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 (>or= 10(4) 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.

Oral adhesion and survival of probiotic and other lactobacilli and bifidobacteria in vitro.

INTRODUCTION: Most probiotic products are consumed orally and hence it is feasible that the bacteria in these products may also attach to oral surfaces; however, the effects of these bacteria on the oral ecosystem are mostly unknown. Our aim was to evaluate the oral colonization potential of different probiotic, dairy, and fecal Lactobacillus and Bifidobacterium strains in vitro. METHODS: The binding of 17 Lactobacillus and seven Bifidobacterium strains to hydroxyapatite and microtitre wells coated with human saliva was tested. Binding of selected strains to human buccal epithelial cells and co-adherence with Fusobacterium nucleatum were also investigated. In addition, the survival in sterilized human whole saliva was examined. RESULTS: There was a large variation in binding to saliva-coated surfaces and buccal epithelial cells but all strains survived in saliva. The binding pattern of the probiotics did not differ from the binding of the fecal strains. F. nucleatum altered the binding of both the low-binding bifidobacteria and the high-binding lactobacilli. CONCLUSION: The differences in binding in vitro may indicate that there are also differences in the persistence of the different probiotic strains in the oral cavity in vivo.

Colonization of Lactobacillus rhamnosus GG in the oral cavity.

BACKGROUND/AIMS: Lactobacillus rhamnosus GG (LGG) is one of the most widely studied probiotic bacterial strain. The benefits of LGG treatment in gastrointestinal disorders are well documented. The aim of the present study was to investigate whether LGG can be detected in the oral cavity after discontinuation of administration of a product prepared with this bacterium. MATERIAL AND METHODS: 56 volunteers consumed Gefilus juice (Valio Ltd, Helsinki, Finland) containing LGG during a 14-day trial period. Saliva samples were collected and cultured onto MRS agar after a clearance period and then daily after a 2-week intervention period for as long as LGG was found. LGG-like colonies were analyzed in saliva samples, identified by characteristic colony morphology, a lactose fermentation test, and PCR with specific primers. RESULTS: LGG was not able to colonize the oral cavity. It could only be temporarily detected. In one female subject, however, whose medical history revealed use of LGG in childhood, the bacterium was detected in all saliva samples taken up to 5 months. (She was excluded from the intervention trial). CONCLUSION: Permanent colonization of LGG in the oral cavity is improbable but seems possible in individual cases.

Short-term consumption of probiotic-containing cheese and its effect on dental caries risk factors.

Cheese is known to contain compounds that reduce the risk of dental caries. The long-term consumption of milk containing Lactobacillus rhamnosus GG, ATCC 53103 (LGG), has been shown to reduce caries risk in children. The aim of the present study was to examine whether short-term consumption of cheese containing LGG and Lactobacillus rhamnosus LC 705 would diminish caries-associated salivary microbial counts in young adults. Altogether, 74 18-35 year-old subjects completed this double-blinded, randomised, placebo-controlled study. During the 3 week intervention, the subjects ate 5 x 15 g cheese per day. Oral examinations were made before and after the study. Stimulated salivary secretion rates, buffer capacity and counts of salivary Streptococcus mutans, yeast and lactobacilli were evaluated before and after the intervention and after a 3 week post-treatment period. The results showed no statistically significant difference between the groups in Streptococcus mutans counts after the intervention, but during the post-treatment period there was a significantly greater reduction in these counts in the intervention group compared to the control group (P=0.05). However, Streptococcus mutans counts decreased in 20% (P=0.01) and yeast counts in 27% (P=0.005) of all the subjects, regardless of the intervention group. Results from logistic regression showed a trend indicating that probiotic intervention might reduce the risk of the highest level of Streptococcus mutans (OR=0.37, 95% CI 0.08-1.75, P=0.21) and salivary yeasts (OR=0.40, 0.09-1.71, P=0.22).