Design of a multispecies probiotic mixture to prevent infectious complications in critically ill patients

Evaluation of Four Multispecies Probiotic Cocktails in a Human Colonic Fermentation Model

Bacteriotherapy represents an attractive approach for both prophylaxis and treatment of human diseases. However, combining probiotic bacteria in "cocktails" is underexplored, despite its potential as an alternative multi-target therapy. Herein, three-strain probiotic mixtures containing different combinations of Bacillus (Bc.) coagulans [ATB-BCS-042], Levilactobacillus (Lv.) brevis [THT 0303101], Lacticaseibacillus (Lc.) paracasei [THT 031901], Bacillus subtilis subsp. natto [ATB-BSN-049], Enterococcus faecium [ATB-EFM-030], and Bifidobacterium (Bf.) animalis subsp. lactis [THT 010802] were prepared. Four cocktails (PA: Bc. coagulans + Lv. brevis + Lc. paracasei, PB: Bc. subtilis subsp. natto + Lv. brevis + Lc. paracasei, PC: E. faecium + Lv. brevis + Lc. paracasei, PD: Bc. coagulans + Lv. brevis + Bf. animalis subsp. lactis) were tested using a short-term (72 h) simulation of the human colonic microbiota in a final dose of 6 × 109 CFU. All these probiotic mixtures significantly increased butyrate production compared to the parallel control experiment. PA and PB promoted a bifidogenic effect and facilitated lactobacilli colonization. Furthermore, reporter gene assays using the AhR_HT29-Lucia cell line revealed that fermentation supernatants from PA and PB notably induced AhR transactivity. Subsequent examination of the metabolic outputs of PA and PB in intestinal epithelial models using cell culture inserts suggested no significant impact on the transepithelial electrical resistance (TEER). Assessment of the expression of proinflammatory and anti-inflammatory cytokines, as well as AhR-related target genes in the Caco-2 cell monolayers indicated that PB's metabolic output upregulated most of the measured endpoints. This in vitro investigation evaluated the potential impact of four multispecies probiotic mixtures in the human colonic microbiota and identified a promising formulation comprising a combination of Bc. subtilis subsp. natto, Lv. brevis, and Lc. paracasei as a promising formulation for further study.

Metabolic network construction reveals probiotic-specific alterations in the metabolic activity of a synthetic small intestinal community

IMPORTANCE

The development of probiotic therapies targeted at the small intestinal microbiota represents a significant advancement in the field of probiotic interventions. This region poses unique opportunities due to its low number of gut microbiota, along with the presence of heightened immune and metabolic host responses. However, progress in this area has been hindered by a lack of detailed understanding regarding the molecular mechanisms through which probiotics exert their effects in the small intestine. Our study, utilizing a synthetic community of three small intestinal bacterial strains and the addition of two different probiotic species, and kynurenine as a representative dietary or endogenously produced compound, highlights the importance of selecting probiotic species with diverse genetic capabilities that complement the functional capacity of the resident microbiota, or alternatively, constructing a multispecies formula. This approach holds great promise for the development of effective probiotic therapies and underscores the need to consider the functional capacity of probiotic species when designing interventions.

Resilience and probiotic interventions to prevent and recover from shrimp gut dysbiosis

To counter the recurrent outbreaks of bacterial (acute hepatopancreatic necrosis disease; AHPND) and viral (white spot disease; WSD) shrimp diseases, which still remain a threat to the global industry, shrimp gut microbiota research has been gaining more attention in recent years, and the use of probiotics in aquaculture has had promising results in improving shrimp gut health and immunity. In this review based on our studies on AHPND and WSD, we summarize our current understanding of the shrimp gastrointestinal tract and the role of the microbiota in disease, as well as effects of probiotics. We focus particularly on the concept of microbiota resilience, and consider strategies that can be used to restore shrimp gut health by probiotic intervention at a crucial time during gut microbiota dysbiosis. Based on the available scientific evidence, we argue that the use of probiotics potentially has an important role in controlling disease in shrimp aquaculture.

Postbiotic metabolites, antioxidant and anticancer activities of probiotic Leuconostoc pseudomesenteroides strains in natural pickles

In this study, five strains of Leuconostoc pseudomesenteroides were thought to have probiotic properties and anticancer activity isolated from natural pickles and identified by performing the 16S rRNA sequence analysis. The probiotic properties, postbiotic amounts, the capacity to adhere to the L-929, HT-29 and Caco-2 cell lines, the effects of postbiotic and bacterial extracts on cell viability and biochemical activities were investigated in the strains. In the results, Leu. pseudomesenteroides Y6 strain was detected to have the best resistance to the stomach and intestinal environments, and the quantities of postbiotic metabolites are similar to each other. The bacterial adhesion capacities were found to be in the range of 1.66-8.5%. Furthermore, postbiotic metabolites of all isolates had good anticancer activity (27.67-86.05%) and the activity of bacterial extractions increased depending on concentration. Leu. pseudomesenteroides Y4 and Y6 strains generally showed better activity than controls and all strains were strong 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavengers in the antioxidant studies. In conclusion, the Y6 strain, which had the best probiotic feature, was found to show significantly good biological activity. It is thought that this isolate will be supported by new in vivo studies and eventually be brought to the food and health industry.

The microbial ecology of Escherichia coli in the vertebrate gut

Escherichia coli has a rich history as biology's 'rock star', driving advances across many fields. In the wild, E. coli resides innocuously in the gut of humans and animals but is also a versatile pathogen commonly associated with intestinal and extraintestinal infections and antimicrobial resistance-including large foodborne outbreaks such as the one that swept across Europe in 2011, killing 54 individuals and causing approximately 4000 infections and 900 cases of haemolytic uraemic syndrome. Given that most E. coli are harmless gut colonizers, an important ecological question plaguing microbiologists is what makes E. coli an occasionally devastating pathogen? To address this question requires an enhanced understanding of the ecology of the organism as a commensal. Here, we review how our knowledge of the ecology and within-host diversity of this organism in the vertebrate gut has progressed in the 137 years since E. coli was first described. We also review current approaches to the study of within-host bacterial diversity. In closing, we discuss some of the outstanding questions yet to be addressed and prospects for future research.

Assessment of the Safety of Lactobacillus casei IMV B-7280 Probiotic Strain on a Mouse Model

Probiotics, in particular Lactobacillus (lactic acid bacteria, LAB) strains, are widely used in clinical practice. Despite that these probiotics have GRAS (generally regarded as safe) and qualified presumption of safety (QPS) statuses, the safety of particular strains still needs to be thoroughly studied. The aim of the study was to evaluate the safety of Lact. casei IMV B-7280 strain by investigating toxicity and the effects on gut microbiota in experimental animal model. Male BALB/c mice (7-8 weeks, weight 20-24 g) were treated with amounts of Lact. casei IMV B-7280 strain: 5 × 106, 5 × 108, or 5 × 109 CFU/animal once per day during 7 days, or in the amount of 1 × 1010 CFU/animal once per day during 3 days (most of the proposed probiotic doses for humans-from 108 to 109 CFU) and monitored during 14 days. Blood tests and serum biochemistry were conducted; the cecal content from mice of the experimental and control groups were freshly collected and analyzed. At the end of the experiments (15th day), the presence of LAB in the heart, liver, kidney, and mesenteric lymph nodes and peripheral blood was determined; histology of the brain, liver, heart, fragments of the small and large intestine, and mesenteric lymph nodes was conducted. Survival rate of BALB/c mice treated with Lact. casei IMV B-7280 strain in different concentrations in toxicity experiments during 14 days was 100%. We observed no signs of toxicity as changes in gait, lethargy, sleep, somatomotor activity as well as changes in fur, eyes, skin and mucous membranes, tremors, behavior pattern, convulsions, salivation, diarrhea, and local injuries in mice from all experimental groups. After administration of probiotic strain, the number of opportunistic bacteria in cecal contents, such as Staphylococcus spp., Candida spp., Pseudomonas spp., and total aerobic and optionally anaerobic bacteria decreased compared to controls; the population of beneficial bacteria such as lactobacilli increased in cecal contents of these mice. LAB were not detected in the peripheral blood, heart, liver, kidneys, and mesenteric lymph nodes after administration of this strain to intact mice. Lact. casei IMV B-7280 strain is safe at dose up to 1010 CFU/animal during 3- and 7-day oral administration to mice and has a positive effect on the gut microbiota composition; it could be potentially considered as safe probiotic for humans.

The synergy of dietary supplements Lactobacillus salivarius LI01 and Bifidobacterium longum TC01 in alleviating liver failure in rats treated with D-galactosamine

Lactobacillus salivarius (L. salivarius) has been widely used in dietary supplements and clinical treatments. Previous studies demonstrated the protective effect of L. salivarius LI01 on liver injury induced by D-galactosamine (D-GaIN) in rats. Accumulating evidence indicates that Lactobacillus and Bifidobacterium are highly coordinated; so in this study, we focus on the synergistic effect of L. salivarius LI01 and B. longum TC01 on the alleviation of liver injury caused by D-GaIN in rats and aim to find out the underlying interaction between the two strains. We observed reduced hepatic damage in the D-GaIN-treated rats with probiotic pre-administration, characterized by lower levels of AST and ALT (p < 0.05) and decreased HAI (Histological Activity Index) scores. Moreover, cotreatment with LI01 and TC01 more effectively decreases proinflammatory cytokines TNF-α, MCP-1 and M-CSF (p < 0.05) so as to inhibit systemic inflammation. Gut barrier dysfunction was ameliorated with compound probiotic pretreatment, as evidenced by the ultrastructure integrity, decreased histological score and elevated TJP-1 expression. What's more, supplementation with LI01 and TC01 markedly alleviates gut dysbiosis in the G-DaIN-treated rats, with enrichment of short chain fatty acid (SCFA) producers Faecalibaculum and Eubacterium_xylanophilum_group, a decreased Firmicutes/Bacteroidetes (F/B) ratio and depletion of proinflammatory microbes, such as Peptococcaeae and Ruminococcaceae_UCG-005. This study highlights the synergistic effect of dietary supplements LI01 and TC01 on the protection against liver failure, which is probably via altering gut microbiota.

Evaluation of acrylamide-removing properties of bacterial consortia under simulated gastrointestinal conditions

BACKGROUND

Previous studies have demonstrated the acrylamide-removing properties of probiotic monocultures; however, potential advantages of consortia over monocultures in reducing the dietary exposure to acrylamide have not been proven. Hence this work aims to assess the acrylamide (AA)-binding properties of bacterial consortia, consisting of either probiotic strains and / or representative bacteria of duodenal microbiota, exposed to simulated gastrointestinal conditions (SGC). The AA binding capacity of ten probiotic strains (PS) and six duodenal strains (NDS) was evaluated under different conditions; then, three different consortia (PS, NDS, and PS + NDS) were assessed under SGC.

RESULTS

Among individual PS, Bacillus coagulans GBI-30, Lactobacillus fermentum J23, L. pentosus J37 and J24, and L. casei Shirota, exhibited the highest AA-binding capacity (80-87%), while Bifidobacterium catenulatun ATCC27676, Streptococcus salivarius subsp. thermophilus ATCC19258, and S. gallolyticus ATCC9809 were the best (ca. 68%) NDS monocultures. Probiotic strain consortia showed higher (P < 0.05) AA binding capacity (> 90%) than monoculture bacteria. Conversely, individual NDS cultures displayed higher (P < 0.05) binding capacity than NDS consortia (60%). A significant reduction (P < 0.05) in AA removal capacity was observed when consortia were exposed to SGC, PS consortia being the most effective (> 60% removal).

CONCLUSION

These results suggest that consortia of specific PS could play an important role in reducing the intestinal availability of acrylamide. © 2021 Society of Chemical Industry.

Mixture of probiotics reduces inflammatory biomarkers and improves the oxidative/nitrosative profile in people with rheumatoid arthritis

OBJECTIVES

Studies have demonstrated that the gut microbiota of people with rheumatoid arthritis (RA) is different from that of healthy individuals and could influence inflammation and oxidative stress. In this study, we sought to evaluate the effects of supplementation with a mixture of probiotics on cytokine plasma levels, inflammatory biomarkers, oxidative/nitrosative stress profile, and Disease Activity Score-28 in people with RA.

METHODS

A randomized and double-blind placebo-controlled study was carried out with 42 participants with RA divided into two groups-the probiotic group (n = 21), who over 60 d took a daily ingestion of probiotics in a sachet containing 109 CFU/g each of five freeze-dried strains: Lactobacillus acidophilus La-14, Lactobacillus casei Lc-11, Lactococcus lactis Ll-23, Bifidobacterium lactis Bl-04 and B. bifidum Bb-06; and the placebo group (n = 21) who over 60 d took a daily ingestion of maltodextrin.

RESULTS

The probiotic group showed a significant reduction in white blood cell count (P = 0.012) and tumor necrosis factor-α (P = 0.004) and interleukin 6 plasma levels (P = 0.039). However, no differences were observed in interleukin-10, adiponectin, C-reactive protein, erythrocyte sedimentation rate, ferritin, or Disease Activity Score-28 between the two groups. Regarding oxidative/nitrosative stress biomarkers, the probiotic group showed lower nitric oxide metabolites (P = 0.004) and higher sulfhydryl group (P = 0.028) and total radical-trapping antioxidant parameters (P = 0.019) than the placebo group. However, lipid hydroperoxide and protein carbonyl did not differ between groups (P > 0.05).

CONCLUSIONS

The mixture of probiotics reduced inflammatory biomarkers and improved the oxidative/nitrosative profile in people with RA.

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.

Study protocol of a double-blind randomised placebo-controlled trial on the effect of a multispecies probiotic on the incidence of antibiotic-associated diarrhoea in persons with spinal cord injury

STUDY DESIGN

Multi-centre, double-blind randomised placebo-controlled study.

OBJECTIVE

To investigate whether the use of a multispecies probiotic can prevent antibiotic-associated diarrhoea in people with spinal cord injury (SCI).

SETTING

Three Dutch SCI rehabilitation centres.

METHODS

Fifty-six people aged 18-75 years with SCI during inpatient rehabilitation, who require antibiotics, will be given probiotics or placebo randomly assigned (T0). After cessation of the antibiotics (T1), the participants will use probiotics/placebo for 3 more weeks (T2). Defaecation, assessed by the Bristol Stool Scale, and bowel management will be monitored daily until 2 weeks after cessation of probiotics/placebo intake (T3). Also, the degree of nausea and information on quality of life will be collected at T0, T1, T2 and T3.

MAIN OUTCOME MEASURES

The difference between the incidence of antibiotic-associated diarrhoea between people with SCI using probiotics compared to those using a placebo at the moment the antibiotics stops, the probiotics stops and two weeks thereafter.

SECONDARY OUTCOME MEASURES

The time to reach effective bowel management, degree of nausea and quality of life.

REGISTRATION

The Dutch Trial Register- NTR 5831.

Genetic risk for autoimmunity is associated with distinct changes in the human gut microbiome

Susceptibility to many human autoimmune diseases is under strong genetic control by class II human leukocyte antigen (HLA) allele combinations. These genes remain by far the greatest risk factors in the development of type 1 diabetes and celiac disease. Despite this, little is known about HLA influences on the composition of the human gut microbiome, a potential source of environmental influence on disease. Here, using a general population cohort from the All Babies in Southeast Sweden study, we report that genetic risk for developing type 1 diabetes autoimmunity is associated with distinct changes in the gut microbiome. Both the core microbiome and beta diversity differ with HLA risk group and genotype. In addition, protective HLA haplotypes are associated with bacterial genera Intestinibacter and Romboutsia. Thus, general population cohorts are valuable in identifying potential environmental triggers or protective factors for autoimmune diseases that may otherwise be masked by strong genetic control.

Emerging Trends in "Smart Probiotics": Functional Consideration for the Development of Novel Health and Industrial Applications

The link between gut microbiota and human health is well-recognized and described. This ultimate impact on the host has contributed to explain the mutual dependence between humans and their gut bacteria. Gut microbiota can be manipulated through passive or active strategies. The former includes diet, lifestyle, and environment, while the latter comprise antibiotics, pre- and probiotics. Historically, conventional probiotic strategies included a phylogenetically limited diversity of bacteria and some yeast strains. However, biotherapeutic strategies evolved in the last years with the advent of fecal microbiota transplant (FMT), successfully applied for treating CDI, IBD, and other diseases. Despite the positive outcomes, long-term effects resulting from the uncharacterized nature of FMT are not sufficiently studied. Thus, developing strategies to simulate the FMT, using characterized gut colonizers with identified phylogenetic diversity, may be a promising alternative. As the definition of probiotics states that the microorganism should have beneficial effects on the host, several bacterial species with proven efficacy have been considered next generation probiotics. Non-conventional candidate strains include Akkermansia muciniphila, Faecalibacterium prausnitzii, Bacteroides fragilis, and members of the Clostridia clusters IV, XIVa, and XVIII. However, viable intestinal delivery is one of the current challenges, due to their stringent survival conditions. In this review, we will cover current perspectives on the development and assessment of next generation probiotics and the approaches that industry and stakeholders must consider for a successful outcome.

Bifidobacterium animalis in combination with human origin of Lactobacillus plantarum ameliorate neuroinflammation in experimental model of multiple sclerosis by altering CD4+ T cell subset balance

BACKGROUND

Multiple Sclerosis (MS) is a chronic inflammatory autoimmune disease of the central nervous system (CNS). Recent reports have shown that probiotics can induce immunomodulatory activity with promising effects in inflammatory diseases. This study was designed to reveal the molecular and cellular mechanisms underlying the effect of Lactobacillus plantarum A7, which comprises human commensal bacteria, and Bifidobacterium animalis, a potential probiotic strain, on alleviation of experimental autoimmune encephalomyelitis (EAE), an animal model of MS.

METHODS

To evaluate the therapeutic effects of probiotic strains, female C57BL/6 mice (8-10 wks old) received Lactobacillus plantarum A7, Bifidobacterium animalis PTCC 1631or a mixture of both strains through oral administration daily for 22days beginning simultaneous with induction of EAE. The clinical parameters were recorded daily. On Day 22, each mouse was bled, and their spinal cord was removed for histology analysis. The effects of the treatments on regulatory T (Treg) cells level were evaluated using flow cytometry, and T-cell proliferation was assessed using a BrdU incorporation assay. The supernatants of spleen and lymph nodes cultured and mononuclear cells were collected for quantification of different panel of pro and anti-inflammatory cytokines by ELISA. The analysis of gene expression was performed at RNA level for transcription factors by real-time PCR.

RESULTS

The results showed that treatment with a mixture of the two strains caused a more significant delay in the time of disease onset and clinical score compared to when the strains were used alone. The pathological features of the disease, such as mononuclear infiltration into the CNS, were also inhibited more significantly by the combinational approach. The results also revealed that treatment with combination of both strains enhanced the population of CD4⁺CD25⁺Foxp3⁺-expressing T-cells in the lymph nodes and the spleen.

TREATMENT

with our probiotic strains markedly inhibited disease associated cytokines while increased anti-inflammatory cytokines. Additionally, L. plantarumA7 and B. animalis ameliorated EAE condition by favoring Th2 and Treg differentiation via up-regulation of Foxp3 and GATA3 in the brain and spleen as well as inhibited the differentiation of Th1 and Th17 cells.

CONCLUSIONS

The current research provided evidence that probiotic therapy with L. plantarum and B. animalis can effectively attenuate EAE progression as well as reinforce the polarization of regulatory T-cells.

Strain-specific probiotic properties of lactic acid bacteria and their interference with human intestinal pathogens invasion

BACKGROUND

One of the working mechanisms of probiotic bacteria is their ability to compete with pathogens. To define the probiotic properties of seven Lactic Acid Bacteria (LAB) strains, we tested them for survival in simulated gastro-intestinal conditions, antimicrobial activities, co-aggregative abilities, and interferences studies against five human intestinal pathogens (Salmonella enteritidis ATCC 13076, Listeria monocytogenes ATCC 7644, Escherichia coli O157: H7 ATCC 35150, Cronobacter sakazakii ATCC 29544 and Campylobacter jejuni ATCC 33291).

RESULTS

The LAB strains were able to survive the stomach simulated conditions, and varied in their abilities to survive the small intestinal-simulated conditions. The strains showed antibiotic susceptibility profiles with values equal or below the breakpoints set by the European Food and Safety Authority. The LAB cell-free cultures supernatants showed antimicrobial activities, with inhibition zones ranging from 10.0 to 17.2 mm. All the LAB strains showed moderate auto-aggregation abilities while the greatest co-aggregation abilities were observed for Bifidobacterium bifidum W23, Lactobacillus plantarum W21 and Lactobacillus rhamnosus W71. The individual LAB strains showed strain-specific abilities to reduce the invasion of intestinal pathogens in an interference model with Caco-2 cells. Increased invasion inhibition was found when different combinations of LAB strains were used in the interference tests.

CONCLUSION

The LAB strains examined in this study may protect the intestinal epithelium through a series of barriers (antimicrobial activity, co-aggregation with pathogens, adherence) and interference mechanisms. Consequently, these LAB strains may be considered candidates for prophylactic use to prevent intestinal infections.

Dual-coated lactic acid bacteria: an emerging innovative technology in the field of probiotics

Probiotics are living micro-organisms that do not naturally have shelf life, and normally are weakly protected against the digestive action of the GI tract. A new dual coating technology has been developed in an effort to maximize survival, that is, to be able to reach the intestine alive and in sufficient numbers to confer the beneficial health effects on the host. Dual-coating of lactic acid bacteria (LAB) is the result of fourth-generation coating technology for the protection of these bacteria at least 100-fold or greater than the uncoated LAB. This innovative technique involves a first pH-dependent protein layer that protects bacteria from gastric acid and bile salt, and a second polysaccharide matrix that protects bacteria from external factors, such as humidity, temperature and pressure, as well as the digestive action during the passage through the GI tract. Dual-coated probiotic formulation is applicable to different therapeutic areas, including irritable bowel syndrome, atopic dermatitis, acute diarrhea, chronic constipation, Helicobacter pylori eradication, and prevention of antibiotic-associated diarrhea. An updated review of the efficacy of doubly coated probiotic strains for improving bacterial survival in the intestinal tract and its consequent clinical benefits in humans is here presented.

In vitro evidence for efficacy in food intolerance for the multispecies probiotic formulation Ecologic® Tolerance (Syngut™)

The beneficial effects of probiotics are currently the subject of extensive studies in health and medical research. The aim of this research was to specifically design a new probiotic formulation for supplementation in people suffering from food intolerance. The selection of strains was focussed on the capacity to influence mechanisms of action that are important in development of food intolerance with the following parameters measure: in vitro capacity to produce β-galactosidase, in vitro strengthening of the epithelial barrier, in vitro stimulation of cytokines produced by regulatory T cells, in addition to assessing fundamental quality criteria (stability, gastrointestinal (GI)-survival, multispecies concept, allergen-free). Ecologic®Tolerance/Syngut™ was subsequently developed consisting of a multispecies concept using 4 different probiotic strains (Bifidobacterium lactis W51, Lactobacillus acidophilus W22, Lactobacillus plantarum W21 and Lactococcus lactis W19). Each of these strains demonstrated ability to survive the GI-tract and strain specific effects in producing β-galactosidase, strengthening the gut barrier function after immunological-induced stress and inhibiting Th2 cytokines (IL-4, IL-5 and IL-13 (≥50%), in addition to stimulating interleukin-10 levels; thus, providing in vitro evidence for the efficacy of the selected strains to provide beneficial effects in patients suffering from food intolerance.

Is there a role for probiotics in the prevention of preterm birth?

Preterm birth (PTB) continues to be a global health challenge. An over-production of inflammatory cytokines and chemokines, as well as an altered maternal vaginal microbiome has been implicated in the pathogenesis of inflammation/infection-associated PTB. Lactobacillus represents the dominant species in the vagina of most healthy pregnant women. The depletion of Lactobacillus in women with bacterial vaginosis (BV) has been associated with an increased risk of PTB. It remains unknown at what point an aberrant vaginal microbiome composition specifically induces the cascade leading to PTB. The ability of oral or vaginal lactobacilli probiotics to reduce BV occurrence and/or dampen inflammation is being considered as a means to prevent PTB. Certain anti-inflammatory properties of lactobacilli suggest potential mechanisms. To date, clinical studies have not been powered with sufficiently high rates of PTB, but overall, there is merit in examining this promising area of clinical science.

Randomized clinical trial on the effect of a multispecies probiotic on visceroperception in hypersensitive IBS patients

BACKGROUND

Irritable bowel syndrome (IBS) is characterized by heterogeneous pathophysiology and low response to treatment. Up to 60% of IBS patients suffers from visceral hypersensitivity, which is associated with symptom severity and underlying pathophysiological mechanisms. Recently, positive effects of probiotics in IBS have been reported, but overall the response was modest. We performed a study in IBS patients, characterized by visceral hypersensitivity measured with the rectal barostat, aiming to assess the effect of 6 weeks of multispecies probiotic mix on visceral pain perception.

METHODS

We conducted a randomized, placebo-controlled, double-blind trial in forty Rome III IBS patients with visceral hypersensitivity. Prior to intake, patients kept a 2-week symptom diary and underwent a rectal barostat measurement. When hypersensitivity was confirmed, participation was allowed and patients received a multispecies probiotic with in vitro proven potential beneficial effects on mechanisms contributing to visceral hypersensitivity (six different probiotic strains; 10(9)  cfu/g), or a placebo product of one sachet (5 g) per day for 6 weeks. At the end of the intervention period, visceroperception and symptoms were reassessed.

KEY RESULTS

Thirty-five patients completed the trial. The percentage of patients with visceral hypersensitivity decreased significantly in the probiotic and placebo group (76.5% and 71.4%, respectively; N.S. between groups). Improvement in pain scores and mean symptom score did not differ between the probiotic and placebo group.

CONCLUSIONS & INFERENCES

In this placebo-controlled trial in IBS patients with visceral hypersensitivity, no significant effect of a multispecies probiotic on viscerperception was observed. The study has been registered in the US National Library of Medicine (http://www.clinicaltrials.gov, NCT00702026).

Effects of probiotic supplementation on markers of acute pancreatitis in rats

BACKGROUND

Intestinal barrier disruption followed by bacterial translocation seems to play a role in secondary pancreatic infection in acute pancreatitis. The use of probiotics as a possible adjuvant strategy in the treatment of acute pancreatitis needs to be investigated.

OBJECTIVE

The aim of this study was to determine the effects of dietary supplementation with a prophylactically administered multispecies probiotic mixture on the markers of acute pancreatitis and on the occurrence of bacterial translocation.

METHODS

Thirty adult male Wistar rats were randomly assigned to 1 of 3 groups of 10 rats each: (1) the PS group, in which the rats were given probiotic supplementation prior to induction of acute pancreatitis; (2) the WP group, in which the rats underwent surgery to induce acute pancreatitis without prior probiotic supplementation; and (3) the control group, in which the rats underwent sham surgery. For 14 days before surgery, animals in the PS group received a single daily dose containing ~1.2 × 10(9) colony-forming units of a probiotic mixture administered intragastrically as a bolus. On day 15, the animals underwent surgery to induce acute pancreatitis (PS and WP groups) or simulated surgery (control group). Blood samples were collected to determine leukocyte count, amylase and lipase activities, and glucose and calcium concentrations immediately before and 6 and 12 hours after the beginning of the procedure. Samples of pancreas, spleen, liver, and mesenteric lymph nodes were harvested for microbiologic and histopathologic analysis after the last blood sample collection. The pathologist examining the histopathology was blinded to treatment assignment.

RESULTS

The mean leukocyte count was significantly increased in the PS group compared with the WP group (P = 0.018), whereas the serum amylase and lipase activities and the serum glucose and calcium concentrations were not significantly different between the 2 groups. Comparing the risk for tissue colonization in the PS group with that of the WP group, the odds ratio (OR) for pancreas was 2.91 (95% CI, 0.13-67.10); liver, 66.55 (95% CI, 1.89-2282.66); spleen, 88.58 (95% CI, 3.04-2583.08); and mesenteric lymph nodes, 1.23 (95% CI, 0.06-25.48). When the risks for histopathologic changes were compared between the 2 groups, the OR for acinar necrosis was 1.73 (95% CI, 0.21-12.17); steatonecrosis, 12.08 (95% CI, 1.26-115.54); hemorrhage, 1.38 (95% CI, 0.21-9.53); and leukocyte infiltration, 5.91 (95% CI, 0.64-54.89).

CONCLUSION

Probiotic supplementation before the induction of acute pancreatitis was associated with a greater degree of bacterial translocation and pancreatic tissue damage in this animal model.

Extracellular vesicles modulate host-microbe responses by altering TLR2 activity and phagocytosis

Oral delivery of Gram positive bacteria, often derived from the genera Lactobacillus or Bifidobacterium, can modulate immune function. Although the exact mechanisms remain unclear, immunomodulatory effects may be elicited through the direct interaction of these bacteria with the intestinal epithelium or resident dendritic cell (DC) populations. We analyzed the immune activation properties of Lactobacilli and Bifidobacterium species and made the surprising observation that cellular responses in vitro were differentially influenced by the presence of serum, specifically the extracellular vesicle (EV) fraction. In contrast to the tested Lactobacilli species, tested Bifidobacterium species induce TLR2/6 activity which is inhibited by the presence of EVs. Using specific TLR ligands, EVs were found to enhance cellular TLR2/1 and TLR4 responses while TLR2/6 responses were suppressed. No effect could be observed on cellular TLR5 responses. We determined that EVs play a role in bacterial aggregation, suggesting that EVs interact with bacterial surfaces. EVs were found to slightly enhance DC phagocytosis of Bifidobacterium breve whereas phagocytosis of Lactobacillus rhamnosus was virtually absent upon serum EV depletion. DC uptake of a non-microbial substance (dextran) was not affected by the different serum fractions suggesting that EVs do not interfere with DC phagocytic capacity but rather modify the DC-microbe interaction. Depending on the microbe, combined effects of EVs on TLR activity and phagocytosis result in a differential proinflammatory DC cytokine release. Overall, these data suggest that EVs play a yet unrecognized role in host-microbe responses, not by interfering in recipient cellular responses but via attachment to, or scavenging of, microbe-associated molecular patterns. EVs can be found in any tissue or bodily fluid, therefore insights into EV-microbe interactions are important in understanding the mechanism of action of potential probiotics and gut immune homeostasis.

Probiotics for preventing ventilator-associated pneumonia: a systematic review and meta-analysis of high-quality randomized controlled trials

Background

Ventilator-associated pneumonia (VAP) is considered to be a worldwide issue along with the development of supportive ventilation. The preventing strategy is of great importance for its poor prognostic and difficulties in treatment. Probiotics have been advocated as one of the possible preventive measures. We conducted a systematic review and meta-analysis to explore the potential benefits of probiotics.

Methods

The databases, Web of science, PubMed, Ovid and Cochrane lib were searched for randomized controlled trials (RCTs) publications that compared the effectiveness of probiotics with placebo in the prevention of VAP. The incidence of VAP was considered as the primary endpoint, mortality, length of stay in intensive care units (ICUs), etiology of the infections were considered as secondary endpoints.

Results

A total of 844 patients from 5 trials were subjected to meta-analysis. Probiotics did not significantly decrease the incidence of VAP (RR 0.94, 95%CI 0.85-1.04, p=0.22), however, the administration of probiotics reduced the risk of VAP caused by Pseudomonas aeruginosa (P. aeruginosa) (RR 0.30, 95%CI 0.11-0.91, P=0.03). It failed to affect any other endpoints.

Conclusion

Probiotic prophylaxis of ventilator-associated pneumonia remained inconclusive and it failed to improve the prognosis of general mechanically ventilated patients. It was noteworthy that infections caused by P. aeruginosa was reduced by administration of probiotics. In further, it is recommended that advanced studies should exploit transformation in pathogenic microorganisms owing to administration of probiotics as well as the specific population.

Bactofencin A, a new type of cationic bacteriocin with unusual immunity

Bacteriocin production is an important probiotic trait of intestinal bacteria. In this study, we identify a new type of bacteriocin, bactofencin A, produced by a porcine intestinal isolate Lactobacillus salivarius DPC6502, and assess its potency against pathogenic species including Staphylococcus aureus and Listeria monocytogenes. Genome sequencing of the bacteriocin producer revealed bfnA, which encodes the mature and highly basic (pI 10.59), 22-amino-acid defensin-like peptide. Matrix-assisted laser desorption ionization–time of flight (MALDI-TOF) mass spectral analysis determined that bactofencin A has a molecular mass of 2,782 Da and contains two cysteine residues that form an intramolecular disulfide bond. Although an ABC transporter and transport accessory protein were also present within the bacteriocin gene cluster, a classical bacteriocin immunity gene was not detected. Interestingly, a dltB homologue was identified downstream of bfnA. DltB is usually encoded within the dlt operon of many Gram-positive bacteria. It is responsible for d-alanylation of teichoic acids in the cell wall and has previously been associated with bacterial resistance to cationic antimicrobial peptides. Heterologous expression of this gene conferred bactofencin A-specific immunity on sensitive strains of L. salivarius and S. aureus (although not L. monocytogenes), establishing its role in bacteriocin immunity. An analysis of the distribution of bfnA revealed that it was present in four additional isolates derived from porcine origin and absent from five human isolates, suggesting that its distribution is host specific. Given its novelty, we anticipate that bactofencin A represents the prototype of a new class of bacteriocins characterized as being cationic, with a DltB homologue providing a cognate immunity function.

This study describes the identification, purification, and characterization of bactofencin A, a novel type of bacteriocin produced by L. salivarius DPC6502. Interestingly, bactofencin A is not similar to any other known bacteriocin but instead shares similarity with eukaryotic cationic antimicrobial peptides, and here, we demonstrate that it inhibits two medically significant pathogens. Genome sequence analysis of the producing strain also revealed the presence of an atypical dltB homologue in the bacteriocin gene cluster, which was lacking a classical bacteriocin immunity gene. Furthermore, cloning this gene rendered sensitive strains resistant to the bacteriocin, thereby establishing its role in providing cognate bacteriocin immunity. Four additional L. salivarius isolates, also of porcine origin, were found to contain the bacteriocin biosynthesis genes and successfully produced bactofencin A, while these genes were absent from five human-derived strains investigated.

Lack of correlation between in vitro antibiosis and in vivo protection against enteropathogenic bacteria by probiotic lactobacilli

Increased resistance to infection is one of the beneficial effects attributed to probiotic microorganisms. This effect may be due to several mechanisms: production of inhibitory substances, blocking of adhesion sites on the intestinal surface, competition for nutrients and stimulation of mucosal and systemic immunity. The present study aimed to investigate the correlation between in vitro and in vivo antimicrobial activity of probiotic lactobacilli. The agar spot test was used to show that twenty Lactobacillus strains were able to inhibit the enteropathogenic bacterium Yersinia enterocolitica. This inhibition was mainly attributable to a decrease in pH resulting from dextrose fermentation by lactobacilli. The inhibition of Y. enterocolitica, Salmonella enterica serovar Typhimurium and Listeria monocytogenes by two probiotic strains, Lactobacillus casei C1 and Lactobacillus plantarum C4, was also associated with the pH decrease. However, both strains lacked protective effects in mouse experimental infection models, with the exception of long-lasting pre-treatment with L. plantarum C4, which exerted a partial protective effect against S. Typhimurium that was attributable to an immunostimulatory mechanism. Our results show that in vitro antibiosis tests do not provide useful information on the probiotic potential of Lactobacillus strains.

Hypocaloric diet supplemented with probiotic cheese improves body mass index and blood pressure indices of obese hypertensive patients--a randomized double-blind placebo-controlled pilot study

Background

Gut lactobacilli can affect the metabolic functions of healthy humans. We tested whether a 1500 kcal/d diet supplemented with cheese containing the probiotic Lactobacillus plantarum TENSIA (Deutsche Sammlung für Mikroorganismen, DSM 21380) could reduce some symptoms of metabolic syndrome in Russian adults with obesity and hypertension.

Methods

In this 3-week, randomized, double-blind, placebo-controlled, parallel pilot study, 25 subjects ingested probiotic cheese and 15 ingested control cheese. Fifty grams of each cheese provided 175 kcal of energy. Blood pressure (BP), anthropometric characteristics, markers of liver and kidney function, metabolic indices (plasma glucose, lipids, and cholesterol), and urine polyamines were measured. Counts of fecal lactobacilli and L. plantarum TENSIA were evaluated using molecular methods. The data were analyzed by t-test for independent samples and Spearman’s partial correlation analysis.

Results

The probiotic L. plantarum TENSIA was present in variable amounts (529.6 ± 232.5 gene copies) in 16/25 (64%) study subjects. Body mass index (BMI) was significantly reduced (p = 0.031) in the probiotic cheese group versus the control cheese group. The changes in BMI were closely associated with the water content of the body (r = 0.570, p = 0.0007) when adjusted for sex and age. Higher values of intestinal lactobacilli after probiotic cheese consumption were associated with higher BMI (r = 0.383, p = 0.0305) and urinary putrescine content (r = 0.475, p = 0.006). In patients simultaneously treated with BP-lowering drugs, similar reductions of BP were observed in both groups. A positive association was detected between TENSIA colonization and the extent of change of morning diastolic BP (r = 0.617, p = 0.0248) and a trend toward lower values of morning systolic BP (r = −0.527, p = 0.0640) at the end of the study after adjusting for BMI, age, and sex.

Conclusion

In a pilot study of obese hypertensive patients, a hypocaloric diet supplemented with a probiotic cheese helps to reduce BMI and arterial BP values, recognized symptoms of metabolic syndrome.

Trial registration

Current Controlled Trials ISRCTN76271778

Draft genome sequence of Lactobacillus casei W56

We announce the draft genome sequence of Lactobacillus casei W56 in one contig. This strain shows immunomodulatory and probiotic properties. The strain is also an ingredient of commercially available probiotic products.

Effects of Bacillus subtilis var. natto and Saccharomyces cerevisiae fermented liquid feed on growth performance, relative organ weight, intestinal microflora, and organ antioxidant status in Landes geese

The aim of this study was to investigate the effect of Bacillus subtilis var. natto N21 (BAC) and Saccharomyces cerevisiae Y10 (SAC) fermented liquid feed (FLF) during different incubation times on the growth performance, relative organ weight, intestinal microflora, and organ antioxidative status in Landes geese. Two hundred forty male Landes geese (10 wk old) with the BW of 4.163 ± 0.108 kg were selected for a 3-wk trial and randomly allotted to 3 treatments according to their BW (10 replicates/treatment and 8 geese/replicate). The treatments included 1) CON, dry basal feed (corn-soybean basal diet mixed with water) before feeding (2:1 wt/wt), 2) FLF24, 24 h FLF, and 3) FLF48, 48 h FLF. The FLF diet was prepared by storing basal diet with 10(9) cfu/g feed of each BAC and SAC and water (2:1 wt/wt) in a closed tank at 20°C fermented for 24 or 48 h. The BW gain and feed intake of geese fed FLF24 and FLF48 was greater (P < 0.05) than CON treatment. Feeding geese with FLF24 and FLF48 feeds increased (P < 0.05) the relative weight of leg muscle whereas the liver was heavier (P < 0.05) in FLF48 treatment than CON and FLF24 treatments. The FLF24 and FLF48 increased (P < 0.05) the Lactobacillus population and depressed (P < 0.05) Escherichia coli population in small and large intestine. The high-density lipoprotein cholesterol concentration was greatest (P < 0.05) in FLF48 whereas the total cholesterol and low-density lipoprotein cholesterol was less (P < 0.05) in FLF24 and FLF48 treatments than CON. Geese fed FLF48 diet had greater glutathione peroxidase activity and less malondialdehyde content in heart and liver than those fed CON diet. In breast muscle, the superoxide dismutase activity were increased (P < 0.05) by FLF24 and FLF48 treatments than CON diet. In conclusion, the results indicated that feeding geese with BAC and SAC mix FLF can improve growth and feed intake, modulate the intestine ecology, and decrease the blood cholesterol concentrations; it also can improve the antioxidative status of organs and breast muscle.

Lactobacillus acidophilus and Lactobacillus reuteri modulate cytokine responses in gnotobiotic pigs infected with human rotavirus

Probiotic lactic acid bacteria (LAB) have been shown to alleviate inflammation, enhance the immunogenicity of rotavirus vaccines, or reduce the severity of rotavirus diarrhoea. Although the mechanisms are not clear, the differential Th1/Th2/Th3-driving capacities and modulating effects on cytokine production of different LAB strains may be the key. Our goal was to delineate the influence of combining two probiotic strains of Lactobacillus acidophilus and Lactobacillus reuteri on the development of cytokine responses in neonatal gnotobiotic pigs infected with human rotavirus (HRV). We demonstrated that HRV alone, or HRV plus LAB, but not LAB alone, initiated serum cytokine responses, as indicated by significantly higher concentrations of IFN-α, IFN-γ, IL-12, and IL-10 at postinoculation day (PID) 2 in the HRV only and LAB+HRV+ pigs compared to LAB only and LAB-HRV- pigs. Peak cytokine responses coincided with the peak of HRV replication. LAB further enhanced the Th1 and Th2 cytokine responses to HRV infection as indicated by significantly higher concentrations of IL-12, IFN-γ, IL-4 and IL-10 in the LAB+HRV+ pigs compared to the LAB-HRV+ pigs. The LAB+HRV+ pigs maintained relatively constant concentrations of TGF-β compared to the HRV only group which had a significant increase at PID 2 and decrease at PID 7, suggesting a regulatory role of LAB in maintaining gut homeostasis. At PID 28, cytokine secreting cell (CSC) responses, measured by ELISpot, showed increased Th1 (IL-12, IFN-γ) CSC numbers in the LAB+HRV+ and LAB-HRV+ groups compared to LAB only and LAB-HRV- pigs, with significantly increased IL-12 CSCs in spleen and PBMCs and IFN-γ CSCs in spleen of the LAB+HRV+ group. Thus, HRV infection alone, but not LAB alone was effective in inducing cytokine responses but LAB significantly enhanced both Th1 and Th2 cytokines in HRV-infected pigs. LAB may also help to maintain immunological homeostasis during HRV infection by regulating TGF-β production.

Safety and persistence of orally administered human Lactobacillus sp. strains in healthy adults

The aim of the study was to evaluate the safety and persistence of selected Lactobacillus strains in the gastrointestinal tract (GIT) of healthy adult volunteers after oral consumption of high doses of lactobacilli to identify potential candidates for probiotic and biotechnological applications. In the first phase of the study, nine individuals consumed capsules containing Lactobacillus gasseri 177 and E16B7, Lactobacillus acidophilus 821-3, Lactobacillus paracasei 317 and Lactobacillus fermentum 338-1-1 (each daily dose 1×1010 cfu) for 5 consecutive days. Data on gut health, blood parameters, and liver and kidney function were collected. The persistence of Lactobacillus strains was assessed by culturing combined with arbitrarily primed polymerase chain reaction (AP-PCR) and PCR-denaturing gradient gel electrophoresis (PCR-DGGE) on days 0, 5, 8, 10 and 20 from faecal samples. All strains survived gastrointestinal passage and were detected on the 5th day. L. acidophilus 821-3 was detected in four volunteers on the 8th day (4.3 to 7.0 log10 cfu/g) and in two on the 10th day (8.3 and 3.9 log10 cfu/g, respectively). In the second phase of the study, five additional volunteers consumed L. acidophilus 821-3 (daily 1×1010 cfu) for 5 consecutive days. The strain was subsequently detected in faeces of all individuals using real-time PCR on the 10th day (range 4.6-6.7; median 6.0 log10 cell/g) in both phases of the study for at least 5 days after discontinuation of consumption. The administration of high doses of different Lactobacillus strains did not result in any severe adverse effects in GIT and/or abnormal values of blood indices. Thus, the strain L. acidophilus 821-3 is a promising candidate for probiotic and biotechnological applications. Further studies will be performed to confirm the strain persistence and safety in a larger number of individuals.

Potential probiotic Kluyveromyces marxianus B0399 modulates the immune response in Caco-2 cells and peripheral blood mononuclear cells and impacts the human gut microbiota in an in vitro colonic model system

Considering the increase in the consumption of yeasts as human probiotics, the aim of this study was to broadly investigate the beneficial properties of the lactic yeast Kluyveromyces marxianus (formerly Kluyveromyces fragilis) B0399. Several potential probiotic traits of K. marxianus B0399 were investigated by using in vitro assays, including adhesion and immune modulation, and the effect of the administration of 10(7) CFU/day of K. marxianus B0399 on the composition and metabolic activity of the human intestinal microbiota was investigated in a 3-stage continuous-culture system simulating the human colon. We demonstrated that this strain was highly adhesive to human enterocyte-like Caco-2 cells and modulated the immune response, inducing proinflammatory cytokines in peripheral blood mononuclear cells (PBMCs). In the presence of inflammatory stimulation with lipopolysaccharide (LPS), K. marxianus B0399 provoked decreases in the levels of production of proinflammatory cytokines in PBMCs and Caco-2 cells, thus ameliorating the inflammatory response. Furthermore, K. marxianus B0399 impacted the colonic microbiota, increasing the bifidobacterial concentration in the stages of the colonic model system simulating the proximal and transverse colon. The amounts of the short-chain fatty acids acetate and propionate also increased following yeast supplementation. Finally, K. marxianus B0399 was found to induce a decrease of the cytotoxic potential of the culture supernatant from the first stage of the colonic model system. The effects of K. marxianus B0399 on adhesion, immune function, and colonic microbiota demonstrate that this strain possesses a number of beneficial and strain-specific properties desirable for a microorganism considered for application as a probiotic.

Comparative effects of six probiotic strains on immune function in vitro

There is considerable interest in the strain specificity of immune modulation by probiotics. The present study compared the immunomodulatory properties of six probiotic strains of different species and two genera in a human peripheral blood mononuclear cell (PBMC) model in vitro. Live cells of lactobacilli (Lactobacillus casei Shirota, L. rhamnosus GG, L. plantarum NCIMB 8826 and L. reuteri NCIMB 11951) and bifidobacteria (Bifidobacterium longum SP 07/3 and B. bifidum MF 20/5) were individually incubated with PBMC from seven healthy subjects for 24 h. Probiotic strains increased the proportion of CD69+ on lymphocytes, T cells, T cell subsets and natural killer (NK) cells, and increased the proportion of CD25+, mainly on lymphocytes and NK cells. The effects on activation marker expression did not appear to be strain specific. NK cell activity was significantly increased by all six strains, without any significant difference between strains. Probiotic strains increased production of IL-1β, IL-6, IL-10, TNF-α, granulocyte-macrophage colony-stimulating factor and macrophage inflammatory protein 1α to different extents, but had no effect on the production of IL-2, IL-4, IL-5 or TNF-β. The cytokines that showed strain-specific modulation included IL-10, interferon-γ, TNF-α, IL-12p70, IL-6 and monocyte chemotactic protein-1. The Lactobacillus strains tended to promote T helper 1 cytokines, whereas bifidobacterial strains tended to produce a more anti-inflammatory profile. The results suggest that there was limited evidence of strain-specific effects of probiotics with respect to T cell and NK cell activation or NK cell activity, whereas production of some cytokines was differentially influenced by probiotic strains.

Gut derived lactic acid bacteria induce strain specific CD4(+) T cell responses in human PBMC

BACKGROUND & AIMS

Probiotic bacteria are used as food supplement in many different disease settings. The immune modulating capacity of different strains is not always properly tested which might result in a suboptimal choice of strains for clinical use.

METHODS

The CD4 T cell responses to 19 different gut derived lactic acid bacteria were tested with different methods to show their diversity in immune modulation and to make a well-founded choice on which strains to use in future clinical trials. After co-culture of PBMC with bacteria, the induction of CD4(+) T cell subsets (regulatory T cells, T helper type (TH)1, TH2 and TH17) was analysed by rtPCR of transcription factor mRNA, intracellular FACS staining of transcription factors and cytokine production.

RESULTS

Bacterial strains all have diverse, unique immune modulatory properties. Strains can induce Treg, TH1, TH2 and TH17 cells which can be shown at different levels of T cell activation, and is consistent for most strains tested. For TH1, TH17 and Treg, a positive correlation between the different methods was found. For TH2 cells the correlation was less consistent.

CONCLUSIONS

Probiotic bacteria have very different immune modulating capacities. Analysis of transcription factor mRNA is a suitable method for in vitro characterization of strains prior to clinical application.

Influence of prophylactic probiotics and selective decontamination on bacterial translocation in patients undergoing pancreatic surgery: a randomized controlled trial

Bacterial translocation (BT) is suspected to play a major role in the development of infections in surgical patients. However, the clinical association between intestinal barrier dysfunction, BT, and septic morbidity has remained unconfirmed. The objective of this study was to study BT in patients undergoing major abdominal surgery and the effects of probiotics, selective decontamination of the digestive tract (SDD), and standard treatment on intestinal barrier function. In a randomized controlled setting, 30 consecutive patients planned for elective pylorus-preserving pancreaticoduodenectomy (PPPD) were allocated to receive perioperatively probiotics, SDD, or standard treatment. To assess intestinal barrier function, intestinal fatty acid-binding protein (mucosal damage) and polyethylene glycol recovery (intestinal permeability) in urine were measured perioperatively. BT was assessed by real-time polymerase chain reaction and multiplex ligation-dependent probe amplification (MLPA) in mesenteric lymph nodes (MLNs) harvested early (baseline control) and at the end of surgery ("end-of-surgery" MLNs, after 3h in PPPD patients). Polymerase chain reaction detected bacterial DNA in 18 of 27 end-of-surgery MLNs and in 13 of 23 control MLNs (P = 0.378). Probiotics and SDD had no significant effect on the number of positive MLNs or the change in bacterial DNA during operation. Multiplex ligation-dependent probe amplification analysis showed significantly increased expression of only 4 of 30 inflammatory mediator-related genes in end-of-surgery compared with early sampled MLN (P < 0.05). Polyethylene glycol recovery was unaffected by operation, probiotics and SDD as compared with standard treatment. Intestinal fatty acid-binding protein levels were increased shortly postoperatively only in patients treated with SDD (P = 0.02). Probiotics and SDD did not influence BT, intestinal permeability, or inflammatory mediator expression. Bacterial translocation after abdominal surgery may be part of normal antigen-sampling processes of the gut.

Probiotics versus antibiotic decontamination of the digestive tract: infection and mortality

PURPOSE

Selective decontamination of the digestive tract (SDD) has been shown to decrease the infection rate and mortality in intensive care units (ICUs); Lactobacillus plantarum 299/299v plus fibre (LAB) has been used for infection prevention and does not harbour the potential disadvantages of antibiotics. The objective was to assess whether LAB is not inferior to SDD in infection prevention.

METHODS

Two hundred fifty-four consecutive ICU patients with expected mechanical ventilation ≥ 48 h and/or expected ICU stay ≥ 72 h were assigned to receive SDD: four times daily an oral paste (polymyxin E, gentamicin, amphotericin B), enteral solution (same antibiotics), intravenous cefotaxime (first 4 days) or LAB: two times daily L. plantarum 299/299v with rose-hip.

RESULTS

The primary endpoint was infection rate. A difference <12% between both groups indicated non-inferiority of LAB. The trial was prematurely stopped after a study reporting increased mortality in critically ill pancreatitis patients receiving probiotics. No significant difference in infection rate [31% in the LAB group, 24% in the SDD group (OR 1.68, 95% CI 0.91-3.08; p = 0.10)] was found. ICU mortality was 26% and not significantly different between the LAB and SDD groups. Gram-positive cocci and Pseudomonas aeruginosa were significantly more frequently isolated from surveillance cultures in the SDD group compared to the LAB group (for sputum: 18 vs. 10% and 33 vs. 14%). Significantly more Enterobacteriaceae were found in the LAB group (23 vs. 50%). No increase in antibiotic resistance was found during and after SDD or LAB use.

CONCLUSIONS

The trial could not demonstrate the non-inferiority of LAB compared with SDD in infection prevention. Results suggest no increased ICU mortality risk in the LAB group.

Lactobacillus GG as treatment for diarrhea during enteral feeding in critical illness: randomized controlled trial

BACKGROUND

Diarrhea is a common problem in critical illness. The aim of this study was to investigate the effect of probiotic treatment with Lactobacillus rhamnosus GG on established diarrhea in critically ill patients.

METHODS

This prospective randomized blinded trial in the adult intensive care unit of a large tertiary referral teaching hospital compared probiotic treatment with placebo. Thirty-six consecutive critically ill enterally fed adults with diarrhea were randomized to receive 2 capsules per day for 7 days of either Lactobacillus GG in an inulin base (Culturelle) or inulin alone (placebo). Diarrhea was defined as ≥3 unformed stools or >200 mL stool volume within 24 hours. Prospectively defined primary end point was duration of diarrhea, and secondary end point was mean number of loose stools per day during the 14 days from the first capsule. Results by intention-to-treat analysis: No significant difference was observed for any end point. There was a trend toward more diarrhea in the probiotic treatment group. Mean (standard deviation) duration of diarrhea was 3.83 (2.39) days for the probiotic group and 2.56 (1.85) days for the placebo group (P = .096). Mean number of loose stools per day during the 14 days from the first capsule was 1.58 (0.88) in the probiotic group and 1.10 (0.79) in the placebo group (P = .150).

CONCLUSIONS

This study does not support the use of Lactobacillus GG as a treatment for established diarrhea in enterally fed critically ill patients.

Lactobacillus strains differentially modulate cytokine production by hPBMC from pollen-allergic patients

The objective of this study was to assess the potential immunomodulatory effect of six Lactobacillus strains on human peripheral blood mononuclear cells (hPBMC) isolated from allergic patients. hPBMC from patients allergic to birch pollen or grass pollen were cultured in vitro in the presence or absence of selective bacterial strains. Cultures were left unstimulated or stimulated with αCD3/αCD28 or Bet v 1. After 1, 4 and 8 days, cells and culture supernatants were harvested and the effect on cellular proliferation and the supernatant levels of several cytokines was assessed. All strains had the ability to repress IL-13 production but did show a differential effect on IFN-γ induction. Both strains B223 and B1697 showed a lower IFN-γ, IL-12 and TNF-α induction as compared with the other tested strains. Strain B633 showed the best proliferation-suppressive properties in αCD3/αCD28-stimulated cells. Suppression of the T-helper type 2 (Th2) cytokine induction and induction of the Th1 cytokine production by specific strains might be beneficial for allergic patients having a disturbed Th1/Th2 immune balance. Furthermore, hPBMC of patients with seasonal allergy outside the pollen season can be used to determine the immunomodulatory activities of probiotic bacteria.