Salivary IgA response to probiotic bacteria and mutans streptococci after the use of chewing gum containing Lactobacillus reuteri

Intake of probiotics as an option for reducing oral and prosthetic microbiota: A clinical study

STATEMENT OF PROBLEM

The accumulation of microorganisms on complete dentures has adverse effects on general health. Precautions should be taken to prevent colonization by these harmful pathogens, but whether an intake of probiotics effectively reduces microbiota is unclear.

PURPOSE

The purpose of this clinical study was to examine the effectiveness of probiotics against the microbial colonization of dentures and the oral regions.

MATERIAL AND METHODS

Sixty-one edentulous participants with dentures were recruited, and samples were collected from the palate, cheek, tongue, and denture surface using sterile erasers before and after applying probiotics containing Lactobacillus acidophilus, Lactobacillus rhamnosus, Lactobacillus casei, and Bifidobacterium bifidum. The count of bacterial species in the original culture was calculated by multiplying the number of colonies by the dilution factor of cells per mL [log10 (CFU/mL)] for different media. Spread plating was used to colonize in vitro. A Wilcoxon test was used to compare the groups according to time reveal. Kruskal-Wallis and Mann-Whitney U tests were performed to compare the values in the various regions studied (α=.05).

RESULTS

A statistical difference in microbial count was found before and after probiotic intake (P<.05). For each medium, the microbial count values were statistically lower on the tongue, palate, dentures, and cheek after probiotic intake (P<.05), except for in malt medium on dentures (P>.05).

CONCLUSIONS

Probiotics reduced the microbial count in the oral region and showed promising results for oral health and denture hygiene. Since the oral microbiota has among the highest levels of species diversity in the human body, further studies are needed.

Lactobacilli and Klebsiella: Two Opposites in the Fight for Human Health

The problem of antibiotic resistance is currently very acute. Numerous research and development of new antibacterial drugs are being carried out that could help cope with various infectious agents. One of the promising directions for the search for new antibacterial drugs is the search among the probiotic strains present in the human gastrointestinal tract. This review is devoted to characteristics of one of these probiotic strains that have been studied to date: Limosilactobacillus reuteri. The review discusses its properties, synthesis of various compounds, as well as role of this strain in modulating various systems of the human body. The review also examines key characteristics of one of the most harmful among the currently known pathogenic organisms, Klebsiella, which is significantly resistant to antibiotics existing in medical practice, and also poses a great threat of nosocomial infections. Discussion of characteristics of the two strains, which have opposite effects on human health, may help in creation of new effective antibacterial drugs without significant side effects.

Lactiplantibacillus Plantarum CCFM8724 Reduces the Amounts of Oral Pathogens and Alters the Oral Microbiota in Children With Dental Caries: a Randomized, Double-Blind, Placebo-Controlled Trial

Objective Early childhood caries (ECC) is closely related to the disorders of oral microbiota. Probiotics antagonize pathogenic bacteria and regulate the composition of the microbiota. We aimed to investigate the effects of Lactiplantibacillus plantarum CCFM8724 on Streptococcus mutans, Candida albicans, and oral microbiota of patients.Methods Children with ECC aged 3‒6 years were randomly divided into probiotic and placebo groups in the double-blind controlled trial. The intervention and washout periods were 28 days and 14 days, respectively. On days 1 and 28, dental plaques were collected. The effects of L. plantarum CCFM8724 on the oral microbiota of patients were investigated by sequencing the V3-V4 region of 16S rDNA. On days 1, 14, 28 and 42, qPCR was used to investigate the effect of L. plantarum CCFM8724 on the amounts of S. mutans and C. albicans in the saliva of children with ECC.Results L. plantarum CCFM8724 significantly reduced the amounts of S. mutans and C. albicans in saliva of children with ECC (p < 0.01). After consumption of L. plantarum CCFM8724, the abundance of Firmicutes, Granulicatella and Gemella increased, whereas the abundance of Proteobacteria, Neisseria, Bifidobacterium and Catonella decreased. Conclusion: Our results emphasize that probiotics could play a beneficial role in the prevention and treatment of ECC in children from an oral microecological perspective.

Diverse impact of a probiotic strain, Lacticaseibacillus paracasei Shirota, on peripheral mononuclear phagocytic cells in healthy Japanese office workers: a randomized, double-blind, controlled trial

Mononuclear phagocytic cells (MPCs) are classified into monocytes (Mos)/macrophages and dendritic cells (DCs) based on their functions. Cells of MPCs lineage act as immune modulators by affecting effector cells, such as NK cells, T cells, and B cells. This study aimed to investigate the effects of Lacticaseibacillus paracasei strain Shirota (LcS) ingestion on peripheral MPCs, particularly on their expression of functional cell-surface molecules enhanced in healthy adults. Thus, twelve healthy office workers consumed a fermented milk drink containing 1.0 × 10¹¹ cfu of LcS (LcS-FM) or a control unfermented milk drink (CM) once a day for 6 weeks. Peripheral blood mononuclear cells (PBMCs) were prepared from blood samples, and immune cells and functional cell-surface molecules were analyzed. We observed remarkable differences in the expression of HLAABC, MICA, CD40, and GPR43 in plasmacytoid DCs (pDCs) between the LcS-FM and CM groups, whereas no difference was found in CD86 or HLADR expression. The LcS-FM group exhibited higher CD40 expression in both conventional DCs (cDCs) and Mos, especially in type 2 conventional DCs (cDC2s) and classical monocytes (cMos); higher percentages of cMos, intermediate monocytes (iMos), and nonclassical monocytes; and higher numbers of cMos and iMos in PBMCs than the CM group. LcS ingestion increased the expression of HLAABC, MICA, CD40, and GPR43 in pDCs and CD40 in cDCs and Mos, particularly cDC2s and cMos. These results suggest that LcS modulates the function of MPCs that may lead to the regulation of immune effector functions in healthy adults.

The Effect of Oral Probiotics (Streptococcus Salivarius k12) on the Salivary Level of Secretory Immunoglobulin A, Salivation Rate, and Oral Biofilm: A Pilot Randomized Clinical Trial

We aimed to assess the effect of oral probiotics containing the Streptococcus salivarius K12 strain on the salivary level of secretory immunoglobulin A, salivation rate, and oral biofilm. Thirty-one consenting patients meeting the inclusion criteria were recruited in this double-blind, placebo-controlled, two-arm, parallel-group study and randomly divided into probiotic (n = 15) and placebo (n = 16) groups. Unstimulated salivation rate, concentration of salivary secretory immunoglobulin A, Turesky index, and Papillary-Marginal-Attached index were assessed after 4 weeks of intervention and 2 weeks of washout. Thirty patients completed the entire study protocol. We found no increase in salivary secretory immunoglobulin A levels and salivary flow rates in the probiotic group compared with placebo. Baseline and outcome salivary secretory immunoglobulin A concentrations (mg/L) were 226 ± 130 and 200 ± 113 for the probiotic group and 205 ± 92 and 191 ± 97 for the placebo group, respectively. A significant decrease in plaque accumulation was observed in the probiotic group at 4 and 6 weeks. Within the limitations of the present study, it may be concluded that probiotic intake (Streptococcus salivarius K12) does not affect salivation rates and secretory immunoglobulin A salivary levels but exhibits a positive effect on plaque accumulation. Trial registration NCT05039320. Funding: none.

Viable and Heat-Killed Probiotic Strains Improve Oral Immunity by Elevating the IgA Concentration in the Oral Mucosa

Oral-nasal mucosal immunity plays a crucial role in protecting the body against bacterial and viral invasion. Safe probiotic products have been used to enhance human immunity and oral health. In this study, we verified the beneficial effects of mixed viable probiotic tablets, consisting of Lactobacillus salivarius subsp. salicinius AP-32, Bifidobacterium animalis subsp. lactis CP-9, and Lactobacillus paracasei ET-66, and heat-killed probiotic tablets, consisting of L. salivarius subsp. salicinius AP-32 and L. paracasei ET-66, on oral immunity among 45 healthy participants. Participants were randomly divided into viable probiotic, heat-killed probiotic, and placebo groups. The administration of treatment lasted for 4 weeks. Saliva samples were collected at Weeks 0, 2, 4, and 6, and Lactobacillus, Bifidobacterium and Streptococcus mutans populations and IgA concentration were measured. IgA concentrations, levels of TGF-beta and IL-10 in PBMCs cells were quantified by ELISA method. Results showed that salivary IgA levels were significantly increased on administration of both the viable (119.30 ± 12.63%, ***P < 0.001) and heat-killed (116.78 ± 12.28%, ***P < 0.001) probiotics for 4 weeks. Among three probiotic strains, AP-32 would effectively increase the levels of TGF-beta and IL-10 in PBMCs. The oral pathogen Streptococcus mutans was significantly reduced on viable probiotic tablet administration (49.60 ± 31.01%, ***P < 0.001). The in vitro antibacterial test confirmed that viable probiotics effectively limited the survival rate of oral pathogens. Thus, this clinical pilot study demonstrated that oral probiotic tablets both in viable form or heat-killed form could exert beneficial effects on oral immunity via IL-10, TGB-beta mediated IgA secretion. The effective dosage of viable probiotic content in the oral tablet was 10⁹ CFUs/g and the heat-killed oral tablet was 1 × 10¹⁰ cells/g.

Antagonistic effect of isolated and commercially available probiotics on the growth of Candida albicans on acrylic resin denture surfaces

STATEMENT OF PROBLEM

Biofilms can be retained on dental prostheses leading to the development of infections. The indiscriminate use of antifungal drugs can result in the development of microorganisms that are resistant to these antimicrobial agents. Whether probiotics are a suitable alternative for reducing the prevalence of oral candidiasis is unclear.

PURPOSE

The purpose of this in vitro study was to evaluate the influence of 6 different live strains of probiotics and 2 commercially available probiotic supplements used for inhibiting the growth of Candida albicans biofilm in heat-polymerized acrylic resin denture base material and to determine whether biofilm byproducts modify the surface of specimens.

MATERIAL AND METHODS

Biofilms of C. albicans were formed on acrylic resin specimens in the presence of probiotics and quantified by colony-forming units (CFUs), and the surface roughness (Ra) of the specimens was assessed before and after the formation of biofilms. The CFU and roughness data were analyzed by analysis of variance and the Tukey HSD test (α=.05).

RESULTS

A significant decrease in the number (CFU/mL) of C. albicans cells was found when they were cultured with 4 probiotics: B. lactis (P=.045), B. longum (P<.001), L. casei (P<.001), and L. helveticus (P<.001) and with the commercially available probiotic Prolive (P=.05). The Ra of specimens decreased after exposure to different microbial biofilms (P≤.05) except in 3 experimental groups.

CONCLUSIONS

In general, the tested probiotics had an antagonistic effect on the growth of C. albicans, and the surface of acrylic resin was altered after exposure to biofilm byproducts.

Effects of probiotics on salivary cytokines and immunoglobulines: a systematic review and meta-analysis on clinical trials

Findings on the effects of probiotics on salivary cytokines and immunoglobulines have been conflicting. We aimed to perform a systematic review and meta-analysis on clinical trials that examined the effects of oral intake and local administration of probiotics on salivary cytokines and immunoglobulines in adults. We searched PubMed, MEDLINE, SCOPUS, EMBASE, and Google Scholar up to April 2020 for all relevant published papers assessing probiotic intakes and salivary cytokines and immunoglobulines. We included all randomized clinical trials that investigated the effect of oral probiotic supplementation or lozenges tablets on inflammatory biomarkers in adults. Studies that reported their effect sizes as mean ± SD or mean ± SEM were included. After excluding non-relevant papers, 8 studies remained in this review. Combining findings from 3 studies with 4 effect sizes, we found no significant reduction in salivary IgA concentrations after oral probiotic supplementation [weighted mean difference (WMD): -0.26; 95% CI: (-0.86, 0.35)]. A significant increase in salivary IL-1β concentrations reached after local probiotic supplementation (WMD: 28.21; 95% CI: 18.42, 38.01); however, no significant changes in salivary IL-6 concentrations after local probiotic supplementation was found (WMD: 0.36; 95% CI: -0.85, 1.56). We observed a significant increase in salivary IL-8 concentrations after local probiotic supplementation (WMD: 31.82; 95% CI: 27.56, 36.08). In case of salivary IL-10 concentrations after local probiotic administration, no significant reduction was seen (WMD: -0.02; 95% CI: -0.10, 0.06). we found that oral and local administrations of probiotics might influence some of salivary cytokines. However, additional clinical trials are required to examine these effects on further pro- and anti-inflammatory cytokines and immunoglobulines.

Effect of Lactobacillus reuteri on Cell Viability and PGE2 Production in Human Gingival Fibroblasts

Emerging evidence suggests that probiotic therapy can play a role in the prevention and management of oral inflammatory diseases through immunomodulation and down-regulation of the inflammatory cascade. The aim of this in vitro study was to investigate the viability of human gingival fibroblasts (HGF) and its production of prostaglandin E₂ (PGE₂), when exposed to supernatants of two mixed Lactobacillus reuteri strains (ATCC PTA 5289 and DSM 17938). The experiments were conducted in the presence and absence of the pro-inflammatory cytokine IL-1β. L. reuteri strains were grown and the bacterial supernatant was collected. The cell-free supernatant was diluted to concentrations equivalent to the ones produced by 0.5 to 5.0 × 10⁷ CFU/mL bacteria. Cell viability was assessed with the MTT colorimetric assay and the amount of PGE₂ in the cell culture medium was determined using the monoclonal enzyme immune assay kits. Our findings showed that none of the L. reuteri supernatants were cytotoxic or affected the viability of HGF. The most concentrated bacterial supernatant stimulated the production of PGE₂ by the gingival cells in a significant way in the presence of IL-1β (p < 0.05), suggesting that bacterial products secreted from L. reuteri might play a role in the resolution of inflammation in HGF. Thus, our findings justify further investigations on the influence of probiotic bacteria on gingival inflammatory reactions.

Role of Lactobacillus reuteri in Human Health and Diseases

Lactobacillus reuteri (L. reuteri) is a well-studied probiotic bacterium that can colonize a large number of mammals. In humans, L. reuteri is found in different body sites, including the gastrointestinal tract, urinary tract, skin, and breast milk. The abundance of L. reuteri varies among different individuals. Several beneficial effects of L. reuteri have been noted. First, L. reuteri can produce antimicrobial molecules, such as organic acids, ethanol, and reuterin. Due to its antimicrobial activity, L. reuteri is able to inhibit the colonization of pathogenic microbes and remodel the commensal microbiota composition in the host. Second, L. reuteri can benefit the host immune system. For instance, some L. reuteri strains can reduce the production of pro-inflammatory cytokines while promoting regulatory T cell development and function. Third, bearing the ability to strengthen the intestinal barrier, the colonization of L. reuteri may decrease the microbial translocation from the gut lumen to the tissues. Microbial translocation across the intestinal epithelium has been hypothesized as an initiator of inflammation. Therefore, inflammatory diseases, including those located in the gut as well as in remote tissues, may be ameliorated by increasing the colonization of L. reuteri. Notably, the decrease in the abundance of L. reuteri in humans in the past decades is correlated with an increase in the incidences of inflammatory diseases over the same period of time. Direct supplementation or prebiotic modulation of L. reuteri may be an attractive preventive and/or therapeutic avenue against inflammatory diseases.

Presence of Lactobacillus reuteri in saliva coincide with higher salivary IgA in young adults after intake of probiotic lozenges

The aim of this study was to compare the concentration of salivary immunoglobulin A (IgA) and the selected interleukins (IL)-1β, IL-6, IL-8 and IL-10 in young individuals with presence and non-presence of Lactobacillus reuteri in saliva after a three-week intervention with probiotic lozenges. The study group consisted of 47 healthy individuals aged 18-32 years with no clinical signs of oral inflammation. In a randomised, double-blind, placebo-controlled, cross-over trial participants ingested two lozenges per day containing two strains of the probiotic bacterium L. reuteri or placebo lozenges. The intervention and wash-out periods were three weeks. Stimulated and unstimulated whole saliva was collected at baseline and immediately after termination of the intervention periods. The samples were analysed for total protein, salivary IgA and selected cytokines. In this extended analysis, data were collected by analysing baseline and follow-up saliva samples related to ingestion of the probiotic lozenges for the presence of L. reuteri through DNA-extraction, PCR-amplification and gel-electrophoresis. At baseline, 27% of the individuals displayed presence of L. reuteri and 42% were positive immediately after the three-week probiotic intervention. Individuals with presence of L. reuteri in saliva had significantly higher (P<0.05) concentrations of salivary IgA and %IgA/protein at the termination of the probiotic intake compared with non-presence. No differences in the cytokine levels were observed. In conclusion, detectable levels of L. reuteri in saliva coincided with higher concentrations of salivary IgA and %IgA/protein in stimulated whole saliva after the three-week daily intake of probiotic lozenges. Our findings suggest that monitoring the presence of probiotic candidates in the oral environment is important to interpret and understand their possible immune-modulating role in maintaining oral health.

Lactobacillus reuteri supplements do not affect salivary IgA or cytokine levels in healthy subjects: A randomized, double-blind, placebo-controlled, cross-over trial

OBJECTIVES

To evaluate the effect of daily ingestion of probiotic lactobacilli on the levels of secretory IgA (sIgA) and selected cytokines in whole saliva of healthy young adults.

MATERIALS AND METHODS

The study group consisted of 47 healthy adults (18-32 years) who volunteered for a randomized, double-blind, placebo-controlled, cross-over trial after informed consent. During intervention, the subjects ingested two lozenges per day containing two strains of the probiotic bacterium Lactobacillus reuteri (DSM 17938 and ATCC PTA 5289) or placebo lozenges. The intervention and wash-out periods were 3 weeks. Saliva samples were collected at baseline, immediately after each intervention period and 3 weeks post-intervention. ELISA was used to measure sIgA and luminex technology was used to measure the interleukins (IL)-1β, IL-6, IL-8 and IL-10. For statistical analyses a mixed ANOVA model was employed to calculate changes in the salivary outcome variables.

RESULTS

Forty-one subjects completed the study and reported a good compliance. No significant differences in the concentrations of salivary sIgA or cytokines were recorded between the L. reuteri and placebo interventions or between baseline and 3 weeks post-intervention levels. No side- or adverse effects were reported.

CONCLUSIONS

Supplementation with two strains of the probiotic L. reuteri did not affect sIgA or cytokine levels in whole saliva in healthy young adults. The results thereby indicate that daily oral supplementation with L. reuteri do not seem to modulate the salivary oral immune response in healthy young subjects (ClinicalTrials.gov NCT02017886).

Bifidobacteria inhibit the growth of Porphyromonas gingivalis but not of Streptococcus mutans in an in vitro biofilm model

There is growing interest in the use of probiotic bifidobacteria for enhancement of the therapy, and in the prevention, of oral microbial diseases. However, the results of clinical studies assessing the effects of bifidobacteria on the oral microbiota are controversial, and the mechanisms of actions of probiotics in the oral cavity remain largely unknown. In addition, very little is known about the role of commensal bifidobacteria in oral health. Our aim was to study the integration of the probiotic Bifidobacterium animalis subsp. lactis Bb12 and of oral Bifidobacterium dentium and Bifidobacterium longum isolates in supragingival and subgingival biofilm models and their effects on other bacteria in biofilms in vitro using two different in vitro biofilms and agar-overlay assays. All bifidobacteria integrated well into the subgingival biofilms composed of Porphyromonas gingivalis, Actinomyces naeslundii, and Fusobacterium nucleatum and decreased significantly only the number of P. gingivalis in the biofilms. The integration of bifidobacteria into the supragingival biofilms containing Streptococcus mutans and A. naeslundii was less efficient, and bifidobacteria did not affect the number of S. mutans in biofilms. Therefore, our results suggest that bifidobacteria may have a positive effect on subgingival biofilm and thereby potential in enhancing gingival health; however, their effect on supragingival biofilm may be limited.

Effect of Probiotic Bacteria on Oral Candida in Frail Elderly

The aim of this study was to investigate the effect of a daily intake of probiotic lactobacilli on the prevalence and counts of oral Candida in frail elderly patients living in nursing homes. The study had a double-blind randomized placebo-controlled design with 2 parallel arms. The study group consisted of 215 older adults (range, 60 to 102 y) who were enrolled after informed consent. After baseline examination and randomization, the subjects were given 1 lozenge containing 2 strains of the probiotic bacterium Lactobacillus reuteri (DSM 17938 and ATCC PTA 5289) or placebo twice daily (morning and evening). The intervention period was 12 wk, and saliva and plaque samples were collected at baseline and follow-up. The primary end point was prevalence of high Candida counts assessed from chairside tests. Secondary end points were levels of dental plaque and gingival inflammation. The groups were balanced at baseline. The attrition rate to follow-up was 19%. There was a statistically significant reduction in the prevalence of high Candida counts in the probiotic group but not in the placebo group, and the difference was statistically significant in both saliva and plaque (P < 0.05). No significant differences between the groups were noted concerning the levels of supragingival plaque or bleeding on probing. Thus, daily use of probiotic lozenges may reduce the prevalence of high oral Candida counts in frail elderly nursing homes residents (ClinicalTrials.gov NCT02391532).

Enhancement of salivary human neutrophil peptide 1-3 levels by probiotic supplementation

Background

Probiotic supplementation can reduce mutans streptococci (MS) numbers. One of its proposed mechanisms is immunomodulation. Salivary human neutrophil peptide 1–3 (HNP1-3) levels have previously been demonstrated to be higher in caries-free than in caries-susceptible children, suggesting their preventive role against caries. We aimed to compare salivary HNP1-3 levels between an intervention group with probiotics and a control group.

Methods

A randomized double-blinded clinical trial was conducted. Sixty schoolchildren were equally allocated to either an intervention or control group. The use of a probiotic strain, Lactobacillus paracasei SD1, has shown to reduce MS numbers in volunteers. In unstimulated whole saliva, HNP1-3 levels were assayed by ELISA, and MS and lactobacilli counts were assayed by colony counting at baseline (T0) and at 3 (T3), 6 (T6), and 12 months (T12). The International Caries Detection and Assessment system was used to assess caries status.

Results

In the intervention group, salivary HNP1-3 levels were significantly greater than those in the control group at T3 and T6 (p < 0.001), whereas MS counts were significantly decreased (p < 0.01). In the intervention group, positive and negative correlations were found between HNP1-3 levels and lactobacilli counts and between MS and lactobacilli counts, respectively. However, there was no significant correlation between enhanced HNP1-3 levels and decreased MS numbers. The caries increment for the pit and fissure surface, but not for the smooth surfaces, was significantly decreased in the intervention group compared with the control group (p = 0.01).

Conclusions

Probiotics can temporarily enhance salivary HNP1-3 levels; however, their action to reduce new pit and fissure caries probably involves microbial interactions.

Trial registration

TCTR20130904001 (registration date: September 04, 2013).

Electronic supplementary material

The online version of this article (doi:10.1186/s12903-015-0003-0) contains supplementary material, which is available to authorized users.

The early administration of Lactobacillus reuteri DSM 17938 controls regurgitation episodes in full-term breastfed infants

Forty breastfed full-term infants were randomly, double blind assigned to receive orally Lactobacillus reuteri (L. reuteri) DSM 17938, 5 drops/daily (10(8) colony-forming units), for 4 weeks (n = 20) or an identical placebo (n = 20), starting before third day of life. They underwent basal and final visit to monitor growth parameters and gastrointestinal (GI) disease. Parents registered daily: crying minutes, stool frequency and consistency, numbers of regurgitations, adverse events. Secretory IgA (sIgA) has been measured in saliva on 28th day. Treated infants demonstrated a reduction in daily regurgitations at the end of treatment (p = 0.02), three neonates in the placebo group only needed simethicone for GI pain, sIgA level was similar in both groups. Random casualty produced an unbalanced gender distribution in the groups, but this bias did not affect the results. Therefore, early administration of L. reuteri DSM 17938 resulted beneficial in preventing regurgitation episodes during the first month of life.