Modulation of anti-pathogenic activity in canine-derived Lactobacillus species by carbohydrate growth substrate

Comparative Genome Analysis and Characterization of the Probiotic Properties of Lactic Acid Bacteria Isolated from the Gastrointestinal Tract of Wild Boars in the Czech Republic

Probiotics are crucial components for maintaining a healthy gut microbiota in pigs, especially during the weaning period. Lactic acid bacteria (LAB) derived from the gastrointestinal tract of wild boars can serve as an abundant source of beneficial probiotic strains with suitable properties for use in pig husbandry. In this study, we analyzed and characterized 15 strains of Limosilactobacillus mucosae obtained from the gut contents of wild boars to assess their safety and suitability as probiotic candidates. The strains were compared using pan-genomic analysis with 49 L. mucosae strains obtained from the NCBI database. All isolated strains demonstrated their safety by showing an absence of transferrable antimicrobial resistance genes and hemolysin activity. Based on the presence of beneficial genes, five candidates with probiotic properties were selected and subjected to phenotypic profiling. These five selected isolates exhibited the ability to survive conditions mimicking passage through the host's digestive tract, such as low pH and the presence of bile salts. Furthermore, five selected strains demonstrated the presence of corresponding carbohydrate-active enzymes and the ability to utilize various carbohydrate substrates. These strains can enhance the digestibility of oligosaccharide or polysaccharide substrates found in food or feed, specifically resistant starch, α-galactosides, cellobiose, gentiobiose, and arabinoxylans. Based on the results obtained, the L. mucosae isolates tested in this study appear to be promising candidates for use as probiotics in pigs.

Efficacy of probiotics, prebiotics and synbiotics in irritable bowel syndrome: a systematic review and meta-analysis of randomized, double-blind, placebo-controlled trials

Introduction. Irritable bowel syndrome (IBS) is a common gastrointestinal disorder that affects the quality of life of numerous people worldwide.Gap statement. The therapeutic role of gut microbiota modulation in IBS remains controversial.Aim. We aimed to assess the efficacy of probiotics, prebiotics or synbiotics in patients with IBS.Methodology. We searched MEDLINE and EMBASE up to 1 August 2023, to identify the randomized, double-blind, placebo-controlled trials investigating the effectiveness of probiotics, prebiotics or synbiotics among patients with IBS. Pooled analyses of the effects of probiotics in relieving IBS symptoms were calculated using a random-effects model. Further subgroup analyses were performed by different genera, doses and duration of treatment.Results. Our final analysis included 52 trials involving 6289 IBS patients. Probiotics significantly increased the overall response rate (RR:1.64; P<0.00001), subjective relief rate (RR:1.50; P=0.0002) and abdominal pain relief rate (RR:1.69; P<0.00001). As for specific genera, mixed probiotics (RR:1.41; P=0.0001), Bifidobacterium (RR:1.76; P<0.00001), Lactobacillus (RR:1.97; P=0.0004) and Saccharomyces (RR:1.31; P=0.0004) markedly relieved IBS symptoms. Mixed probiotics (RR:1.31; P=0.005), Lactobacillus (RR:2.22; P=0.04) and Bifidobacterium (RR:1.62; P<0.0001) elevated patients' subjective relief rate. Besides, probiotics effectively relieved the abdominal pain in IBS patients (RR:1.69; P<0.00001). Probiotics appeared to show a remarkable beneficial role at a dose of 109 c.f.u./day or above (RR:1.662; P<0.0001) and started to work at 4 weeks (RR 1.72; P<0.00001). Efficacy of prebiotics and synbiotics in IBS remained uncertain, due to the deficiency of available RCTs.Conclusions. Probiotics have a therapeutic role in IBS. However, the effect of different probiotics varies. The minimal effective dose of probiotics may be 109 c.f.u./day. With appropriate probiotic formula, the therapeutic effect can occur at 4 weeks. These data provide a basis for further research on the optimal probiotic therapy in IBS.

How Do Diet Patterns, Single Foods, Prebiotics and Probiotics Impact Gut Microbiota?

The human gastrointestinal tract hosts a complex and dynamic population of commensal bacterial species, which have coevolved with the host, generating a symbiotic relationship. Some compounds present in foods, such as polyols, prebiotic fibers, or phenolic compounds, are poorly metabolized and absorbed by the host before the transformation guided by the colonic microbiota. By influencing gut microbiota, diet plays a fundamental role in understanding the beneficial effects of the gut microbiota on the host, including its long-term metabolism. The idea that probiotics can act not only by influencing the colonizing microbiota opens the door to a wider range of probiotic possibilities, encouraging innovation in the field. Furthermore, it has been shown both that some probiotics increase phagocytosis or the activity of natural killer cells. Current prebiotics are mainly based on carbohydrates, but other substances, such as polyphenols and polyunsaturated fatty acids, could exert prebiotic effects. A prebiotic substance has been defined as ‘a substrate that is selectively used by host microorganisms that confer a health benefit’, and so can interact with the gut microbiota through competition for nutrients, antagonism, cross-feeding, and support for microbiota stability. Influencing its composition in terms of richness and diversity, food components have a key impact on the intestinal microbiota. Eating habits can strongly influence the composition of the intestinal microbiota. A healthy intestinal microbiota is essential for maintaining general health, and diet is one of the major modulators of this fascinating world of microorganisms. This must give us one more reason to adopt a healthy lifestyle.

Immunological consequences of microbiome-based therapeutics

The complex network of microscopic organisms living on and within humans, collectively referred to as the microbiome, produce wide array of biologically active molecules that shape our health. Disruption of the microbiome is associated with susceptibility to a range of diseases such as cancer, diabetes, allergy, obesity, and infection. A new series of next-generation microbiome-based therapies are being developed to treat these diseases by transplanting bacteria or bacterial-derived byproducts into a diseased individual to reset the recipient's microbiome and restore health. Microbiome transplantation therapy is still in its early stages of being a routine treatment option and, with a few notable exceptions, has had limited success in clinical trials. In this review, we highlight the successes and challenges of implementing these therapies to treat disease with a focus on interactions between the immune system and microbiome-based therapeutics. The immune activation status of the microbiome transplant recipient prior to transplantation has an important role in supporting bacterial engraftment. Following engraftment, microbiome transplant derived signals can modulate immune function to ameliorate disease. As novel microbiome-based therapeutics are developed, consideration of how the transplants will interact with the immune system will be a key factor in determining whether the microbiome-based transplant elicits its intended therapeutic effect.

Levilactobacillus brevis from carnivores can ameliorate hypercholesterolemia: in vitro and in vivo mechanistic evidence

AIMS

To explore the probiotic and hypocholesterolemic potential of two Levilactobacillus brevis strains of carnivore origin along with selected underlying mechanisms.

METHODS AND RESULTS

L. brevis MT950194 and L. brevis MW365351 were analyzed in vitro for oro-gastro-intestinal stress tolerance, cholesterol reduction, cholesterol adsorption (through scanning electron microscopy) and bile salt hydrolase (BSH) activity. Strains could survive (> 80%) in oro-gastro-intestinal conditions, reduce high amount of cholesterol (35% and 54%) from media containing bile salts (0.3%) as compared with Lactobacillus acidophilus ATCC4356 and presented least pathogenicity towards mammalian cells. Exopolysaccharide production, cell surface cholesterol adherence and BSH activity were witnessed as possible cholesterol lowering mechanisms. In in vivo experiment, the treatments of hypercholesterolemic rats with L. brevis MT950194, L. brevis MW365351 and their mixture led to significant (p < 0.05) reduction in serum and hepatic cholesterol, low density lipids, cholesterol ratio, liver steatosis, and size of adipocytes. It further ameliorated diet induced changes in hepatic enzymes.

CONCLUSIONS

L. brevis MT950194 and L. brevis MW365351 from carnivores have probiotic pharmacological potential and can reduce serum cholesterol through surface adherence and BSH production.

SIGNIFICANCE AND IMPACT OF STUDY

These strains may be utilized in treating hypercholesterolemia and production of low fat functional foods.

The forgotten sugar: A review on multifarious applications of melezitose

Although, 187 years elapsed after the discovery of melezitose, it is a high time to deduce some solid applications as there are only 13 more years left to celebrate a double century of this sugar. The forgotten sugar has multifarious applications; it is used as a metabolic marker to differentiate melezitose fermenting microorganisms, as a carbon source to culture specific microorganisms, as a potential surfactant and excipient to stabilize pharmaceuticals, as a lyoprotectant or cryoprotectant for several industrial applications, as an edibility enhancer in food industry, as a hair smoothening agent in cosmetic industry, and provide protective & nourishing effects in fisheries and aquaculture industries. In entomological research, it is used to study niche differentiation, increased longevity of insects and also as a biocontrol agent. This review brings out the best possible applications of melezitose and present in the form of a mnemonic to remember this forgotten sugar.

Prebiotics in vitro digestion by gut microbes, products' chemistry, and clinical relevance

Several investigations have elucidated the chemistry of prebiotics based on their fermentation by the colonic microbes, which release metabolites that are often implicated in host's gut and whole body health. The present study aims at providing a preview of prebiotics and their interactions with the colonic microbiota for a slow fermentation in vitro. The metabolites produced, mainly short chain fatty acids (SCFA), their chemistry, interactions with prebiotic structural mechanisms, and beneficial impacts on the host were also reported. The present review further considers the clinical relevance of the SCFAs produced. It was deduced that the physicochemical properties of prebiotics would influence their colonic fermentation rate, microbial choice, and growth as well as SCFA type and ratios. This will in turn be of utmost clinical significance. KEY POINTS: • Prebiotics affect the composition of gut microorganisms. • The chemistry of short chain fatty acids are described. • Microbial and clinical applications of SCFAs were provided.

Fermentation of prebiotics by human colonic microbiota in vitro and short-chain fatty acids production: a critical review

Prebiotics are known for their health benefits to man, including reducing cardiovascular disease and improving gut health. This review takes a critical assessment of the impact of dietary fibres and prebiotics on the gastrointestinal microbiota in vitro. The roles of colonic organisms, slow fermentation of prebiotics, production of high butyric and propionic acids and positive modulation of the host health were taken into cognizance. Also, the short-chain fatty acids (SCFAs) molecular signalling mechanisms associated with their prebiotic substrate structural conformations and the phenotypic responses related to the gut microbes composition were discussed. Furthermore, common dietary fibres such as resistant starch, pectin, hemicelluloses, β-glucan and fructan in context of their prebiotic potentials for human health were also explained. Finally, the in vitro human colonic fermentation depends on prebiotic type and its physicochemical characteristics, which will then affect the rate of fermentation, selectivity of micro-organisms to multiply, and SCFAs concentrations and compositions.

Immune boosting functional foods and their mechanisms: A critical evaluation of probiotics and prebiotics

Comprehensive studies conducted on the link between the gut microbiome and immunity in recent decades have correspondingly led to ever increasing interests in functional foods, especially probiotics and prebiotics. Probiotics and prebiotics play crucial roles in managing the intestinal microbiota in order to improve host health, even though their influence on other body sites are being investigated. Different colonic bacteria metabolize dietary prebiotics to produce beneficial metabolites, especially short chain fatty acids (SCFAs) that improve luminal contents and intestinal performance, while positively affecting overall host physiology. Thus, this review provides a general perspective of the immune system, the gut immune system and its microbiota. The review also evaluates functional foods with critical but comprehensive perspectives into probiotics and prebiotics, their immune boosting and mechanisms of action. It is recommended that further mechanistic and translational studies are conducted to promote health, social life and also empower poverty-stricken communities.

Effects of fructans and probiotics on the inhibition of Klebsiella oxytoca and the production of short-chain fatty acids assessed by NMR spectroscopy

Generally, the selection of fructans prebiotics and probiotics for the formulation of a symbiotic has been based on arbitrary considerations and in vitro tests that fail to take into account competitiveness and other interactions with autochthonous members of the intestinal microbiota. However, such analyzes may be a valuable step in the development of the symbiotic. The present study, therefore, aims to investigate the effect of lactobacilli strains and fructans (prebiotic compounds) on the growth of the intestinal competitor Klebsiella oxytoca, and to assess the correlation with short-chain fatty acids production. The short-chain fatty acids formed in the fermentation of the probiotic/prebiotic combination were investigated using NMR spectroscopy, and the inhibitory activities were assessed by agar diffusion and co-culture methods. The results showed that Lactobacillus strains can inhibit K. oxytoca, and that this antagonism is influenced by the fructans source and probably associated with organic acid production.

Comparative Genomics Analysis of Lactobacillus mucosae from Different Niches

The potential probiotic benefits of Lactobacillus mucosae have received increasing attention. To investigate the genetic diversity of L. mucosae, comparative genomic analyses of 93 strains isolated from different niches (human and animal gut, human vagina, etc.) and eight strains of published genomes were conducted. The results showed that the core genome of L. mucosae mainly encoded translation and transcription, amino acid biosynthesis, sugar metabolism, and defense function while the pan-genomic curve tended to be close. The genetic diversity of L. mucosae mainly reflected in carbohydrate metabolism and immune/competitive-related factors, such as exopolysaccharide (EPS), enterolysin A, and clustered regularly interspaced short palindromic repeats (CRISPR)-Cas. It was worth noting that this research firstly predicted the complete EPS operon shared among L. mucosae. Additionally, the type IIIA CRISPR-Cas system was discovered in L. mucosae for the first time. This work provided new ideas for the study of this species.

The International Scientific Association for Probiotics and Prebiotics (ISAPP) consensus statement on the definition and scope of synbiotics

In May 2019, the International Scientific Association for Probiotics and Prebiotics (ISAPP) convened a panel of nutritionists, physiologists and microbiologists to review the definition and scope of synbiotics. The panel updated the definition of a synbiotic to "a mixture comprising live microorganisms and substrate(s) selectively utilized by host microorganisms that confers a health benefit on the host". The panel concluded that defining synbiotics as simply a mixture of probiotics and prebiotics could suppress the innovation of synbiotics that are designed to function cooperatively. Requiring that each component must meet the evidence and dose requirements for probiotics and prebiotics individually could also present an obstacle. Rather, the panel clarified that a complementary synbiotic, which has not been designed so that its component parts function cooperatively, must be composed of a probiotic plus a prebiotic, whereas a synergistic synbiotic does not need to be so. A synergistic synbiotic is a synbiotic for which the substrate is designed to be selectively utilized by the co-administered microorganisms. This Consensus Statement further explores the levels of evidence (existing and required), safety, effects upon targets and implications for stakeholders of the synbiotic concept.

Probiotics and prebiotics in intestinal health and disease: from biology to the clinic

Probiotics and prebiotics are microbiota-management tools for improving host health. They target gastrointestinal effects via the gut, although direct application to other sites such as the oral cavity, vaginal tract and skin is being explored. Here, we describe gut-derived effects in humans. In the past decade, research on the gut microbiome has rapidly accumulated and has been accompanied by increased interest in probiotics and prebiotics as a means to modulate the gut microbiota. Given the importance of these approaches for public health, it is timely to reiterate factual and supporting information on their clinical application and use. In this Review, we discuss scientific evidence on probiotics and prebiotics, including mechanistic insights into health effects. Strains of Lactobacillus, Bifidobacterium and Saccharomyces have a long history of safe and effective use as probiotics, but Roseburia spp., Akkermansia spp., Propionibacterium spp. and Faecalibacterium spp. show promise for the future. For prebiotics, glucans and fructans are well proven, and evidence is building on the prebiotic effects of other substances (for example, oligomers of mannose, glucose, xylose, pectin, starches, human milk and polyphenols).

Increased propionate concentration in Lactobacillus mucosae-fermented wet brewers grains and during in vitro rumen fermentation

AIMS

This study was conducted to isolate and identify propionate-producing bacteria that can be used as an inoculum in improving wet brewers grains and rumen fermentation via increasing propionate concentration.

METHODS AND RESULTS

A strain of Lactobacillus that exhibits high levels of propionate production was identified and characterized as Lactobacillus mucosae 521129 by 16S rRNA gene sequencing and phylogenetic analyses. Wet brewers grains were fermented through L. mucosae inoculation and resulted in an increase in propionate concentration. Fermented wet brewers grains were used in in vitro rumen fermentation and revealed that L. mucosae-fermented wet brewers grains produced more gas and had higher accumulations propionate and total volatile fatty acid (VFA) than the control. The fewest methanogen DNA copies were detected in L. mucosae-fermented wet brewers grains.

CONCLUSION

Identified L. mucosae improved the fermentation of wet brewers grains and the in vitro rumen fermentation via increasing propionate and total VFA concentrations.

SIGNIFICANCE AND IMPACT OF THE STUDY

The presented research provided the identification of L. mucosae 521129 as a propionate producer and was metabolically profiled. Furthermore, data present the putative application of this organism in improving the fermentation of wet brewers grains and in vitro rumen fermentation.

Understanding the canine intestinal microbiota and its modification by pro-, pre- and synbiotics - what is the evidence?

Interest in the composition of the intestinal microbiota and possibilities of its therapeutic modifications has soared over the last decade and more detailed knowledge specific to the canine microbiota at different mucosal sites including the gut is available. Probiotics, prebiotics or their combination (synbiotics) are a way of modifying the intestinal microbiota and exert effects on the host immune response. Probiotics are proposed to exert their beneficial effects through various pathways, for example production of antimicrobial peptides, enhancing growth of favourable endogenous microorganisms, competition for epithelial colonisation sites and immune‐modulatory functions. Despite widespread use of pro‐, pre‐ and synbiotics, scientific evidence of their beneficial effects in different conditions of the dog is scarce. Specific effects of different strains, their combination or their potential side‐effects have not been evaluated sufficiently. In some instances, in vitro results have been promising, but could not be transferred consistently into in vivo situations. Specific canine gastrointestinal (GI) diseases or conditions where probiotics would be beneficial, their most appropriate dosage and application have not been assessed extensively. This review summarises the current knowledge of the intestinal microbiome composition in the dog and evaluates the evidence for probiotic use in canine GI diseases to date. It wishes to provide veterinarians with evidence‐based information on when and why these products could be useful in preventing or treating canine GI conditions. It also outlines knowledge about safety and approval of commercial probiotic products, and the potential use of faecal microbial transplantation, as they are related to the topic of probiotic usage.

Identification of Lactobacillus strains with probiotic features from the bottlenose dolphin (Tursiops truncatus)

Aims

In order to develop complementary health management strategies for marine mammals, we used culture-based and culture-independent approaches to identify gastrointestinal lactobacilli of the common bottlenose dolphin, Tursiops truncatus.

Methods and Results

We screened 307 bacterial isolates from oral and rectal swabs, milk and gastric fluid, collected from 38 dolphins in the U.S. Navy Marine Mammal Program, for potentially beneficial features. We focused our search on lactobacilli and evaluated their ability to modulate TNF secretion by host cells and inhibit growth of pathogens. We recovered Lactobacillus salivarius strains which secreted factors that stimulated TNF production by human monocytoid cells. These Lact. salivarius isolates inhibited growth of selected marine mammal and human bacterial pathogens. In addition, we identified a novel Lactobacillus species by culture and direct sequencing with 96·3% 16S rDNA sequence similarity to Lactobacillus ceti.

Conclusions

Dolphin-derived Lact. salivarius isolates possess features making them candidate probiotics for clinical studies in marine mammals.

Significance and Impact of the Study

This is the first study to isolate lactobacilli from dolphins, including a novel Lactobacillus species and a new strain of Lact. salivarius, with potential for veterinary probiotic applications. The isolation and identification of novel Lactobacillus spp. and other indigenous microbes from bottlenose dolphins will enable the study of the biology of symbiotic members of the dolphin microbiota and facilitate the understanding of the microbiomes of these unique animals.

Incorporating a mucosal environment in a dynamic gut model results in a more representative colonization by lactobacilli

To avoid detrimental interactions with intestinal microbes, the human epithelium is covered with a protective mucus layer that traps host defence molecules. Microbial properties such as adhesion to mucus further result in a unique mucosal microbiota with a great potential to interact with the host. As mucosal microbes are difficult to study in vivo, we incorporated mucin-covered microcosms in a dynamic in vitro gut model, the simulator of the human intestinal microbial ecosystem (SHIME). We assessed the importance of the mucosal environment in this M-SHIME (mucosal-SHIME) for the colonization of lactobacilli, a group for which the mucus binding domain was recently discovered. Whereas the two dominant resident Lactobacilli, Lactobacillus mucosae and Pediococcus acidilactici, were both present in the lumen, L. mucosae was strongly enriched in mucus. As a possible explanation, the gene encoding a mucus binding (mub) protein was detected by PCR in L. mucosae. Also the strongly adherent Lactobacillus rhamnosus GG (LGG) specifically colonized mucus upon inoculation. Short-term assays confirmed the strong mucin-binding of both L. mucosae and LGG compared with P.acidilactici. The mucosal environment also increased long-term colonization of L. mucosae and enhanced its stability upon antibiotic treatment (tetracycline, amoxicillin and ciprofloxacin). Incorporating a mucosal environment thus allowed colonization of specific microbes such as L. mucosae and LGG, in correspondence with the in vivo situation. This may lead to more in vivo-like microbial communities in such dynamic, long-term in vitro simulations and allow the study of the unique mucosal microbiota in health and disease.

Functional oligosaccharides: application and manufacture

Oligosaccharides are attracting increasing interest as prebiotic functional food ingredients. They can be extracted or obtained by enzymatic hydrolysis from a variety of biomass sources or synthesized from simple oligosaccharides by enzymatic transfer reactions. The major prebiotic oligosaccharides on the market are inulin, fructo-oligosaccharides, and galacto-oligosaccharides. They have been evaluated using a range of in vitro and in vivo methods, although there is a need for more large-scale human trials using modern microbiological methods. Prebiotics are being studied for their effects on gut health and well being and specific clinical conditions, including colon cancer, inflammatory bowel disease (IBD), acute infections, and mineral absorption. Developing understanding of the functional ecology of the human gut is influencing current thinking on what a prebiotic might achieve and is providing new targets for prebiotic intervention.

In vitro activity of potential probiotic Lactobacillus murinus isolated from the dog

AIMS

The aim of this study was to isolate and identify Lactobacillus spp. isolates from faeces of a healthy dog, and to characterize their potential as probiotics in order to evaluate their possible use as probiotics for dogs.

METHODS AND RESULTS

An in vitro approach was used to characterize the isolates as potential probiotics including the evaluation of pH and bile salts tolerance, production of antimicrobial substances, biofilm formation on glass and polystyrene surfaces, aggregation ability and adhesion to canine intestinal mucus. The isolates survived to different pH and bile salts conditions, inhibited the in vitro growth of Escherichia coli and Clostridium perfringens, and adhered to glass and intestinal mucus.

CONCLUSIONS

The properties shown by these isolates may indicate that they could colonize and persist in the gastrointestinal tract and induce beneficial effects to the host.

SIGNIFICANCE AND IMPACT OF STUDY

The evaluation of native canine isolates and future experimental feeding assays may be useful tools to develop probiotics to improve animal health and reduce the risk of gastrointestinal disorders.

Screening from pickled vegetables the potential probiotic strains of lactic acid bacteria able to inhibit the Salmonella invasion in mice

AIMS

To screen from pickled vegetables the potential probiotic lactic acid bacteria (LAB) strains with antagonistic activity against Salmonella invasion in host.

METHODS AND RESULTS

Probiotic properties including acid and bile tolerance as well as inhibition on pathogenic bacteria were used for screening of LAB strains from pickled vegetables. Two strains, i.e Pediococcus pentosaceus MP12 and Lactobacillus plantarum LAP6, were selected and further assayed for their activities against Salmonella invasion in mouse liver and spleen. For these two LAB strains, strain LAP6 was able to adhere to the mouse intestinal epithelium cells.

CONCLUSIONS

In screening of the probiotic strains able to inhibit the Salmonella invasion in host, factors other than the adherence to host intestinal epithelium may contribute some roles.

SIGNIFICANCE AND IMPACT OF THE STUDY

Probiotic LAB strains with activity against Salmonella invasion in host could be isolated from vegetable origins. These strains may be used for vegetable processing.

Effects of dietary scFOS on immunoglobulins in colostrums and milk of bitches

Fructo-oligosaccharides (scFOS) are prebiotic ingredients that improve protection against pathogens probably through promoting the growth of gastrointestinal bacteria-like Bifidobacteria and Lactobacilli: this stimulation may lead to a better development of immune repertoire and/or stimulation of the local immune response. According to the existence of the immune entero-mammary link, we were wondering if the dietary supplementation with scFOS could enhance the mucosal immunoglobulin level in mammary secretions. Results in this study show that bitches supplemented with scFOS exhibit higher colostrum and milk IgM content without concomitant effect on IgG1, IgG2 and IgA. In addition, intranasally immunized puppies exhibited a trend to higher Bordetella bronchiseptica-specific IgM immune response. The dietary supplementation with scFOS increased the IgM level in colostrums and milk of bitches by mechanisms which remain to be elucidated.

Lactic acid bacteria isolated from canine faeces

AIMS

Lactic acid bacteria (LAB) were isolated and sequenced from the faeces of healthy dogs. Five of these strains were selected and further characterized to clarify the potential of these strains as probiotics for canine.

METHODS AND RESULTS

LAB were found in 67% (14/21) of the canine faeces samples when plated on Lactobacilli Selective Media without acetic acid. Out of 13 species identified with partial 16S rRNA gene sequencing, Lactobacillus fermentum LAB8, L. mucosae LAB12, L. rhamnosus LAB11, L. salivarius LAB9 and Weissella confusa LAB10 were selected as candidate probiotic strains based on their frequency, quantity in faeces, growth density, acid tolerance and antimicrobial activity. The minimal inhibitory concentration values of these isolates were determined for 14 antibiotics. L. salivarius LAB9, W. confusa LAB10 and L. mucosae LAB12 were viable in pH 2 for 4 h (mLBS), indicating tolerance to acidity and thus the potential to survive in gastrointestinal tract of the canine. The LAB8-LAB12 strains showed antimicrobial activity against Micrococcus luteus A1 NCIMB86166.

CONCLUSIONS

Thirteen different LAB species were found from the faecal microbiota of the healthy canines. Five acid tolerant and antimicrobially active LAB strains with the capacity to grow to high densities both aerobically and anaerobically were chosen to serve as candidate probiotics.

SIGNIFICANCE AND IMPACT OF THE STUDY

The selected LAB strains are among the first host-specific LAB with antimicrobial activity isolated from canines that could serve as potential probiotics for canine use.

The effect of prebiotics on production of antimicrobial compounds, resistance to growth at low pH and in the presence of bile, and adhesion of probiotic cells to intestinal mucus

AIMS

Screening of five bile salt-resistant and low pH-tolerant lactic acid bacteria for inhibitory activity against lactic acid bacteria and bacterial strains isolated from the faeces of children with HIV/AIDS. Determining the effect of prebiotics and soy milk-base on cell viability and adhesion of cells to intestinal mucus.

METHODS AND RESULTS

Lactobacillus plantarum 423, Lactobacillus casei LHS, Lactobacillus salivarius 241, Lactobacillus curvatus DF 38 and Pediococcus pentosaceus 34 produced the highest level of antimicrobial activity (12,800 AU ml(-1)) when grown in MRS broth supplemented with 2% (m/v) dextrose. Growth in the presence of Raftilose Synergy1, Raftilose L95 and Raftiline GR did not lead to increased levels of antimicrobial activity. Cells grown in the presence of Raftilose Synergy1 took longer to adhere to intestinal mucus, whilst cells grown in the absence of prebiotics showed a linear rate of binding.

CONCLUSIONS

A broad range of gram-positive and gram-negative bacteria were inhibited. Dextrose stimulated the production of antimicrobial compounds. Adhesion to intestinal mucus did not increase with the addition of prebiotics.

SIGNIFICANCE AND IMPACT OF THE STUDY

The strains may be incorporated in food supplements for HIV/AIDS patients suffering from gastro-intestinal disorders.

Bacteria in the gut: friends and foes and how to alter the balance

The activities of the bacteria resident in the colon of companion animals can have an impact upon the health of the host. Our understanding of this microbial ecosystem is presently increasing due to the development of DNA-based microbiological tools that allow identification and enumeration of nonculturable microorganisms. These techniques are changing our view of the bacteria that live in the gut, and they are facilitating dietary-intervention approaches to modulate the colonic ecosystem. This is generally achieved by the feeding of either live bacteria (probiotics) or nondigestible oligosaccharides (prebiotics) that selectively feed the indigenous probiotics. Feeding studies with a Lactobacillus acidophilus probiotic have shown positive effects on carriage of Clostridium spp. in canines and on recovery from Campylobacter spp. infection in felines. Immune function was improved in both species. Prebiotic feeding studies with lactosucrose and fructo-oligosaccharides in both cats and dogs have shown positive effects on the microflora balance. Recently synbiotic forms (a probiotic together with a prebiotic) targeted at canines have been developed that show promise as dietary-intervention tools.