Single Probiotic Strain Research Articles

Evaluation of Bacillus subtilis R0179 on gastrointestinal viability and general wellness: a randomised, double-blind, placebo-controlled trial in healthy adults.

A probiotic formulation of Enterococcus faecium R0026 and Bacillus subtilis R0179 has been evaluated in previous clinical trials. However, B. subtilis R0179 has not been evaluated as a single probiotic strain or in combination with other strains at doses higher than 0.1×109 cfu. To establish oral dose-response tolerance and gastrointestinal (GI) viability of B. subtilis R0179, a randomised, double-blind, placebo-controlled trial in healthy adults (n=81; 18-50 years old) was conducted. Participants received B. subtilis R0179 at 0.1, 1.0 or 10×109 cfu/capsule/day or placebo for four weeks. General wellness was assessed using a daily questionnaire evaluating GI, cephalic, ear-nose-throat, behavioural, emetic, and epidermal symptoms. GI symptoms were further evaluated using a weekly gastrointestinal symptom rating scale (GSRS). GI transit viability of B. subtilis R0179 was assessed by plating and microbiota analysis by 16S rRNA at baseline, week 4 of the intervention and washout. General wellness and GI function were not affected by oral consumption of B. subtilis R0179 at any dose. Daily questionnaire syndrome scores were not different from baseline and did not exceed a clinically significant score of 1. GSRS syndrome scores were not different from baseline and ranged from 1.1±0.1 to 1.9±0.2. Faecal viable counts of B. subtilis R0179 demonstrated a dose response: the placebo group (1.1±0.1 log10 cfu/g) differed from 0.1×109 (4.6±0.1 log10 cfu/g), 1×109 (5.6±0.1 log10 cfu/g) and 10×109 (6.4±0.1 log10 cfu/g) (P<0.0001). No significant changes in phyla were observed, but sequence reads binned to multiple operational taxonomic units matching closest to Ruminococci increased during probiotic supplementation. B. subtilis R0179 survives passage through the human GI tract and is well tolerated by healthy adults at intakes from 0.1 to 10×109 cfu/day. The trial has been registered at www.clinicaltrials.gov under NCT01802151.

Not all probiotics are the same: Gut microbiota modulation with a multistrain probiotics

The highest incidence of invasive candidiasis infection (ICI) occurs in low birth weight infant with an estimated incidence of 4% and of 15% in extremely low birth weight infant. Low birth weight is an important risk factor. The other main risk factors associated with invasive candidiasis are the use of multiple antibiotics and central venous catheters, immunosuppression, parenteral nutrition, fungal colonization, and necrotizing enterocolitis. In this population, ICI cause high mortality, lead to significant neurodevelopmental impairment, and result in increate length of hospitalization and cost.[1] Originality of the study is the use of probiotics combination Alkem Batch PWS3002C comprising Bifidobacterium infantis, Lactobacillus acidophilus, Bifidobacterium longum, and Bifidum lactis. These preparations are considered more effective than single probiotic strain, characterized instead by a single bacterial strain. In fact, a recent study showed that the use of a multistrain probiotics have an action of greater efficacy.[2] Important focal point is gastrointestinal symptoms. Another interesting result of this study is that the control group presented a higher percentage of gastrointestinal symptoms than did the probiotic group, which showed an increased food tolerance, shortening the period of parenteral nutrition probably due to its changes in intestinal flora, improvement in mucosal barrier and anti-infiammatory properties. Reduction of stool fungal colonization is an important principal outcome parameter in the probiotics group by reduced invasive fungal sepsis is an important outcome parameter in the probiotics group because reduced invasive fungal sepsis 55.4% in probiotics group versus 75% in the control group.[3] Also the number of days to full enteral feeds and duration of hospitalization was less in probiotic group. Candida albicans is the most commonly isolated species, although C. parapsilosis. These species are commonly isolated in invasive candidiasis, while C. glabrata and C. krusei are isolated only in 3% of ICI. The published data show that fluconazolo use since birth is highly effective in preventing both colonization and infection in preterm neonates. This can lead to a high prevalence of azole-resistant Candida species.[4] In this study 35 (7%) newborns of control group presented C. glabrata infection, while the probiotics group presented only C. albicans. Loss of gut commensals, such as Bifidobacteria and Lactobacilli, due to the difficulties in oral feeding, translates into an increased susceptibility to pathogenic gut colonization. Probiotics are increasingly being used for their beneficial properties, considered to be particularly useful in reducing some symptoms related to gastrointestinal disorders.[5] In particular, preparations of a multistrain, consisting of different bacterial strains but belonging to the same species or anyway similar species are considered more effective than single probiotic strain. Evidence regarding the potential beneficial effects of probiotics supplementation in preterm infants is encouraging. Further studies to assess clinically relevant outcomes are needed.

Combined probiotic bacteria promotes intestinal epithelial barrier function in interleukin-10-gene-deficient mice.

To investigate the protective effects of combinations of probiotic (Bifico) on interleukin (IL)-10-gene-deficient (IL-10 KO) mice and Caco-2 cell monolayers. IL-10 KO mice were used to assess the benefits of Bifico in vivo. IL-10 KO and control mice received approximately 1.5 × 10(8) cfu/d of Bifico for 4 wk. Colons were then removed and analyzed for epithelial barrier function by Ussing Chamber, while an ELISA was used to evaluate proinflammatory cytokines. The colon epithelial cell line, Caco-2, was used to test the benefit of Bifico in vitro. Enteroinvasive Escherichia coli (EIEC) and the probiotic mixture Bifico, or single probiotic strains, were applied to cultured Caco-2 monolayers. Barrier function was determined by measuring transepithelial electrical resistance and tight junction protein expression. Treatment of IL-10 KO mice with Bifico partially restored body weight, colon length, and epithelial barrier integrity to wild-type levels. In addition, IL-10 KO mice receiving Bifico treatment had reduced mucosal secretion of tumor necrosis factor-α and interferon-γ, and attenuated colonic disease. Moreover, treatment of Caco-2 monolayers with Bifico or single-strain probiotics in vitro inhibited EIEC invasion and reduced the secretion of proinflammatory cytokines. Bifico reduced colon inflammation in IL-10 KO mice, and promoted and improved epithelial-barrier function, enhanced resistance to EIEC invasion, and decreased proinflammatory cytokine secretion.

Probiotics L. plantarum and L. curvatus in Combination Alter Hepatic Lipid Metabolism and Suppress Diet‐Induced Obesity

To determine the effects of naturally derived probiotic strains individually or combination on a short-term diet-induced obesity model. C57BL/6J mice (n = 50) were randomly divided into five groups, then fed a high-fat high-cholesterol diet (HFCD), HFCD and Lactobacillus plantarum KY1032 (PL, 10(10) cfu/day), HFCD and Lactobacillus curvatus HY7601 (CU, 10(10) cfu/day), HFCD and in combination with PL+CU (10(10) cfu/day), or a normal diet (ND) for 9 weeks. PL and CU showed distinct and shared metabolic activity against a panel of 50 carbohydrates. Fat accumulation in adipose tissue and liver was significantly reduced by probiotic strains CU or PL+CU. Probiotic strains CU or PL+CU reduced cholesterol in plasma and liver, while PL+CL had a synergistic effect on hepatic triglycerides. Probiotic strains PL+CU combination was more effective for inhibiting gene expressions of various fatty acid synthesis enzymes in the liver, concomitant with decreases in fatty acid oxidation-related enzyme activities and their gene expressions. Multi-strain probiotics may prove more beneficial than single-strain probiotics to combat fat accumulation and metabolic alterations in diet-induced obesity.

The Effects of Multistrain Probiotic Compound on Bismuth‐Containing Quadruple Therapy for Helicobacter pylori Infection: A Randomized Placebo‐Controlled Triple‐Blind Study

Evidence has shown benefits of single-strain probiotics for Helicobacter pylori eradication. We investigated the effects of adding a multistrain probiotic compound on bismuth-containing quadruple therapy for H.pylori infection. Adult patients with peptic ulcer disease and confirmed H.pylori infection (n=180) were randomized to receive bismuth-containing quadruple therapy (omeprazole, bismuth subcitrate, amoxicillin, and clarithromycin) plus a probiotic compound or placebo for 2weeks. The probiotic compound contained seven bacterial species including Lactobacillus and Bifidobacterium strains and Streptococcus thermophiles. Eradication of H.pylori was assessed 4weeks after medication by (13) C urea breath test. Other outcomes were dyspepsia symptoms, therapy-related adverse effects, and patient's tolerance. Eighty-four patients in the probiotic and 86 in the placebo group completed the trial. With per-protocol (intention to treat) analysis, H.pylori was eradicated in 82.1% (76.6%) of the probiotic and 84.8% (81.1%) of the placebo group, p=.392 (0.292). Symptoms were significantly improved with similar trends in both groups. Regarding the adverse effects, diarrhea was less frequent (2.2 vs 11.1%, p=.016), while abdominal pain was more frequent (10 vs 2.2%, p=.029) in the probiotic group. The two groups were similar in treatment tolerance (p=.851). In overall, our studied multistrain probiotic compound has not beneficial effects in the treatment of H.pylori infection. It might be related to the low dosage of our probiotic regimen and/or high frequency of upper gastrointestinal adverse effects which in turn could decrease the eradication efficacy.

Economic production of probiotics from kitchen waste

In the present work, a novel treatment method of kitchen waste for economic production of probiotics was investigated. This required the selection of suitable probiotic microorganisms. Based on the pure cultures of probiotic strains for the fermentation kitchen waste, 5 strains of microorganisms including 1 strain of Lactobacillus, 2 strains of Bacillus, and 2 strains of yeast were selected, respectively. These probiotic microorganisms were mixed at the same ratio and cultured using the kitchen waste as culture medium at pH of 7.2 and temperature of 37°C. After 24 h, the total count of the viable cells reached 2.24 ×1010 CFU/g, which was higher than that obtained in any single probiotic strain pure culture. It was found that the presence of yeasts and Bacillus species enhanced the growth of Lactobacillus strain. Bench scale experiments were also done in a self-designed rotating drum type bioreactor. The experimental results indicate that there is a good possibility of utilizing kitchen waste for the economic production of probiotics.

Impact of selected nutraceuticals on viability of probiotic strains in milk during refrigerated storage at 4 °C for 15 days

The objective of this study was to establish suitable combinations of selected probiotics and nutraceuticals. Interactions among 24 probiotic strains were investigated, and the effect of a blend of isoflavones and phytosterols on viability of single and mixed probiotic strains under incubation and refrigeration storage in milk was assessed. Upon incubation, counts of single strains increased by 7–15 times, while mixed strains showed slight insignificant decrease. Both single and mixed probiotic strains retained high counts (&gt;log 8) throughout refrigeration storage. Eight probiotic strains showed nil or very weak interactions. Results revealed the possibility of developing novel multibenefits synbiotic products using combinations of these probiotic strains and nutraceuticals.

Probiotics and health: a review of the evidence

SummaryProbiotics are live microorganisms – mainly bacteria – which when administered in adequate amounts confer a health benefit on the host. There is rising interest in this area, but reports in the media are often conflicting. The aim of this review is to consider the current evidence on the effects of probiotics on health, focusing on gut‐related health issues and the immune system, with the objective to provide a clearer picture of whether and how probiotics can be beneficial for health. The outcomes of this review are based on more than 100 original studies, meta‐analyses and systematic reviews. A variety of different strains have been used in studies on probiotics, and it is important to remember that the effectiveness of probiotics is strain‐specific, which means that each single probiotic strain has to be tested to assess its potential health benefits.Overall, despite the diversity of strains used in the studies included in this review, there is evidence that probiotics have the potential to be beneficial for our health. Studies in patients with inflammatory bowel disease show probiotic strains to be able to decrease the recurrence of ulcerative colitis and occurrence and recurrence of pouchitis, however, current evidence suggests that probiotics are ineffective in treating patients with Crohn's disease. Patients with irritable bowel syndrome show a reduction in symptoms when treated with selected probiotic strains, but high placebo effects have been reported as well. The evidence of the efficacy of probiotics in patients suffering from constipation is limited, but the evidence seems promising for some strains to bring relief to patients suffering from constipation.There is good evidence that a number of probiotic strains are effective in preventing antibiotic‐associated diarrhoea. The most commonly studied strains are Lactobacillus rhamnosus GG (LGG) and Saccharomyces boulardii, but other strains and mixtures of strains seem to be effective as well. There is also promising evidence of a preventive effect of probiotics in Clostridium difficile‐associated diarrhoea, although some studies have been too small to obtain statistically significant findings. The effect of probiotics in acute diarrhoea, particularly in children, is well studied. Selected probiotic strains seem to be effective in reducing the duration of acute diarrhoea. LGG and S. boulardii are again the most commonly used strains and a number of studies have shown them to be effective, although one meta‐analysis showed that the effect of LGG was only significant in children in Western countries, not in children in developing countries, which may be due to different causes of diarrhoea in these regions. Studies investigating the preventive effect of probiotics in the context of common cold and flu infections show that the studied strains failed to lower the incidence of episodes but that they have the potential to decrease the duration of episodes, which suggests that the immune system may be more efficient in fighting off common cold and flu infections after consuming these strains. The evidence so far does not suggest that probiotics are effective in preventing or treating allergies or in treating eczema. However, some probiotic strains seem to lower the risk of developing eczema if taken by pregnant women and their infants in early life.

Practical prebiotics, probiotics and synbiotics for allergists: how useful are they?

With the advent of the hygiene hypothesis, probiotics have provided an avenue of hope in curbing the allergic epidemic. The initial enthusiasm has been tempered by recognition of the inherent complexities of this approach. This review examines the current clinical evidence and practical issues in using probiotics and related products, for the prevention and treatment of allergic disease. So far, probiotics have shown more promise, albeit limited, in the primary prevention of allergic disease rather than in the treatment of established disease. These effects have largely been limited to the prevention of early childhood conditions such as eczema, with no consistent effects on other allergic outcomes. There is emerging evidence that clinical effects may be strain specific, but again these findings have been inconsistent. While there have been several meta-analyses to examine probiotics in both the prevention and the treatment of allergic disease, these have been hampered by significant heterogeneity between studies, including wide variations in the strains used, the methods and timing of administration and the age and assessment of allergic outcomes. In any case, these have also become outdated by a series of new studies published in the last year. Although it is not yet clear exactly how the growing number of new studies will modify the results of meta-analyses, it is likely that these will add yet further heterogeneity that will continue to make interpretation of pooled data difficult. At this stage, the effects of prebiotics, synbiotics and postbiotics are even less clear. Thus, while there is little doubt that microbiota modulate immune development and can prevent the allergic phenotype, the optimal way of achieving this is far from clear. Given the current level of evidence, it is not appropriate to recommend prebiotics/probiotics/synbiotics or postbiotics as a part of standard therapy or for the prevention of any allergic conditions. Further studies are needed to address the growing speculation that supplementation with a single probiotic strain may be oversimplistic and that approaches that have a more global effect on colonization may be warranted.

Growth Performance and Antibody Response of Broiler Chicks Fed Yeast Derived β-Glucan and Single-strain Probiotics

A study was conducted to evaluate the effects of dietary yeast derived β-glucan and single-strain probiotics on the growth performance and antibody response in broiler chicks. Six hundred and thirty 1-d-old male broiler chicks were divided into seven groups, placed into three pens per group (30 birds per pen) and fed one of seven non-medicated corn-SBM based experimental diets containing 0.025, 0.05 or 0.1% Saccharomyces cerevisiae β-glucan and 0.05, 0.1 or 0.2% Bacillus amyloliquefaciens (BA-pro, 1.3x10 9 /g) or devoid of them for 5 wk. The body weight gains in groups fed diets containing 0.025 or 0.1% β-glucan, 0.1% or 0.2% BA-pro were significantly higher (p<0.05) than the control over 1-35 d. Feed conversion rates of groups fed β-glucan and BA-pro tended to be improved compared to the control group. There were no significant differences in the relative weights of liver, abdominal fat and breast muscle. No significant differences were observed in the activities of serum enzymes and concentrations of various cholesterol fractions. The antibody titers against Newcastle disease or infectious bronchitis virus in the chicks fed diets containing β-glucan and BA-pro were significantly higher (p<0.05) than in the control. The concentrations of cecal lactic acid bacteria in all groups fed BA-pro were significantly increased (p<0.05) compared to the control. These results indicated that dietary yeast derived β-glucan and BA-pro exerted growth-promoting and immune-enhancing effects in broiler chickens. In addition, BA-pro added to the diets modulated the profiles of cecal microflora, reflecting a potential to be beneficial microorganisms in chickens.

The role of a probiotics mixture in the treatment of childhood constipation: a pilot study

BackgroundInconsistent data exist about the efficacy of probiotics in the treatment of constipation. Several studies in adults with constipation showed positive effects of probiotics on constipation. Inconsistent data exist regarding the effect of a single probiotic strain in constipated children. The aim of this pilot study was to determine the effect of a mixture of probiotics containing bifidobacteria and lactobacilli in the treatment of childhood constipation.MethodsChildren aged 4–16 years with constipation as defined by the Rome III criteria were eligible for the study. During a 4 week period, children received a daily mix of 4 × 109 colony forming units of a probiotic mixture (Ecologic®Relief) containing Bifidobacteria (B.) bifidum, B. infantis, B. longum, Lactobacilli (L.) casei, L. plantarum and L. rhamnosus. Primary outcome measures were frequency of bowel movements (BMs) per week and stool consistency. Secondary outcome measures were number of faecal incontinence episodes per week, abdominal pain and side effects.ResultsTwenty children, 50% male, median age 8 (range 4–16) were included.The frequency of BMs per week increased from 2.0 (1.0–5.0) to 4.2 (0.0–16.0) in week 2 (p = 0.10) and 3.8 (2.1–7.0) in week 4 (p = 0.13). In 12 children presenting with <3 BMs/week, BMs per week increased significantly from 1.0 (0.0–2.0) to 3.0 (0.0–7.0) in week 2 (p = 0.01) and 3.0 (0.0–10.0) in week 4 (p = 0.01). The stool consistency was reported as hard in 7 children at baseline, in 4 children at week 2 (p = 0.23) and in 6 children after 4 weeks of treatment (p = 1.00). A significant decrease in number of faecal incontinence episodes per week was found in the entire group: 4.0 (0.0–35.0) to 1.5 (0.0–14.0) in week 2 (p = 0.01) and 0.3 (0.0–7.0) in week 4 (p = 0.001). The presence of abdominal pain decreased significantly from 45% to 25% in week 2 (p = 0.04) and 20% at week 4 (p = 0.006). No side effects were reported.ConclusionThis pilot study shows that a mixture of probiotics, has positive effects on symptoms of constipation. To confirm these findings, a large randomised placebo controlled trial is required.

Prebiotics and Synbiotics in Clinical Medicine

Pharmaceutical medicine has thus far been unable to stop the increasing global morbidity and mortality both in acute and chronic diseases. Typically, medical practice has focused on reducing the aggressor with treatments such as antibiotics; little interest has been given to efforts to increase the individual's resistance to disease. The increased morbidity has occurred in parallel to a deviation from a large consumption of fresh fruits, vegetables, and tubers rich in live lactic acid bacteria (LAB), plant fibers, and natural antioxidants to an industry-produced diet rich in fat and refined sugar but containing little fiber, antioxidants, and LAB. Plant fiber/prebiotics, plant-derived antioxidants, and LAB/probiotics are known to have the potential to reinforce the immune system of the body and increase resistance to disease. However, this depends on the type of fiber, antioxidant, and strain or combination of strain used. At this stage, only about 10% of the LAB studied have proven strong immunosupportive effects. Similarly, only a few plants contain what has been called superantioxidants, antioxidants 10 or more times stronger than vitamin C and E. Increasing evidence suggests that combining several probiotic bacteria into multistrain probiotics will achieve stronger effects than single-strain probiotics. And combining probiotics and prebiotics into "synbiotics" will further enhance the immunosupportive effects. There is little evidence that a single-strain-based "superprobiotic"/magic LAB will ever be found. Instead, combining several specific and defined probiotics and several key plant fibers into multistrain/multifiber synbiotics appears to be the most promising alternative. Some edge-cutting effects from using multistrain and multifiber compositions are reported both from animal and controlled clinical studies.

Incorporation of selected nutraceuticals and probiotic bacteria into a fermented milk

Abstract Yoghurts were produced from a base milk containing three important nutraceuticals, namely ω-3-fatty acids, isoflavones and phytosterols. The cultures employed to make the yoghurts were single probiotic strains of Lactobacillus gasseri or Bifidobacterium infantis and, to achieve a short production time, a two-stage fermentation procedure was used with Streptococcus thermophilus and Lactobacillus delbrueckii subsp. bulgaricus providing the rapid acidification. Yoghurts containing counts of >1.0×108 cfu mL−1 of the individual probiotics and high counts of the traditional species from yoghurt were awarded overall scores for sensory acceptability >4.0 out of 5.0; the nutraceuticals appeared to have no adverse effect on flavour. Storage trials at 5 °C showed that the viability of the probiotic cultures was retained over 15 days.

Evaluation of the Lactobacillus gasseri K7 and LF221 strains in weaned piglets for their possible probiotic use and their detection in the faeces

Lactobacillus gasseri LF221 and K7 are human isolates that were recognised in previous studies as potential probiotics. In the present study, the detection of LF221 or K7 strains in the faeces as well as their effects on the faecal coliform and lactobacilli counts and on the production parameters were studied in 18 weaned piglets. The animals were divided into three groups: an untreated control group and two groups dosed for 14 days, Lb. gasseri K7 or LF221. The experimental period lasted 25 days. For the discrimination among strains LF221, K7 and other faecal microflora, a combined approach that included culturing on selective media, testing of antimicrobial activity and random amplified polymorphic DNA (RAPD) analysis was used. The administration of a single probiotic strain (a daily dose of 5 × 10 10 cfu per piglet) did not significantly influence the viable counts of the coliforms (P > 0.05). A significantly higher number of lactobacilli in comparison with the control group was found in the K7 group after 15 days of probiotic bacteria administration (P = 0.02) but not in the LF221 group. The probiotic treatment did not have a significant influence on feed intake (P > 0.05) and weight gain (P > 0.05). The feed conversion efficiency in the K7 treated group during the whole period was significantly more favourable (P < 0.05) than in the non-treated control group (1.51 and 1.87, respectively). All the piglets remained healthy and no case of diarrhoea was observed. The LF221 and K7 strains survived the passage through the intestines and were successfully detected in the faeces. The colonies identical to the LF221 and K7 strains were isolated only from the faeces of animals fed with the LF221 or K7 strain, respectively.

Safety Aspects ofLactobacillusandBifidobacteriumSpecies Originating from Human Oro-gastrointestinal Tract or from Probiotic Products

Probiotics are live microbial preparations, which have documented health benefits for the consumers by maintaining or improving their intestinal microbiota balance. Established probiotic effects include improved lactose digestion, modulation of gut microbiota, immune modulation, reduced duration of rotavirus diarrhoea, changes in biomarkers such as harmful faecal enzyme activities, alleviation of atopic dermatitis symptoms in babies, and positive effects against superficial bladder cancer and cervical cancer. Most bacteria that have probiotic properties belong to the genera Lactobacillus and Bifidobacterium . Since probiotic consumption involves ingestion of large numbers of viable bacterial cells (daily dosage between log 9 and log 11 CFU) safety aspects of probiotic consumption are of utmost importance. Knowledge on the survival of probiotics in the GI-tract, their translocation and colonisation properties and the fate of probiotic-derived active components is important for the evaluation of possible negative and positive effects of probiotic consumption. Assessing the risks of probiotic consumption can be a very expensive and time-consuming task. While considering the risk of probiotic consumption we have to keep in mind that lactic acid bacteria have been globally consumed in a myriad of fermented food varieties (milk, meat, vegetable and cereal products) for a very long time without an indication that they could be generally harmful to the consumers’ health. In Finland lactobacilli strains isolated from bacteremia have been systematically characterised. Although the yearly consumption of probiotic products containing lactobacilli has increased during the last 10 years, the incidence of lactobacillemia has not increased. There is one local infection case with an indistinguishable isolate to L. rhamnosus GG. The extensive follow-up period indicates that the risk of serious infection by one single probiotic strain is very low. Simultaneously, it is difficult to estimate all the health benefits the same probiotic strain has implemented, also in immunocompromised patients. However, no live bacterium can be guaranteed for a zero risk in each individual host since the outcome of bacterial ingestion (passage through GI-tract, colonisation, infection) is determined both by the host and the bacterium. Keywords: Lactobacillus , Bifidobacterium , infection, bacteremia, sepsis, endocarditis.

Safety Aspects of Lactobacillus and Bifidobacterium Species Originating from Human Oro-gastrointestinal Tract or from Probiotic Products

Probiotics are live microbial preparations, which have documented health benefits for the consumers by maintaining or improving their intestinal microbiota balance. Established probiotic effects include improved lactose digestion, modulation of gut microbiota, immune modulation, reduced duration of rotavirus diarrhoea, changes in biomarkers such as harmful faecal enzyme activities, alleviation of atopic dermatitis symptoms in babies, and positive effects against superficial bladder cancer and cervical cancer. Most bacteria that have probiotic properties belong to the genera Lactobacillus and Bifidobacterium . Since probiotic consumption involves ingestion of large numbers of viable bacterial cells (daily dosage between log 9 and log 11 CFU) safety aspects of probiotic consumption are of utmost importance. Knowledge on the survival of probiotics in the GI-tract, their translocation and colonisation properties and the fate of probiotic-derived active components is important for the evaluation of possible negative and positive effects of probiotic consumption. Assessing the risks of probiotic consumption can be a very expensive and time-consuming task. While considering the risk of probiotic consumption we have to keep in mind that lactic acid bacteria have been globally consumed in a myriad of fermented food varieties (milk, meat, vegetable and cereal products) for a very long time without an indication that they could be generally harmful to the consumers’ health. In Finland lactobacilli strains isolated from bacteremia have been systematically characterised. Although the yearly consumption of probiotic products containing lactobacilli has increased during the last 10 years, the incidence of lactobacillemia has not increased. There is one local infection case with an indistinguishable isolate to L. rhamnosus GG. The extensive follow-up period indicates that the risk of serious infection by one single probiotic strain is very low. Simultaneously, it is difficult to estimate all the health benefits the same probiotic strain has implemented, also in immunocompromised patients. However, no live bacterium can be guaranteed for a zero risk in each individual host since the outcome of bacterial ingestion (passage through GI-tract, colonisation, infection) is determined both by the host and the bacterium. Keywords: Lactobacillus , Bifidobacterium , infection, bacteremia, sepsis, endocarditis.