocytes. Ingesting prebiotics, nonviable probiotics or probiotic derivatives, and human lactoferrin may provide alternatives for reducing/preventing diarrhea.

SUMMARY

Enteral feeding is not generally considered the primary cause of diarrhea, which is frequently linked to prescribed medications. When diarrhea is apparent, healthcare members should evaluate the possible risk factors and systematically attempt to eliminate the underlying causes of diarrhea before reducing or suspending enteral feeding. Lower FODMAPs formula, prebiotics, probiotic derivatives, and lactoferrin may be used to manage enteral feeding-related diarrhea.

Probiotics in Clostridium difficile infection: reviewing the need for a multistrain probiotic

In the past two years an enormous amount of molecular, genetic, metabolomic and mechanistic data on the host-bacterium interaction, a healthy gut microbiota and a possible role for probiotics in Clostridium difficile infection (CDI) has been accumulated. Also, new hypervirulent strains of C. difficile have emerged. Yet, clinical trials in CDI have been less promising than in antibiotic associated diarrhoea in general, with more meta-analysis than primary papers on CDI-clinical-trials. The fact that C. difficile is a spore former, producing at least three different toxins has not yet been incorporated in the rational design of probiotics for (recurrent) CDI. Here we postulate that the plethora of effects of C. difficile and the vast amount of data on the role of commensal gut residents and probiotics point towards a multistrain mixture of probiotics to reduce CDI, but also to limit (nosocomial) transmission and/or endogenous reinfection. On the basis of a retrospective chart review of a series of ten CDI patients where recurrence was expected, all patients on adjunctive probiotic therapy with multistrain cocktail (Ecologic®AAD/OMNiBiOTiC® 10) showed complete clinical resolution. This result, and recent success in faecal transplants in CDI treatment, are supportive for the rational design of multistrain probiotics for CDI.

Immunomodulatory approaches for prevention and treatment of infectious diseases

With increasing pathogen resistance to antibiotics, population ageing, and threat of pandemics there is a strong interest in the development of new approaches for the treatment of infectious diseases. Immunomodulatory therapies are defined as interventions that target the host rather than the pathogen, modulating the immune response with the aim of disease prevention or treatment. Our growing understanding of the immune system continues to offer novel drug targets and approaches for immunomodulatory interventions. In this review we will cover prominent examples of immunomodulatory therapies already in clinical use, as well as the recent advances in the development of new immunomodulators in ongoing clinical trials.

Microbial modulators for treatment of liver failure with endotoxemia: Research progress

Intestinal endotoxemia is one of the important mechanisms behind the onset and development of liver failure. Intestinal flora or intestinal barrier dysfunction can cause intestinal endotoxemia. Various kinds of microbial products can decrease serum levels of endotoxin and reduce complications and mortality by improving intestinal microflora imbalance and inhibiting Gram-negative bacterial overgrowth. Microbial modulators show significant therapeutic effects in the treatment of liver failure, which has become a research focus in improving endotoxemia associated with liver failure. However, the compatibility of various microbial modulators and antibiotics when combined should arouse the attention of clinicians. This article reviews the types of microbial modulators, their mechanisms of action and combination use with probiotics, and the compatibility when combined with antibiotics.

The endogenous bacteria alter gut epithelial apoptosis and decrease mortality following Pseudomonas aeruginosa pneumonia

The endogenous bacteria have been hypothesized to play a significant role in the pathophysiology of critical illness, although their role in sepsis is poorly understood. The purpose of this study was to determine how commensal bacteria alter the host response to sepsis. Conventional and germ-free (GF) C57Bl/6 mice were subjected to Pseudomonas aeruginosa pneumonia. All GF mice died within 2 days, whereas 44% of conventional mice survived for 7 days (P = 0.001). Diluting the dose of bacteria 10-fold in GF mice led to similar survival in GF and conventional mice. When animals with similar mortality were assayed for intestinal integrity, GF mice had lower levels of intestinal epithelial apoptosis but similar levels of proliferation and intestinal permeability. Germ-free mice had significantly lower levels of tumor necrosis factor and interleukin 1β in bronchoalveolar lavage fluid compared with conventional mice without changes in systemic cytokine production. Under conventional conditions, sepsis unmasks lymphocyte control of intestinal epithelial apoptosis, because sepsis induces a greater increase in gut apoptosis in Rag-1 mice than in wild-type mice. However, in a separate set of experiments, gut apoptosis was similar between septic GF Rag-1 mice and septic GF wild-type mice. These data demonstrate that the endogenous bacteria play a protective role in mediating mortality from pneumonia-induced sepsis, potentially mediated through altered intestinal apoptosis and the local proinflammatory response. In addition, sepsis-induced lymphocyte-dependent increases in gut epithelial apoptosis appear to be mediated by the endogenous bacteria.

The gut is the epicentre of antibiotic resistance

The gut contains very large numbers of bacteria. Changes in the composition of the gut flora, due in particular to antibiotics, can happen silently, leading to the selection of highly resistant bacteria and Candida species. These resistant organisms may remain for months in the gut of the carrier without causing any symptoms or translocate through the gut epithelium, induce healthcare-associated infections, undergo cross-transmission to other individuals, and cause limited outbreaks. Techniques are available to prevent, detect, and treat the carriage of resistant organisms in the gut. However, evidence on these techniques is scant, the only exception being selective digestive decontamination (SDD), which has been extensively studied in neutropenic and ICU patients. After the destruction of resistant colonizing bacteria, which has been successfully obtained in several studies, the gut could be re-colonized with normal faecal flora or probiotics. Studies are warranted to evaluate this concept.

A mathematical model to guide antibiotic treatment strategies

Over the past few decades, the emergence of multidrug resistance (MDR) to antibiotics in bacteria has led to major difficulties in the management of infected patients. At present, there is a serious lack of development of new antibacterial agents. Mathematical models are one approach to understand how antibiotic usage patterns may be optimized. However, the classical approach to modeling the emergence of MDR relies on the simplifying assumption that resistance is acquired at a constant rate. In their model, Obolski and Hadany introduce the notion of horizontal gene transfer and stress-induced mutation, with antibiotics constituting an environmental stressor of particular relevance. Finally, from this complex mathematical model, the authors propose predictions for minimizing MDR in bacteria depending on strategies of antibiotic treatment. Please see related article: http://www.biomedcentral.com/1741-7015/10/89.

The role of prebiotics and probiotics in prevention and treatment of childhood infectious diseases

Infant formulae and food products marketed for children have been increasingly supplemented with probiotics and/or prebiotics. A vast number of studies have accounted for the transit of probiotic use from alternative to more evidence-based medicine. Data support the use of certain probiotics for the adjunct treatment of acute viral gastroenteritis, and for prevention of gastrointestinal diseases. Further roles of prebiotics and probiotics are seen in the prevention of overall infectious diseases and respiratory infections. Data from well-conducted randomized-controlled trials support the therapeutic role for probiotics toward necrotizing enterocolitis in preterm infants. However, it is difficult to translate heterogeneous-based study results, which are mainly due to varying genera, strains, doses, study settings and measured outcomes, into evidence-based recommendations. This article focuses on the evidence of clinical benefits of prebiotics, probiotics and synbiotics toward prevention and treatment of pediatric infectious diseases.