Enhanced clearance of Candida albicans from the oral cavities of mice following oral administration of Lactobacillus acidophilus

Vaginal microbiota: Potential targets for vulvovaginal candidiasis infection

Vulvovaginal candidiasis (VVC) is the second most common cause of vaginal infection globally after bacterial vaginosis (BV) and associated with adverse reproductive and obstetric outcomes, including preterm delivery, sexually transmitted infections and pelvic inflammatory disease. Although effective control of VVC is achievable with the use of traditional treatment strategies (i.e., antifungals), the possibility of drug intolerance, treatment failure and recurrence, as well as the appearance of antifungal-resistant Candida species remain critical challenges. Therefore, alternative therapeutic strategies against VVC are urgently required. In recent years, an improved understanding of the dysbiotic vaginal microbiota (VMB) during VVC has prompted the consideration of administering -biotics to restore the balance of the VMB within the context of VVC prevention and treatment. Here, we aim to summarize the current evidence of the anti-Candida effects of probiotics, postbiotics and synbiotics and their potential use as an alternative/complementary therapy against VVC. Additionally, this review discusses advantages and challenges associated with the application of -biotics in VVC to provide guidance for their later use. We also review new developments in VVC therapy, i.e., vaginal microbiota transplantation (VMT) as an emerging live biotherapeutic therapy against VVC and discuss existing shortcomings associated with this nascent field, expecting to stimulate further investigations for introduction of new therapies against VVC.

A Denture Use Model Associated with Candida spp. in Immunocompetent Male and Female Rats

Denture stomatitis (DS) is a common infection in denture wearers, especially women. This study evaluated the induction of DS using acrylic devices attached to the palate of rats combined with inoculation of Candida spp. Immunocompetent male and female rats received a carbohydrate-rich diet. Impressions were taken from the rats’ palate to individually fabricate acrylic devices. Mono- and multispecies biofilms of C. albicans, C. glabrata, and C. tropicalis were grown on the devices, which were then cemented on posterior teeth and kept in the rats’ palate for four weeks. Microbial samples from the palate and the device were quantified. Oral microbiome of rats inoculated with C. albicans was analyzed by 16S rRNA gene sequencing. Log10(CFU/mL) were analyzed by mixed or two-way MANOVA (α = 0.05). Candida spp. and acrylic device did not induce palatal inflammation macroscopically nor microscopically. Although there was an increase (p < 0.001) of the total microbiota and female rats demonstrated higher (p = 0.007) recovery of Candida spp. from the palate, the gender differences were not biologically relevant. The microbiome results indicate an increase in inflammatory microbiota and reduction in health-associated micro-organisms. Although Candida spp. and acrylic device did not induce DS in immunocompetent rats, the shift in microbiota may precede manifestation of inflammation.

Effectiveness of Oral Probiotics in Reducing S. Mutans Count in Caries-active Children: A Comparison with Chlorhexidine and Herbal Mouthrinse (Hiora®)

Aim

The purpose of this study was to compare the reduction in salivary mutans streptococci counts and to evaluate any change in the salivary pH values after the use of oral probiotics, chlorhexidine, and herbal mouthrinse.

Method

Oral probiotics, chlorhexidine, and herbal mouthrinse [Hiora^®] were evaluated for their efficacy against S. mutans in 75 caries-active children, aged 6-14 years.

Results

The values obtained were subjected to statistical analysis. Oral probiotics showed lesser reduction in the S. mutans count as compared to chlorhexidine but the values were statistically insignificant. Herbal mouthrinse was not as effective as the oral probiotics or chlorhexidine in reducing the S. mutans count.

Conclusion

Oral probiotics show a similar efficacy as the gold standard, chlorhexidine, in reduction of oral S. mutans.

How to cite this article

Kamble A, Jabin Z, Agarwal N, et al. Effectiveness of Oral Probiotics in Reducing S. Mutans Count in Caries-active Children: A Comparison with Chlorhexidine and Herbal Mouth-rinse (Hiora®). Int J Clin Pediatr Dent 2022;15(S-2):S207-S211.

Effect of the local probiotics in the therapy of periodontitis A randomized prospective study

OBJECTIVES

The use of local probiotics in the therapy of periodontitis is reflected in their ability to antagonize periodontopathogens and modulates the immune response of the host to the presence of pathogenic microorganisms. The aim of this study was to investigate the use of local probiotics in the treatment of periodontitis as an adjunctive therapy to scaling and root planning (SRP).

METHODS

The study involved 80 patients diagnosed with periodontitis. All participants underwent SRP therapy. Semi-solid probiotic was then locally applied to the periodontal pocket in randomly selected patients for the test group (40 of them). The other 40 patients were in the control group. Clinical parameters including periodontal pocket depth (PPD), bleeding on probing (BOP) and plaque index (PI) were measured at baseline, and at 7 and 30 days after treatment.

RESULTS

Seven days after the applied therapy in the test and control group, there was a significant decrease in the values or BOP (p < .001), while the values of other parameters did not show a statistically significant difference (p < .05). One month after the therapy in both groups, there was a statistically significant difference in the values of all clinical parameters (p < .001).

CONCLUSIONS

Based on the results of this pilot study, it can be said that, during periodontal treatment, topical application of probiotics in combination with SRP increases the effectiveness of conventional non-surgical therapy of periodontitis.

Protective Effects of the Probiotic Bacterium Streptococcus thermophilus on Candida albicans Morphogenesis and a Murine Model of Oral Candidiasis

Background

Oral candidiasis is a frequent form of candidiasis, caused by Candida species, in particular, Candida albicans (C. albicans). The transition of C. albicans from yeast to hyphae allows its attachment to epithelial cells, followed by biofilm formation, invasion, and tissue damage. Hence, we investigated the effect of Streptococcus salivarius subspecies thermophilus (S thermophilus) on the growth as well as biofilm and germ-tube formation of C. albicans both in vitro and in vivo in a murine model.

Methods

This experimental study was performed in the Department of Medical Mycology and Parasitology, School of Medicine, in collaboration with the Central Research Laboratory and the Comparative Biomedical Center, Shiraz University of Medical Sciences, Shiraz, Iran (2017 to 2018). The inhibitory activity of S. thermophilus against Candida species growth was evaluated using the broth microdilution method, and the inhibition of C. albicans biofilm formation was measured using the XTT assay. The inhibition of C. albicans germ-tube formation by S. thermophilus was evaluated using the plate assay and fluorescence microscopy. The experimental activity of the probiotic bacterium was assessed by culture and histopathological methods in six groups of five mice, comprising those treated with four concentrations of probiotics, fluconazole, and distilled water. The one-way analysis of variance, followed by a Tukey post hoc test, was used and a P value of less than 0.05 was considered significant.

Results

S. thermophilus inhibited Candida species growth at concentrations of 16 to 512 µg/mL. This probiotic inhibited the formation of C. albicans biofilms and germ tubes in a dose-dependent manner. S. thermophilus significantly reduced the colony-forming units in the mice receiving 30 mg/mL of this probiotic treatment compared with the control group (P=0.024). The histopathological analysis showed that Candida colonization was diminished in the mice following the administration of the probiotic.

Conclusion

Given the inhibitory activity of S. thermophilus against the growth, transition, and biofilm formation of C. albicans, it could be used in the management of oral candidiasis.

Effect of probiotic bacteria on oral Candida in head- and neck-radiotherapy patients: A randomized clinical trial

Objective

The aim of the study is to assess the effect of probiotic bacteria on oral Candida counts in cancer patients who are undergoing head- and neck-radiotherapy in a tertiary care center.

Study Design

The study was a randomized clinical trial including 90 patients who just completed head- and neck-radiotherapy.

Materials and Methods

Participants were randomly allocated into three equal sized groups, i.e., probiotics group, candid group, and combination groups. Oral rinse samples of the patients were collected before and after the intervention for the identification of Candida. The samples were incubated on Sabouraud's Dextrose Agar with Chloramphenicol at 37°C for 48 h, to assess the counts of colony-forming units/milliliter (CFU/ml) of Candida in saliva, and further on chrome agar plates to identify the Candida spp. Data were analyzed using mixed ANOVA to compare mean CFU/ml of Candida among three groups before and after the intervention.

Results

A total of 86 patients were included in the final analysis and there was a statistically significant reduction in mean Candida spp. Counts (CFU/ml) after intervention in all the three groups (P = 0.000) and significant reductions identified in both probiotic and combination therapy groups. Apart from reduction in Candida albicans, significant decrease in Candida glabrata and Candida tropicalis was observed after probiotics usage compared to other groups.

Conclusions

The present study suggests that probiotic bacteria were effective in reducing oral Candida spp which can be recommended alone or in combination with traditional antifungal agents for effective reduction in oral Candida in head- and neck-radiotherapy patients.

Probiotics as a prophylaxis to prevent oral candidiasis in patients with Sjogren's syndrome: a double-blinded, placebo-controlled, randomized trial

Patients with Sjögren's syndrome are at a higher risk to develop oral candidiasis than the general population. As antifungals have many side-effects, new approaches are needed to address this problem. This randomized controlled study aimed to evaluate the short-term efficacy of probiotics in the reduction of oral candidal growth in patients with SS. Thirty-two Sjogren's syndrome patients were randomly allocated in two groups receiving either Probiotics or placebo capsules twice a day for 5 weeks. The strains included in the probiotic capsule were Lactobacillus acidophilus, Lactobacillus bulgaricus, Streptococcus thermophilus and Bifidobacteriumbifidum. Oral rinse solution samples were collected and candidal levels were determined (CFU/mL) at baseline and after the 5-week experimental period. Pain, erythema and angular cheilitis were also assessed at baseline and after 2, 4 and 5-week. In the probiotic group, there was a statistically significant reduction of the candidal load from baseline to the 5th week respectively. However, the change in candidal load at the same time in the placebo group was not statistically significant. The tested probiotic product may represent an unconventional method to reduce candidal colonization, to prevent oral candidosis in patients with Sjogren's syndrome.Clinical trials registration ID NCT03840538 (https://clinicaltrials.gov/show/NCT03840538).

Development of Probiotic Formulations for Oral Candidiasis Prevention: Gellan Gum as a Carrier To Deliver Lactobacillus paracasei 28.4

Probiotics might provide an alternative approach for the control of oral candidiasis. However, studies on the antifungal activity of probiotics in the oral cavity are based on the consumption of yogurt or other dietary products, and it is necessary to use appropriate biomaterials and specific strains to obtain probiotic formulations targeted for local oral administration. In this study, we impregnated gellan gum, a natural biopolymer used as a food additive, with a probiotic and investigated its antifungal activity against Candida albicans Lactobacillus paracasei 28.4, a strain recently isolated from the oral cavity of a caries-free individual, was incorporated in several concentrations of gellan gum (0.6% to 1% [wt/vol]). All tested concentrations could incorporate L. paracasei cells while maintaining bacterial viability. Probiotic-gellan gum formulations were stable for 7 days when stored at room temperature or 4°C. Long-term storage of bacterium-impregnated gellan gum was achieved when L. paracasei 28.4 was lyophilized. The probiotic-gellan gum formulations provided a release of L. paracasei cells over 24 h that was sufficient to inhibit the growth of C. albicans, with effects dependent on the cell concentrations incorporated into gellan gum. The probiotic-gellan gum formulations also had inhibitory activity against Candida sp. biofilms by reducing the number of Candida sp. cells (P < 0.0001), decreasing the total biomass (P = 0.0003), and impairing hyphae formation (P = 0.0002), compared to the control group which received no treatment. Interestingly, a probiotic formulation of 1% (wt/vol) gellan gum provided an oral colonization of L. paracasei in mice with approximately 6 log CFU/ml after 10 days. This formulation inhibited C. albicans growth (P < 0.0001), prevented the development of candidiasis lesions (P = 0.0013), and suppressed inflammation (P = 0.0006) compared to the mice not treated in the microscopic analysis of the tongue dorsum. These results indicate that gellan gum is a promising biomaterial and can be used as a carrier system to promote oral colonization for probiotics that prevent oral candidiasis.

The Dysbiosis and Inter-Kingdom Synergy Model in Oropharyngeal Candidiasis, a New Perspective in Pathogenesis

As more information emerges on oral microbiota using advanced sequencing methodologies, it is imperative to examine how organisms modulate the capacity of each other to colonize or trigger infection. Most mouse models of oral C. albicans infection have focused on interactions with single bacterial species. Thus, little is known about the microbiome-mediated interactions that control the switch of C. albicans from commensalism to infection. Evidence is accumulating that in immunosuppression where mucosal candidiasis is more prevalent, there is an altered oral bacterial microbiome with reduced diversity, but not an altered mycobiome. Oropharyngeal candidiasis in immunosuppressed humans and mice is associated with a further reduction in oral bacterial diversity and a dysbiotic shift with significant enrichment of streptococcal and enterococcal species. Our recent studies in a cancer chemotherapy mouse model supported the combined profound effect of immunosuppression and C. albicans in reducing oral bacterial diversity and provided the first direct evidence that these changes contribute to pathogenesis, representing dysbiosis. There is still a gap in understanding the relationship between Candida and the oral bacterial microbiome. We propose that certain oral commensal bacteria contribute to fungal pathogenesis and we identify gaps in our understanding of the mechanisms involved in this cooperative virulence.

Promising Alternative Therapeutics for Oral Candidiasis

:

Candida is the main human fungal pathogen causing infections (candidiasis), mostly in the elderly and immunocompromised hosts. Even though Candida spp. is a member of the oral microbiota in symbiosis, in some circumstances, it can cause microbial imbalance leading to dysbiosis, resulting in oral diseases. Alternative therapies are urgently needed to treat oral candidiasis (usually associated to biofilms), as several antifungal drugs’ activity has been compromised. This has occurred especially due to an increasing occurrence of drugresistant in Candida spp. strains. The overuse of antifungal medications, systemic toxicity, cross-reactivity with other drugs and a presently low number of drug molecules with antifungal activity, have contributed to important clinical limitations.

:

We undertook a structured search of bibliographic databases (PubMed Central, Elsevier’s ScienceDirect, SCOPUS and Springer’s SpringerLink) for peer-reviewed research literature using a focused review in the areas of alternatives to manage oral candidiasis. The keywords used were “candidiasis”, “oral candidiasis”, “biofilm + candida”, “alternative treatment”, “combination therapy + candida” and the reports from the last 10 to 15 years were considered for this review.

:

This review identified several promising new approaches in the treatment of oral candidiasis: combination anti-Candida therapies, denture cleansers, mouth rinses as alternatives for disrupting candidal biofilms, natural compounds (e.g. honey, probiotics, plant extracts and essential oils) and photodynamic therapy.

:

The findings of this review confirm the importance and the urgency of the development of efficacious therapies for oral candidal infections.

In vivo effectiveness and safety of probiotics on prophylaxis and treatment of oral candidiasis: a systematic review and meta-analysis

Background

To systematically review and assess the in vivo effectiveness and safety of probiotics for prophylaxis and treating oral candidiasis.

Methods

A literature search for studies published in English until August 1, 2018 was conducted in the following databases: PubMed, EMBASE, Cochrane Library, and Web of Science. Randomized controlled clinical trials and experimental mouse animal model studies comparing probiotics (at any dosage and in any form) with control groups (placebo, blank control or other agents) and reporting outcomes of the prophylactic and therapeutic effects were considered for inclusion. A descriptive study and, potentially, a meta-analysis were planned.

Results

Six randomized controlled clinical trials and 5 controlled experiments of mouse animal models were included in the systematic review. Four randomized controlled clinical trials comparing a probiotics group with a placebo/blank control group in 480 elderly and denture wearers were included in the meta-analysis. The overall combined odds ratio of the (random effects) meta-analysis was 0.24 (95% CI =0.09–0.63, P < 0.01). The overall combined odds ratio of the (fixed effects) sensitivity analysis was 0.39 (95% CI =0.25–0.60, P < 0.01) by excluding a study with the smallest sample size. These analyses showed that there was a statistically significant difference in the effect of probiotics compared with the control groups in elderly and denture wearers. The remaining 2 studies compared probiotics with other agents in a population aged 18–75 years and children aged 6–14 years respectively, and were analyzed descriptively. Meta-analysis and descriptive analyses indicated that probiotics were potentially effective in reducing morbidity, improving clinical symptoms and reducing oral Candida counts in oral candidiasis. The biases of the included studies were low or uncertain. The relatively common complaints reported were gastrointestinal discomfort and unpleasant taste, and no severe adverse events were reported.

Conclusions

Probiotics were superior to the placebo and blank control in preventing and treating oral candidiasis in the elderly and denture wearers. Although probiotics showed a favorable effect in treating oral candidiasis, more evidence is required to warrant their effectiveness when compared with conventional antifungal treatments. Moreover, data on the safety of probiotics are still insufficient, and further research is needed.

Lactobacillus species increase the survival of Galleria mellonella infected with Candida albicans and non-albicans Candida clinical isolates

Investigation into new therapeutic strategies, such as the use of bacterial isolates with probiotic characteristics, has increased in importance due to the high incidence of Candida albicans and non-albicans Candida infections. This study evaluates Lactobacillus paracasei, Lactobacillus fermentum and Lactobacillus rhamnosus strains as prophylactic and therapeutic agents against infection caused by Candida albicans, Candida glabrata, Candida krusei, and Candida tropicalis in a Galleria mellonella model. Prophylactic treatment provided greater benefits during Candida spp. infection, increasing G. mellonella survival, compared to therapeutic treatment. This study demonstrated that the different Lactobacillus species are potent prophylactic agents of Candida species infection.

Ecological Therapeutic Opportunities for Oral Diseases

The three main oral diseases of humans, that is, caries, periodontal diseases, and oral candidiasis, are associated with microbiome shifts initiated by changes in the oral environment and/or decreased effectiveness of mucosal immune surveillance. In this review, we discuss the role that microbial-based therapies may have in the control of these conditions. Most investigations on the use of microorganisms for management of oral disease have been conducted with probiotic strains with some positive but very discrete clinical outcomes. Other strategies such as whole oral microbiome transplantation or modification of community function by enrichment with health-promoting indigenous oral strains may offer more promise, but research in this field is still in its infancy. Any microbial-based therapeutics for oral conditions, however, are likely to be only one component within a holistic preventive strategy that should also aim at modification of the environmental influences responsible for the initiation and perpetuation of microbiome shifts associated with oral dysbiosis.

Lactobacillus paracasei 28.4 reduces in vitro hyphae formation of Candida albicans and prevents the filamentation in an experimental model of Caenorhabditis elegans

The objective of this study was to evaluate the influence of microbe-microbe interactions to identify a strain of Lactobacillus that could reduce the filamentation of Candida albicans ATCC 18804 using in vitro and in vivo models. Thus presenting a probiotic effect against the fungal pathogen. First, we analyzed the ability of 25 clinical isolates of Lactobacillus to reduce filamentation in C. albicans in vitro. We found that L. paracasei isolate 28.4 exhibited the greatest reduction of C. albicans hyphae (p = 0.0109). This reduction was confirmed by scanning electron microscopy analysis. The influence of C. albicans filamentation was found to be contributed through reduced gene expression of filament associated genes (TEC1 and UME6). In an in vivo study, prophylactic provisions with L. paracasei increased the survival of Caenorhabditis elegans worms infected with C. albicans (p = 0.0001) by 29%. Prolonged survival was accompanied by the prevention of cuticle rupture of 27% of the worms by filamentation of C. albicans, a phenotype that is characteristic of C. albicans killing of nematodes, compared to the control group. Lactobacillus paracasei isolate 28.4 reduced the filamentation of C. albicans in vitro by negatively regulating the TEC1 and UME6 genes that are essential for the production of hyphae. Prophylactic provision of Lactobacillus paracasei 28.4 protected C. elegans against candidiasis in vivo. L. paracasei 28.4 has the potential to be employed as an alternative method to control candidiasis.

Probiotic Bacteria Alter Pattern-Recognition Receptor Expression and Cytokine Profile in a Human Macrophage Model Challenged with Candida albicans and Lipopolysaccharide

Probiotics are live microorganisms that confer benefits to the host health. The infection rate of potentially pathogenic organisms such as Candida albicans, the most common agent associated with mucosal candidiasis, can be reduced by probiotics. However, the mechanisms by which the probiotics interfere with the immune system are largely unknown. We evaluated the effect of probiotic bacteria on C. albicans challenged human macrophages. Macrophages were pretreated with lactobacilli alone (Lactobacillus rhamnosus LR32, Lactobacillus casei L324m, or Lactobacillus acidophilus NCFM) or associated with Escherichia coli lipopolysaccharide (LPS), followed by the challenge with C. albicans or LPS in a co-culture assay. The expression of pattern-recognition receptors genes (CLE7A, TLR2, and TLR4) was determined by RT-qPCR, and dectin-1 reduced levels were confirmed by flow cytometry. The cytokine profile was determined by ELISA using the macrophage cell supernatant. Overall probiotic lactobacilli down-regulated the transcription of CLEC7A (p < 0.05), resulting in the decreased expression of dectin-1 on probiotic pretreated macrophages. The tested Lactobacillus species down-regulated TLR4, and increased TLR2 mRNA levels in macrophages challenged with C. albicans. The cytokines profile of macrophages challenged with C. albicans or LPS were altered by the probiotics, which generally led to increased levels of IL-10 and IL-1β, and reduction of IL-12 production by macrophages (p < 0.05). Our data suggest that probiotic lactobacilli impair the recognition of PAMPs by macrophages, and alter the production of pro/anti-inflammatory cytokines, thus modulating inflammation.

Probiotics Reduce the Prevalence of Oral Candida in the Elderly—a Randomized Controlled Trial

Overgrowth of oral yeast is a common problem among the elderly. Probiotic bacteria are known to inhibit the growth of pathogenic microbes. We tested the hypothesis that cheese containing probiotic bacteria can reduce the prevalence of oral Candida. During this 16-week, randomized, double-blind, placebo-controlled study, 276 elderly people consumed daily 50 g of either probiotic (n = 136) or control cheese (n = 140). The primary outcome measure was the prevalence of a high salivary yeast count (≥ 104 cfu/mL) analyzed by the Dentocult® method. The prevalence decreased in the probiotic group from 30% to 21% (32% reduction), and increased in the control group from 28% to 34%. Probiotic intervention reduced the risk of high yeast counts by 75% (OR = 0.25, 95%CI 0.10–0.65, p = 0.004), and the risk of hyposalivation by 56% (OR = 0.44, 95%CI 0.19–1.01, p = 0.05). Thus, probiotic bacteria can be effective in controlling oral Candida and hyposalivation in the elderly.

Antimicrobial Efficacy of Probiotic and Herbal Oral Rinses against Candida albicans in Children: A Randomized Clinical Trial

Background: A growing number of dentists are embracing the philosophy that natural agents are better for children’s oral health. Knowledge of probiotics on host immune system has entered a new phase of research, and progression in this field is likely to offer novel means by modulating host immunity for prevention and treatment of a wide variety of oral diseases.

Aim: To compare the antimicrobial efficacy of probiotics in reducing salivary Candida albicans counts with commonly used antimicrobial agents like 0.2% chlorhexidine and herbal rinse.

Materials and methods: A randomized clinical trial was conducted on 60 subjects aged between 6 and 14 years, for a period of 9 months. The subjects were randomly divided into three groups comprising 20 subjects in each group. Three oral agents were administered twice daily for a maximum period of 1 week. Candida albicans counts were recorded before and after intervention and the results were submitted for statistical analysis using Statistical Package for the Social Sciences (SPSS) version 15.0 software.

Results: The change in mean log₁₀ colony-forming unit (CFU)/ ml of C. albicans in groups A to C was 0.43 ± 0.72, 0.68 ± 1.05 and 0.22 ± 0.66 CFU/ml respectively.

Conclusion: Data obtained from the study demonstrated that probiotic rinse was equally effective as 0.2% chlorhexidine digluconate rinse in reducing C. albicans counts after 1 week of intervention. Herbal oral rinse was least effective. Probiotic oral rinses have opened new horizons in improvement of oral health by maintaining healthy ecosystem. However, a longitudinal study with larger sample size needs to be undertaken to evaluate the therapeutic effects of probiotics and herbal agents.

How to cite this article: Mishra R, Tandon S, Rathore M, Banerjee M. Antimicrobial Efficacy of Probiotic and Herbal Oral Rinses against Candida albicans in Children: A Randomized Clinical Trial. Int J Clin Pediatr Dent 2016;9(1):25-30.

Inhibitory activity in vitro of probiotic lactobacilli against oral Candida under different fermentation conditions

Clinical studies have shown that probiotics positively affect oral health by decreasing gum bleeding and/or reducing salivary counts of certain oral pathogens. Our aim was to investigate the inhibitory effect of six probiotic lactobacilli against opportunistic oral Candida species. Sugar utilisation by both lactobacilli and Candida was also assessed. Agar overlay assay was utilised to study growth inhibition of Candida albicans, Candida glabrata and Candida krusei by Lactobacillus rhamnosus GG, Lactobacillus casei Shirota, Lactobacillus reuteri SD2112, Lactobacillus brevis CD2, Lactobacillus bulgaricus LB86 and L. bulgaricus LB Lact. The inhibitory effect was measured at pH 5.5, 6.4, and 7.2, respectively, and in the presence of five different carbohydrates in growth medium (glucose, fructose, lactose, sucrose, and sorbitol). Growth and final pH values were measured at two-hour time points to 24 h. L. rhamnosus GG showed the strongest inhibitory activity in fructose and glucose medium against C. albicans, followed by L. casei Shirota, L. reuteri SD2112 and L. brevis CD2. None of the lactobacilli tested affected the growth of C. krusei. Only L. rhamnosus GG produced slight inhibitory effect on C. glabrata. The lower pH values led to larger inhibition zones. Sugar fermentation profiles varied between the strains. L. casei Shirota grew in the presence of all sugars tested, whereas L. brevis CD2 could utilise only glucose and fructose. All Candida species metabolised the available sugars but the most rapid growth was observed with C. glabrata. The results suggest that commercially available probiotics differ in their inhibitory activity and carbohydrate utilisation; the above properties are modified by different pH values and sugars with more pronounced inhibition at lower pH.

Therapeutic Application of Synbiotics, a Fusion of Probiotics and Prebiotics, and Biogenics as a New Concept for Oral Candida Infections: A Mini Review

Candida is a major human fungal pathogen causing infectious conditions predominantly in the elderly and immunocompromised hosts. Although Candida resides as a member of the oral indigenous microbiota in symbiosis, some circumstances may cause microbial imbalance leading to dysbiosis and resultant oral candidiasis. Therefore, oral microbial symbiosis that suppresses the overgrowth of Candida is important for a healthy oral ecosystem. In this regard, probiotics, prebiotics, and synbiotics can be considered a potential therapeutic and preventive strategy against oral candidiasis. Prebiotics have a direct effect on microbial growth as they stimulate the growth of beneficial bacteria and suppress the growth of pathogens. Probiotics render a local protective effect against pathogens and a systemic indirect effect on immunological amelioration. Synbiotics are fusion products of prebiotics and probiotics. This mini review discusses the potential use and associated limitations of probiotics, prebiotics, and synbiotics for the prevention and treatment of oral candidiasis. We will also introduce biogenics, a recent concept derived from the work on probiotics. Biogenics advocates the use of beneficial bioactive substances produced by probiotic bacteria, whose activities are independent from the viability of probiotic bacteria in human bodies.

Innate Immunity and Saliva in Candida albicans-mediated Oral Diseases

The oral cavity is a unique niche where Candida albicans infections occur in immunocompetent as well as immunosuppressed individuals. Here we critically review the significance of human innate immune response in preventing oral candidiasis. One important line of defense against oropharyngeal candidiasis is the oral microbiota that prevents infection by competing for space and nutrients as well as by secreting antagonistic molecules and triggering local inflammatory responses. C. albicans is able to induce mucosal defenses through activation of immune cells and production of cytokines. Also, saliva contains various proteins that affect C. albicans growth positively by promoting mucosal adherence and negatively through immune exclusion and direct fungicidal activity. We further discuss the role of saliva in unifying host innate immune defenses against C. albicans as a communicating medium and how C. albicans overgrowth in the oral cavity may be a result of aberrations ranging from microbial dysbiosis and salivary dysfunction to epithelial damage. Last we underscore select oral diseases in which C. albicans is a contributory microorganism in immune-competent individuals.

Supplementation of xylitol-containing chewing gum with probiotics: a double blind, randomised pilot study focusing on saliva flow and saliva properties

The aim of this study was to investigate the impact of daily chewing, for 12 weeks, of 2 different probiotic gums compared with placebo on saliva flow rate, saliva IgA levels and saliva pH.

Probiotics: can they be used to improve oral health?

The role of probiotic bacteria in improving human health has been an attractive subject for researchers since the beginning of the 20(th) century. They have been used to control gastro-intestinal infections, to promote immunity and to prevent various diseases (allergies, urogenital infections, etc.). However, the use of beneficial bacteria in the field of dentistry has only recently gained interest. Investigation of the effects of probiotic bacteria on oral health has become an important research subject. These studies are still in the early stages, however results show that probiotic bacteria are effective against tooth caries, periodontal disease, oral mucosal lesions and oral malodour. This review provides information on the effects of probiotics--well-known for their effects on general health, and therefore more widely used in healthcare--on oral and dental health, in order to promote their use/prescription by physicians and patients.

New insight into an old concept: role of immature erythroid cells in immune pathogenesis of neonatal infection

Newborns are exceedingly susceptible to infection. However, very little is known about what governs the immunological differences seen in early life that result in extreme vulnerability to infection, nor how this changes during infancy. Herein, I provide evidence that the reduced ability to mount a protective immune response to pathogens is not due to an inherent immaturity of neonatal immune cells but instead the functions of these immune cells are actively suppressed by CD71⁺ erythroid cells. Furthermore, the role of CD71⁺ erythroid cells in host defense against infection is examined. CD71⁺ erythroid cells are enriched in newborns and have distinctive immunosuppressive properties that leave them vulnerable to infection. Moreover, immature erythroid cells possess exclusive immunomodulatory properties and may play a role in immune ontogeny. In addition to these distinct features, CD71⁺ erythroid cells impact digestive health by preventing excessive inflammation following the sudden transition from a sterile in utero setting to excessive colonization with commensals in the external environment. Ongoing research in identifying the beneficial and/or detrimental effects of immature erythrocytes on immune responses may serve to enhance protective newborn immune responses to infection and enable better vaccination strategies for the young to be designed.

Pneumonia pathogen detection and microbial interactions in polymicrobial episodes

Recent reports show that microbial communities associated with respiratory infections, such as pneumonia and cystic fibrosis, are more complex than expected. Most of these communities are polymicrobial and might comprise microorganisms originating from several diverse biological and ecological sources. Moreover, unexpected bacteria in the etiology of these respiratory infections have been increasingly identified. These findings were established with the use of efficient microbiological diagnostic tools, particularly molecular tools based on common gene amplification, followed by cloning and sequencing approaches, which facilitated the identification of the polymicrobial flora. Similarly, recent investigations reported that microbial interactions might exist between species in polymicrobial communities, including typical pneumonia pathogens, such as Pseudomonas aeruginosa and Candida albicans. Here, we review recent tools for microbial diagnosis, in particular, of intensive care unit pneumonia and the reported interactions between microbial species that have primarily been identified in the etiology of these infections.

Effects of probiotic bacteria on Candida presence and IgA anti-Candida in the oral cavity of elderly

Imbalance in the resident microbiota may promote the growth of opportunistic microorganisms, such as yeasts of Candida genus and the development of diseases, especially in aged people. This study evaluated whether the consumption of the probiotic Yakult LB® (Lactobacillus casei and Bifidobacterium breve) was able to influence on the specific immunological response against Candida and on the presence of these yeasts in the oral cavity of 42 healthy aged individuals. Saliva samples were collected before and after the probiotic use for 30 days, 3 times a week. The samples were plated in Dextrose Saboraud Agar with chloramphenicol, the colony-forming units (CFU/mL) were counted and the Candida species were identified. Anti-Candida IgA analysis was conducted using the ELISA technique. ANOVA and Student's t-test were used for normally distributed data and the Wilcoxon test was used for data with non-normal distribution (α=0.05). The results showed a statistically significant reduction (p<0.05) in Candida prevalence (from 92.9% to 85.7%), in CFU/mL counts of Candida and in the number of non-albicans species after consumption of the probiotic. Immunological analysis demonstrated a significant increase (p<0.05) in anti-Candida IgA levels. In conclusion, probiotic bacteria reduced Candida numbers in the oral cavity of the elderly and increased specific secretory immune response against these yeasts, suggesting its possible use in controlling oral candidosis.

Potential role of probiotic bacteria in the treatment and prevention of localised candidosis

The extensive use of immunosuppressive therapies in recent years has increased the number of patients prone to or actually suffering from localised candidosis. As Candida species gain increasing resistance towards common antifungal drugs, new strategies are needed to prevent and treat infections caused by these pathogens. Probiotic bacteria have been in vogue in the past two decades. More and more dairy products containing such organisms offer promising potential beneficial effects on human health and well-being. Because of the ability of probiotic bacteria to inhibit the growth of pathogens and to modulate human immune responses, these bacteria could provide new possibilities in antifungal therapy. We summarise the recent findings concerning the usefulness of probiotic treatment in localised candidosis, as well as discussing possible risks of probiotic treatment and highlighting the molecular mechanisms that are believed to contribute to probiotic effects.

Host-pathogen interactions and virulence-associated genes during Candida albicans oral infections

Oral infections with Candida albicans are very common diseases in even only mildly immunocompromised patients. By using genome-wide microarrays, in vitro infection models and samples from patients with pseudomembranous candidiasis, several genes have been identified which encode known and unknown fungal factors associated with oral infection. The expression of selected genes has been investigated via qRT-PCR in both in vitro models and in vivo samples from patients. Several lines of evidence suggest that fungal morphology plays a key role in adhesion to and invasion into oral epithelial cells and mutants lacking regulators of hyphal formation are attenuated in their ability to invade and damage epithelial cells. Adhesion is mediated by hyphal-associated factors such as Hwp1 and the Als adhesin family. Hyphal formation facilitates epithelial invasion via two routes: active penetration and induced endocytosis. While induced endocytosis is predominantly mediated by the adhesin and invasin Als3, active penetration seems to be supported by hydrolase activity and mechanical pressure. Expression profiles reflect the morphological switch and an adaptive response to neutral pH, non-glucose carbon sources, and nitrosative stress.

How beneficial is bacterial prophylaxis to periodontal health?

The term "probiotics" has become common among general practitioners. There has been an explosion in the interest regarding this topic, which is reflected in the number of scientific publications. The World Health Organization defined probiotics as: "Living microorganisms which when administered in adequate amount confirms a health benefit on the host". Probiotics have been studied extensively in the gastrointestinal tract for their health-promoting effects and have shown promising results. However, in recent times, probiotics have also been used in periodontal health and have shown promising results in controlling gastrointestinal tract infections. Probiotics have potential, but as with many other clinical situations, multicenter or randomized, controlled studies on humans are still required before they can be recommended as prophylaxis for caries or periodontal disease. In the present study, we review the effects of probiotics on maintaining periodontal health. Relevant studies were identified from 1970 to February 2010 using Old Medline, Cochrane Library, and Google Scholar.

The patient with sore throat

Sore throat is a common medical complaint seen by the emergency practitioner, internist, pediatrician, and otolaryngologist. The differential for sore throat is vast. However, with a directed history this can often be narrowed down to 2 to 3 possible diagnoses. By paying particular attention to the associated symptoms and duration of symptoms, common self-limited etiologies like viral pharyngitis and nonstreptococcal tonsillitis can be distinguished from those that require more investigation, such as supraglottitis and tonsillar cancer. A sore throat is most commonly caused by an infectious, inflammatory, or neoplastic etiologic factor.

Influence of probiotics on Candida presence and IgA anti-Candida in the oral cavity

Probiotics are defined as microorganisms that promote benefits to host health, mainly by regulating resident microbiota. Disequilibrium in microbiota can favor the growth of opportunist microorganisms and the development of pathologies, like candidosis caused by yeasts of the Candida genus. This work evaluated whether probiotics consumption was able to influence a specific immunological response to Candida and the presence of these yeasts in the oral cavity. Saliva samples were collected from healthy individuals and plated in Dextrose Saboraud Agar with chloramphenicol. Individuals presenting Candida in the oral cavity used the probiotic Yakult LB® for 20 days, after which new collections and identifications were performed. Anti-Candida IgA analysis was conducted using the ELISA technique. Analysis of the results showed a significant reduction in Candida prevalence (46%) and mean Candida CFU/mL counts (65%). The Candida species identified were C. albicans (98%) and C.tropicalis (2%), before and after probiotics consumption. Immunological analysis demonstrated a significant reduction in anti-Candida IgA levels after probiotics use, probably due to less antigenic stimulation. In conclusion, in the individuals studied, probiotics use significantly reduced the amount of Candida in the oral cavity, possibly due to competition between the yeasts rather than by specific secretory immune response stimulation.

Early markers of allergic disease in a primary prevention study using probiotics: 2.5-year follow-up phase

BACKGROUND

We previously reported that a Lactobacillus acidophilus probiotic strain (LAFTI) L10/LAVRI-A1) given for the first 6 months of life increased the risk of allergen sensitization at 1 year of age.

METHODS

To assess the effects on subsequent allergic outcomes, 153 children from the initial prevention cohort (n = 178) were reviewed at 2.5 years of age. Clinical outcomes were assessed in relation to (i) probiotic supplementation; and (ii) immune function previously assessed at 6 months of age.

RESULTS

Supplementation with this probiotic did not reduce the risk of dermatitis at 2.5 years (31/74, 42%) compared with that in placebo group (25/76, 34%). There was no significant reduction in any other allergic disease or allergen sensitization. Inhalant sensitization at 2.5 years (n = 29) was associated with higher proportions of circulating CD4+ CD25+ regulatory T-cell populations (P = 0.005) and higher allergen-induced FOXP3 levels (P = 0.003) at 6 months. This was also seen in children with dermatitis. Children with dermatitis at 2.5 years also had significantly lower toll-like receptor 4 lipopolysaccharide responses at 6 months of age (IL-12 P = 0.04, IL-6 P = 0.039) and lower polyclonal (PHA) responses (IFN-gamma P = 0.005, IL-10 P = 0.001, and IL-6 P = 0.001). Children who had previously received the probiotic had fewer gastrointestinal infections in the preceding 18 months (P = 0.023).

CONCLUSION

The LAFTI L10 probiotic strain did not have any significant effect on allergy outcomes. Allergic children showed a number of early differences in immune function including altered regulatory T-cell markers and innate immune function.

Interaction de Pseudomonas aeruginosa avec Candida albicans dans les voies respiratoires: de la physiopathologie à une perspective thérapeutique

Several studies evidenced a pathogenic interaction between P. aeruginosa and C. albicans. P. aeruginosa is one of the most frequent microorganisms responsible for ventilator-associated pneumonia (VAP) and C. albicans usually colonize tracheo-bronchial tract of patients undergoing mechanical ventilation in the intensive care unit. In vitro, P. aeruginosa exploits filamentous fungi resulting in fungal killing and limitation of C. albicans growth in the host. Biofilm also play an important role as a persistent source of infectious material for recurrent episodes of VAP. Indeed, Candida spp and P. aeruginosa are the most common pathogens retrieved from endotracheal tube biofilm and tracheal secretions in patients with VAP. Finally, it has been demonstrated that previous tracheo-bronchial C. albicans colonization enhanced the incidence of P. aeruginosa pneumonia in a murine model. A recent study performed in patients requiring intubation and mechanical ventilation identified Candida spp tracheo-bronchial colonization as a risk factor for P. aeruginosa VAP. In addition, a retrospective study suggested that antifungal treatment might reduce P. aeruginosa VAP or tracheo-bronchial colonization in intubated patients with Candida spp tracheo-bronchial colonization. These interactions have major environmental and medical consequences. Experimental studies providing a better understanding of the mechanisms of interaction and clinical studies evaluating the necessity of a antifungal treatment might improve the management of these opportunistic infections.

Orally administeredLactobacillus plantarumreduces pro-inflammatory interleukin secretion in sera fromListeria monocytogenesinfected mice

Lactic acid bacteria have traditionally been thought to have immunomodulating effects. To verify this property,Lactobacillus plantarumwas orally administered to mice (5 × 107colony forming units (c.f.u.)), prior to infection withListeria monocytogenesin order to evaluate the host resistance against an infectious micro-organism and to better define the influence ofL. plantarumon such responses. Balb/c mice were treated daily withL. plantarumor received PBS (sham-treated mice as controls) for 4 weeks. Subsequently, mice were intravenously infected with a clinical isolate ofL. monocytogenes. Our study revealed that the administration ofL. plantarumdid not significantly increase the survival (P = 0·13) of mice (fifteen in each group) afterL. monocytogenesinfection (106 c.f.u./ml), whereas a sub-lethal dose ofL. monocytogenes(105 c.f.u./ml) was eliminated from liver and spleen 5 d after the challenge in bothL. plantarum- and sham-treated mice (n5). Nevertheless, the levels of IL-1β and IL-6 from sera of orally administeredL. plantarumwere drastically reduced at 0, 4 (P < 0·01) and 6 d afterL. monocytogenesinfection, whereas TNF-α production was unaltered. In conclusion, administration ofL. plantarumreduced pro-inflammatory IL production after challenge withL. monocytogenes, although it did not significantly impact the survival of mice. We speculate thatL. plantarumcould exert anti-inflammatory effects, which may represent an important model to reduce inflammatory disorders. Therefore, further studies in human subjects should determine the role ofL. plantarumas an immunomodulatory micro-organism and its relationship in the host protection to pathogens.

Probiotics: contributions to oral health

Probiotics have been extensively studied for their health-promoting effects. The main field of research has been in the gastrointestinal tract. However, in the past few years probiotics have also been investigated in the oral health perspective, which is the topic of the present review. We discuss the mechanisms of bacterial adhesion, potential of probiotics in oral cavity colonization, interspecies interactions, and possible effects on immunomodulation, and means of probiotic administration. We suggest that probiotic treatment of diseases other than dental caries and periodontal disease should also be systematically investigated. In general, hardly any randomized controlled trials have been conducted in this area and the studies on probiotics vs oral health are still in their cradle. Hence, much more investigations are called for before any evidence-based conclusions can be drawn: if or not probiotic therapy can be recommended for oral health purposes.

Use of prophylactic antifungals in the immunocompromised host

Oral candidiasis is a significant infection in patients being treated with chemotherapy and radiotherapy for cancer, and in patients who are immunocompromised because of HIV infection and AIDS. Candida albicans is the most common fungal pathogen and has developed an extensive array of putative virulent mechanisms that allows successful colonization and infection of the host under suitable predisposing conditions. The purpose of this review of the literature was to assess the effectiveness of interventions for the prevention of oral candidiasis in immunocompromised patients and in patients treated for cancer with radiotherapy and/or chemotherapy. These patient categories were selected because they have been the topic of published randomized controlled clinical trials. The studies reviewed provide strong evidence that oral candidiasis is associated with greater morbidity and mortality in these populations, which substantiates the aggressive treatment and prophylaxis of this infection. The literature supports the recommendation that systemically applied antifungal drugs have the greatest efficacy for the treatment of oral candidiasis in cancer and immunocompromised patients; however, these therapies must be prescribed with a thorough assessment for the risk for developing drug-induced toxicities. Guidelines on the prevention of drug-resistant oral candidiasis in these patients are not available and require elucidation. Further studies are required to expand the knowledge base of evidence-based antifungal therapies in a wider variety of immunocompromised patients and conditions, such as Sjögren's syndrome, diabetes, and denture wearers. Additional exploration is needed to determine which antifungal drug formulation, dose, and method of delivery is preferable for the type of fungal infection and the underlying etiology.

Kefir: a symbiotic yeasts-bacteria community with alleged healthy capabilities

Kefir is a fermented milk beverage. The milk fermentation is achieved by the of kefir grains, a cluster of microorganisms held together by a polysaccharide matrix named kefiran. Kefir grains are an example of symbiosis between yeast and bacteria. They have been used over years to produce kefir, a fermented beverage that is consumed all over the world, although its origin is Caucasian. A vast variety of different species of organisms forming the kefir grains, comprising yeast and bacteria, have been isolated and identified. Kefir is a probiotic food. Probiotics have shown to be beneficial to health, being presently of great interest to the food industry. Kefir has been accredited with antibacterial, antifungal and antitumoural activities among other beneficial attributes. This review includes a critical revision of the microbiological composition of kefir along with its beneficial properties to human health.

Fungal—bacterial interactions: a mixed bag of mingling microbes

Fungi and bacteria co-inhabit a wide variety of environments, from soils and food products to plants and mammals. Interactions between bacteria and fungi can have dramatic effects on the survival, colonization and pathogenesis of these organisms. There are instances where bacteria provide fungi with compounds that enhance the production of fungal virulence determinants. Other bacteria produce factors that are likely to inhibit pathogenesis by repressing fungal filamentation. Furthermore, mixed bacterial-fungal biofilms can have properties that are distinct from their single-species counterparts. Clinical studies, in combination with in vitro model systems, are necessary to understand how bacterial-fungal interactions impact human health.

Reversal in fatigued athletes of a defect in interferon gamma secretion after administration of Lactobacillus acidophilus

BACKGROUND

Fatigue and impaired performance in athletes is well recognised and has been loosely linked to "overtraining". Reduced concentration of IgA in the saliva and increased shedding of Epstein Barr virus (EBV) have been associated with intense training in elite athletes.

OBJECTIVE

To determine whether athletes presenting with fatigue and impaired performance had an immune defect relevant to defective containment of EBV infection, and whether a probiotic preparation (Lactobacillus acidophilus) shown to enhance mucosal immunity in animal models could reverse any detected abnormality.

RESULTS

The fatigued athletes had clinical characteristics consistent with re-activation of EBV infection and significantly (p = 0.02) less secretion of interferon (IFN) gamma from blood CD4 positive T cells. After one month of daily capsules containing 2 x 10(10) colony forming units of L acidophilus, secretion of IFNgamma from T cells had increased significantly (p = 0.01) to levels found in healthy control athletes. A significant (p = 0.03) increase in salivary IFNgamma concentrations in healthy control athletes after the one month course of L acidophilus demonstrated in man the capacity for this probiotic to enhance the mucosal IFNgamma concentration.

CONCLUSION

This is the first evidence of a T cell defect in fatigued athletes, and of its reversal following probiotic therapy.