Growth inhibition of oral mutans streptococci and candida by commercial probiotic lactobacilli - an in vitro study

<p>Abstract</p> <p>Background</p> <p>Probiotic bacteria are suggested to play a role in the maintenance of oral health. Such health promoting bacteria are added to different commercial probiotic products. The aim of the study was to investigate the ability of a selection of lactobacilli strains, used in commercially available probiotic products, to inhibit growth of oral mutans streptococci and <it>C. albicans in vitro</it>.</p> <p>Methods</p> <p>Eight probiotic lactobacilli strains were tested for growth inhibition on three reference strains and two clinical isolates of mutans streptococci as well as two reference strains and three clinical isolates of <it>Candida albicans </it>with an agar overlay method.</p> <p>Results</p> <p>At concentrations ranging from 10⁹to 10⁵CFU/ml, all lactobacilli strains inhibited the growth of the mutans streptococci completely with the exception of <it>L. acidophilus </it>La5 that executed only a slight inhibition of some strains at concentrations corresponding to 10⁷and 10⁵CFU/ml. At the lowest cell concentration (10³CFU/ml), only <it>L. plantarum </it>299v and <it>L. plantarum </it>931 displayed a total growth inhibition while a slight inhibition was seen for all five mutans streptococci strains by <it>L. rhamnosus </it>LB21, <it>L. paracasei </it>F19, <it>L. reuteri </it>PTA 5289 and <it>L. reuteri </it>ATCC 55730. All the tested lactobacilli strains reduced candida growth but the effect was generally weaker than for mutans streptococci. The two <it>L. plantarum </it>strains and <it>L. reuteri </it>ATCC 55730 displayed the strongest inhibition on <it>Candida albicans</it>. No significant differences were observed between the reference strains and the clinical isolates.</p> <p>Conclusion</p> <p>The selected probiotic strains showed a significant but somewhat varying ability to inhibit growth of oral mutans streptococci and <it>Candida albicans in vitro</it>.</p

Probiotic Lactobacillus paracasei effect on cariogenic bacterial flora

Lactobacillus paracasei has been demonstrated to inhibit the growth of many pathogenic microbes such as Streptococcus mutans, in vitro. However, its clinical application remains unclear. Here, we examined whether a novel probiotic L. paracasei GMNL-33 may reduce the caries-associated salivary microbial counts in healthy adults. Seventy-eight subjects (aged 20 to 26) had completed this double-blinded, randomized, placebo-controlled study. A probiotic/test (n = 42) and a control group (n = 36) took a L. paracasei GMNL-33 and a placebo oral tablet three times per day for 2 weeks, respectively. Bacterial counts of salivary S. mutans, lactobacilli, and salivary buffer capacity were measured with chair-side kits at the beginning (T1), the completion (T2) of medication, and 2 weeks after medication (T3). The results did not show differences in the counts of S. mutans and lactobacilli between probiotic and control groups at T1, T2, and T3. Nevertheless, within the probiotic group, an interesting probiotic effect was noticed. Between T1 and T2, no inhibitory effect against S. mutans was observed. However, a significant count reduction in the salivary S. mutans was detected between T2 and T3 (p = 0.016). Thus, a 2-week period of medication via oral administration route may be needed for L. paracasei GMNL-33 to be effective in the probiotic action

Therapeutic potential of enoxaparin in lichen planus: Exploring reasons for inconsistent reports

Lichen planus (LP) is an uncommon mucocutaneous inflammatory condition, that is immunologically mediated, typically pruritic and often recurs. The currently advocated therapies are either not highly effective or associated with severe side effects. Enoxaparin, a widely used anticoagulant, is composed of both anticoagulant and non-anticoagulant fragments. Enoxaparin is reported to have anti-inflammatory properties and it was found to be effective in LP. However, the results from clinical studies have varied substantially and, therefore, the clinical role of enoxaparin in LP remains uncertain. This review focuses on potential reasons for the reported inconsistent outcomes, as well as proposing solutions; these include identifying batch-to-batch inconsistency in the composition of enoxaparin. The potential therapeutic value of enoxaparin in LP must be explored using well-designed clinical trials, combined with experimental studies that focus on identifying the anti-inflammatory fragments of enoxaparin and elucidating the mechanism of action of these non-anticoagulant fragments

Prospects for the development of probiotics and prebiotics for oral applications

There has been a paradigm shift towards an ecological and microbial community-based approach to understanding oral diseases. This has significant implications for approaches to therapy and has raised the possibility of developing novel strategies through manipulation of the resident oral microbiota and modulation of host immune responses. The increased popularity of using probiotic bacteria and/or prebiotic supplements to improve gastrointestinal health has prompted interest in the utility of this approach for oral applications. Evidence now suggests that probiotics may function not only by direct inhibition of, or enhanced competition with, pathogenic micro-organisms, but also by more subtle mechanisms including modulation of the mucosal immune system. Similarly, prebiotics could promote the growth of beneficial micro-organisms that comprise part of the resident microbiota. The evidence for the use of pro or prebiotics for the prevention of caries or periodontal diseases is reviewed, and issues that could arise from their use, as well as questions that still need to be answered, are raised. A complete understanding of the broad ecological changes induced in the mouth by probiotics or prebiotics will be essential to assess their long-term consequences for oral health and disease

Probiotic lactobacilli inhibit early stages of Candida albicans biofilm development by reducing their growth, cell adhesion, and filamentation

We evaluated the inhibitory effects of the probiotic Lactobacillus species on different phases of Candida albicans biofilm development. Quantification of biofilm growth and ultrastructural analyses were performed on C. albicans biofilms treated with Lactobacillus rhamnosus, Lactobacillus casei, and Lactobacillus acidophilus planktonic cell suspensions as well as their supernatants. Planktonic lactobacilli induced a significant reduction (p\ua0\ua00.05), but significantly reduced the early stages of Candida biofilm formation (p\ua

Immunological aspects of oral lichen planus. Studies on the expression of cytokines, T cell receptor V-families and delayed-type hypersensitivity reactions

Oral lichen planus (OLP) is a chronic inflammatory disease of unknown etiology. In lesions, T lymphocytes constitute the major infiltrating cell type. The present series of studies focussed on studying phenotypic, distributional and functional aspects of T cells in lesions and in blood in OLP patients, by virtue of the central role of these cells in mediating inflammatory reactions. The expression of T cell receptor V-families was assessed in biopsies. The frequency and distribution of mRNA positive cells for IFN-g, IL-2, IL-4, IL-10, TNF-a and TGF-b were assessed in OLP infiltrates, in situ. The number of IFN-g producing cells and the level of secretion of this cytokine was determined in blood mononuclear cells, from patients and from matched controls. Finally, the in vivo capacity of T lymphocytes to elicit delayed-type hypersensitivity reactions in skin was compared in OLP and in matched controls.Of the eleven T cell receptor V-families investigated, the Vb3 and the Va2 families were represented on approximately 24 % of the infiltrating cells in OLP. By contrast, in control sections from C. albicans infiltrates, the two V-families were found in only 0-7 % of the total number of infiltrating cells, corresponding with levels detected for each V-family in healthy blood donors. The remaining V-families were each expressed in low frequency. The restricted V-family expression in OLP lesions was interpreted as potentially being initiated by superantigens.The number of cytokine mRNA producing cells in lesions was estimated to 1 % (IFN-g) or range between 1-2 % (IL-2, IL-4, IL-10, TNF-a and TGF-b), respectively. The mRNA positive cells were distributed in association with the basement membrane, in a majority of the biopsies, suggesting that interaction with antigen-presenting cells occurs in this region. The low frequency of cytokine mRNA positive cells also suggests that the disease is maintained by few antigen-specific T lymphocytes.Similar numbers of IFN-g producing cells in blood was found in patients and controls, in response to mitogen (phytohaemagglutinin), Candida albicans antigen or when cells were left unstimulated. The levels of IFN-g that were secreted in supernatants were equivalent in patients and matched controls, for the respective antigens. Delayed-type hypersensitivity responses to the recall antigens mumps, tuberculin and streptokinase/streptodornase were reduced in oral lichen planus patients compared with matched controls. By contrast, the reponse to C. albicans was similar in patients and controls. This finding suggests that memory T cell responses to infrequently encountered antigens, represented by mumps, tuberculin and streptokinase/streptodornase may be qualitatively and/or quantitatively reduced in OLP. Memory responses to frequently recognized antigens or antigens that are part of the ubiquitous flora, such as C. albicans, may instead remain unaltered