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 Lactobacilli in the context of dental caries as a biofilm-mediated disease

Background: The World Health Organization defines probiotics as ‘live microorganisms which, when administered in adequate amounts, confer a health benefit to the host’. Traditionally, probiotic microorganisms have been used to prevent or treat gastrointestinal tract diseases. In the last 15 years, there has been increasing interest of a possible probiotic impact on the oral microbiota and dental caries. Dental caries is a multifactorial disease, and the causative factor in the oral microbiota includes a shift from a balanced microflora to a microflora that includes more aciduric species such as mutans streptococci (MS), non-mutans streptococci, and Actinomyces. MS is considered an opportunistic pathogen although several other bacteria also contribute to the disease. Early acquisition of MS is associated with early development of caries; therefore a desirable complement to other prophylactic measures would be a MS colonization inhibitor. Objective: To better understand how selected strains of probiotic lactobacilli interact with MS in vitro and in vivo and to study the impact of probiotic lactobacilli on caries development during childhood. Material and methods: The in vitro properties of probiotic lactobacilli were studied with regard to (i) acid production from sugars and sugar alcohols, (ii) growth inhibition capacity on clinical isolates and reference strains of MS as well as Candida albicans and (iii) the capacity to co-aggregate with MS. A randomized controlled trial (RCT) tested the short-term effect of intervention with two Lactobacillus reuteri strains on MS, which was evaluated after treatment with chlorhexidine. The re-growth patterns of MS and 19 other selected strains were also evaluated. In the second clinical study  we investigated the long-term effect on MS prevalence and dental caries after an intervention with Lactobacillus paracasei ssp. paracasei F19 (LF19) between 4 and 13 months of age. Results: The results from the in vitro testing showed that strains of probiotic lactobacilli differed in their fermentation patterns, inhibition capacity and their capacity to co-aggregate, which should be kept in mind in the translation to clinical research. The clinical study on short-term effects of two L. reuteri strains on MS and other oral strains showed no effect on re-growth patterns after intervention. The clinical study on long-term effects of LF19 showed no effect on the prevalence of MS. Furthermore, the clinical follow-up at 9 years of age showed no differences in either decayed, missing, and filled surface (dmfs) or DMFS between the probiotic and placebo groups. Evaluation of saliva samples showed no signs of oral colonization with LF19 in the study group. Conclusion: The in vitro testing showed potentials of the selected probiotic Lactobacillus strains for interference with MS and C. albicans. The results from the clinical studies showed no such effect on MS or dental caries. Evidence regarding the effectiveness of specific probiotic applications in the prevention of dental caries is limited and does not allow for conclusions concerning the use of probiotic bacteria as a preventive measure

Prevention of Recurrent Childhood Caries with Probiotic Supplements : A Randomized Controlled Trial with a 12-Month Follow-Up

The aim of this study was to evaluate the effect of drops containing probiotic bacteria on the recurrence of dental caries in preschool children. The study employed a randomized, placebo-controlled, double-blinded design with two parallel arms. 38 preschool children were enrolled after comprehensive restorative treatment under general anesthesia or conscious sedation (baseline), and they were followed up after 6 and 12 months. Parents of children in the test group were instructed to give 5 daily drops containing two strains of Limosilactobacillus reuteri (DSM 17938 and ATCC PTA 5289) at bedtime. The placebo drops were identically composed but lacked bacteria. The duration of the intervention was 12 months. The primary endpoint was recurrence of new caries lesions on subject level (yes/no), and secondary endpoints were presence of dental plaque and gingivitis. We found high rate of recurrent moderate and extensive lesions after 12 months (67%) but there were no significant differences between the groups. We observed no beneficial effects on dental plaque or gingival inflammation. The findings were however uncertain and inconclusive due to lack of power, a consequence of the COVID-19 pandemic. ClinTrials.gov Identifier: (NCT04929340), June 18, 2021; retrospectively registered

Oral Microbiota Profile Associates with Sugar Intake and Taste Preference Genes

Oral microbiota ecology is influenced by environmental and host conditions, but few studies have evaluated associations between untargeted measures of the entire oral microbiome and potentially relevant environmental and host factors. This study aimed to identify salivary microbiota cluster groups using hierarchical cluster analyses (Wards method) based on 16S rRNA gene amplicon sequencing, and identify lifestyle and host factors which were associated with these groups. Group members (n = 175) were distinctly separated by microbiota profiles and differed in reported sucrose intake and allelic variation in the taste-preference-associated genes TAS1R1 (rs731024) and GNAT3 (rs2074673). Groups with higher sucrose intake were either characterized by a wide panel of species or phylotypes with fewer aciduric species, or by a narrower profile that included documented aciduric- and caries-associated species. The inferred functional profiles of the latter type were dominated by metabolic pathways associated with the carbohydrate metabolism with enrichment of glycosidase functions. In conclusion, this study supported in vivo associations between sugar intake and oral microbiota ecology, but it also found evidence for a variable microbiota response to sugar, highlighting the importance of modifying host factors and microbes beyond the commonly targeted acidogenic and acid-tolerant species. The results should be confirmed under controlled settings with comprehensive phenotypic and genotypic data

Early intervention with probiotic Lactobacillus paracasei F19 has no long-term effect on caries experience

The aim of the study was to evaluate possible long-term effects of a cereal diet supplemented with Lactobacillus paracasei F19 (LF19) during weaning on caries experience, mutans streptococci (MS) and lactobacilli (LBC) in a group of 9-year-old children. A secondary aim was to evaluate if the intervention resulted in the permanent integration of LF19 as part of the oral microbiota. The study followed up on a double-blind placebo-controlled randomised trial. Among 179 infants that were randomised to a daily diet that included cereals with or without LF19 from 4 to 13 months of age, 56 from the probiotic group and 62 from the placebo group participated in the follow-up at 9 years. Data were collected by oral clinical examination and questionnaires. MS and LBC levels were assessed with conventional cultivation; LF19 was detected by using randomly amplified polymerase chain reactions (RAPD-PCR). At the follow-up, neither decayed, missing and filled surfaces for primary teeth (dmfs) nor decayed, missing and filled surfaces for permanent teeth (DMFS) differed significantly between the probiotic and placebo groups (p &gt; 0.05). MS and LBC levels were similar in both groups (p &gt; 0.05). RAPD-PCR showed no evidence of oral colonisation with LF19 in the study group. It is concluded that an early intervention with LF19 did not affect the frequency of dental caries, MS or LBC. LF19 did not establish itself as a permanent facet of the oral microbiota in any of the subjects included in this study.Originally included in thesis in accepted form</p

Using Oral Microbiota Data to Design a Short Sucrose Intake Index

Excessive sucrose consumption is associated with numerous health problems, including dental caries, and is considered to play a critical role in shaping the human microbiota. Here, we aimed to confirm the association between sucrose exposure and oral microbiota profile, develop a short food-based index capturing variation among sucrose consumers and validate it against oral microbiota and dental caries in a derivation cohort with 16- to 79-year-old participants (n = 427). Intake and food preferences were recorded by questionnaires and saliva microbiota by 16S rDNA sequencing. Taxonomic similarities clustered participants into five clusters, where one stood out with highest sucrose intake and predicted sugar related metabolic pathways but lowest species diversity in the microbiota. Multivariate modelling of food intake and preferences revealed foods suitable for a sucrose index. This, similarly to sucrose intake, was related to bacterial pattern and caries status. The validity of the sucrose index was replicated in the population-based Gene-Lifestyle Interactions in Dental Endpoints (GLIDE, n = 105,520 Swedish adults) cohort. This suggested that the index captured clinically relevant variation in sucrose intake and that FFQ derived information may be suitable for screening of sucrose intake in the clinic and epidemiological studies, although adjustments to local consumption habits are needed

Genetic Preference for Sweet Taste in Mothers Associates with Mother-Child Preference and Intake

Taste perception is a well-documented driving force in food selection, with variations in, e.g., taste receptor encoding and glucose transporter genes conferring differences in taste sensitivity and food intake. We explored the impact of maternal innate driving forces on sweet taste preference and intake and assessed whether their children differed in their intake of sweet foods or traits related to sweet intake. A total of 133 single nucleotide polymorphisms (SNPs) in genes reported to associate with eating preferences were sequenced from saliva-DNA from 187 mother-and-child pairs. Preference and intake of sweet-, bitter-, sour-, and umami-tasting foods were estimated from questionnaires. A total of 32 SNP variants associated with a preference for sweet taste or intake at a p-value &lt; 0.05 in additive, dominant major, or dominant minor allele models, with two passing corrections for multiple testing (q &lt; 0.05). These were rs7513755 in the TAS1R2 gene and rs34162196 in the OR10G3 gene. Having the T allele of rs34162196 was associated with higher sweet intake in mothers and their children, along with a higher BMI in mothers. Having the G allele of rs7513755 was associated with a higher preference for sweets in the mothers. The rs34162196 might be a candidate for a genetic score for sweet intake to complement self-reported intakes. </p

Vitamin D Insufficiency among Women Post-Partum in Northern Sweden : A Public Health Concern

Pregnancy and post-partum represent a period of susceptibility for vitamin D insufficiency. This study investigated S-25 [OH] D levels in women in northern Sweden 4 weeks post-partum and its association with selected background factors. Blood from 100 healthy women were analyzed for iron status and serum levels of S-25[OH] D using ionization-mass spectrometry (HPLC-APCI-MS). &lt;50 nmol/L was categorized as insufficiency and &lt;25 nmol/L as deficiency. Maternal BMI, dietary habits, fungal infections during pregnancy, and infant birth characteristics were collected using questionnaires and medical charts. 58% were vitamin D insufficient whereas 10% had deficiency. Insufficiency was most common during winter (OR = 2.77; 95% CI = 1.1-6.96) and women with deficiency reported lower milk consumption; 11.3 ± 22.8 intakes per months vs. 34.0 ± 28.9 for those above 25 nmol/L (p &lt; 0.05). Vitamin D-insufficient women had lower serum ferritin levels (p &lt; 0.01) and higher serum transferrin levels (p &lt; 0.05). A history of vaginal fungal infection during pregnancy was associated with insufficiency (OR = 5.10; 95% CI = 1.01-25.73), however, the confidence interval of the estimate was wide, resulting in uncertainty. It is concluded that vitamin D insufficiency 4 weeks post-partum was common in women living at 63°49'N. The odds of being insufficient were increased during winter whereas milk consumption was negatively associated with deficiency. The low vitamin D-levels particularly during winter is a public health concern. From a public health perspective it has to be considered whether dietary advices alone should be modified or if supplementation with vitamin D during pregnancy and the post-partum period also is needed