Metagenomic and proteomic approaches in elucidating aflatoxin B1 detoxification mechanisms of probiotic Lactobacillus casei Shirota towards intestine

The modulation of gut microbiota and proteome due to aflatoxin B₁ (AFB₁) by probiotics remains unclear. This study investigated the alterations of gut microbiota and proteome in AFB₁-exposed rats treated with probiotic Lactobacillus casei Shirota (Lcs). Forty male Sprague Dawley rats were randomly divided into five groups (n = 8) comprised control, AFB₁, AFB₁+activated charcoal, AFB₁+Lcs, and Lcs groups. The rats were subjected to different treatments via oral gavage for four weeks. Urine and serum were collected for the measurement of AFB₁ biomarkers and organs were harvested for histological analysis. Metagenomic sequencing was performed on fecal samples to profile gut microbiota. Besides, AFB₁ most affected organ i.e. jejunum was subjected to proteomic analysis. The results indicated that Lcs intervention significantly reduced AFB₁ biomarkers. H&E-stained intestine showed Lcs alleviated AFB₁-induced inflammation and abnormal cell growth, particularly at the jejunum. Although AFB₁ increased potentially pathogenic bacteria and reduced beneficial bacteria abundance in feces, the microbiota composition was normalized with Lcs treatment. The gut proteome analysis of the jejunum sample showed several pathways of AFB₁ toxicity, wherein Lcs treatment demonstrated its protective effect. It is concluded that metagenomic and proteomic approaches are useful tools to understand AFB₁-Lcs interaction and detoxification mechanism in the gut.

The differences in the number of fibroblasts and blood vessels after the topical and systemic administration of Lactobacillus casei Shirota probiotics for the treatment of traumatic ulcers in Wistar rats (Rattus norvegicus)

Background and Aim

The use of drugs as a therapy for traumatic ulcers may lead to drug resistance and other side effects. Lactobacillus casei Shirota can affect the number of fibroblasts and blood vessels in wound healing. The aim of this study was to investigate the difference in the number of fibroblast cells and blood vessels after the topical and systemic administration of L. casei Shirota probiotics in Wistar rats with traumatic ulcer.

Materials and Methods

Overall, 36 healthy male Wistar rats aged 2-3 months old and weighing 175-250 g in body weight were used as a sample. Traumatic ulcer was made on the labial fornix incisive inferior. The subject rats were divided into groups: (1) A control group over 3 days, (2) a group that used distilled water over 7 days, (3) a group that underwent topical treatment over 3 days, (4) a group that used probiotics administered topically over 7 days, (5) a group that underwent systemic treatment over 3 days, and (6) a group that took oral probiotics for the traumatic ulcers over 7 days. The number of fibroblasts and blood vessels was observed through a hematoxylin-eosin examination.

Results

Based on the results of the study, a significant difference was observed in the number of fibroblasts (p=0.00) and blood vessels (p=0.018) in the 3-day topical group that underwent a 3-day systemic administration of probiotics compared with the number of fibroblast cells in the 7-day topical group and 7-day systemic group (p=0.00).

Conclusion

Overall, significant differences were observed in the number of fibroblasts and blood vessels in Wistar rats with traumatic ulcer after undergoing the topical and systemic administration of L. casei Shirota probiotics.

The probiotic Lactobacillus casei Shirota attenuates symptoms of vestibular migraine: a randomised placebo-controlled double-blind clinical trial

Vestibular migraine (VM) has emerged as one of the major vestibular syndromes. Although probiotics have exhibited beneficial effects on migraine headache, its effect on VM is not clear. This trial aimed to investigate the treatment efficacy of the probiotic Lactobacillus casei Shirota (LcS) on symptoms of VM. 247 VM patients were enrolled, of which 204 eligible patients receiving either LcS or placebo on a daily basis completed the 4 month study. They were re-visited at 2 and 4 months after study initiation to assess treatment outcomes. The primary endpoints were vestibular symptoms, evaluated by the number of vertiginous attacks during the past week, the Vertigo Severity Score (VSS), and Dizziness Handicap Inventory (DHI) scores. The secondary endpoints were anxiety and depressive symptoms, evaluated using Beck Anxiety Inventory (BAI) and Beck Depression Inventory (BDI) scores. Efficacy of LcS over placebo was not obvious at 2 month follow-up. At 4 month follow-up, while both LcS and placebo groups of VM patients displayed alleviated symptoms, the extents of the improvements were significantly better in LcS group than those of placebo group, with regard to vestibular symptoms using DHI and VSS, as well as anxiety and depressive symptoms using BAI and BDI. Although placebo effect cannot be ignored in intervention for VM patients, the probiotic LcS still exhibits considerable efficacy against VM symptoms over a 4 month study period, supporting further clinical study of a larger and more diverse cohort.

Effects of citrus juice fermented with Lactobacillus plantarum YIT 0132 on Japanese cedar pollinosis during probiotic consumption: an open study

Certain strains of lactic acid bacteria (LAB) have beneficial effects on Japanese cedar pollinosis (JCPsis), which is a major concern in Japan. Heat-killed Lactobacillus plantarum YIT 0132 (LP0132), selected for its ability to induce interleukin (IL)-10, has been shown to suppress JCPsis symptoms. Lactobacillus casei Shirota (LcS), a popular probiotic, potentially induces a high level of IL-12 and is reported to delay the onset of JCPsis symptoms. However, it is unclear whether a combination of different types of LAB exerts additional effects without interfering with the benefits of each individual LAB. Thus, we conducted a pilot study to investigate the effects of LP0132-fermented citrus juice on JCPsis during simultaneous consumption of LcS-fermented milk. Fifty-nine subjects with JCPsis were allocated to two groups after a 2-week preconsumption period: one group consumed LP0132-fermented citrus juice and LcS-fermented milk (LcS+LP0132 group) for 12 weeks, while the other consumed LcS-fermented milk alone (LcS group). JCPsis symptoms, JCPsis-associated quality of life (QOL) impairment, and bowel movements were assessed by questionnaires. Compared with the LcS group, the LcS+LP0132 group showed significant alleviation of total symptoms and total ocular symptoms during the consumption period, as well as relief of impaired QOL. Bowel movements were significantly improved during the consumption period compared with the baseline in a combined analysis of all subjects in the two groups. In conclusion, LP0132-fermented citrus juice appears to have positive effects on some JCPsis symptoms and QOL in a population consuming immunomodulating probiotics such as LcS-fermented milk.

Isolation of Yeasts from Guajillo Pepper (Capsicum annuum L.) Fermentation and Study of Some Probiotic Characteristics

Three yeast strains were isolated from the spontaneous fermentation of guajillo pepper: Hanseniaspora opuntiae, Pichia kudriavzevii, and Wickerhamomyces anomalus, which were identified by amplification of the ITS/5.8S ribosomal DNA. Some probiotic characteristics of these strains were evaluated and compared with one commercial probiotic yeast (Saccharomyces boulardii). The survival percentage of all the yeasts was similar to that of the commercial product. They showed different hydrophobicity characteristics with hydrocarbons, autoaggregation > 90%, and characteristics of co-aggregation with pathogenic microorganisms. The adhesion capacity to mucin of the three yeast samples was similar to the reference yeast. The antioxidant activity of the yeasts varied between 155 and 178 μM Trolox equivalents. All exhibited cholesterol reduction capacity, and W. anomalus was able to decrease up to 83% of cholesterol after 48 h of incubation. The 7.5-fold concentrated H. opuntiae supernatant had antimicrobial activity against Salmonella enterica ser. Typhimurium ATCC 14028 and Candida albicans ENCBDM2; tests suggest this activity against S. Typhimurium is due to a proteinaceous metabolite with a weight between 10 and 30 kDa. Among the yeasts, P. kudriavzevii exhibited the highest protective effect on the viability of Lactobacillus casei Shirota in gastric and intestinal conditions. These results suggest that yeasts isolated from guajillo pepper may have a probiotic potential.

Oral administration of Lactobacillus casei Shirota improves recovery of hand functions after distal radius fracture among elder patients: a placebo-controlled, double-blind, and randomized trial

Background

To evaluate the effect of oral Lactobacillus casei Shirota (LcS) administration on recovery of hand functions in senior patients diagnosed with an acute distal radius fracture.

Methods

This clinical trial is double-blind and placebo-controlled, in which 293 senior patients with distal radius fracture were initially enrolled. After exclusion, 264 eligible patients were randomly assigned to receive oral placebo or LcS daily for a period of 3 months after the fracture. Treatment outcomes were Michigan Hand Questionnaire (MHQ) score, radial deviation and inclination, and ulnar deviation and variance, all of which were monitored and measured every month.

Results

Throughout the length of this study, MHQ score, radial deviation and inclination, and ulnar deviation and variance of patients on oral LcS displayed a significantly faster improvement in comparison to those receiving placebo, over the 3-month intervention period.

Conclusion

Oral administration of LcS dramatically accelerated hand function recovery in senior patients with distal radius fracture.

Gut Microbiota Profiling of Aflatoxin B1-Induced Rats Treated with Lactobacillus casei Shirota

Aflatoxin B1 (AFB1) is a ubiquitous carcinogenic food contaminant. Gut microbiota is of vital importance for the host's health, regrettably, limited studies have reported the effects of xenobiotic toxins towards gut microbiota. Thus, the present study aims to investigate the interactions between AFB1 and the gut microbiota. Besides, an AFB1-binding microorganism, Lactobacillus casei Shirota (Lcs) was tested on its ability to ameliorate the changes on gut microbiota induced by AFB1. The fecal contents of three groups of rats included an untreated control group, an AFB1 group, as well as an Lcs + AFB1 group, were analyzed. Using the MiSeq platform, the PCR products of 16S rDNA gene extracted from the feces were subjected to next-generation sequencing. The alpha diversity index (Shannon) showed that the richness of communities increased significantly in the Lcs + AFB1 group compared to the control and AFB1 groups. Meanwhile, beta diversity indices demonstrated that AFB1 group significantly deviated from the control and Lcs + AFB1 groups. AFB1-exposed rats were especially high in Alloprevotella spp. abundance. Such alteration in the bacterial composition might give an insight on the interactions of AFB1 towards gut microbiota and how Lcs plays its role in detoxification of AFB1.

Oral Administration of Probiotic Lactobacillus Casei Shirota Decreases Pneumonia and Increases Pulmonary Functions after Single Rib Fracture: A Randomized Double-Blind, Placebo-Controlled Clinical Trial

Considerate proportion of elderly patients with a rib fracture is susceptible to pulmonary complications, especially pneumonia. We aimed to assess the effect of oral administration of the probiotic Lactobacillus casei Shirota (LcS) on pneumonia and pulmonary functions among elderly patients with single rib fracture. The current study including 204 eligible elderly patients with a single rib fracture was conducted. Patients were randomly assigned to receive oral administration of skimmed milk containing either a commercial probiotic LcS or placebo daily for 1 mo after the fracture, followed by pneumonia assessments, pulmonary function testing including forced expiratory volume (FEV), negative inspiratory pressure (NIP), and forced vital capacity (FVC), as well as evaluation of potential adverse effects including myocardial infarction, acute kidney injury, nonunion of fractured bone, or stroke. After 1 mo consumption, patients in the LcS group exhibited decreased pneumonia and increased recovery of pulmonary functions, in terms of FEV, FVC, and NIP, compared to the placebo group. No difference was observed in incidence of adverse events between the 2 groups. In patients with a single rib fracture, oral administration of the probiotic LcS was associated with a lower incidence of pneumonia and increased pulmonary functions without causing severe adverse effects.

PRACTICAL APPLICATION

To conclude, after 1-mo LcS consumption, in patients with a single rib fracture, oral administration of the probiotic LcS was associated with a lower incidence of pneumonia and increased pulmonary functions without causing severe adverse effects.

The Binding Efficiency and Interaction of Lactobacillus casei Shirota Toward Aflatoxin B1

The use of probiotic as dietary approach to prevent exposure to food contaminant, aflatoxin B1 (AFB1) has greatly increased. Several studies found that AFB1 binding to the bacterial cell wall is strain-specific. Moreover, the interaction between AFB1 and bacterial cell wall is not well-understood, thus warrants further investigation. This research was conducted to assess the ability of Lactobacillus casei Shirota (Lcs) to bind AFB1 at different concentrations and to determine AFB1 binding efficiency of different Lcs cell components including live cell, heat-treated, and cell wall. In addition, the interaction between AFB1 and Lcs was also evaluated via scanning electron microscopy (SEM) and through an animal study. The binding of AFB1 by all Lcs cell components depends on the concentration of available AFB1. Among all Lcs cell components, the live Lcs cells exhibited the highest binding efficiency (98%) toward AFB1. Besides, the SEM micrographs showed that AFB1 induced structural changes on the bacterial cell surface and morphology including rough and irregular surface along with a curve rod-shaped. In vivo experiment revealed that Lcs is capable to neutralize the toxicity of AFB1 on body weight and intestine through the binding process. The animal’s growth was stunted due to AFB1 exposure, however, such effect was significantly (p < 0.05) alleviated by Lcs. This phenomenon can be explained by a significant (p < 0.05) decreased level of blood serum AFB1 by Lcs (49.6 ± 8.05 ng/mL) compared to AFB1-exposed rats without treatment (88.12 ± 10.65 ng/mL). Taken together, this study highlights the potential use of Lcs as a preventive agent against aflatoxicosis via its strong binding capability.

Probiotic Lactobacillus casei Shirota improves efficacy of amoxicillin-sulbactam against childhood fast breathing pneumonia in a randomized placebo-controlled double blind clinical study

The aim of the present study was to investigate the efficacy of oral administration of probiotic Lactobacillus casei Shirota and amoxicillin-sulbactam in treating childhood fast breathing pneumonia. 518 children diagnosed of fast breathing pneumonia were enrolled and randomly assigned to be administered either amoxicillin-sulbactam + Lactobacillus casei Shirota or amoxicillin-sulbactam + placebo. Primary outcome was defined as treatment failure before day 3, and secondary outcome was defined as treatment failure during follow-ups on day 6 and 12. Serum levels of tumor necrosis factor-α and interferon-γ were also examined at the end of day 3. Treatment failure rate before day 3 was significantly reduced in amoxicillin-sulbactam + Lactobacillus casei Shirota group compared to amoxicillin-sulbactam + placebo group. Serum levels of tumor necrosis factor-α and interferon-γ were both significantly reduced in amoxicillin-sulbactam + placebo group on day 3. On day 6 and 12, although treatment failure rates were higher than on day 3 in both groups, it was still significantly reduced in amoxicillin-sulbactam + Lactobacillus casei Shirota group. No severe adverse effects were observed in either treatment group. In conclusion, Probiotic Lactobacillus casei Shirota, in combination with amoxicillin-sulbactam, is more effective in treating childhood fast breathing pneumonia, which supports the potential clinical application of Lactobacillus casei Shirota as a safe supplement to amoxicillin-sulbactam therapy against childhood fast breathing pneumonia.

Effects of Lactobacillus casei Shirota intake on caries risk in children

Background/purpose

Yakult is a well-known probiotic beverage consisting of a single live bacterial species, Lactobacillus casei Shirota. However, the potential cariogenic/cariostatic effects of Yakult intake among children have not been studied yet. Hence, this study aimed to investigate the clinical effects of short-term Yakult intake on oral biofilm acidogenicity, cariogenic bacterial counts, and caries risk in children.

Materials and methods

Eighteen children, 7–11 years of age, consumed standard Yakult daily for 7 days. Prior to and after intervention, functional oral biofilm acidogenicity characterized by the Stephan curve, Lactobacillus and Streptococcus mutans counts, and caries risk were determined.

Results

Probiotic intervention demonstrated significant increase in minimum pH from 4.88 to 5.14 (P = 0.02), 18.2% reduction in area under the Stephen curve [area under the curve (AUC)], and 29.3% decrease in pH recovery time, although these two differences were not statistically significant. No difference was observed in S. mutans and Lactobacillus counts or caries risk after intervention (all P > 0.05). However, on subgroup analysis using “reduction of AUC” to separate “responders” from the “nonresponders”, the significant cariostatic effects on oral biofilm acidogenicity, among “responders”, were revealed by an increase in minimum pH (P = 0.005) and a reduction in pH recovery time (P = 0.003).

Conclusion

There may be a potential cariostatic effect of short-term Yakult intake in reducing functional biofilm acidogenicity in children with certain oral biofilm and risk profile. Further studies may be needed to validate this probiotic effect. Quality risk assessment may be critical prior to prescribing/recommending Yakult as an adjunct caries-preventive treatment for children.

Valorisation of food waste via fungal hydrolysis and lactic acid fermentation with Lactobacillus casei Shirota

Food waste recycling via fungal hydrolysis and lactic acid (LA) fermentation has been investigated. Hydrolysates derived from mixed food waste and bakery waste were rich in glucose (80.0-100.2gL(-1)), fructose (7.6gL(-1)) and free amino nitrogen (947-1081mgL(-1)). In the fermentation with Lactobacillus casei Shirota, 94.0gL(-1) and 82.6gL(-1) of LA were produced with productivity of 2.61gL(-1)h(-1) and 2.50gL(-1)h(-1) for mixed food waste and bakery waste hydrolysate, respectively. The yield was 0.94gg(-1) for both hydrolysates. Similar results were obtained using food waste powder hydrolysate, in which 90.1gL(-1) of LA was produced with a yield and productivity of 0.92gg(-1) and 2.50gL(-1)h(-1). The results demonstrate the feasibility of an efficient bioconversion of food waste to LA and a decentralized approach of food waste recycling in urban area.

Effect of supplementation of fermented milk drink containing probiotic Lactobacillus casei Shirota on the concentrations of aflatoxin biomarkers among employees of Universiti Putra Malaysia: a randomised, double-blind, cross-over, placebo-controlled study

Human exposure to aflatoxin is through the diet, and probiotics are able to bind aflatoxin and prevent its absorption in the small intestine. This study aimed to determine the effectiveness of a fermented milk drink containing Lactobacillus casei Shirota (LcS) (probiotic drink) to prevent aflatoxin absorption and reduce serum aflatoxin B1-lysine adduct (AFB1-lys) and urinary aflatoxin M1 concentrations. The present study was a randomised, double-blind, cross-over, placebo-controlled study with two 4-week intervention phases. In all, seventy-one subjects recruited from the screening stage were divided into two groups--the Yellow group and the Blue group. In the 1st phase, one group received probiotic drinks twice a day and the other group received placebo drinks. Blood and urine samples were collected at baseline, 2nd and 4th week of the intervention. After a 2-week wash-out period, the treatments were switched between the groups, and blood and urine samples were collected at the 6th, 8th and 10th week (2nd phase) of the intervention. No significant differences in aflatoxin biomarker concentrations were observed during the intervention. A within-group analysis was further carried out. Aflatoxin biomarker concentrations were not significantly different in the Yellow group. Nevertheless, ANOVA for repeated measurements indicated that AFB1-lys concentrations were significantly different (P=0·035) with the probiotic intervention in the Blue group. The 2nd week AFB1-lys concentrations (5·14 (SD 2·15) pg/mg albumin (ALB)) were significantly reduced (P=0·048) compared with the baseline (6·24 (SD 3·42) pg/mg ALB). Besides, the 4th week AFB1-lys concentrations were significantly lower (P<0·05) with probiotic supplementation than with the placebo. Based on these findings, a longer intervention study is warranted to investigate the effects of continuous LcS consumption to prevent dietary aflatoxin exposure.

Effect of Probiotic Supplement on Cytokine Levels in HIV-Infected Individuals: A Preliminary Study

Inflammation persists in patients infected with HIV. Reduction of inflammatory cytokines and microbial translocation might be one way that this could be managed. Purpose: The anti-inflammatory properties of certain probiotic strains prompted us to investigate whether a probiotic could reduce the inflammatory index of HIV-infected patients. Methods: The study involved 30 HIV+ males on antiretroviral therapy, who were given one bottle of fermented milk Yakult Light^® containing Lactobacillus casei Shirota (LcS) twice a day for four weeks. Results: The probiotic LcS was associated with an increase of T lymphocytes and a significant increase of CD56+ cells (p = 0.04). There was also a significant decrease of mRNA levels of TGFβ, IL-10 and IL-12 (p < 0.001) and IL-1β expression (p < 0.001) and an increase of serum IL-23 (p = 0.03). In addition, decreased inflammation and cardiovascular risk were observed, as shown by a reduction of cystatin C (p < 0.001). Conclusions: These data provide preliminary evidence that probiotic supplementation may modulate certain immunological parameters and some of the cytokines that were analyzed. Thus, we propose that LcS may be an inexpensive and practical strategy to support the immune function of HIV+ patients.

Evaluation of probiotic milk on salivary mutans streptococci count: an in vivo microbiological study

OBJECTIVE

The objective of the present study was to investigate the effect of probiotic Lactobacillus casei Shirota on the values of mutans streptococci counts in saliva.

STUDY DESIGN

31 children were included in this double blinded study. Study design included 4 periods which consisted of a run in period, two intervention periods and a washout period. During the intervention periods children were either given probiotic milk or control milk for 10 days. Pre and post intervention salivary samples were subjected to microbiological evaluation. Then numbers of mutans streptococci were taken by identifying colony morphology.

RESULTS

A statistically significant reduction of mutans streptococci colony count was noted in the probiotic group (p=.003). The reduction in children with higher levels of mutans streptococci (105) after intervention was 34% in the probiotic group.

CONCLUSION

Daily consumption of milk containing probiotic bacteria can reduce the levels of mutans streptococci and may contribute to the prevention of dental caries.

The effect of a commercial probiotic drink containing Lactobacillus casei strain Shirota on oral health in healthy dentate people

BACKGROUND

In the past decade, the use of probiotic-containing products has been explored as a potential alternative in oral health therapy. A widely available probiotic drink, Yakult, was evaluated for oral health applications in this longitudinal study. Selected oral health parameters, such as levels and composition of salivary and tongue plaque microbiota and of malodorous gases, in dentate healthy individuals were investigated for changes. The persistence of the probiotic strain in the oral cavity was monitored throughout the study period.

METHODS

A three-phase study (7 weeks) was designed to investigate simultaneously the effect of 4-week consumption of the probiotic-containing milk drink Yakult on the microbiota of saliva and dorsum tongue coating in healthy dentate people (n = 22) and levels of volatile sulphur compounds (VSCs) in morning breath. Study phases comprised one baseline visit, at which 'control' levels of oral parameters were obtained prior to the probiotic product consumption; a 4-week period of daily consumption of one 65 ml bottle of Yakult, each bottle containing a minimum of 6.5×10(9) viable cells of Lactobacillus casei strain Shirota (LcS); and a 2-week washout period. The microbial viability and composition of saliva and tongue dorsum coating were assessed using a range of solid media. The presence of LcS in the oral cavity was investigated using a novel selective medium, 'LcS Select'. Portable sulphur monitors Halimeter(®) and OralChroma(TM) were used to measure levels of VSCs in morning breath.

RESULTS

Utilization of the LcS Select medium revealed a significant (p < 0.05) but temporary and consumption-dependent presence of LcS in saliva and tongue plaque samples from healthy dentate individuals (n = 19) during the probiotic intervention phase. LcS was undetectable with culture after 2 weeks of ceasing its consumption. Morning breath scores measured with Halimeter and OralChroma were not significantly affected throughout the trial, except in a small number of individual cases where Halimeter scores were significantly reduced during the probiotic intervention period. Natural fluctuations in resident acidogenic populations, and numbers of Candida and anaerobic species, including malodourous Gram-negative anaerobes, were unaffected.

CONCLUSION

While no broad ecological changes in the mouth were induced by consumption of Yakult in healthy dentate individuals, findings of this study confirm the temporary and intake-dependent presence of LcS. Future studies could focus on subjects at greater risk of oral infection, where ill-defined microbiota (e.g. an increased presence of periopathogens) or clinically diagnosed halitosis might be significantly affected by consumption of this probiotic.

Probiotic Beverage with Soy Isoflavone Consumption for Breast Cancer Prevention: A Case-control Study

The purpose of this study is to evaluate how beverages containing Lactobacillus casei Shirota (BLS) and soy isoflavone consumption since adolescence affected the incidence of breast cancer. In a population-based case-control study, three hundred and six cases with breast cancer and 662 controls aged 40 to 55 were matched for age and residential area and included in the analyses. Diet, lifestyle and other breast cancer risk factors were investigated using the self-administered questionnaire and interview. Odds ratios (ORs) of BLS and soy isoflavone consumption for breast cancer incidence were independently and jointly estimated using a conditional logistic regression. The ORs of BLS consumption (≥ four times a week against < four times a week) was 0.65 and statistically significant (p = 0.048). The analysis of association between soy consumption and breast cancer incidence showed the more the isoflavone consumption is, the lower the odds of breast cancer becomes. Adjusted ORs for breast cancer in the second, the third and the fourth quartiles of soy consumption against the first quartile were 0.76, 0.53 and 0.48, respectively (trend test, p = 0.0002). The BLS-isoflavone interaction was not statistically significant; however, a biological interaction was suggested. Regular consumption of BLS and isoflavones since adolescence was inversely associated with the incidence of breast cancer in Japanese women.

The effect of a commercial probiotic drink on oral microbiota in healthy complete denture wearers

Background

It is acknowledged that oral and general health status declines with age. The global population of denture wearers is increasing, so is the incidence of denture biofilm-related problems, such as denture-associated stomatitis, aspiration pneumonia and malodour. It has been suggested that consumption of probiotic bacteria may improve oral health. However, the effects of probiotics on the oral microbiota of denture wearers have received little attention.

Methods

The aim of this study was to investigate the effect of consumption of a commercial probiotic product (Yakult) on microbiota of saliva, tongue and denture biofilm in healthy complete denture wearers. Eight healthy complete denture-wearing National Health Service (NHS) patients undertook a 7-week trial comprising three phases: baseline; 4-week consumption of one bottle of Yakult per day, each containing a minimum 6.5×10⁹ viable cells of Lactobacillus casei strain Shirota (LcS); 4-week washout period. The microbial viability and composition of saliva, tongue dorsum coating and denture biofilm were assessed using a range of solid selective and indicator media. Questionnaires were used to explore participants’ denture cleaning habits and impact of wearing dentures on their life quality and well-being [modified oral health impact profile (OHIP-14)] prior to and after the study.

Results

Seven volunteers (1 male, 6 females) completed the trial. LcS temporarily colonised oral cavity and denture surface. There was no significant change in the viability of Streptococcus mutans, acidogenic microorganisms, total anaerobic species and Gram-negative obligate anaerobes between study phases. There was no obvious effect of LcS on occurrence and viability of Candida. Participants presented a good general knowledge of denture hygiene and their responses to OHIP-14 questionnaires improved after completing the study (p=0.16).

Conclusion

It appeared that 4-week consumption of probiotic drink had no overall effect on selected oral parameters in healthy denture wearers despite temporary presence of LcS.