Adhesion to host tissues and bacterial aggregation (auto- and coaggregation) are the highly important criteria for selecting strains with probiotic potential. These abilities are commonly involved with surface-charged characteristics. This is the first study to investigate the oral Lactobacillus species using an oral keratinocyte cell line. Significant results were found for the correlations between the adhesion and surface charge characteristics and for aggregation among certain strains of Lactobacillus gasseri, Lactobacillus fermentum and Lactobacillus paracasei. This observation could be useful when collecting background information for the selection of probiotic strains for use in oral health.
Background: A previous study revealed Lactobacillus paracasei SD1, a probiotic strain, could reduce mutans streptococci (MS). The aim of this study was to evaluate the long-term effects of L. paracasei SD1 on the colonization of MS, and whether caries lesions developed. Methods: After informed consent, 122 children were recruited and randomly assigned to the probiotic or control groups. The probiotic group received milk-powder containing L. paracasei SD1 and the control group received standard milk-powder once daily for six months. Salivary MS and lactobacilli were enumerated using differential culture at baseline and at three-month intervals for 12 months. The persistence of L. paracasei SD1 was investigated using AP-PCR for DNA-fingerprinting. Oral health was examined at baseline and at the end of the study according to WHO criteria. Results: The long-term consumption could prolong colonization of L. paracasei SD1. Significantly reduced MS counts and increased lactobacilli levels were found among children in the probiotic group. There were less caries lesions in the probiotic group at the end of the study. A significant reduction of the development of new caries lesions (4.5 times) was observed in the high caries risk group but not in the low caries risk group. Conclusions: Results demonstrate that the long-term daily ingestion of the human-derived probiotic L. paracasei SD1 significantly reduces the number of MS and caries risk in the high caries group.
Background/purpose
Our previous study revealed that probiotic
Lactobacillus paracasei
SD1 could reduce mutans streptococci as evaluated by cultivation-method as well as stimulate innate immunity. This study aimed to further investigate the effect of the probiotic on various oral bacteria by real-time PCR and salivary IgA levels.
Materials and methods
Forty children were included by randomization from either probiotic or control group in the previous study. The probiotic or control received milk-powder with or without
L
.
paracasei
SD1, respectively once daily for 6 months. Saliva were collected at baseline 3-, 6-, and 12-months and were evaluated for total bacteria, total lactobacilli (TL),
L. paracasei/L. casei
(LP/LC), total streptococci (TS) and
Streptococcus mutans
using the real-time PCR. The salivary IgA (sIgA) was examined using the ELISA method.
Results
All target bacterial levels were not significantly different at baseline in both groups. After milk-powder consumption, TL and LP/LC levels were significantly increased in the probiotic group, whereas TS and
S. mutans
levels were significantly decreased compared to baseline. TS and
S. mutans
levels were significantly lower, while the sIgA was greater in the probiotic compared to the control group. In the probiotic group, a positive correlation was found between LP/LC and sIgA, while negative correlations were observed between TS or
S. mutans
levels and sIgA.
Conclusion
L. paracasei
SD1 could control
S. mutans
level and could stimulate sIgA. Results indicate that the
L. paracasei
SD1 strain may have a benefit for prevention of dental caries.
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