Probiotics and intestinal health effects: a clinical perspective

A survey of multiple candidate probiotic bacteria reveals specificity in the ability to modify the effects of key wound pathogens

We have evaluated the inhibitory effects of supernatants and lysates derived from several candidate probiotics, on the growth and biofilm formation of wound pathogens, and their ability to protect human primary epidermal keratinocytes from the toxic effects of pathogens. Supernatants (neutralized and non-neutralized) and lysates (via sonication) from Lactiplantibacillus plantarum, Limosilactobacillus reuteri, Bifidobacterium longum, Lacticaseibacillus rhamnosus GG, and Escherichia coli Nissle 1917 were tested for their inhibitory effects against Staphylococcus aureus, Streptococcus pyogenes, Escherichia coli, Pseudomonas aeruginosa, and Acinetobacter baumanni. The supernatants of L. plantarum, L. rhamnosus, B. longum, and L. rhamnosus GG reduced the growth of S. aureus, E. coli, and A. baumanni. B. longum additionally inhibited P. aeruginosa growth. However, neutralized Lactobacillus supernatants did not inhibit growth and in some cases were stimulatory. Lysates of L. plantarum and L. reuteri inhibited S. pyogenes while B. longum lysates inhibited E. coli and S. aureus growth. E. coli Nissle 1917 lysates enhanced the growth of S. pyogenes and P. aeruginosa. Biofilm formation by E. coli was reduced by lysates of L. reuteri and neutralized supernatants of all candidate probiotics. P. aeruginosa biofilm formation was reduced by E. coli Nissle supernatant but increased by L. plantarum, L. reuteri, and Bifidobacterium longum lysates. L. reuteri decreased the toxic effects of S. aureus on keratinocytes while E. coli Nissle 1917 lysates protected keratinocytes from S. pyogenes toxicity. In conclusion, lactobacilli and E. coli Nissle lysates confer inhibitory effects on pathogenic growth independently of acidification and may beneficially alter the outcome of interactions between host cell-pathogen in a species-specific manner.IMPORTANCEOne of the attributes of probiotics is their ability to inhibit pathogens. For this reason, many lactobacilli have been investigated for their effects as potential topical therapeutics against skin pathogens. However, this field is in its infancy. Even though probiotics are known to be safe when taken orally, the potential safety concerns when applied to potentially compromised skin are unknown. For this reason, we believe that extracts of probiotics will offer advantages over the use of live bacteria. In this study, we have surveyed five candidate probiotics, when used as extracts, in terms of their effects against common wound pathogens. Our data demonstrate that some probiotic extracts promote the growth of pathogens and highlight the need for careful selection of species and strains when probiotics are to be used topically.

Novel Synergistic Probiotic Intervention: Transcriptomic and Metabolomic Analysis Reveals Ameliorative Effects on Immunity, Gut Barrier, and Metabolism of Mice during Salmonella typhimurium Infection

Salmonella typhimurium (S. typhimurium), a prevalent cause of foodborne infection, induces significant changes in the host transcriptome and metabolome. The lack of therapeutics with minimal or no side effects prompts the scientific community to explore alternative therapies. This study investigates the therapeutic potential of a probiotic mixture comprising Lactobacillus acidophilus (L. acidophilus 1.3251) and Lactobacillus plantarum (L. plantarum 9513) against S. typhimurium, utilizing transcriptome and metabolomic analyses, a novel approach that has not been previously documented. Twenty-four SPF-BALB/c mice were divided into four groups: control negative group (CNG); positive control group (CPG); probiotic-supplemented non-challenged group (LAPG); and probiotic-supplemented Salmonella-challenged group (LAPST). An RNA-sequencing analysis of small intestinal (ileum) tissue revealed 2907 upregulated and 394 downregulated DEGs in the LAPST vs. CPG group. A functional analysis of DEGs highlighted their significantly altered gene ontology (GO) terms related to metabolism, gut integrity, cellular development, and immunity (p ≤ 0.05). The KEGG analysis showed that differentially expressed genes (DEGs) in the LAPST group were primarily involved in pathways related to gut integrity, immunity, and metabolism, such as MAPK, PI3K-Akt, AMPK, the tryptophan metabolism, the glycine, serine, and threonine metabolism, ECM-receptor interaction, and others. Additionally, the fecal metabolic analysis identified 1215 upregulated and 305 downregulated metabolites in the LAPST vs. CPG group, implying their involvement in KEGG pathways including bile secretion, propanoate metabolism, arginine and proline metabolism, amino acid biosynthesis, and protein digestion and absorption, which are vital for maintaining barrier integrity, immunity, and metabolism. In conclusion, these findings suggest that the administration of a probiotic mixture improves immunity, maintains gut homeostasis and barrier integrity, and enhances metabolism in Salmonella infection.

A review of the auditory-gut-brain axis

Hearing loss places a substantial burden on medical resources across the world and impacts quality of life for those affected. Further, it can occur peripherally and/or centrally. With many possible causes of hearing loss, there is scope for investigating the underlying mechanisms involved. Various signaling pathways connecting gut microbes and the brain (the gut-brain axis) have been identified and well established in a variety of diseases and disorders. However, the role of these pathways in providing links to other parts of the body has not been explored in much depth. Therefore, the aim of this review is to explore potential underlying mechanisms that connect the auditory system to the gut-brain axis. Using select keywords in PubMed, and additional hand-searching in google scholar, relevant studies were identified. In this review we summarize the key players in the auditory-gut-brain axis under four subheadings: anatomical, extracellular, immune and dietary. Firstly, we identify important anatomical structures in the auditory-gut-brain axis, particularly highlighting a direct connection provided by the vagus nerve. Leading on from this we discuss several extracellular signaling pathways which might connect the ear, gut and brain. A link is established between inflammatory responses in the ear and gut microbiome-altering interventions, highlighting a contribution of the immune system. Finally, we discuss the contribution of diet to the auditory-gut-brain axis. Based on the reviewed literature, we propose numerous possible key players connecting the auditory system to the gut-brain axis. In the future, a more thorough investigation of these key players in animal models and human research may provide insight and assist in developing effective interventions for treating hearing loss.

Study protocol for economic evaluation of probiotic intervention for prevention of neonatal sepsis in 0-2-month old low-birth weight infants in India: the ProSPoNS trial

INTRODUCTION

The ProSPoNS trial is a multicentre, double-blind, placebo-controlled trial to evaluate the role of probiotics in prevention of neonatal sepsis. The present protocol describes the data and methodology for the cost utility of the probiotic intervention alongside the controlled trial.

METHODS AND ANALYSIS

A societal perspective will be adopted in the economic evaluation. Direct medical and non-medical costs associated with neonatal sepsis and its treatment would be ascertained in both the intervention and the control arm. Intervention costs will be facilitated through primary data collection and programme budgetary records. Treatment cost for neonatal sepsis and associated conditions will be accessed from Indian national costing database estimating healthcare system costs. A cost-utility design will be employed with outcome as incremental cost per disability-adjusted life year averted. Considering a time-horizon of 6 months, trial estimates will be extrapolated to model the cost and consequences among high-risk neonatal population in India. A discount rate of 3% will be used. Impact of uncertainties present in analysis will be addressed through both deterministic and probabilistic sensitivity analysis.

ETHICS AND DISSEMINATION

Has been obtained from EC of the six participating sites (MGIMS Wardha, KEM Pune, JIPMER Puducherry, AIPH, Bhubaneswar, LHMC New Delhi, SMC Meerut) as well as from the ERC of LSTM, UK. A peer-reviewed article will be published after completion of the study. Findings will be disseminated to the community of the study sites, with academic bodies and policymakers.

REGISTRATION

The protocol has been approved by the regulatory authority (Central Drugs Standards Control Organisation; CDSCO) in India (CT-NOC No. CT/NOC/17/2019 dated 1 March 2019). The ProSPoNS trial is registered at the Clinical Trial Registry of India (CTRI). Registered on 16 May 2019.

TRIAL REGISTRATION NUMBER

CTRI/2019/05/019197; Clinical Trial Registry.

Strain-specific alterations in gut microbiome and host immune responses elicited by tolerogenic Bifidobacterium pseudolongum

The beneficial effects attributed to Bifidobacterium are largely attributed to their immunomodulatory capabilities, which are likely to be species- and even strain-specific. However, their strain-specificity in direct and indirect immune modulation remain largely uncharacterized. We have shown that B. pseudolongum UMB-MBP-01, a murine isolate strain, is capable of suppressing inflammation and reducing fibrosis in vivo. To ascertain the mechanism driving this activity and to determine if it is specific to UMB-MBP-01, we compared it to a porcine tropic strain B. pseudolongum ATCC25526 using a combination of cell culture and in vivo experimentation and comparative genomics approaches. Despite many shared features, we demonstrate that these two strains possess distinct genetic repertoires in carbohydrate assimilation, differential activation signatures and cytokine responses signatures in innate immune cells, and differential effects on lymph node morphology with unique local and systemic leukocyte distribution. Importantly, the administration of each B. pseudolongum strain resulted in major divergence in the structure, composition, and function of gut microbiota. This was accompanied by markedly different changes in intestinal transcriptional activities, suggesting strain-specific modulation of the endogenous gut microbiota as a key to immune modulatory host responses. Our study demonstrated a single probiotic strain can influence local, regional, and systemic immunity through both innate and adaptive pathways in a strain-specific manner. It highlights the importance to investigate both the endogenous gut microbiome and the intestinal responses in response to probiotic supplementation, which underpins the mechanisms through which the probiotic strains drive the strain-specific effect to impact health outcomes.

Positive effect of Bifidobacterium animalis subsp. lactis VHProbi YB11 in improving gastrointestinal movement of mice having constipation

INTRODUCTION

The aim of this study was to investigate the effects of Bifidobacterium animalis subsp. lactis VHProbi® YB11 (YB11) on attenuating sucralfate-induced constipation in BALB/c mice. The strain of YB11 exhibited favorable tolerance of simulated gastrointestinal (GI) juice. Only 0.42 Log value declined when the live cells of YB11 were co-incubated with simulated GI juice. Meanwhile, this strain also displayed perfect ability to adhere the intestinal epithelium Caco-2 cells with adhesion index of 18.5. 24 of female mice were randomized into four groups.

METHODS

The normal group (NOR) was fed with a normal diet, whereas the placebo group (PLA), positive group (POS), and probiotic group (PRO) were fed with sucralfate to induce constipation. After first successfully establishing the constipation model, groups NOR and PLA received the oral administration of saline solutions. Meanwhile, the POS and PRO groups were orally administered phenolphthalein and YB11 suspensions, respectively. Several indices, including fecal water content, GI transit time, short-chain fatty acids (SCFAs), intestinal neuropeptides level, and histopathology of colonic tissues, were investigated.

RESULTS AND DISCUSSION

Compared with PLA, YB11 had a positive effect in increasing the fecal water content and intestinal peristalsis. Some positive trends, including the acetic and total acids level of fecal samples, and the colonic tissue histopathology, were also observed. Furthermore, YB11 had an ability to upregulate the levels of gut excitatory neuropeptides including motilin, gastrin, and substance P, whereas it downregulated the levels of inhibitory neuropeptides including endothelin-1, somatostatin, and vasoactive intestinal peptide. We conclude that the strain YB11 has a positive impact on improving gastrointestinal mobility and reducing the severity of constipation.

Lactic acid bacteria: prominent player in the fight against human pathogens

INTRODUCTION

The human microbiome is a unique repository of diverse bacteria. Over 1000 microbial species reside in the human gut, which predominantly influences the host's internal environment and plays a significant role in host health. Lactic acid bacteria have long been employed for multiple purposes, ranging from food to medicines. Lactobacilli, which are often used in commercial food fermentation, have improved to the point that they might be helpful in medical applications.

AREAS COVERED

This review summarises various clinical and experimental evidence on efficacy of lactobacilli in treating a wide range of infections. Both laboratory based and clinical studies have been discussed.

EXPERT OPINION

Lactobacilli are widely accepted as safe biological treatments and host immune modulators (GRAS- Generally regarded as safe) by the US Food and Drug Administration and Qualified Presumption of Safety. Understanding the molecular mechanisms of lactobacilli in the treatment and pathogenicity of bacterial infections can help with the prediction and development of innovative therapeutics aimed at pathogens which have gained resistance to antimicrobials. To formulate effective lactobacilli based therapy significant research on the effectiveness of different lactobacilli strains and its association with demographic distribution is required. Also, the side effects of such therapy needs to be evaluated.

The Age of Next-Generation Therapeutic-Microbe Discovery: Exploiting Microbe-Microbe and Host-Microbe Interactions for Disease Prevention

Humans are considered "superorganisms," harboring a diverse microbial collective that outnumbers human cells 10 to 1. Complex and gravely understudied host- and microbe-microbe interactions-the product of millions of years of host-microbe coevolution-govern the superorganism in almost every aspect of life functions and overall well-being. Abruptly disrupting these interactions via extrinsic factors has undesirable consequences for the host. On the other hand, supplementing commensal or beneficial microbes may mitigate perturbed interactions or enhance the interactive relationships that ultimately benefit all parties. Hence, immense efforts have focused on dissecting the innumerable host- and microbe-microbe relationships to characterize if a "positive" or "negative" interaction is at play and to exploit such behavior for broader implications. For example, microbiome research has worked to identify and isolate naturally antipathogenic microbes that may offer therapeutic potential either in a direct, one-on-one application or by leveraging its unique metabolic properties. However, the discovery and isolation of such desired therapeutic microbes from complex microbiota have proven challenging. Currently, there is no conventional technique to universally and functionally screen for these microbes. With this said, we first describe in this review the historical (probiotics) and current (fecal microbiota or defined consortia) perspectives on therapeutic microbes, present the discoveries of therapeutic microbes through exploiting microbe-microbe and host-microbe interactions, and detail our team's efforts in discovering therapeutic microbes via our novel microbiome screening platform. We conclude this minireview by briefly discussing challenges and possible solutions with therapeutic microbes' applications and paths ahead for discovery.

Probiotics Exhibit Strain-Specific Protective Effects in T84 Cells Challenged With Clostridioides difficile-Infected Fecal Water

Clostridioides difficile infection (CDI) is frequently associated with intestinal injury and mucosal barrier dysfunction, leading to an inflammatory response involving neutrophil localization and upregulation of pro-inflammatory cytokines. The severity of clinical manifestations is associated with the extent of the immune response, which requires mitigation for better clinical management. Probiotics could play a protective role in this disorder due to their immunomodulatory ability in gastrointestinal disorders. We assessed five single-strain and three multi-strain probiotics for their ability to modulate CDI fecal water (FW)-induced effects on T84 cells. The CDI-FW significantly (p < 0.05) decreased T84 cell viability. The CDI-FW-exposed cells also exhibited increased pro-inflammatory cytokine production as characterized by interleukin (IL)-8, C-X-C motif chemokine 5, macrophage inhibitory factor (MIF), IL-32, and tumor necrosis factor (TNF) ligand superfamily member 8. Probiotics were associated with strain-specific attenuation of the CDI-FW mediated effects, whereby Saccharomyces boulardii CNCM I-1079 and Lacticaseibacillus rhamnosus R0011 were most effective in reducing pro-inflammatory cytokine production and in increasing T84 cell viability. ProtecFlor™, Lactobacillus helveticus R0052, and Bifidobacterium longum R0175 showed moderate effectiveness, and L. rhamnosus GG R0343 along with the two other multi-strain combinations were the least effective. Overall, the findings showed that probiotic strains possess the capability to modulate the CDI-mediated inflammatory response in the gut lumen.

Novel Anthocyanin-Based Colorimetric Assay for the Rapid, Sensitive, and Quantitative Detection of Helicobacter pylori

Several different diagnostic tests have been reported for rapid, sensitive, and economical detection of bacterial pathogens, but most lack widespread and practical use in the clinic. In this study, we used anthocyanins from red cabbage (Brassica oleracea) as a natural pH indicator and, for the first time, incorporated this agent into a simple, rapid, and economical colorimetric strategy for the detection of Helicobacter pylori (H. pylori) (RCE@test). We prepared two sets of RCE@test solutions (test 1 is purple, and test 2 is blue) in different forms, including liquid, adsorbed filter paper, and agar, and investigated the performance of each RCE@test as a function of the test volume, H. pylori concentration, and reaction time. To elucidate the effect of the pathophysiological environment on these RCE@tests, H. pylori in an artificial gastric fluid was also detected. The 10 and 1 CFU/mL H. pylori suspensions were detected in 15 min and 3 h, respectively, and the limit of detection was determined down to 1 CFU/mL. We experimentally demonstrated the advantages of the RCE@test for detection of H. pylori by comparing it to a commercially available rapid urease test, the "CLO test (Campylobacter-like organism test)". In addition to colorimetric detection by the naked eyes, RGB (Red Green Blue) and Delta-E analysis in image-processing software was run to quantitatively monitor changes of color in the RCE@test using a smartphone application. Finally, we propose that this test provides simple, effective, rapid, and inexpensive detection and that it can be easily implemented for clinical use.

Improved digestive stability of probiotics encapsulated within poly(vinyl alcohol)/cellulose acetate hybrid fibers

Novel cellulose acetate (CA) and poly(vinyl alcohol) (PVA) hybrid fibers, fabricated via angled dual-nozzle electrospinning, were used for the encapsulation of probiotics to enhance their gastrointestinal stability. In this study, Escherichia coli strain Nissle 1917 (EcN) cells were encapsulated within PVA/CA composite mats, where CA enhanced the bacterial stability under gastric conditions and PVA provided protection against the toxic solvent during the electrospinning process. Scanning electron microscopy images revealed that EcN was successfully encapsulated within the hybrid fibers. In the simulated digestive system, free cells lost their viability within 100 min, whereas PVA/CA-encapsulated cells survived with a final count of 3.9 log CFU/mL (from an initial count of 7.8 log CFU/mL), an increase of 1 log CFU/mL compared with those in PVA/PVA fibers. Considering the enhanced viability of the encapsulated cells in the gastrointestinal system, multi-nozzle electrospinning is a promising technique for the fabrication of novel matrices for probiotic encapsulation.

State-of-the-Art of the Nutritional Alternatives to the Use of Antibiotics in Humans and Monogastric Animals

Simple Summary

Antibiotic resistance represents a worldwide recognized issue affecting both human and veterinary medicine, with a particular focus being directed towards monogastric animals destined for human consumption. This scenario is the result of frequent utilization of the antibiotics either for therapeutic purposes (humans and animals) or as growth promoters (farmed animals). Therefore, the search for nutritional alternatives has progressively been the object of significant efforts by the scientific community. So far, probiotics, prebiotics and postbiotics are considered the most promising products, as they are capable of preventing or treating gastrointestinal diseases as well as restoring a eubiosis condition after antibiotic-induced dysbiosis development. This review provides an updated state-of-the-art of these nutritional alternatives in both humans and monogastric animals.

Abstract

In recent years, the indiscriminate use of antibiotics has been perpetrated across human medicine, animals destined for zootechnical productions and companion animals. Apart from increasing the resistance rate of numerous microorganisms and generating multi-drug resistance (MDR), the nonrational administration of antibiotics causes sudden changes in the structure of the intestinal microbiota such as dysbiotic phenomena that can have a great clinical significance for both humans and animals. The aim of this review is to describe the state-of-the-art of alternative therapies to the use of antibiotics and their effectiveness in humans and monogastric animals (poultry, pigs, fish, rabbits, dogs and cats). In particular, those molecules (probiotics, prebiotics and postbiotics) which have a direct function on the gastrointestinal health are herein critically analysed in the prevention or treatment of gastrointestinal diseases or dysbiosis induced by the consumption of antibiotics.

Probiotic Supplementation in a Clostridium difficile-Infected Gastrointestinal Model Is Associated with Restoring Metabolic Function of Microbiota

Clostridium (C.) difficile-infection (CDI), a nosocomial gastrointestinal disorder, is of growing concern due to its rapid rise in recent years. Antibiotic therapy of CDI is associated with disrupted metabolic function and altered gut microbiota. The use of probiotics as an adjunct is being studied extensively due to their potential to modulate metabolic functions and the gut microbiota. In the present study, we assessed the ability of several single strain probiotics and a probiotic mixture to change the metabolic functions of normal and C. difficile-infected fecal samples. The production of short-chain fatty acids (SCFAs), hydrogen sulfide (H₂S), and ammonia was measured, and changes in microbial composition were assessed by 16S rRNA gene amplicon sequencing. The C. difficile-infection in fecal samples resulted in a significant decrease (p < 0.05) in SCFA and H₂S production, with a lower microbial alpha diversity. All probiotic treatments were associated with significantly increased (p < 0.05) levels of SCFAs and restored H₂S levels. Probiotics showed no effect on microbial composition of either normal or C. difficile-infected fecal samples. These findings indicate that probiotics may be useful to improve the metabolic dysregulation associated with C. difficile infection.

Association of Vitamin B12, Lactate Dehydrogenase, and Regulation of NF-κB in the Mitigation of Sodium Arsenite-Induced ROS Generation in Uterine Tissue by Commercially Available Probiotics

Managing arsenic intoxication with conventional metal chelators is a global challenge. The present study demonstrated the therapeutic role of probiotics against arsenic-induced oxidative stress and female reproductive dysfunction. Sodium arsenite-treated (1.0 mg/100 g body weight) Wistar female rats were followed up by a post-treatment of commercially available probiotic mixture in powder form (0.25 mg/100 g body weight) orally. Rats that experienced arsenic ingestion showed a significant lessening in the activities of uterine superoxide dismutase (SOD), catalase activities, and the level of non-protein soluble thiol (NPSH) with a concomitant increase in malondialdehyde (MDA) and conjugated dienes (CD). Exposure to arsenic significantly lowered the levels of vitamin B₁₂ and estradiol. Exposure to arsenic highly expressed the inflammatory marker and transcription factor NF-κB. Arsenic-mediated instability of these above parameters was controlled by the probiotics with a rebuilding of better function of anti-oxidant components. Besides its function in regulating endogenous anti-oxidant system, probiotics were able to augment the protection against mutagenic uterine DNA-breakage, necrosis, and ovarian-uterine tissue damages in arsenicated rats.

Effects of Queso Blanco Cheese Containing Bifidobacterium longum KACC 91563 on the Intestinal Microbiota and Short Chain Fatty Acid in Healthy Companion Dogs

The effects of Queso Blanco cheese containing Bifidobacterium longum KACC 91563 was studied on the intestinal microbiota and short chain fatty acids (SCFAs) in healthy companion dogs. There were three experimental groups with five healthy dogs each: a control group, not fed with any cheese, and groups fed with Queso Blanco cheese with (QCB) or without B. longum KACC 91563 (QC) for 8 weeks. Fecal samples were collected 5 times before, during, and after feeding with cheese. Intestinal microbiota was analyzed using two non-selective agar plates (BL and TS) and five selective agar plates (BS, NN, LBS, TATAC, and MacConkey). SPME-GC-MS method was applied to confirm SCFAs and indole in dog feces. The six intestinal metabolites such as acetic, propionic, butyric, valeric, isovaleric acid and indole were identified in dog feces. Administration of B. longum KACC 91563 (QCB) for 8 weeks significantly increased the beneficial intestinal bacteria such as Bifidobacterium (8.4±0.55) and reduced harmful bacteria such as Enterobacteriaceae and Clostridium (p<0.05). SCFA such as acetic and propionic acid were significantly higher in the QCB group than in the Control group (p<0.05). In conclusion, this study demonstrates that administration of Queso Blanco cheese containing B. longum KACC 91563 had positive effects on intestinal microbiota and metabolites in companion dogs. These results suggest that Queso Blanco cheese containing B. longum KACC 91563 could be used as a functional food for companion animals and humans.

A Surface Protein From Lactobacillus plantarum Increases the Adhesion of Lactobacillus Strains to Human Epithelial Cells

Adhesion to epithelial cells is considered important for Lactobacillus to exert probiotic effects. In this study, we found that trypsin treatment decreased the adhesion ability of Lactobacillus plantarum AR326 and AR269, which exhibit good adhesion ability, and surface proteins extracts increased the adhesion of the strains with poor adhesion ability. By SDS–polyacrylamide gel electrophoresis and mass spectrometry analysis, the main component of the surface proteins was detected and identified as a protein of approximately 37 kDa. It was 100% homologous with glyceraldehyde-3-phosphate dehydrogenase (GAPDH) from L. plantarum WCFS1. The adhesion of AR326 and AR269 was decreased significantly by blocking with the anti-GAPDH antibody, and GAPDH restored the adhesion of AR326 and AR269 treated with trypsin. In addition, purified GAPDH significantly increased the adhesion of the strains with poor adhesion ability. These results indicated that GAPDH mediates the adhesion of these highly adhesive lactobacilli to epithelial cells and can be used to improve the adhesion ability of probiotics or other bacteria of interest.

Interactions of Gut Microbiota, Endotoxemia, Immune Function, and Diet in Exertional Heatstroke

Exertional heatstroke (EHS) is a medical emergency that cannot be predicted, requires immediate whole-body cooling to reduce elevated internal body temperature, and is influenced by numerous host and environmental factors. Widely accepted predisposing factors (PDF) include prolonged or intense exercise, lack of heat acclimatization, sleep deprivation, dehydration, diet, alcohol abuse, drug use, chronic inflammation, febrile illness, older age, and nonsteroidal anti-inflammatory drug use. The present review links these factors to the human intestinal microbiota (IM) and diet, which previously have not been appreciated as PDF. This review also describes plausible mechanisms by which these PDF lead to EHS: endotoxemia resulting from elevated plasma lipopolysaccharide (i.e., a structural component of the outer membrane of Gram-negative bacteria) and tissue injury from oxygen free radicals. We propose that recognizing the lifestyle and host factors which are influenced by intestine-microbial interactions, and modifying habitual dietary patterns to alter the IM ecosystem, will encourage efficient immune function, optimize the intestinal epithelial barrier, and reduce EHS morbidity and mortality.

Invited review: Bioactive compounds produced during cheese ripening and health effects associated with aged cheese consumption

Traditionally, cheese is manufactured by converting fluid milk to a semisolid mass through the use of a coagulating agent, such as rennet, acid, heat plus acid, or a combination thereof. Cheese can vary widely in its characteristics, including color, aroma, texture, flavor, and firmness, which can generally be attributed to the production technology, source of the milk, moisture content, and length of aging, in addition to the presence of specific molds, yeast, and bacteria. Among the most important bacteria, lactic acid bacteria (LAB) play a critical role during the cheese-making process. In general, LAB contain cell-envelope proteinases that contribute to the proteolysis of cheese proteins, breaking them down into oligopeptides that can be subsequently taken up by cells via specific peptide transport systems or further degraded into shorter peptides and amino acids through the collaborative action of various intracellular peptidases. Such peptides, amino acids, and their derivatives contribute to the development of texture and flavor in the final cheese. In vitro and in vivo assays have demonstrated that specific sequences of released peptides exhibit biological properties including antioxidant, antimicrobial, anti-inflammatory, immunomodulatory, and analgesic/opioid activity, in addition to angiotensin-converting enzyme inhibition and antiproliferative activity. Some LAB also produce functional lipids (e.g., conjugated linoleic acid) with anti-inflammatory and anticarcinogenic activity, synthesize vitamins and antimicrobial peptides (bacteriocins), or release γ-aminobutyric acid, a nonprotein amino acid that participates in physiological functions, such as neurotransmission and hypotension induction, with diuretic effects. This review provides an overview of the main bioactive components present or released during the ripening process of different types of cheese.

DNA aptamer functionalized gold nanostructures for molecular recognition and photothermal inactivation of methicillin-Resistant Staphylococcus aureus

In this work, we report the development of DNA aptamer-functionalized gold nanoparticles (Apt@Au NPs) and gold nanorods (Apt@Au NRs) for inactivation of Methicillin-resistant Staphylococcus aureus (MRSA) with targeted photothermal therapy (PTT). Although both Apt@Au NPs and Apt@Au NRs specifically bind to MRSA cells, Apt@Au NPs and Apt@Au NRs inactivated ∼5% and over 95% of the cells,respectively through PTT. This difference in inactivation was based on the relatively high longitudinal absorption of near-infrared (NIR) radiation and strong photothermal conversion capability for the Apt@Au NRs compared to the Apt@Au NPs. The Au NRs served as a nanoplatform for the loading of thiolated aptamer and also provided multivalent effects for increasing binding strength and affinity to MRSA. Our results indicate that the type of aptamer and the degree of multivalent effect(s) are important factors for MRSA inactivation efficiency in PTT. We show that the Apt@Au NRs are a very effective and promising nanosystem for specific cell recognition and in vitro PTT.

Probiotics, Soluble Fiber, and L-Glutamine (GLN) Reduce Nelfinavir (NFV)or Lopinavir/Ritonavir (LPV/r)-related Diarrhea

Purpose: Highly active antiretroviral therapy (HAART) can be associated with diarrhea and other gastrointestinal (GI) side effects. Reducing these side effects may improve treatment durability and quality of life (QOL). This study assessed the impact of nutritional co-therapies known to reduce diarrhea in HIV-positive men treated with nelfinavir (NFV)- or lopinavir/ritonavir (LPV/r)-containing regimens. Methods: Thirty-five HIV-positive men treated with NFV (n = 27) or LPV/r (n = 8) with diarrhea (± two liquid stools/day [d]) participated in a 12-week prospective study. Twenty-eight subjects were randomly assigned supplements (S), seven received standard of care (C). Group S received probiotics (1.2g/d) and soluble fiber (11g/d). If diarrhea persisted at week 4, 30g/d L-Glutamine (GLN) was added. Diarrhea incidence, as well as supplement and antidiarrheal use, was assessed monthly. Results: Weight, CD4 count, and HIV RNA were unchanged in both groups. Diarrhea completely resolved in 10 of 28 (36 percent) S subjects. The mean (± SD) number of stools/d declined [3.40 ± 1.25 to 2.54 ± 1.34 (p < 0.01)]. Diarrhea (loose, watery stools/d) lessened in S from 2.84 ± 1.42 to 0.74 ± 1.03 (p < 0.0001). Fifteen S subjects did not obtain full relief with probiotics and fiber, but stools/d decreased from 4.08 ± 1.35 to 3.06 ± 1.68 (p < 0.05) after starting GLN. In C, stools/d, 4.14 ± 4.86 to 3.44 ± 1.68(p = 0.678) and incidence of diarrhea/d, 3.00 ± 4.82 to 1.36 ± 1.29 (p= 0.361) was unchanged. In S, loperamide use decreased from 1.69 ± 2.34 to 0.31 ± 0.69 mg/d (p < 0.01); 18 versus eight subjects used loperamide at 0 and 12 weeks, respectively. Conclusion: Probiotics, soluble fiber, and GLN significantly reduced diarrhea for subjects receiving NFV or LPV/r. Nutritional co-therapies show clinical benefit in HIV-positive men with diarrhea.

The Effect of Probiotic Plus Prebiotic Supplementation on the Tolerance and Efficacy of Helicobacter Pylori Eradication Quadruple Therapy: a Randomized Prospective Double Blind Controlled Trial

BACKGROUND

Standard anti-Helicobacter pylori (H. pylori) treatment fails in the eradication of the organism in almost 10-35% of the patients and has different side effects. Recent studies have proposed that probiotic supplementations with or without prebiotic may improve the eradication rate and diminish the side effects, although it is still a controversial issue. We aimed to investigate the effect of probiotic with prebiotic supplementation on the eradication rate and side effects of anti H. pylori quadruple therapy.

METHODS

76 patients with a positive biopsy specimen for H. pylori were enrolled. They were randomized to receive quadruple therapy of bismuth, clarithromycin, amoxicillin, and omeprazole for 14 days and also the synbiotic or the placebo. We asked them to answer study questionnaires at the beginning and during the treatment. Finally, urea breath test was done 8 weeks after the treatment.

RESULTS

The eradication rate was significantly better in the synbiotic group by intention-to-treat analysis (p<0.05). Treatment side effects such as diarrhea, nausea, vomiting, epigastric pain, flatulence, constipation, and taste abnormality were similar in both groups but anorexia was significantly better in the synbiotic group (p <0.05).

CONCLUSION

The eradication rate was significantly better in the synbiotic group by intention-to-treat analysis (p<0.05). Treatment side effects such as diarrhea, nausea, vomiting, epigastric pain, flatulence, but could improve the eradication by augmenting the treatment tolerance and compliance.

Identification of surface-associated proteins of Bifidobacterium animalis ssp. lactis KLDS 2.0603 by enzymatic shaving

Bifidobacteria are commensal microorganisms of the human and animal intestinal tract, and their surface proteins can mediate bacterial communication and chemical sensing in the environment, as well as facilitate interactions between bacteria and the host. However, a systematic study of the outer surface-associated proteome of bifidobacteria has not been undertaken. In the present study, the proteins located on the surface of Bifidobacterium animalis ssp. lactis KLDS 2.0603 were systematically identified by a nongel proteomic approach, which consisted of the shaving of the bacterial surface with trypsin and an analysis of the released peptides by liquid chromatography-tandem mass spectrometry. A total of 105 surface-associated proteins were found, of which 15 proteins could potentially be involved in adhesion and interactions between bifidobacteria and the host. The proteins related to adhesion and interaction between bacteria and the host include pilus structure proteins (Fim A, Fim B), 10 moonlighting proteins, an NLP/P60 family protein, an immunogenic secreted protein, and a putative sugar-binding secreted protein. The results provide the basis for future studies on the molecular mechanisms of the interactions between bifidobacteria and the host.

Endomicroscopy Will Track Injected Mesenchymal Stem Cells in Rat Colitis Models

BACKGROUND

Mesenchymal stem cells (MSCs) have demonstrated significant potentials for the treatment of inflammatory bowel disease. Clinical feasible methods to individually document the MSC recruitment to intestinal mucosa is lacking. Here, we proposed that endomicroscopy could noninvasively track MSCs in vivo at cellular resolution.

METHOD

Isolated Sprague Dawley rat MSC was characterized, fluorescently labeled, and imaged ex vivo using an endomicroscope. Then enhanced green fluorescent protein (eGFP)-labeled MSC was tracked in vivo, and acquired images were compared with immunofluorescence, immunohistology, and fluorescent in situ hybridization results.

RESULTS

Endomicroscopy visualized clearly the eGFP-labeled or carboxyfluorescein succinimidyl ester-stained MSC ex vivo. Endomicroscopy using the FIVE1 system could track eGFP-labeled MSC with distinct in vivo features. Immunofluorescence, immunohistochemistry, and fluorescent in situ hybridization confirmed the presence of eGFP-positive cells. In vivo endomicroscopy could quantify the transplanted MSCs that homed to colonic mucosa of the recipient rat in multiple models, including the rat-to-rat allograft, human-to-rat xenograft, hypoxia-induced MSC, and busulfan immunosuppressed recipient rat models. After hypoxia induction, there was a trend of enhanced rat MSC homing to the inflamed mucosa as visualized by endomicroscopy (114.1 in hypoxia group versus 34.3 in other 3 groups combined, t = 2.14, P = 0.0644).

CONCLUSIONS

Endomicroscopy is a novel and promising tool to track transplanted MSCs to the colonic mucosa. This clinical available noninvasive cellular tracking method may provide new insight to individualize each recipient's regimen in the future.

Role of probiotics VSL#3 in prevention of suspected sepsis in low birthweight infants in India: a randomised controlled trial

OBJECTIVES

To assess the effect of the probiotic VSL#3 in prevention of neonatal sepsis in low birthweight (LBW) infants.

DESIGN

Randomised, double-blind, placebo-controlled trial.

SETTING

Community setting in rural India.

PARTICIPANTS

LBW infants aged 3-7 days.

INTERVENTIONS

Infants were randomised to receive probiotic (VSL#3, 10 billion colony-forming units (cfu)) or placebo for 30 days, and were followed up for 2 months.

MAIN OUTCOME MEASURE

Possible serious bacterial infection (PSBI) as per the Integrated Management of Neonatal Childhood Illnesses algorithm, as diagnosed by fieldworkers/physicians.

RESULTS

668 infants were randomised to VSL#3 and 672 to placebo. By intention-to-treat analysis, the risk of PSBI among infants in the overall population of LBW infants was not statistically significant (RR 0.79 (95% CI 0.56 to 1.03)). Probiotics reduced median days of hospitalisation (6 days vs 3 days in probiotics) (p=0.018) but not the risk of hospitalisation (RR 0.66 (95% CI 0.42 to 1.04). The onset of PSBI in 10% of infants occurred on the 40th day in the probiotics arm versus the 25th day in the control arm (p=0.063).

CONCLUSIONS

Daily supplementation of LBW infants with probiotics VSL#3 (10 billion cfu) for 30 days led to a non-significant 21% reduction in risk of neonatal sepsis. A larger study with sufficient power and a more specific primary end point is warranted to confirm the preventive effect of VSL#3 on neonatal sepsis in LBW infants.

TRIAL REGISTRATION NUMBER

The study is registered at the Clinical Trial Registry of India (CTRI/2008/091/000049).

Molecular recognition of live methicillin-resistant staphylococcus aureus cells using DNA aptamers

AIM: To generate DNA-aptamers binding to Methicillin-resistant Staphylococcus aureus (MRSA).

METHODS: The Cell-Systematic Evolution of Ligands by Exponential Enrichment (SELEX) technology was used to run the selection against MRSA bacteria and develop target-specific aptamers. MRSA bacteria were targeted while Enterococcus faecalis bacteria were used for counter selection during that process. Binding assays to determine the right aptamer candidates as well as binding assays on clinical samples were performed through flow cytometry and analyzed using the FlowJo software. The characterization of the aptamers was done by determination of their K_d values and determined by analysis of flow data at different aptamer concentration using SigmaPlot. Finally, the recognition of the complex Gold-nanoparticle-aptamer to the bacteria cells was observed using transmission electron microscopy (TEM).

RESULTS: During the cell-SELEX selection process, 17 rounds were necessary to generate enrichment of the pool. While the selection was run using fixed cells, it was shown that the binding of the pools with live cells was giving similar results. After sequencing and analysis of the two last pools, four sequences were identified to be aptamer candidates. The characterization of those aptamers showed that based on their K_d values, DTMRSA4 presented the best binding with a K_d value of 94.61 ± 18.82 nmol/L. A total of ten clinical samples of MRSA, S. aureus and Enterococcus faecalis were obtained to test those aptamers and determine their binding on a panel of samples. DTMRSA1 and DTMRSA3 showed the best results regarding their specificity to MRSA, DTMRSA1 being the most specific of all. Finally, those aptamers were coupled with gold-nanoparticle and their binding to MRSA cells was visualized through TEM showing that adduction of nanoparticles on the aptamers did not change their binding property.

CONCLUSION: A total of four aptamers that bind to MRSA were obtained with K_d values ranking from 94 to 200 nmol/L.

Secretion of biologically active heterologous oxalate decarboxylase (OxdC) in Lactobacillus plantarum WCFS1 using homologous signal peptides

Current treatment options for patients with hyperoxaluria and calcium oxalate stone diseases are limited and do not always lead to sufficient reduction in urinary oxalate excretion. Oxalate degrading bacteria have been suggested for degrading intestinal oxalate for the prevention of calcium oxalate stone. Here, we reported a recombinant Lactobacillus plantarum WCFS1 (L. plantarum) secreting heterologous oxalate decarboxylase (OxdC) that may provide possible therapeutic approach by degrading intestinal oxalate. The results showed secretion and functional expression of OxdC protein in L. plantarum driven by signal peptides Lp_0373 and Lp_3050. Supernatant of the recombinant strain containing pLp_0373sOxdC and pLp_3050sOxdC showed OxdC activity of 0.05 U/mg and 0.02 U/mg protein, while the purified OxdC from the supernatant showed specific activity of 18.3 U/mg and 17.5 U/mg protein, respectively. The concentration of OxdC protein in the supernatant was 8–12 μg/mL. The recombinant strain showed up to 50% oxalate reduction in medium containing 10 mM oxalate. In conclusion, the recombinant L. plantarum harboring pLp_0373sOxdC and pLp_3050sOxdC can express and secrete functional OxdC and degrade oxalate up to 50% and 30%, respectively.

Health benefits of probiotics: a review

Probiotic bacteria have become increasingly popular during the last two decades as a result of the continuously expanding scientific evidence pointing to their beneficial effects on human health. As a result they have been applied as various products with the food industry having been very active in studying and promoting them. Within this market the probiotics have been incorporated in various products, mainly fermented dairy foods. In light of this ongoing trend and despite the strong scientific evidence associating these microorganisms to various health benefits, further research is needed in order to establish them and evaluate their safety as well as their nutritional aspects. The purpose of this paper is to review the current documentation on the concept and the possible beneficial properties of probiotic bacteria in the literature, focusing on those available in food.

Pro- und Präbiotika

Die rasante Entwicklung der Molekularbiologie und eine inzwischen beachtliche Fülle an Daten aus klinischen Studien haben in der vergangenen Dekade eine neue solide wissenschaftliche Basis für den Einsatz probiotischer Bakterien, speziell von Laktobazillen und Bifidobakterien ergeben. Entgegen manchen Postulierungen existiert jedoch ganz offenkundig sowohl in experimentellen als auch in klinischen Studien eine strenge Stammspezifik von Funktionen und Wirkungen dieser Spezies probiotischer Bakterien. Eine wissenschaftliche Rationale für die Nutzung von Laktobazillen und Bifidobakterien als Probiotika ist bisher nur für vergleichsweise wenige Stämme nachgewiesen worden. Dies gilt für lebende und hitzebehandelte Bakterien gleichermaßen, ob mit oder ohne Mitverwendung ihres Kulturüberstands in den Studienansätzen.

Application of probiotics in the treatment of intestinal diseases

Probiotics has been widely applied to medical treatment and health and food industries thanks to its regulatory effect on the micro-ecological balance of the human body. Recent advances in research of intestinal diseases have led to a better understanding of the effectiveness of probiotics in the treatment of these diseases. This paper summarizes the beneficial functions of probiotics and mechanisms involved. Meanwhile, we review its application in the treatment of intestinal diseases.

'Gut health': a new objective in medicine?

'Gut health' is a term increasingly used in the medical literature and by the food industry. It covers multiple positive aspects of the gastrointestinal (GI) tract, such as the effective digestion and absorption of food, the absence of GI illness, normal and stable intestinal microbiota, effective immune status and a state of well-being. From a scientific point of view, however, it is still extremely unclear exactly what gut health is, how it can be defined and how it can be measured. The GI barrier adjacent to the GI microbiota appears to be the key to understanding the complex mechanisms that maintain gut health. Any impairment of the GI barrier can increase the risk of developing infectious, inflammatory and functional GI diseases, as well as extraintestinal diseases such as immune-mediated and metabolic disorders. Less clear, however, is whether GI discomfort in general can also be related to GI barrier functions. In any case, methods of assessing, improving and maintaining gut health-related GI functions are of major interest in preventive medicine.

Effects of Lactobacillus rhamnosus GG on saliva-derived microcosms

OBJECTIVE

The probiotic strain Lactobacillus rhamnosus GG (LGG) is shown to hamper the presence of mutans streptococci in saliva and may have positive effects on oral health. We investigated the effects of LGG on the cariogenic potential and microbial composition of saliva-derived microcosms.

DESIGN

Single and dual species biofilms of LGG and Streptococcus mutans, and saliva-derived microcosms with or without LGG were grown in an Active Attachment Biofilm model. The microcosms were grown on bovine dentin/enamel discs in the presence or absence of sucrose (suc+/suc-). The presence of LGG was determined by multiplex ligation-dependent probe amplification (MLPA) and real-time PCR. Mutans streptococci (MS) and total viable counts, pH of the spent medium, capacity of lactate formation and integrated mineral loss in dentin was assessed. MLPA was used for identification and relative quantification of 20 oral microorganisms in the microcosms. Principal Component Analysis was applied to MLPA data.

RESULTS

LGG inhibited the growth of S. mutans in dual species biofilms and did not affect the pH. LGG established in saliva-derived microcosms and reduced MS counts significantly, but did not affect pH or dentin demineralization. Simultaneous growth of the microcosms with LGG under heavy cariogenic conditions (suc+) introduced a compositional shift in the microbial community. The CFU, real-time PCR and MLPA data correlated significantly.

CONCLUSION

We conclude that LGG established into and inhibited the growth of MS in complex saliva-derived biofilms, but this had no significant effect on cariogenic potential of the microcosms. This suggests that other microorganisms besides MS were responsible for increased cariogenicity of sucrose-exposed biofilms.

Clinical trial on the efficacy of a new symbiotic formulation, Flortec, in patients with acute diarrhea: a multicenter, randomized study in primary care

OBJECTIVES

Few randomized studies have been carried out on adult patients affected by acute diarrhea especially in primary care, which is the natural context for this kind of disorder. Lactobacillus paracasei B 21060 is a novel strain of lactobacillus, which has been shown to be effective in relieving symptoms associated with diarrhea of irritable bowel syndrome subtype and in shortening diarrhea duration. In this study, we compared the therapeutic efficacy, safety, and tolerability of a new symbiotic formulation, Flortec, containing L. paracasei B-21060, with lactobacillus GG (FlorVis GG) in the treatment of acute presumed infectious diarrhea.

METHODS

Fourteen general practitioners working in the Perugia health authority district carried out a randomized controlled, parallel-group, open trial in 174 adult patients suffering from acute diarrhea (87 enrolled in the Flortec group and 87 in the FlorVis group). Both the products were administered according to their standard recommended dosage. The main efficacy criterion was the duration of diarrhea after beginning treatment. Treatment duration was 10 days. Enrolled patients kept a careful track of their symptoms noting them in a personal diary for 12 days.

RESULTS

The 2 groups resulted to be homogeneous at baseline with regard to prognostic variables. The mean duration of diarrhea from the start of treatment in the Flortec group was 4.24 (2.73 SD) days versus 5.09 (3.72 SD) days in the FlorVis group (P=0.09).Clinical success rates in terms of absence of abdominal pain and absence of diarrhea (defined as <2 bowel movements of watery or loose stool consistency) recorded at different time-points were statistically superior in the Flortec group (Kaplan-Meyer P=0.05 for both the symptoms). The physician judged that overall efficacy was good or very good in 91.8% of the patients in the Flortec group. The corresponding value in the FlorVis group was 83.7% (P=0.003). The 2 treatments showed a very good tolerability profile, with negligible and similar adverse event rates and similar concomitant medication usage rates.

CONCLUSIONS

Oral therapy with Flortec proved to be more effective than FlorVis GG in the treatment of acute diarrhea in adults treated at a primary care setting.

Effect of probiotic supplemented diet on marine shrimp survival after challenge with Vibrio harveyi

The effect of a Lactobacillus plantarum-supplemented diet on shrimp growth, digestive tract bacterial microbiota, survival, and some hemato-immunological parameters after an experimental challenge with Vibrio harveyi was studied. No difference (P>0.05) was observed in shrimp survival (80±6%) and final weight (6.63±0.56g) after 60 days feeding trial. Total bacteria count and Vibrio spp. count in the digestive tract were not diferent (P>0.05) until day 40, but they were lower (P<0.05) in the probiotic-supplemented group on day 60. Total lactic bacteria in the shrimp digestive tract was higher after day 20 in the probiotic-supplemented group. Ten hours after V. harveyi challenge, survival of the probiotic-supplemented group (65.7±2.9%) was higher (P>0.05) than the control group (39.9±4.4%). Bacterial counts in hemolymph and hepatopancreas was lower (P<0.05) in the probiotic-supplemented group than in the control group after V. harveyi challenge. Total hemocyte count and serum agglutination activity were higher (P>0.05) in the probiotic-supplemented group after challenge with V. harveyi. Probiotic-supplemented diet modifies shrimp digestive tract bacterial microbiota, increasing resistance to V. harveyi infection.

Probiotic fortified diet reduces bacterial colonization and translocation in a long-term neonatal rabbit model

BACKGROUND

Probiotic fortified diet reduces bacterial colonization and translocation in a short-term neonatal rabbit model when continuously challenged with pathogen. The purpose of this study was to determine if live probiotic diet could remain effective at decreasing colonization/translocation of pathogens in a long-term neonatal rabbit model without ill effects of the probiotic outside the gastrointestinal (GI) tract.

METHODS

Rabbit pups were born via cesarean delivery 1 day preterm and assigned to 2 diets: a newly formulated diet (controls) vs the same diet fortified with the live probiotic Lactoccocus lactis. Enterobacter cloacae was added to both preparations before each feed. Pups were gavage fed twice daily, and weights were recorded. Rabbits were sacrificed on day 7, and organs were harvested and cultured for target organism growth.

RESULTS

The probiotic fortified diet resulted in a significant decrease in Enterobacter translocation to the liver and decreased colonization in the stomach and lungs. There was no evidence of Lactococccus translocation or colonization outside of the GI tract.

CONCLUSION

This probiotic fortified diet was effective at decreasing pathogenic bacteria colonization and translocation in a long-term neonatal model. The addition of L lactis to the diet resulted in appropriate growth without any colonization or translocation of the probiotic outside of the GI tract.

Synbiotics growth optimization of Bifidobacterium pseudocatenulatum G4 with prebiotics using a statistical methodology

AIMS

This study demonstrated the optimum growth of Bifidobacterium pseudocatenulatum G4 with prebiotics via statistical model.

METHODS AND RESULTS

Commercial prebiotics [inulin and fructooligosaccharide (FOS)], together with sorbitol, arabinan and inoculum rate, were tested by fractional factorial design to determine their impact on growth of Bif. pseudocatenulatum G4 in skim milk. At 48 h incubation, bacterial growth was mainly influenced by FOS and inoculum rate. Growth reduction was observed in all samples incubated for 72 h. Central composite design (CCD) was adopted using FOS and inoculum rate at 48 h incubation to develop the statistical model for optimization. The model predicted that 2.461 log CFU ml(-1) produced the optimum growth increase of Bif. pseudocatenulatum G4. The combination that produced the optimum point was 2.86% FOS (g/v) and 0.67% inoculum rate (v/v).

CONCLUSION

At optimum combination of inoculum rate and FOS, validation experiments recorded 2.40 +/- 10.02 log CFU ml(-1). The application in 1-l bioreactor for 24 h showed higher growth increase of 2.95 log CFU ml(-1).

SIGNIFICANT AND IMPACT OF THE STUDY

Response surface methodology approach is useful to develop optimum synbiotics combination for strain G4 with FOS.

Heterologous expression of oxalate decarboxylase in Lactobacillus plantarum NC8

Lactic acid bacteria (LABs) are being used as a probiotic very often for various enteric problems. Many genetically modified LABs are created by different workers for various novel applications. In this study we examine the expression of heterologous oxalate decarboxylase (oxdc) in Lactobacillus plantarum NC8. Generally, this enzyme is not present in Lactobacillus spp. Oxdc gene from Bacillus subtilis was polymerase chain reaction-amplified and cloned in a shuttle vector pSIP400 series, downstream of the inducible promoter, P(orfx). In the presence of an inducing peptide, Sakacin-P, the expression of OxdC was observed in sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The cell-free extract and the purified protein from the recombinant LABs showed the presence of OxdC activity. The above recombinant LABs, with desired modifications, can be used as a possible probiotic for the degradation of intestinal dietary oxalate for preventing enteric hyperoxaluria.

Understanding why probiotic therapies can be effective in treating IBD

Probiotics, for the treatment of inflammatory bowel disease, are a group of specific nonpathogenic bacteria that are functionally and genetically defined by their ability to reduce inflammation in the intestine. Although probiotics also seem to have broad beneficial effects in humans, both as a food and as a therapeutic agent, there are specific identified mechanisms in some, but not all, of these bacteria that are important relative to the pathogenesis of inflammatory bowel disease. Recently, studies relative to the mechanism of action of probiotics have identified that these organisms can have a direct effect on epithelial cell function and intestinal health, including enhancing epithelial barrier function, modulating epithelial cytokine secretion into an anti-inflammatory dominant profile, altering mucus production, changing bacterial luminal flora, modifying the innate and systemic immune system, and inducing regulatory T-cell effects. For probiotics to have a therapeutic role in the management of clinical inflammatory bowel disease, their therapeutic mechanism of action must be aligned with the pathogenic mechanism of action of the disease. In this regard, the role of probiotics for the clinical treatment of inflammatory bowel disease is emerging as the mechanisms and pathogenesis are being unraveled. It remains clear that probiotics are able to reduce gastrointestinal inflammation by exerting positive effects on epithelial cell and mucosal immune dysfunction.

The role of colonic metabolism in lactose intolerance

Lactose maldigestion and intolerance affect a large part of the world population. The underlying factors of lactose intolerance are not fully understood. In this review, the role of colonic metabolism is discussed, i.e. fermentation of lactose by the colonic microbiota, colonic processing of the fermentation metabolites and how these processes would play a role in the pathophysiology of lactose intolerance. We suggest that the balance between the removal and production rate of osmotic-active components (lactose, and intermediate metabolites, e.g. lactate, succinate, etc.) in the colon is a key factor in the development of symptoms. The involvement of the colon may provide the basis for designing new targeted strategies for dietary and clinical management of lactose intolerance.