Relationship Between Mutans Streptococci and Lactobacilli in the Oral Cavity and Intestine of Obese and Eutrophic Children With Early Childhood Caries—Preliminary Findings of a Cross-Sectional Study

Abstract

This brief communication assessed whether there was any relationship between the counts of lactobacilli (LB) and mutans streptococci (MS) in the oral cavity and intestine of obese and eutrophic children with early childhood caries (ECC). Seventy-eight preschoolers were assigned into the following groups: 1. obese children with ECC (OECC), 2. eutrophic children with ECC (EECC), 3. obese caries-free children (OCF), and 4. eutrophic caries-free children (ECF). The diagnosis of obesity and ECC was based on the World Health Organization criteria. Dental plaque and fecal samples were collected to assess the counts of MS and LB using selective media. Data were evaluated by Poisson regression analysis, Wilcoxon test, and Sign test. Microbial indicators of ECC in obese children were MS counts in the intestine [rate ratio (RR): 4.38] and presence of LB in the oral cavity (RR: 2.12). The indicators in eutrophic children were MS levels and the presence of LB, both in the oral cavity (RR: 6.35/1.50) and intestine (RR: 2.35/2.38) (p < 0.05). The comparison between MS levels in the mouth and in the intestine revealed significant differences only in the ECF group (p = 0.04). Regarding LB presence in the mouth vs. in the intestine, except for the OCF group (p = 0.03), no other statistical differences were found. Our preliminary findings highlighted that the levels of MS and the presence of LB in the oral cavity, as well as in the lower gastrointestinal tract were associated with ECC. Moreover, obesity was found to influence this relationship.

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“…Precise information of the LB species is crucial to investigate their role in the disease course or even in health status, and long-term investigations assessing mouth colonization by probiotic bacteria are still necessary for possible future therapy application/development. Currently, it has been suggested that the oral microbiota may reflect the intestinal condition [ 34 , 35 ] because it is in the oral cavity that the digestion process begins, and a significant amount of exogenous microbes can be swallowed together with the food bolus, being able to resist the reduced stomach pH and reach the intestine. It is of prime importance to emphasize that the mouth is part of the human body and, therefore, changes occurring in it might be connected to systemic alterations, reinforcing a multidisciplinary and holistic approach for the patient`s health [ 13 ].…”

“…To measure weight and height, a calibrated electronic scale and a non-extensible measuring tape attached to a wooden board at 90° degrees to the ground, together with a headboard, were used, respectively [ 34 , 35 ]. To measure height, children were placed erect, with feet and heels parallel and together, as well as with the Camper Plane parallel to the ground.…”

“…In this regression analysis, the rate ratio reflected the effect-size (3.00, large; 1.86, medium; 1.22, small) [ 36 ]. L. acidophilus and L. gasseri were assessed based on the presence or absence of the bacteria due to their low counts ( L. acidophilus PCR cycle number range: 24.06–37.83; L. gasseri PCR cycle number range: 28.68–37.92) [ 9 , 35 ].…”

“…Considering that the mouth seems to reflect the intestine condition regarding some bacteria [ 34 , 35 ] and that lactobacilli showed important fermentation activities in the physiological regulation of the intestinal microbiome, besides being important for caries development, studying L. acidophilus and L. gasseri in samples from the oral cavity was proposed in the present study. Moreover, no report has evaluated the presence of the species in biological material from the oral cavity, nor a possible influence of ECC on this connection.…”

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“…However, due to the arsenal of adhesive molecules, streptococci can colonize many types of surfaces (87). Intriguingly, some groups of bacteria could overlap in oral and stool samples (88)(89)(90), due to oral bacteria often being swallowed together with saliva and food during the digestion process. A recent study involving preschoolers investigated whether Firmicutes and Bacteroidetes levels in the mouth reflected the gut condition in obesity and ECC, demonstrating that Firmicutes phyla behave differently according to the nutritional status (obesity or eutrophy) and caries experience, and that dental biofilm and gut microbiome might share levels of similarity.…”