1.
Characterization of Lactobacilli isolated from carious dentin after selective caries removal and cavity sealing.
Damé-Teixeira, N, Ev, LD, Bitello-Firmino, L, Soares, VK, Dalalba, RS, Rup, AG, Maltz, M, Parolo, CCF
Archives of oral biology. 2021;:104988
Abstract
OBJECTIVE To characterize lactobacilli isolated from residual carious dentin after selective caries removal (SCR), by observing the changes detected in their prevalence, diversity, and cariogenic potential after starvation stress caused by cavity sealing (CS). DESIGN Lactobacilli were cultured from carious dentin lesions (n = 16 patients) treated in a clinical trial, three months before and after CS. Presumptive lactobacilli were selected, isolated, and analyzed by Gram staining. Housekeeping gene sequences were used to identify the species (groEL, rpoA, pheS, and 16S rRNA). RESULTS N = 86 Lactobacillus spp. (n = 41 before and n = 45 after sealing) were genotyped by AP-PCR and analyzed for their cariogenic potential (acid production and acid tolerance). The proportion of lactobacilli to the total anaerobic counts was high, and a significant decrease was observed after sealing (median before sealing = 78.9; 25th-75th = 60.25-97.35; median after sealing = 0.00; 25th-75th = 0.00-77.08; p = 0.001). L. paracasei was the most prevalent species of lactobacilli in carious dentin (p = 0.02). L. rhamnosus prevalence increased to a proportion similar to L. paracasei after CS (p = 0.001). A total of 28 and 14 different genotypes were found before and after CS, respectively. There was no difference between the L. paracasei and the L. rhamnosus isolated from carious dentin, neither regarding acid production nor acid tolerance. CONCLUSIONS Although there was a significant reduction in lactobacilli in the residual carious dentin after SCR, some strains were capable of surviving after three months of CS. However, the sealed available nutrients are low and not sufficient for caries progression. Also, we believe that a longer follow up period may eliminate all the residual lactobacilli. L. paracasei prevailed in carious dentin in a proportion similar to L. rhamnosus in the sealed dentin. Characterization of lactobacilli after SCR and sealing may help the understanding the importance of genotyping of lactobacilli in carious microbiota.
2.
Effect of Cell Concentration on the Persistence in the Human Intestine of Four Probiotic Strains Administered through a Multispecies Formulation.
Taverniti, V, Koirala, R, Dalla Via, A, Gargari, G, Leonardis, E, Arioli, S, Guglielmetti, S
Nutrients. 2019;(2)
Abstract
Studies devoted to evaluating the outcome of different doses of probiotics are very limited, especially for multistrain formulations. In this context, we performed an intervention study that aimed to compare the effect of the administration of two doses (7 billion and 70 billion bacterial cells) of a multistrain probiotic formulation on the persistence of the four probiotic strains that were present in the product in the fecal samples collected from healthy subjects. The overall persistence of the probiotic strains was significantly higher for the 70 billion formulation than for the 7 billion formulation. Furthermore, probiotic strains were detected earlier and for longer for the 70 billion formulation compared to those for the 7 billion formulation. All probiotic strains were recovered alive from the 70 billion preparation, whereas recovery was not possible in a few fecal samples upon administration of the 7 billion preparation. In addition, the overall number of viable probiotic cells recovered on day 14 (i.e., the last day of consumption) was significantly higher for the 70 billion formulation than that for the 7 billion formulation. Finally, we found that the viability of the probiotic cells was stable over the course of the trial independent of volunteers' handling, demonstrating good manufacturing of the product. In conclusion, this study demonstrated that strains belonging to different taxa may coexist in the human gastrointestinal tract upon ingestion of a multispecies probiotic formulation. Moreover, this study suggests that higher doses of bacterial cells in probiotic formulations may permit a higher, earlier, and longer recovery of the probiotics in the feces of healthy adults.
3.
Children with atopic dermatitis show clinical improvement after Lactobacillus exposure.
Wang, IJ, Wang, JY
Clinical and experimental allergy : journal of the British Society for Allergy and Clinical Immunology. 2015;(4):779-87
Abstract
BACKGROUND The role of probiotics in the treatment of atopic dermatitis (AD) is not clearly established. Further clinical trials with new probiotic formulations are warranted. OBJECTIVES To assess the effects of Lactobacillus paracasei (LP) and Lactobacillus fermentum (LF), and their mixture on the disease severity, quality of life, and immune biomarkers of children with AD. METHOD A double-blind, prospective, randomized placebo-controlled study was conducted on 220 children aged 1-18 years with moderate-to-severe AD (Trial number: NCT01635738). The children were randomized to receive LP, LF, LP + LF mixture, and placebo for 3 months. Changes in severity scoring of atopic dermatitis (SCORAD), Family Dermatology Life Quality Index (FDLQI), and Children's Dermatology Life Quality Index (CDLQI) scores in the different groups and at different visits were evaluated. Skin prick tests, levels of IgE, IFN-γ, IL-4, TGF-β, and TNF-α, and urine biomarkers were also evaluated. RESULTS Children who received LP, LF, and LP + LF mixture showed lower SCORAD scores than the placebo group (P < 0.001), and this difference remained even at 4 months after discontinuing the probiotics. The FDLQI and CDLQI scores were lower in the LP, LF, and LP + LF mixture group than in the placebo group (P = 0.02 and 0.03). IgE, TNF-α, urine eosinophilic protein X, and 8-OHdG levels decreased, whereas IFN-γ and TGF-β increased in the probiotic groups, but these did not reach statistical significance except for IL-4 (P = 0.04). In subgroup analyses, SCORAD scores significantly decreased after probiotic treatment especially in children younger than age 12, with breastfeeding > 6 months, and with mite sensitization (P < 0.001). CONCLUSION Supplementation of a probiotic mixture of LP and LF is associated with clinical improvement in children with AD.