Probiotics: definition, sources, selection, and uses

Autochthonous lactic acid bacteria isolated from pig faeces in Thailand show probiotic properties and antibacterial activity against enteric pathogenic bacteria

Lactic acid bacteria (LAB) play an important role in pig health and performance that arises from their beneficial impacts on the balance of gastrointestinal microbes, ability to fight enteric pathogens, and capacity to support the immune system. The aim of this study was to evaluate the functional and safety aspects of five previously isolated autochthonous LAB strains, (Lactobacillus plantarum 22F, 25F and 31F, Pediococcus acidilactici 72N and Pediococcus pentosaceus 77F) from pig faeces as potential probiotics for a pig feed supplement. The functional and safety properties of the strains were assessed by in vitro tests. The functional properties tested were their abilities in tolerating low pH values under simulated gastric conditions, their cell surface properties (hydrophobicity, auto- and co-aggregation), antibacterial activity against the common enteric pathogenic bacteria in pigs (such as pathogenic Escherichia coli, Salmonella Choleraesuis and Streptococcus suis), and diacetyl production. The safety of the strains was analyzed based on the absent of haemolysis on blood and bile salt hydrolase activity. Although all strains demonstrated diacetyl production, good survivability and antibacterial activities, L. plantarum 22F and 25F showed the best performance with the strongest antibacterial actions against the indicator pathogens. Of the strains, only P. pentosaceus 77F exhibited haemolysis or bile salt hydrolase activity. Furthermore, a principal component analysis revealed that L. plantarum 22F possessed superior functional and safety aspects compared to the other four autochthonous strains and to reference strains L. plantarum JCM 1149 and P. acidilactici DSM 20284. Further in vivo studies using oral administration of the strains are justified to assess their effectiveness as feed supplements for pigs.

Edible Films and Coatings as Carriers of Living Microorganisms: A New Strategy Towards Biopreservation and Healthier Foods

Edible films and coatings have been extensively studied in recent years due to their unique properties and advantages over more traditional conservation techniques. Edible films and coatings improve shelf life and food quality, by providing a protective barrier against physical and mechanical damage, and by creating a controlled atmosphere and acting as a semipermeable barrier for gases, vapor, and water. Edible films and coatings are produced using naturally derived materials, such as polysaccharides, proteins, and lipids, or a mixture of these materials. These films and coatings also offer the possibility of incorporating different functional ingredients such as nutraceuticals, antioxidants, antimicrobials, flavoring, and coloring agents. Films and coatings are also able to incorporate living microorganisms. In the last decade, several works reported the incorporation of bacteria to confer probiotic or antimicrobial properties to these films and coatings. The incorporation of probiotic bacteria in films and coatings allows them to reach the consumers' gut in adequate amounts to confer health benefits to the host, thus creating an added value to the food product. Also, other microorganisms, either bacteria or yeast, can be incorporated into edible films in a biocontrol approach to extend the shelf life of food products. The incorporation of yeasts in films and coatings has been suggested primarily for the control of the postharvest disease. This work provides a comprehensive review of the use of edible films and coatings for the incorporation of living microorganisms, aiming at the biopreservation and probiotic ability of food products.

Current understanding of microbiota- and dietary-therapies for treating inflammatory bowel disease

Inflammatory bowel disease (IBD) is a result of chronic inflammation caused, in some part, by dysbiosis of intestinal microbiota, mainly commensal bacteria. Gut dysbiosis can be caused by multiple factors, including abnormal immune responses which might be related to genetic susceptibility, infection, western dietary habits, and administration of antibiotics. Consequently, the disease itself is characterized as having multiple causes, etiologies, and severities. Recent studies have identified >200 IBD risk loci in the host. It has been postulated that gut microbiota interact with these risk loci resulting in dysbiosis, and this subsequently leads to the development of IBD. Typical gut microbiota in IBD patients are characterized with decrease in species richness and many of the commensal, and beneficial, fecal bacteria such as Firmicutes and Bacteroidetes and an increase or bloom of Proteobacteria. However, at this time, cause and effect relationships have not been rigorously established. While treatments of IBD usually includes medications such as corticosteroids, 5-aminosalicylates, antibiotics, immunomodulators, and anti-TNF agents, restoration of gut dysbiosis seems to be a safer and more sustainable approach. Bacteriotherapies (now called microbiota therapies) and dietary interventions are effective way to modulate gut microbiota. In this review, we summarize factors involved in IBD and studies attempted to treat IBD with probiotics. We also discuss the potential use of microbiota therapies as one promising approach in treating IBD. As therapies based on the modulation of gut microbiota becomes more common, future studies should include individual gut microbiota differences to develop personalized therapy for IBD.

Probiotics as a tool for disease mitigation in wildlife: insights from food production and medicine

The use of beneficial microbes to improve host attributes, referred to as probiotic therapy, has been increasingly applied to industries, including aquaculture, agriculture, and human medicine, and is emerging in the field of wildlife medicine. However, there is a general lack of shared knowledge regarding successful practices as well as ecological processes that underlie host-microbe interactions. Presently, probiotics are being developed specifically for preventing and treating particular infectious diseases as an alternative to antibiotic treatments and chemotherapy. We review research on probiotics developed for mitigation of infectious disease in the aforementioned industries to gain insight into how probiotics may be effective in reducing wildlife disease risk. We examine the trends of successful in vivo probiotic applications for disease systems and identify common objectives to reduce intestinal pathogens and sexually transmitted and respiratory diseases, inhibit skin pathogens, and serve as environmental prophylaxis to reduce pathogen loads in the environment. We conclude by highlighting the frontier of wildlife probiotics research and identifying knowledge gaps where research is needed.

Gut microbiota in kidney disease and hypertension

The human gut microbiota is being composed of more than one hundred trillion microbial cells, including aerobic and anaerobic species as well as gram-positive and negative species. Animal based evidence suggests that the change of normal gut microbiota is responsible for several clinical implications including blood pressure increase and kidney function reduction. Trimethylamine-N-Oxide, short-chain fatty acids and inflammatory factors are originated from the gut microbes and may induce changes in arteries, kidneys and blood pressure. Prebiotics and probiotics change the gut microbiota and may reduce high blood pressure and ameliorate chronic kidney disease suggesting a new treatment target in patients for the initial stages of hypertension concomitant with other life style changes such as increased physical exercise and weight reduction to reduce cardiovascular disease complications.

Bile Salt Hydrolase Activities: A Novel Target to Screen Anti-Giardia Lactobacilli?

Giardia duodenalis is a protozoan parasite responsible for giardiasis, a disease characterized by intestinal malabsorption, diarrhea and abdominal pain in a large number of mammal species. Giardiasis is one of the most common intestinal parasitic diseases in the world and thus a high veterinary, and public health concern. It is well-established that some probiotic bacteria may confer protection against this parasite in vitro and in vivo and we recently documented the implication of bile-salt hydrolase (BSH)-like activities from strain La1 of Lactobacillus johnsonii as mediators of these effects in vitro. We showed that these activities were able to generate deconjugated bile salts that were toxic to the parasite. In the present study, a wide collection of lactobacilli strains from different ecological origins was screened to assay their anti-giardial effects. Our results revealed that the anti-parasitic effects of some of the strains tested were well-correlated with the expression of BSH-like activities. The two most active strains in vitro, La1 and Lactobacillus gasseri CNCM I-4884, were then tested for their capacity to influence G. duodenalis infection in a suckling mice model. Strikingly, only L. gasseri CNCM I-4884 strain was able to significantly antagonize parasite growth with a dramatic reduction of the trophozoites load in the small intestine. Moreover, this strain also significantly reduced the fecal excretion of Giardia cysts after 5 days of treatment, which could contribute to blocking the transmission of the parasite, in contrast of La1 where no effect was observed. This study represents a step toward the development of new prophylactic strategies to combat G. duodenalis infection in both humans and animals.

Gut microbiota, hypertension and chronic kidney disease: Recent advances

A large number of different microbial species populates intestine. Extensive research has studied the entire microbial population and their genes (microbiome) by using metagenomics, metatranscriptomics and metabolomic analysis. Studies suggest that the imbalances of the microbial community causes alterations in the intestinal homeostasis, leading to repercussions on other systems: metabolic, nervous, cardiovascular, immune. These studies have also shown that alterations in the structure and function of the gut microbiota play a key role in the pathogenesis and complications of Hypertension (HTN) and Chronic Kidney Disease (CKD). Increased blood pressure (BP) and CKD are two leading risk factors for cardiovascular disease and their treatment represents a challenge for the clinicians. In this Review, we discuss mechanisms whereby gut microbiota (GM) and its metabolites act on downstream cellular targets to contribute to the pathogenesis of HTN and CKD, and potential therapeutic implications.

In vitro and in silico characterisation of Lactobacillus paraplantarum D2-1, a starter culture for soymilk fermentation

Soymilk contains several functional nutrients and is thus a promising ingredient for production of functional foods. The present research aimed to study starter properties, functional characteristics and safety of Lactobacillus paraplantarum D2-1, a promising starter culture for soymilk fermentation. Strain D2-1 actively fermented soymilk within 24 h but had weak activity of additional acid production after 7 d. Succinate and acetoin, which could be linked to flavour and taste, were accumulated in fermented soymilk. In vitro study revealed that the organism has several beneficial properties, including high survival ability in artificial gastric juice, high abilities of mucus adhesion and biofilm formation and production of γ-aminobutyric acid and conjugated linoleic acid, without any significant risks for consumption. Genome sequencing supported the desirable metabolic properties of the strain. These results indicate that L. paraplantarum D2-1 is a suitable starter for soymilk fermentation and is a promising probiotic candidate that can be used safely.

Decreased microglial activation through gut-brain axis by prebiotics, probiotics, or synbiotics effectively restored cognitive function in obese-insulin resistant rats

BACKGROUND

Chronic high-fat diet (HFD) consumption caused not only obese-insulin resistance, but also cognitive decline and microglial hyperactivity. Modified gut microbiota by prebiotics and probiotics improved obese-insulin resistance. However, the effects of prebiotics, probiotics, and synbiotics on cognition and microglial activity in an obese-insulin resistant condition have not yet been investigated. We aimed to evaluate the effect of prebiotic (Xyloolidosaccharide), probiotic (Lactobacillus paracasei HII01), or synbiotics in male obese-insulin resistant rats induced by a HFD.

METHODS

Male Wistar rats were fed with either a normal diet or a HFD for 12 weeks. At week 13, the rats in each dietary group were randomly divided into four subgroups including vehicle group, prebiotics group, probiotics group, and synbiotics group. Rats received their assigned intervention for an additional 12 weeks. At the end of experimental protocol, the cognitive functioning of each rat was investigated; blood and brain samples were collected to determine metabolic parameters and investigate brain pathology.

RESULTS

We found that chronic HFD consumption leads to gut and systemic inflammation and impaired peripheral insulin sensitivity, which were improved by all treatments. Prebiotics, probiotics, or synbiotics also improved hippocampal plasticity and attenuated brain mitochondrial dysfunction in HFD-fed rats. Interestingly, hippocampal oxidative stress and apoptosis were significantly decreased in HFD-fed rats with all therapies, which also decreased microglial activation, leading to restored cognitive function.

CONCLUSIONS

These findings suggest that consumption of prebiotics, probiotics, and synbiotics restored cognition in obese-insulin resistant subjects through gut-brain axis, leading to improved hippocampal plasticity, brain mitochondrial function, and decreased microglial activation.

Spores of two probiotic Bacillus species enhance cellular immunity in BALB/C mice

Previous studies found that Bacillus subtilis BS02 and B. subtilis subsp. natto BS04 isolated in our laboratory could activate the immune response of murine macrophages in vitro. This study aims to investigate the effects of dietary supplementation with Bacillus species spores on the systemic cellular immune response in BALB/C mice. Results showed that both B. subtilis BS02 and B. subtilis natto BS04 enhanced the phagocytic function of the mononuclear phagocyte system (MPS) and the cytotoxicity of natural killer (NK) cells. In addition, B. subtilis BS02 could increase the respiratory burst activity of blood phagocytes. Furthermore, B. subtilis BS02 and B. subtilis natto BS04 increased the percentage of gamma-interferon-producing CD4+ cells and CD8+ T-cells, but only BS04 increased the percentage of CD3+ cells and CD3+ CD4+ cells in splenocytes. However, there were no effects on other subsets of splenic lymphocytes and mitogen-induced splenic lymphocyte proliferation. All data suggested that oral administration of B. subtilis BS02 or B. subtilis natto BS04 could significantly enhance cellular immunity in BALB/C mice by increasing phagocytic activity of MPS and cytotoxic activity of NK cells in a strain-specific manner.

Treatment of diverticular disease: an update on latest evidence and clinical implications

BACKGROUND

Diverticular disease (DD) is a common condition, especially in Western countries. In about 80% of patients, colonic diverticula remain asymptomatic (diverticulosis), while approximately 20% of patients may develop abdominal symptoms (symptomatic uncomplicated diverticular disease, SUDD) and, eventually complications as acute diverticulitis (AD). The management of this condition has been improved, and in the last five years European countries and the USA have published guidelines and recommendations.

SCOPE

To summarize the latest evidence and clinical implication in treatment of DD focusing the attention either on the treatment of diverticulosis, SUDD and AD together with the primary and secondary prevention of diverticulitis.

FINDINGS

The present review was based on the latest evidence in the treatment of DD in the last 10 years. In the last 5 years, six countries issued guidelines on DD with differences regarding covered topics and recommendations regarding treatments. At present there is a lack of rationale for drug use in patients with asymptomatic diverticulosis, but there are limited indications to suggest an increase in dietary fibre to reduce risk of DD. To achieve symptomatic relief in SUDD patients, several therapeutic strategies with fibre, probiotics, rifaximin and mesalazine have been proposed even if a standard therapeutic approach remained to be defined. Agreement has been reached for the management of AD, since recent guidelines showed that antibiotics can be used selectively, rather than routinely in uncomplicated AD, although use of antibiotics remained crucial in the management of complicated cases. With regard to treatment for the primary and secondary prevention of AD, the efficacy of rifaximin and mesalazine has been proposed although with discordant recommendations among guidelines.

CONCLUSION

Treatment of DD represented an important challenge in clinical practice, especially concerning management of SUDD and the primary and secondary prevention of AD.

Role of Microbiome in Carcinogenesis Process and Epigenetic Regulation of Colorectal Cancer

Epigenetic changes during the development of colorectal cancer (CRC) play a significant role. Along with factors such as diet, lifestyle, and genetics, oncogenic infection, bacteria alone or whole microbiome, has been associated with this tumor type. How gut microbiome contributes to CRC pathogenesis in the host is not fully understood. Most of the epigenetic studies in CRC have been conducted in populations infected with Helicobacter pylori. In the current review, we summarize how the gut microbiota contributes in colon carcinogenesis and the potential role of epigenetic mechanism in gene regulation. We discuss microbiota-mediated initiation and progression of colon tumorigenesis and have also touched upon the role of microbial metabolites as an initiator or an inhibitor for procarcinogenic or antioncogenic activities. The hypothesis of gut microbiota associated CRC revealed the dynamic and complexity of microbial interaction in initiating the development of CRC. In the multifaceted processes of colonic carcinogenesis, gradual alteration of microbiota along with their microenvironment and the potential oncopathogenic microbes mediated modulation of cancer therapy and other factors involved in microbiome dysbiosis leading to the CRC have also been discussed. This review provides a comprehensive summary of the mechanisms of CRC development, the role of microbiome or single bacterial infection in regulating the processes of carcinogenesis, and the intervention by novel therapeutics. Epigenetic mechanism involved in CRC is also discussed.

Lactose malabsorption and intolerance: a review

A review on the current knowledge about lactose malabsorption and intolerance is presented including biochemistry, physiology, diagnosis and dietary management.

Effects of Fermented Milk with Mixed Strains as a Probiotic on the Inhibition of Loperamide-Induced Constipation

To investigate the effects of a single bacterium and a mixture of bacteria as probiotics in loperamide-treated animal models, loperamide (3 mg/kg) was administered to SD rats to induce constipation. The individual lactic acid bacterial doses, Enterococcus faecium (EF), Lactobacillus acidophilus (LA), Streptococcus thermophilus (ST), Bifidobacterium bifidum (BB), Bifidobacterium lactis (BL), Pediococcus pentosaceus (PP), and a mixture of the bacteria were orally administered to loperamide-induced constipated rats at a concentration of 10⁸ CFU/kg for 14 days. The weights and water contents of their stools were found to be significantly higher in PP, CKDB (mixture of 5 strains except PP), and CKDBP (CKDB+PP) groups than in the normal (constipation not induced) and the control (constipation-induced) groups (p<0.05). The intestinal transit ratio was significantly higher in all probiotic-treated groups than in the control group, and was the highest in the CKDBP group (p<0.05). The mucosal length and mucus secretion were significantly improved in all probiotic-treated-groups, as compared to that in the control group, and the CKDBP group was found to be the most effective according to immunohistochemistry (IHC) staining and total short chain fatty acid content analysis (p<0.05). Lastly, PP, CKDB, and CKDBP showed relatively higher Lactobacillus sp. ratios of 61.94%, 60.31% and 51.94%, respectively, compared to the other groups, based on metagenomic analysis.

Effect of tablets containing probiotic candidate strains on gingival inflammation and composition of the salivary microbiome: a randomised controlled trial

The aim of the study was to investigate clinical and microbial effects of probiotic candidate strains in patients with moderate gingivitis. The null hypothesis was that the clinical measurements with treatment would not differ from placebo. 47 adult patients were enrolled in a randomised placebo-controlled trial with a 4-week intervention of tablets containing a mix of Lactobacillus rhamnosus PB01, DSM 14869 and Lactobacillus curvatus EB10, DSM 32307 or placebo. Clinical examinations and samplings were done at baseline and after 2, 4 and 6 weeks. The clinical endpoints were general bleeding on probing (BOP), general plaque index (PI) and flow of gingival crevicular fluid (GCF). In addition, the concentration of selected cytokines (interleukin (IL)-1β, IL-6, IL-8, IL-10, tumour necrosis factor alpha (TNF-α)) in GCF was determined with multiplex immunoassays. The profiles of the salivary microbiome were analysed with Next Generation Sequencing (NGS) and qPCR. In contrast to the placebo group, there was a significant reduction in BOP and amount of GCF (P<0.05) after 4 weeks in the probiotic test group when compared with baseline. The general PI was less affected although there was a tendency of decreased plaque levels in the probiotic group (P=0.05-0.09). The cytokines were unaffected by the intervention as well as the salivary microbiome. The Shannon index showed no significant differences between the groups or alterations over time. The occurrence of both probiotic strains increased in saliva of the test subjects during the intervention but returned to baseline levels within 2 weeks. Although a marked improvement in gingival health was recorded in the probiotic group, the null hypothesis could not be rejected.

Characterization of a Sea Buckthorn Extract and Its Effect on Free and Encapsulated Lactobacillus casei

Probiotics are bacteria that can provide health benefits to consumers and are suitable to be added to a variety of foods. In this research, viability of immobilized Lactobacillus casei in alginate with or without sea buckthorn lipid extract were studied during heat treatment and with an in vitro gastrointestinal model. The characterization of the lipid extract was also done using the UV-Vis spectrometry (UV-Vis), high-performance liquid chromatography photodiode array detection method (HPLC-PDA), gas chromatography coupled with mass spectrometry (GS-MS) and Cryo scanning electron microscopy (Cryo-SEM). During heat treatment, the entrapped probiotic cells proved high viability (>6 CFU log/g), even at temperatures above 50 °C. The rich in monounsaturated fatty acids sea buckthorn fraction improved the in vitro digestion passage regarding the probiotic viability. The survival of the probiotic cells was 15% higher after 2 h in the acidic medium of the simulated gastric fluid in the sample where L. casei was encapsulated with the sea buckthorn extract compared with the samples where no extract was added. Thus, this approach may be effective for the future development of probiotic-supplemented foods as foods with health welfare for the consumers.

Probiotics for vulvovaginal candidiasis in non-pregnant women

BACKGROUND

Vulvovaginal candidiasis (VVC) is estimated to be the second most common form of infection after bacterial vaginosis. The ability of probiotics in maintaining and recovering the normal vaginal microbiota, and their potential ability to resist Candidas give rise to the concept of using probiotics for the treatment of VVC.

OBJECTIVES

To assess the effectiveness and safety of probiotics for the treatment of vulvovaginal candidiasis in non-pregnant women.

SEARCH METHODS

We searched the following databases to October 2017: Sexually Transmitted Infections Cochrane Review Group's Specialized Register, CENTRAL, MEDLINE, Embase and eight other databases. We searched in following international resources: World Health Organization International Clinical Trials Registry Platform, ClinicalTrials.gov, Web of Science and OpenGrey. We checked specialty journals, reference lists of published articles and conference proceedings. We collected information from pharmaceutical companies and experts in the field.

SELECTION CRITERIA

Randomized controlled trials (RCT) using probiotics, alone or as adjuvants to conventional antifungal drugs, to treat VVC in non-pregnant women. Trials recruiting women with recurrent VVC, coinfection with other vulvovaginal infections, diabetes mellitus, immunosuppressive disorders or taking immunosuppressant medication were ineligible for inclusion. Probiotics were included if they were made from single or multiple species and in any preparation type/dosage/route of administration.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed trials for eligibility and quality and extracted data. We resolved any disagreements through consensus. The quality of the evidence was assessed using the GRADE approach.

MAIN RESULTS

Ten RCTs (1656 participants) met our inclusion criteria, and pharmaceutical industry funded none of these trials. All trials used probiotics as adjuvant therapy to antifungal drugs. Probiotics increased the rate of short-term clinical cure (risk ratio (RR) 1.14, 95% confidence interval (CI) 1.05 to 1.24, 695 participants, 5 studies, low quality evidence) and mycological cure (RR 1.06, 95% CI 1.02 to 1.10, 969 participants, 7 studies, low quality evidence) and decreased relapse rate at one month (RR 0.34, 95% CI 0.17 to 0.68, 388 participants, 3 studies, very low quality evidence). However, this effect did not translate into a higher frequency of long-term clinical cure (one month after treatment: RR 1.07, 95% CI 0.86 to 1.33, 172 participants, 1 study, very low quality evidence; three months after treatment: RR 1.30, 95% CI 1.00 to 1.70, 172 participants, one study, very low quality evidence) or mycological cure (one month after treatment: RR 1.26, 95% CI 0.93 to 1.71, 627 participants, 3 studies, very low quality evidence; three months after treatment: RR 1.16, 95% CI 1.00 to 1.35, 172 participants, one study, very low quality evidence). Probiotics use did not increase the frequency of serious (RR 0.80, 95% CI 0.22 to 2.94; 440 participants, 2 studies, low quality evidence). We found no eligible RCTs for outcomes as time to first relapse, need for additional treatment at the end of therapy, patient satisfaction and cost effectiveness.

AUTHORS' CONCLUSIONS

Low and very low quality evidence shows that, compared with conventional treatment, the use of probiotics as an adjuvant therapy could increases the rate of short-term clinical and mycological cure and decrease the relapse rate at one month but this did not translate into a higher frequency of long-term clinical or mycological cure. Probiotics use does not seem to increase the frequency of serious or non-serious adverse events. There is a need for well-designed RCTs with standardized methodologies, longer follow-up and larger sample size.

Safety of transtympanic application of probiotics in a chinchilla animal model

Background

Chronic suppurative otitis media can be recalcitrant and difficult to treat, particularly with the increasing occurrence of antibiotic resistance. Lactobacillus plantarum is a probiotic that has been shown to decrease S. aureus and P. aeruginosa growth in wounds, making it a good candidate for the treatment of chronic suppurative otitis media. However, before it can be applied in the ear, its ototoxicity potential must be evaluated.

Methods

A prospective controlled trial was conducted in a chinchilla animal model at the Animal care research facilities of the Montreal Children’s Hospital Research Institute to determine whether Lactobacillus plantarum is ototoxic when applied transtympanically. Ten chinchillas each had one ear randomly assigned to receive 10⁹ CFU/mL of Lactobacillus plantarum solution, while the contralateral ear received saline. Auditory brainstem responses were measured bilaterally at 8, 20, 25 kHz before, at 7–10 days after application, and at 28 days after application of probiotic or saline. Facial nerve and vestibular function were assessed clinically.

Results

There were no statistically significant differences in hearing thresholds between control and experimental ears at 28 days after application. A difference of 11 dB was noted in the 25 kHz range at day 7–10, but resolved by day 28. No animals receiving probiotics developed vestibular nerve dysfunction. There was no histologic evidence of auditory hair cell damaged evidenced by scanning electron microscopy.

Conclusion

Our study suggests that a single application of Lactobacillus plantarum at 10⁹ CFU/mL does not cause ototoxicity in a chinchilla animal model. These preliminary safety evaluations and the pathogen inhibitory effects of L. plantarum demonstrated by previous studies present this probiotic as a candidate of interest for further investigation.

Electronic supplementary material

The online version of this article (10.1186/s40463-017-0242-y) contains supplementary material, which is available to authorized users.

Probiotics for Modification of the Incidence or Severity of Respiratory Tract Infections

There is increasing interest in probiotics for therapy and prevention of infectious diseases. There are no published trials of probiotics as therapy for respiratory tract infections (RTIs) in children or adults. There is low quality, inconsistent evidence for the efficacy of probiotics for prevention of RTIs or ventilator-associated pneumonia or for modification of the severity of RTIs.

Gut Microbiota and Nonalcoholic Fatty Liver Disease: Insights on Mechanisms and Therapy

The gut microbiota plays critical roles in development of obese-related metabolic diseases such as nonalcoholic fatty liver disease (NAFLD), type 2 diabetes(T2D), and insulin resistance(IR), highlighting the potential of gut microbiota-targeted therapies in these diseases. There are various ways that gut microbiota can be manipulated, including through use of probiotics, prebiotics, synbiotics, antibiotics, and some active components from herbal medicines. In this review, we review the main roles of gut microbiota in mediating the development of NAFLD, and the advances in gut microbiota-targeted therapies for NAFLD in both the experimental and clinical studies, as well as the conclusions on the prospect of gut microbiota-targeted therapies in the future.

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.

Microbial Interactions and Interventions in Colorectal Cancer

Recently, several lines of evidence that indicate a strong link between the development of colorectal cancer (CRC) and aspects of the gut microbiota have become apparent. However, it remains unclear how changes in the gut microbiota might influence carcinogenesis or how regional organization of the gut might influence the microbiota. In this review, we discuss several leading theories that connect gut microbial dysbiosis with CRC and set this against a backdrop of what is known about proximal-distal gut physiology and the pathways of CRC development and progression. Finally, we discuss the potential for gut microbial modulation therapies, for example, probiotics, antibiotics, and others, to target and improve gut microbial dysbiosis as a strategy for the prevention or treatment of CRC.

Probiotics: From Isolation to Application

Probiotics have become highly recognized as supplements for humans and animals because of their beneficial effects on health and well-being. The present review aims to provide an overview of different steps through which microbial strains become applicable probiotics in food and/or feed industries. Isolation of potential probiotic strains is the first step. Lactic acid bacteria are the most frequently used microorganisms as probiotics, which can be isolated from human, animal, plant, and environment. The next steps are identification of the isolates and characterization of them based on the main selection criteria for any potential probiotic microorganism, including resistance to gastric acidity and bile salt, adherence to mucus and/or intestinal epithelial cells and cell lines, and antimicrobial and antagonism activity against potentially pathogenic microbes. There are additional probiotic properties that may be considered for selection of probiotic strains with specific effects, such as cholesterol reduction ability, antioxidant activity, or cytotoxic effect against cancer cells. However, a potential probiotic does not need to fulfill all such selection criteria. As the last step, safety status of probiotics for humans is verified by taxonomy clarification, in vitro and in vivo tests, human trials, and genome sequencing.

Genomic Characteristics of Bifidobacterium thermacidophilum Pig Isolates and Wild Boar Isolates Reveal the Unique Presence of a Putative Mobile Genetic Element with tetW for Pig Farm Isolates

Genomic analysis was performed on seven strains of Bifidobacterium thermacidophilum, a Sus-associated Bifidobacterium. Three strains from the feces of domestic pigs (Sus scrofa domesticus) and four strains from the rectal feces of free-range Japanese wild boars (S. s. scrofa) were compared. The phylogenetic position of these isolates suggested by genomic analyses were not concordant with that suggested by 16S rRNA sequence. There was biased distribution of genes for virulence, phage, metabolism of aromatic compounds, iron acquisition, cell division, and DNA metabolism. In particular four wild boar isolates harbored fiber-degrading enzymes, such as endoglucanase, while two of the pig isolates obtained from those grown under an intensive feeding practice with routine use of antimicrobials, particularly tetracycline harbored a tetracycline resistance gene, which was further proved functional by disk diffusion test. The tetW gene is associated with a serine recombinase of an apparently non-bifidobacterial origin. The insertion site of the tetW cassette was precisely defined by analyzing the corresponding genomic regions in the other tetracycline-susceptible isolates. The cassette may have been transferred from some other bacteria in the pig gut.

Bridging the Gap between Gut Microbial Dysbiosis and Cardiovascular Diseases

The human gut is heavily colonized by a community of microbiota, primarily bacteria, that exists in a symbiotic relationship with the host and plays a critical role in maintaining host homeostasis. The consumption of a high-fat (HF) diet has been shown to induce gut dysbiosis and reduce intestinal integrity. Recent studies have revealed that dysbiosis contributes to the progression of cardiovascular diseases (CVDs) by promoting two major CVD risk factors-atherosclerosis and hypertension. Imbalances in host-microbial interaction impair homeostatic mechanisms that regulate health and can activate multiple pathways leading to CVD risk factor progression. Dysbiosis has been implicated in the development of atherosclerosis through metabolism-independent and metabolite-dependent pathways. This review will illustrate how these pathways contribute to the various stages of atherosclerotic plaque progression. In addition, dysbiosis can promote hypertension through vascular fibrosis and an alteration of vascular tone. As CVD is the number one cause of death globally, investigating the gut microbiota as a locus of intervention presents a novel and clinically relevant avenue for future research, with vast therapeutic potential.

A double-blind, randomized, placebo-controlled trial of Lactobacillus helveticus and Bifidobacterium longum for the symptoms of depression

OBJECTIVES

This trial investigated whether probiotics improved mood, stress and anxiety in a sample selected for low mood. We also tested whether the presence or severity of irritable bowel syndrome symptoms, and levels of proinflammatory cytokines, brain-derived neurotrophic factor and other blood markers, would predict or impact treatment response.

METHOD

Seventy-nine participants (10 dropouts) not currently taking psychotropic medications with at least moderate scores on self-report mood measures were randomly allocated to receive either a probiotic preparation (containing Lactobacillus helveticus and Bifidobacterium longum) or a matched placebo, in a double-blind trial for 8 weeks. Data were analysed as intent-to-treat.

RESULTS

No significant difference was found between the probiotic and placebo groups on any psychological outcome measure (Cohen's d range = 0.07-0.16) or any blood-based biomarker. At end-point, 9 (23%) of those in the probiotic group showed a ⩾60% change on the Montgomery-Åsberg Depression Rating Scale (responders), compared to 10 (26%) of those in the placebo group ([Formula: see text], p = ns). Baseline vitamin D level was found to moderate treatment effect on several outcome measures. Dry mouth and sleep disruption were reported more frequently in the placebo group.

CONCLUSIONS

This study found no evidence that the probiotic formulation is effective in treating low mood, or in moderating the levels of inflammatory and other biomarkers. The lack of observed effect on mood symptoms may be due to the severity, chronicity or treatment resistance of the sample; recruiting an antidepressant-naive sample experiencing mild, acute symptoms of low mood, may well yield a different result. Future studies taking a preventative approach or using probiotics as an adjuvant treatment may also be more effective. Vitamin D levels should be monitored in future studies in the area. The results of this trial are preliminary; future studies in the area should not be discouraged.

Probiotics and gastrointestinal conditions: An overview of evidence from the Cochrane Collaboration

Alterations in the composition of the gut microbiota are associated with a number of gastrointestinal (GI) conditions, including diarrhea, inflammatory bowel diseases (IBD), and liver diseases. Probiotics, live microorganisms that may confer a health benefit to the host when consumed, are commonly used as a therapy for treating these GI conditions by means of modifying the composition or activity of the microbiota. The purpose of this review was to summarize the evidence on probiotics and GI conditions available from Cochrane, a nonprofit organization that produces rigorous and high-quality systematic reviews of health interventions. Findings from this review will help provide more precise guidance for clinical use of probiotics and to identify gaps in probiotic research related to GI conditions.

The effects of probiotic Bacillus subtilis on the cytotoxicity of Clostridium perfringens type a in Caco-2 cell culture

Background

Some Bacillus strains have recently been identified for potential use as probiotics and food additives. The present study evaluated the antimicrobial effects of Bacillus subtilis ATCC 6633 and its metabolite on the enterotoxin and vegetative cells, spore and germinated spore of Clostridium perfringens type A in Caco-2 cells.

Results

We used flow cytometry and MTT assays to evaluate the cytotoxicity effect of treatments. According to the results, the most cell survival was found in the 4% crude antimicrobial substance (CAS) with the vegetative form of C. perfringens among co-cultured groups. Furthermore, the apoptosis and necrosis in co-cultured groups were significantly decreased (P < 0.05).

Conclusion

The present results suggested the crucial role of the current probiotic in the control of various forms of C. perfringens type A which was investigated for the first time. Also, the majority of treatments showed higher cell viability in flow cytometry compared to the MTT assay.

Electronic supplementary material

The online version of this article (doi:10.1186/s12866-017-1051-1) contains supplementary material, which is available to authorized users.

Commercial Probiotic Products: A Call for Improved Quality Control. A Position Paper by the ESPGHAN Working Group for Probiotics and Prebiotics

Probiotics have been proposed for a number of indications ranging from the hypothetical long-term immunomodulatory effects to proven benefits in the management of different clinical conditions.An increasing number of commercial products containing probiotics are available. In those products, irrespective if it is food, food supplement, medical food, or drug, the probiotic microorganisms have to be present in a sufficient number by the end of the shelf-life, to pass through the gastrointestinal tract resisting acid and bile, to colonize the gut, and to retain functional properties required to obtain the suggested beneficial effect. Finally, it should be contamination-free.Studies organized worldwide and summarized in this article have shown that inconsistencies and deviations from the information provided on the product label are surprisingly common. Frequently strains are misidentified and misclassified, products are occasionally contaminated, sometimes with even facultative or obligatory pathogens, strains are not viable, the labeled number of colonies cannot be verified, or the functional properties are diminished to the extent that preclude the proposed health benefit. As the probiotic preparations are commonly used for a wide range of conditions, the aim of the Working Group was to summarize results of the studies looking into the quality of the probiotic products and to raise the awareness of the important issue of their quality control.Based on the results obtained, we strongly suggest a more stringent quality control process. This process should ensure that the probiotic content as mentioned on the label meets the actual content throughout the shelf life of the product, while no contamination is present.

Combined effect of Bacillus coagulans GBI-30, 6086 and HMB supplementation on muscle integrity and cytokine response during intense military training

The purpose of this study was to compare the coadministration of the probiotic Bacillus coagulans GBI-30, 6086 (BC30) with β-hydroxy-β-methylbutyrate (HMB) calcium (CaHMB) to CaHMB alone on inflammatory response and muscle integrity during 40 days of intense military training. Soldiers were randomly assigned to one of two groups: CaHMB with BC30 (CaHMBBC30; n = 9) or CaHMB with placebo (CaHMBPL, n = 9). A third group of participants served as a control (CTL; n = 8). During the first 28 days soldiers were garrisoned on base and participated in the same training tasks. During the final 2 wk soldiers navigated 25–30 km per night in difficult terrain carrying ~35 kg of equipment. All assessments (blood draws and diffusion tensor imaging to assess muscle integrity) were conducted before and ~12 h after final supplement consumption. Analysis of covariance was used to analyze all blood and muscle measures. Significant attenuations were noted in IL-1β, IL-2, IL-6, CX3CL1, and TNF-α for both CaHMBBC30 and CaHMBPL compared with CTL. Plasma IL-10 concentrations were significantly attenuated for CaHMBBC30 compared with CTL only. A significant decrease in apparent diffusion coefficients was also observed for CaHMBBC30 compared with CaHMBPL. Results provide further evidence that HMB supplementation may attenuate the inflammatory response to intense training and that the combination of the probiotic BC30 with CaHMB may be more beneficial than CaHMB alone in maintaining muscle integrity during intense military training.

NEW & NOTEWORTHY β-Hydroxy-β-methylbutyrate (HMB) in its free acid form was reported to attenuate inflammation and maintain muscle integrity during military training. However, this formulation was difficult to maintain in the field. In this investigation, soldiers ingested HMB calcium (CaHMB) with Bacillus coagulans (BC30) or CaHMB alone during 40 days of training. Results indicated that CaHMB attenuated the inflammatory response and that BC30 combined with CaHMB may be more beneficial than CaHMB alone in maintaining muscle integrity during intense military training.

Genome-Wide Search for Genes Required for Bifidobacterial Growth under Iron-Limitation

Bacteria evolved over millennia in the presence of the vital micronutrient iron. Iron is involved in numerous processes within the cell and is essential for nearly all living organisms. The importance of iron to the survival of bacteria is obvious from the large variety of mechanisms by which iron may be acquired from the environment. Random mutagenesis and global gene expression profiling led to the identification of a number of genes, which are essential for Bifidobacterium breve UCC2003 survival under iron-restrictive conditions. These genes encode, among others, Fe-S cluster-associated proteins, a possible ferric iron reductase, a number of cell wall-associated proteins, and various DNA replication and repair proteins. In addition, our study identified several presumed iron uptake systems which were shown to be essential for B. breve UCC2003 growth under conditions of either ferric and/or ferrous iron chelation. Of these, two gene clusters encoding putative iron-uptake systems, bfeUO and sifABCDE, were further characterised, indicating that sifABCDE is involved in ferrous iron transport, while the bfeUO-encoded transport system imports both ferrous and ferric iron. Transcription studies showed that bfeUO and sifABCDE constitute two separate transcriptional units that are induced upon dipyridyl-mediated iron limitation. In the anaerobic gastrointestinal environment ferrous iron is presumed to be of most relevance, though a mutation in the sifABCDE cluster does not affect B. breve UCC2003's ability to colonise the gut of a murine model.

Competitive Exclusion Reduces Transmission and Excretion of Extended-Spectrum-β-Lactamase-Producing Escherichia coli in Broilers

Extended-spectrum β-lactamases (ESBLs) and plasmid-mediated AmpC β-lactamases (pAmpC) are enzymes able to hydrolyze a large variety of β-lactam antibiotics, including third-generation cephalosporins and monobactams. Broilers and broiler meat products can be highly contaminated with ESBL- and pAmpC-producing Escherichia coli strains, also known as extended-spectrum cephalosporin (ESC)-resistant E. coli strains, and can be a source for human infections. As few data on interventions to reduce the presence of ESC-resistant E. coli in broilers are available, we used transmission experiments to examine the role of competitive exclusion (CE) on reducing transmission and excretion in broilers. A broiler model to study the transmission of ESC-resistant E. coli was set up. Day-old chickens were challenged with an ESBL-producing E. coli strain isolated from healthy broilers in the Netherlands. Challenged and not challenged chicks were housed together in pairs or in groups, and ESBL-producing E. coli transmission was monitored via selective culturing of cloacal swab specimens. We observed a statistically significant reduction in both the transmission and excretion of ESBL-producing E. coli in chicks treated with the probiotic flora before E. coli challenge compared to the transmission and excretion in untreated controls. In conclusion, our results support the use of competitive exclusion as an intervention strategy to control ESC-resistant E. coli in the field.IMPORTANCE Extended-spectrum β-lactamases (ESBLs) and plasmid-mediated AmpC β-lactamases are a primary cause of resistance to β-lactam antibiotics among members of the family Enterobacteriaceae in humans, animals, and the environment. Food-producing animals are not exempt from this, with a high prevalence being seen in broilers, and there is evidence pointing to a possible foodborne source for human contamination. We investigated the effect of administration of a commercial probiotic product as an intervention to reduce the amount of ESBL-producing Escherichia coli in broilers. Our results showed a substantial reduction in the level of colonization of broiler intestines by ESBL-producing E. coli after administration of commercial probiotic product. The protective effect provided by these probiotics could be implemented on a larger scale in poultry production. Reductions in the levels of ESBL-producing Enterobacteriaceae in the food chain would considerably benefit public health.

Effect of Probiotics on Metabolic Outcomes in Pregnant Women with Gestational Diabetes: A Systematic Review and Meta-Analysis of Randomized Controlled Trials

The metabolic effects of probiotic administration in women with gestational diabetes mellitus (GDM) is unknown. The objective of this review was to investigate the effect of probiotics on fasting plasma glucose (FPG), insulin resistance (HOMA-IR) and LDL-cholesterol levels in pregnant women diagnosed with GDM. Seven electronic databases were searched for RCTs published in English between 2001 and 2017 investigating the metabolic effects of a 6-8 week dietary probiotic intervention in pregnant women following diagnosis with GDM. Eligible studies were assessed for risk of bias and subjected to qualitative and quantitative synthesis using a random effects model meta-analyses. Four high quality RCTs involving 288 participants were included in the review. Probiotic supplementation was not effective in decreasing FBG (Mean Difference = -0.13; 95% CI -0.32, 0.06, p = 0.18) or LDL-cholesterol (-0.16; 95% CI -0.45, 0.13, p = 0.67) in women with GDM. However, a significant reduction in HOMA-IR was observed following probiotic supplementation (-0.69; 95% CI -1.24, -0.14, p = 0.01). There were no significant differences in gestational weight gain, delivery method or neonatal outcomes between experimental and control groups, and no adverse effects of the probiotics were reported. Probiotic supplementation for 6-8 weeks resulted in a significant reduction in insulin resistance in pregnant women diagnosed with GDM. The use of probiotic supplementation is promising as a potential therapy to assist in the metabolic management of GDM. Further high quality studies of longer duration are required to determine the safety, optimal dose and ideal bacterial composition of probiotics before their routine use can be recommended in this patient group.

Gut Microbiota Modulation and Its Relationship with Obesity Using Prebiotic Fibers and Probiotics: A Review

In the present world scenario, obesity has almost attained the level of a pandemic and is progressing at a rapid rate. This disease is the mother of all other metabolic disorders, which apart from placing an added financial burden on the concerned patient also has a negative impact on his/her well-being and health in the society. Among the various plausible factors for the development of obesity, the role of gut microbiota is very crucial. In general, the gut of an individual is inhabited by trillions of microbes that play a significant role in host energy homeostasis by their symbiotic interactions. Dysbiosis in gut microbiota causes disequilibrium in energy homeostasis that ultimately leads to obesity. Numerous mechanisms have been reported by which gut microbiota induces obesity in experimental models. However, which microbial community is directly linked to obesity is still unknown due to the complex nature of gut microbiota. Prebiotics and probiotics are the safer and effective dietary substances available, which can therapeutically alter the gut microbiota of the host. In this review, an effort was made to discuss the current mechanisms through which gut microbiota interacts with host energy metabolism in the context of obesity. Further, the therapeutic approaches (prebiotics/probiotics) that helped in positively altering the gut microbiota were discussed by taking experimental evidence from animal and human studies. In the closing statement, the challenges and future tasks within the field were discussed.

The Maternal Diet, Gut Bacteria, and Bacterial Metabolites during Pregnancy Influence Offspring Asthma

This review focuses on the current evidence that maternal dietary and gut bacterial exposures during pregnancy influence the developing fetal immune system and subsequent offspring asthma. Part 1 addresses exposure to a farm environment, antibiotics, and prebiotic and probiotic supplementation that together indicate the importance of bacterial experience in immune programming and offspring asthma. Part 2 outlines proposed mechanisms to explain these associations including bacterial exposure of the fetoplacental unit; immunoglobulin-related transplacental transport of gut bacterial components; cytokine signaling producing fetomaternal immune alignment; and immune programming via metabolites produced by gut bacteria. Part 3 focuses on the interplay between diet, gut bacteria, and bacterial metabolites. Maternal diet influences fecal bacterial composition, with dietary microbiota-accessible carbohydrates (MACs) selecting short-chain fatty acid (SCFA)-producing bacteria. Current evidence from mouse models indicates an association between increased maternal dietary MACs, SCFA exposure during pregnancy, and reduced offspring asthma that is, at least in part, mediated by the induction of regulatory T lymphocytes in the fetal lung. Part 4 discusses considerations for future studies investigating maternal diet-by-microbiome determinants of offspring asthma including the challenge of measuring dietary MAC intake; limitations of the existing measures of the gut microbiome composition and metabolic activity; measures of SCFA exposure; and the complexities of childhood respiratory health assessment.

Colonization by non-pathogenic bacteria alters mRNA expression of cytochromes P450 in originally germ-free mice

Gut microbiota provides a wide range of beneficial function for the host and has an immense effect on the host's health state. It has also been shown that gut microbiome is often involved in the biotransformation of xenobiotics; however, the molecular mechanisms of the interaction between the gut bacteria and the metabolism of drugs by the host are still unclear. To investigate the effect of microbial colonization on messenger RNA (mRNA) expression of liver cytochromes P450 (CYPs), the main drug-metabolizing enzymes, we used germ-free (GF) mice, lacking the intestinal flora and mice monocolonized by non-pathogenic bacteria Lactobacillus plantarum ^NIZO2877 or probiotic bacteria Escherichia coli Nissle 1917 compared to specific pathogen-free (SPF) mice. Our results show that the mRNA expression of Cyp1a2 and Cyp2e1 was significantly increased, while the expression of Cyp3a11 mRNA was decreased under GF conditions compared to the SPF mice. The both bacteria L. plantarum ^NIZO2877 and E. coli Nissle 1917 given to the GF mice decreased the level of Cyp1a2 mRNA and normalized it to the control level. On the other hand, the colonization by these bacteria had no effect on the expression of Cyp3a11 mRNA in the liver of the GF mice (which remained decreased). Surprisingly, monocolonization with chosen bacterial strains has shown a different effect on the expression of Cyp2e1 mRNA in GF mice. Increased level of Cyp2e1 expression observed in the GF mice was found also in mice colonized by L. plantarum ^NIZO2877; however, the colonization with probiotic E. coli Nissle 1917 caused a decrease in Cyp2e1 expression and partially restored the SPF mice conditions.

The gut microbiome and microbial translocation in multiple sclerosis

Individuals with multiple sclerosis (MS) have a distinct intestinal microbial community (microbiota) and increased low-grade translocation of bacteria from the intestines into the circulation. The observed change of intestinal bacteria in MS patients regulate immune functions involved in MS pathogenesis. These functions include: systemic and central nervous system (CNS) immunity (including peripheral regulatory T cell function), the blood-brain barrier (BBB) permeability and CNS-resident cell activity. This review discusses the MS intestinal microbiota implication on MS systemic- and CNS-immunopathology. We introduce the possible contributions of MS low-grade microbial translocation (LG-MT) to the development of MS, and end on a discussion on microbiota therapies for MS patients.

Probiotic Lactobacillus reuteri has antifungal effects on oral Candida species in vitro

Background: An alternative approach for managing Candida infections in the oral cavity by modulating the oral microbiota with probiotic bacteria has been proposed.

Objective: The aim was to investigate the antifungal potential of the probiotic bacterium Lactobacillus reuteri (DSM 17938 and ATCC PTA 5289) against six oral Candida species (C. albicans, C. glabrata, C. krusei, C. tropicalis, C. dubliniensis, and C. parapsilosis).

Design: The lactobacilli were tested for their ability to co-aggregate with and inhibit the growth of the yeasts assessed by spectrophotometry and the agar overlay inhibition assay. Additionally, the pH was evaluated with microsensors, and the production of hydrogen peroxide (H2O2) by the lactobacilli was verified.

Results: Both L. reuteri strains showed co-aggregation abilities with the yeasts. The lactobacilli almost completely inhibited the growth of C. albicans and C. parapsilosis, but did not affect C. krusei. Statistically significant differences in co-aggregation and growth inhibition capacities between the two L. reuteri strains were observed (p<0.001). The pH measurements suggested that C. krusei can resist the acids produced by the lactobacilli.

Conclusions:L. reuteri exhibited antifungal properties against five of the six most common oral Candida species. Further, the results reconfirms that the probiotic capacity of L. reuteri is strain specific.

Novel reuterin-related compounds suppress odour by periodontopathic bacteria

OBJECTIVE

Halitosis is caused by volatile sulphur compounds including methyl mercaptan (CH₃ SH) in the oral cavity and is a serious problem that limits interpersonal social communication. The aim of study was to evaluate the effects of reuterin-related compounds (RRCs) on halitosis-related periodontopathic bacteria in vitro.

MATERIALS AND METHODS

RRC-01, RRC-02 and RRC-03 (32 and 64 μg ml^-1 ) in culture media containing Fusobacterium nucleatum JCM8523 and Porphyromonas gingivalis ATCC33277 were used. The effects of RRCs on CH₃ SH production and detectable odour by F. nucleatum and P. gingivalis were examined by CH₃ SH production assay and organoleptic test, respectively. The number of bacterial cells was also measured using an ATP assay. In P. gingivalis treated with RRCs, the expression of mgl gene, which is responsible for CH₃ SH production, was examined by qRT-PCR.

RESULTS

CH₃ SH production and the score of detectable odour from F. nucleatum and P. gingivalis culture media containing RRCs were significantly lower than that without RRCs (P < 0.05). The expression of mgl gene in P. gingivalis was significantly downregulated by RRC-01 (P < 0.01), but not by RRC-02 or RRC-03.

CONCLUSIONS

RRCs are potent oral care products for preventing halitosis via reducing CH₃ SH production.

Probiotics, D-Lactic acidosis, oxidative stress and strain specificity

The existence of an implicit living microscopic world, composed primarily of bacteria, has been known for centuries. The exact mechanisms that govern the contribution of bacteria to human health and disease have only recently become the subject of intense research efforts. Within this very evident shift in paradigms, the rational design of probiotic formulations has led to the creation of an industry that seeks to progress the engineering of probiotic bacteria that produce metabolites that may enhance human host health and prevent disease. The promotion of probiotics is often made in the absence of quality scientific and clinically plausible data. The latest incursions into the probiotic market of claims have posited the amelioration of oxidative stress via potent antioxidant attributes or limiting the administration of probiotics to those species that do not produce D-Lactic acid (i.e., claims that D-Lactic acid acidosis is linked to chronic health conditions) or are strain-specific (shaping an industry point of difference) for appraising a therapeutic effect. Evidence-based research should guide clinical practice, as there is no place in science and medicine that supports unsubstantiated claims. Extravagant industry based notions continue to fuel the imprimatur of distrust and skepticism that is leveled by scientists and clinicians at an industry that is already rife with scientific and medical distrust and questionable views on probiotics. Ignoring scientifically discordant data, when sorting through research innovations and false leads relevant to the actions of probiotics, drives researcher discomfit and keeps the bar low, impeding the progress of knowledge. Biologically plausible posits are obligatory in any research effort; companies formulating probiotics often exhibit a lack of analytical understanding that then fuels questionable investigations failing to build on research capacity.