Effects of human milk on adhesion of Streptococcus mutans to saliva-coated hydroxyapatite in vitro

A longitudinal study on the impact of breastfeeding with or without formula milk on dental caries

Concerns exist about prolonged breastfeeding increasing dental caries risk, but evidence is mixed. This 2-year cohort study followed 486 toddlers, to examine the association between breastfeeding duration and caries at age 3. Caregivers reported feeding practices and potential confounders every 6 months. "Full breastfeeding" was defined as feeding breastmilk without formula milk regardless of other foods/liquids, whereas "any breastfeeding" was feeding breastmilk with/without formula milk. A calibrated dentist performed dental examinations. We used multivariable log-binomial and negative binomial regressions to estimate relative risks (RRs) and 95% confidence intervals (CIs) for caries prevalence and severity, adjusted for confounders. At 3-year-old, 60.3% of children exhibited caries (mean decayed-and-filled-teeth, dft: 3.3). Notably, full breastfeeding for 6-17 months reduced caries prevalence (RR = 0.84, 95%CI 0.73-0.98 for 6-11 months; RR = 0.78, 95%CI 0.63-0.96 for 12-17 months). Conversely, any breastfeeding ≥ 18 months significantly increased caries risk (RR = 1.45, 95%CI 1.31-1.60). Full breastfeeding ≥ 6 months or any breastfeeding 6-17 months was associated with lower dft scores in children. Our findings suggest a complex relationship between breastfeeding duration and caries. Full breastfeeding for moderate durations (6-17 months) offers protective benefits, while any breastfeeding ≥ 18 months increases risk in this population.

Exploring the Possible Impact of Oral Nutritional Supplements on Children's Oral Health: An In Vitro Investigation

Eight pediatric oral nutritional supplements (ONSs) and 0.5% fat bovine milk were examined in vitro regarding their effect on the adhesion of three caries-related bacteria, Streptococcus mutans (strain CCUG 11877T), Lactobacillus gasseri (strain CCUG 31451), and Scardovia wiggsiae (strain CCUG 58090), to saliva-coated hydroxyapatite, as well as their pH and capacity to withstand pH changes. Bacteria were cultivated and radiolabeled. The adhesion assays used synthetic hydroxyapatite coated with whole or parotid saliva. Measurements of pH and titration of the products with HCl and NaOH were conducted in triplicate. Three ONSs promoted the S. mutans adhesion to saliva-coated hydroxyapatite (increase from 35% to >200%), supporting caries risk enhancement. S. wigssiae and L. gasseri adhered only to one and no ONS, respectively. Most supplements had limited buffering capacity to counteract acidification changes, suggesting their low capacity to neutralize acids, and one ONS showed a significant capacity to counteract basic changes, suggesting a high erosive potential. S. mutans adhesion was influenced by the ONS pH and volume NaOH added to reach pH 10. L. gasseri and S. wiggsiae adhesion was influenced by the ONSs' carbohydrate and fat content. Interdisciplinary efforts are needed to increase awareness and prevent the possible negative impact of ONSs on children's oral health.

Streptococcus lactarius MB622 and Streptococcus salivarius MB620 isolated from human milk reduce chemokine IL-8 production in response to TNF-α in Caco-2 cell line, an exploratory study

Streptococci are a predominant genera of the human milk microbiome. Among different lactic acid bacteria (LAB) a few Streptococcal strains are also considered as probiotics. Probiotic bacteria are reported to modulate immunity when consumed in adequate amount and bacterial hydrophobicity can be considered as a preliminary experiment for the adhesive capability of probiotic bacteria to the epithelial cells. The present study aimed to investigate the probiotic, hydrophobic and immune modulation property of Streptococcus lactarius MB622 and Streptococcus salivarius MB620, isolated from human milk. S. lactarius MB622 and S. salivarius MB620 displayed higher hydrophobicity (78 % and 59 % respectively) in addition to intrinsic probiotic properties such as gram positive classification, catalase negative activity, resistance to artificially stimulated gastric juice and gastrointestinal bile salt concentration. In conclusion Streptococcus lactarius MB622 and Streptococcus salivarius MB620 isolated from human milk when administered in sufficient amount and for certain duration could be used to reduce inflammation inside the colon by reducing the production of inflammatory booster (IL-8) in diseased state.

The breast milk and childhood gastrointestinal microbiotas and disease outcomes: a longitudinal study

BACKGROUND

We aimed to characterize breast milk microbiota and define associations with saliva and fecal microbiota and selected diseases in preschool children.

METHODS

In a longitudinal cohort study, the microbiotas from breast milk, mouth, and fecal samples were characterized by 16S rRNA gene sequencing. Questionnaires and medical records provided information on demographics, medical, and dental data.

RESULTS

The phylogeny in breast milk, saliva swabs, and feces differed at all levels (p < 0.0003), though all harbored species in Streptococcus, Veillonella, and Haemophilus. Species richness was highest in breast milk with increasing resemblance with the oral swab microbiota by increasing age. Caries-affected children at age 5 had been fed breast milk with tenfold higher abundance of caries-associated bacteria, e.g., Streptococcus mutans, than caries-free children (p < 0.002). At that age, taxa, e.g., Neisseria sicca were overrepresented in saliva swabs of children with otitis media (LDA score >2, p < 0.05). Gut symbionts, e.g., Bacteroides, were underrepresented in 3-month fecal samples in children later diagnosed with allergic disease (LDA score >2, p < 0.05).

CONCLUSIONS

Distinct microbiotas for the three sources were confirmed, though resemblance between milk and oral swab microbiota increased by age. Future studies should evaluate if the observed associations with disease outcomes are causal.

IMPACT

Few studies have studied the association between breast milk microbiota and gastrointestinal microbiota beyond early infancy. The present study confirms distinct microbiota profiles in breast milk, saliva swabs, and feces in infancy and indicates increasing resemblance between breast milk and the oral microbiota by increasing age. The fecal microbiota at 3 months was associated with later allergic disease; the saliva microbiota by age 5 differed between children with and without otitis media at the same age; and children with caries by age 5 had been fed breast milk with a higher abundance of caries-associated bacteria.

Microbiota of preterm infant develops over time along with the first teeth eruption

Objective

The temporal growth of the infant microbiome in the early years of life influences short- and long-term infant health. The aim of this longitudinal study was to investigate bacterial dynamics in the microbiome of preterm infants during tooth eruption.

Methods

Saliva samples from normally delivered (n = 24) and preterm infants (n = 31) were collected 30 days after birth and after the eruption of two primary mandibular incisors. Based on Illumina MiSeq Sequencing of the 16S rRNA gene, the dynamic microbial changes of newborns at two-time points were investigated. Meanwhile, the Human Oral Microbiome Database was adopted for assigning taxonomy.

Results

Using alpha and beta diversity analyses, different shift patterns of microbiome structures in preterm and healthy participants and bacterial diversity over time were observed. The relative abundance and shifts trend, along with the two lower primary central incisors eruption, of core oral flora varies in full-term and preterm groups, including Gemella spp., Rothia mucilaginosa, Veillonella atypica, etc. Several microorganisms colonize later in the oral microbiome development of premature babies, such as Gemella spp. In addition to teeth eruption, the growth of the saliva microbiome in preterm infants could be influenced by breastfeeding durations and birth weight.

Conclusion

This study provided insights into how the oral microbiota changes during tooth eruption in preterm infants and how the colonization of the oral cavity with bacteria in preterm infants differs significantly from that in full-term infants.

Clinical characteristics of children and guardians possessing CBP-positive Streptococcus mutans strains: a cross-sectional study

Streptococcus mutans is a major etiological agent for dental caries. We previously demonstrated that S. mutans strains expressing collagen-binding proteins (CBPs) were related to the pathogenesis of systemic diseases. However, their acquisition and colonization remain unknown. Here, we investigated the detection rates of CBP-positive S. mutans strains in children and their guardians to clarify the background for the acquisition and colonization in children. Saliva samples were collected from children and their mothers, and detection of S. mutans and collagen-binding genes (cnm, cbm) was performed by PCR after DNA extraction. The oral status of each child was examined, and their mothers were asked to complete a questionnaire. The isolation rate of Cnm-positive S. mutans was significantly higher in mothers than in children. Notably, the possession rates of CBP-positive strains in children were significantly higher in children whose mothers had CBP-positive strains than in children whose mothers did not have these strains. Furthermore, children with CBP-positive strains had a significantly shorter breastfeeding period than children without these strains. The present results suggest that nutritional feeding habits in infancy are one of the factors involved in the acquisition and colonization of CBP-positive S. mutans strains.

Effect of Beverage Consumption Frequency on DMFT Index among Iranian Adult Population: An AZAR Cohort Study

Background

Given the effect of oral and dental condition on emotional and physical health and the different effects of beverage consumption on decayed, missing, and filled teeth (DMFT) as one of the indicators of oral health in different populations, this study aimed to investigate the effect of beverage consumption and its frequency on DMFT among Iranian adult population.

Materials and Methods

The data of this cross-sectional study were obtained from AZAR (Azerbaijan) cohort, conducted on 15,006 adults aged 35 to 70 years old in Shabestar County, Iran. Demographic and nutritional data were collected by nutritionists through the "Food Frequency Questionnaire," and DMFT index by general practitioners trained by a dentist according to the World Health Organization (WHO) guidelines. Beverages including milk, doogh, natural fruit juice, black tea, nonalcoholic beer, coffee, sugar-sweetened beverages, and artificial fruit juice were studied.

Results

A total of 14,966 adults with the mean age of 49.64 ± 9.28 were enrolled. The participants' mean DMFT value was 21.27 ± 8.95. Weekly consumption of tea and coffee beverages resulted in 13% (95% confidence interval: 3% to 22%) lower DMFT compared to daily consumption (p=0.01). However, there was no association between DMFT and other beverages.

Conclusion

The higher DMFT values with the daily consumption of tea and coffee beverages showed that a part of adults' oral health is affected by beverages; therefore, this should be considered by healthcare authorities in order to manage carries development in the communities.

Temporal development of the infant oral microbiome

The human oral microbiome is becoming recognized as playing roles in health and disease well beyond the oral cavity over the lifetime of the individual. The oral microbiome is hypothesized to result from specific colonization events followed by a reproducible and ordered development of complex bacterial communities. Colonization events, proliferation, succession and subsequent community development are dependent on a range of host and environmental factors, most notably the neonate diet. It is now becoming apparent that early childhood and prenatal influences can have long term effects on the development of human oral microbiomes. In this review, the temporal development of the infant human oral microbiome is examined, with the effects of prenatal and postnatal influences and the roles of specific bacteria. Dietary and environmental factors, especially breastfeeding, have a significant influence on the development of the infant oral microbiome. The evidence available regarding the roles and functions of early colonizing bacteria is still limited, and gaps in knowledge where further research is needed to elucidate these specific roles in relation to health and disease still exist.

Oral microbiome: possible harbinger for children's health

The human microbiome functions as an intricate and coordinated microbial network, residing throughout the mucosal surfaces of the skin, oral cavity, gastrointestinal tract, respiratory tract, and reproductive system. The oral microbiome encompasses a highly diverse microbiota, consisting of over 700 microorganisms, including bacteria, fungi, and viruses. As our understanding of the relationship between the oral microbiome and human health has evolved, we have identified a diverse array of oral and systemic diseases associated with this microbial community, including but not limited to caries, periodontal diseases, oral cancer, colorectal cancer, pancreatic cancer, and inflammatory bowel syndrome. The potential predictive relationship between the oral microbiota and these human diseases suggests that the oral cavity is an ideal site for disease diagnosis and development of rapid point-of-care tests. The oral cavity is easily accessible with a non-invasive collection of biological samples. We can envision a future where early life salivary diagnostic tools will be used to predict and prevent future disease via analyzing and shaping the infant’s oral microbiome. In this review, we present evidence for the establishment of the oral microbiome during early childhood, the capability of using childhood oral microbiome to predict future oral and systemic diseases, and the limitations of the current evidence.

Development of Streptococcus mutans biofilm in the presence of human colostrum and 3'-sialyllactose

Aim: To evaluate the initial adhesion and formation of Streptococcus mutans biofilm in vitro in the presence of saliva, human colostrum and 3'-sialyllactose. Methods: Human colostrum and salivas were collected from 30 mothers and newborn postpartum. Eighteen hours culture of S. mutans was treated with colostrum or 3'-sialyllactose in three different moments: before, during, and after 24 h from the microbial inoculation. Salivas were also tested in conjunction with colostrum. The assays were realized in sterile 96-well flat-bottom microtiter plates for 24 h. The biofilms were fixed, washed, stained with crystal violet, and extracted. Absorbance was measured to evaluate biofilm growth mass. Results: Colostrum applied after and during the inoculation decreased biofilm formation when compared with the control (p < .05). The presence of saliva increased the biofilm biomass (p < .05). The application of 3'-sialyllactose reduced biofilm formation independently of moments of application (p < .05). Conclusion: Saliva contributed to the proliferation of biofilm and colostrum did not prevent the initial adhesion, but interfered in the accumulation and development of microorganisms in biofilms. 3'-sialyllactose significantly decreased biofilm formation. This information expands the importance of colostrum as a potent oral antimicrobial biofluid.

Breastfeeding and early childhood caries. Review of the literature, recommendations, and prevention

CONTEXT

Early childhood caries is a chronic disease that affects a child's general state of health. The question of a link between primary tooth caries and breastfeeding has been addressed for many years, with contradictory results. The concomitant decay of primary teeth, effective establishment, or not, of oral hygiene, and alimentary diversification away from breastfeeding are all confounding factors in this topic. The aim of our study was to analyze the links between breastfeeding and the appearance of caries, as described in the scientific literature and in the recommendations of specialist societies.

METHODS

A review of publications written in English and French was carried out, searching for the terms early childhood caries, decay and breastfeeding, focusing on literature reviews and meta-analyses dating from the past 10 years. The PubMed database of the US National Library of Medicine National Institutes of Health (NBCI) was used. Furthermore, a review of specialist dental and pediatric societies was conducted.

RESULTS

Breastfeeding until the age of 1 year is not associated with an increased risk of dental caries, and may even provide protection compared with feeding with formula milk. By contrast, infants who are breastfed beyond the age of 12 months demonstrate an increased risk of caries. However, the results derive from heterogeneous studies that do not always take into account contradictory factors such as eating habits of the mother or infant (feeding during the night, number of meals per day, eating sweet foods etc.), dental hygiene, or the sociocultural context. Moreover, the most recent recommendations of pediatric and dental societies advise breastfeeding until the age of 2 years, suggesting that this be accompanied by toothbrushing and better nutrition by reducing the frequency and consumption of sugary foods, aimed at helping parents choose prolonged breastfeeding.

CONCLUSION

Extended breastfeeding is a protective factor for childhood caries under 1 year of age. Beyond 1 year, it is difficult to conclude between protection and aggravation of caries because of the multiplicity of confounding factors such as dietary patterns, which vary depending on countries and families, and problems of oral hygiene. In practical terms, when breastfeeding continues beyond 1 year, consultation with a dentist is necessary for examination and preventive advice regarding dietary practices (especially sugar intake), oral hygiene, or supplementary fluoride.

Characterization of the in situ pellicle ultrastructure formed under the influence of bovine milk and milk protein isolates

OBJECTIVES

The present study aimed to investigate if bovine milk or milk protein isolates, respectively, alter the ultrastructure of thein situ pellicle and might therefore have an influence on oral health.

METHODS

In situ pellicle samples were formed on bovine enamel slabs exposed in the oral cavity of three subjects for 6, 30, 60 or 120 min. After 3 min of pellicle formation, mouthrinses were performed for 3 min with (non-)homogenized UHT- or fresh milk (0.3% or 3.8% fat), 30% UHT-treated cream or different types of casein- or milk protein isolates containing preparations. The specimens were removed after the exposure times and transmission electron microscopy (TEM) was performed. Native pellicle samples served as controls.

RESULTS

Topical ultrastructural pellicle modifications were detected after mouthrinses with all types of homogenized UHT- or fresh milk and after the application of a 3% native casein micelles containing experimental solution. Atypical globular protein structures, identified as casein micelles, were temporarily adsorbed onto the pellicle. They were closely associated with lipid droplets. Furthermore, the mouthrinses occasionally affected the morphology of salivary bacteria. However, no notable ultrastructural alterations remained after 120 min of pellicle formation.

CONCLUSION

For the first time, bovine milk- and micellar casein-induced pellicle modifications were revealed by TEM. The adsorption of micellar casein is possibly due to its molecular interactions.

CLINICAL SIGNIFICANCE

Bovine milk or micellar caseins provide some potential for the development of preventive strategies against bacterial biofilm formation or erosive processes at the tooth surface.

The role of human milk and sucrose on cariogenicity of microcosm biofilms

This study investigated the effect of human milk, alone and associated with sucrose, in the cariogenicity of biofilms in a microcosm biofilm model and compared with the cariogenicity of sucrose and bovine milk. Microcosm biofilms were grown in enamel discs in 24-well plates. Six growth conditions were studied: DMM (chemically defined artificial saliva - negative control), DMM with 1% of sucrose (DMM+s) (positive control), human milk with DMM, human milk with DMM+s, bovine milk with DMM, and bovine milk with DMM+s. After 5 days, the outcome variables surface hardness change (%SHC), microbiological composition of biofilms, and pH of supernatant were analyzed. All groups had significantly lower hardness loss compared to the DMM group with 1% of sucrose. Human and bovine milk associated with sucrose showed higher hardness loss. The supernatant pH values after 6 hours of different treatments were similar for the groups sucrose and human milk associated with sucrose (p>0.05). After 18 hours at rest in pure DMM, an increase in the pH of the supernatant was observed. Higher values of total microorganisms count were found for sucrose and bovine milk groups compared to the group supplemented only by DMM. Bovine milk group showed greater amount of total aciduric microorganisms in comparison to human milk group. Within the limits of this study, it can be infered that both human and cow milks have some cariogenic potential, although differing from sucrose in terms of mineral loss.

Oral microbiome development during childhood: an ecological succession influenced by postnatal factors and associated with tooth decay

Information on how the oral microbiome develops during early childhood and how external factors influence this ecological process is scarce. We used high-throughput sequencing to characterize bacterial composition in saliva samples collected at 3, 6, 12, 24 months and 7 years of age in 90 longitudinally followed children, for whom clinical, dietary and health data were collected. Bacterial composition patterns changed through time, starting with "early colonizers", including Streptococcus and Veillonella; other bacterial genera such as Neisseria settled after 1 or 2 years of age. Dental caries development was associated with diverging microbial composition through time. Streptococcus cristatus appeared to be associated with increased risk of developing tooth decay and its role as potential biomarker of the disease should be studied with species-specific probes. Infants born by C-section had initially skewed bacterial content compared with vaginally delivered infants, but this was recovered with age. Shorter breastfeeding habits and antibiotic treatment during the first 2 years of age were associated with a distinct bacterial composition at later age. The findings presented describe oral microbiota development as an ecological succession where altered colonization pattern during the first year of life may have long-term consequences for child´s oral and systemic health.

Self-reported bovine milk intake is associated with oral microbiota composition

Bovine milk intake has been associated with various disease outcomes, with modulation of the gastro-intestinal microbiome being suggested as one potential mechanism. The aim of the present study was to explore the oral microbiota in relation to variation in self-reported milk intake. Saliva and tooth biofilm microbiota was characterized by 16S rDNA sequencing, PCR and cultivation in 154 Swedish adolescents, and information on diet and other lifestyle markers were obtained from a questionnaire, and dental caries from clinical examination. A replication cohort of 31,571 adults with similar information on diet intake, other lifestyle markers and caries was also studied. Multivariate partial least squares (PLS) modelling separated adolescents with low milk intake (lowest tertile with <0.4 servings/day) apart from those with high intake of milk (≥3.7 servings/day) based on saliva and tooth biofilm, respectively. Taxa in several genera contributed to this separation, and milk intake was inversely associated with the caries causing Streptococcus mutans in saliva and tooth biofilm samples by sequencing, PCR and cultivation. Despite the difference in S. mutans colonization, caries prevalence did not differ between milk consumption groups in the adolescents or the adults in the replication cohort, which may reflect that a significant positive association between intake of milk and sweet products was present in both the study and replication group. It was concluded that high milk intake correlates with different oral microbiota and it is hypothesized that milk may confer similar effects in the gut. The study also illustrated that reduction of one single disease associated bacterial species, such as S. mutans by milk intake, may modulate but not prevent development of complex diseases, such as caries, due to adverse effects from other causal factors, such as sugar intake in the present study.

Effect of Commonly Prescribed Liquid Medications on Streptococcus mutans Biofilm. An in vitro study

OBJECTIVE

This study addressed the effect of pediatric liquid antibiotic medications on Streptococcus mutans UA159. These suspensions commonly contain sugars such as sucrose to make them more palatable for children. The study was designed to evaluate the effects of oral liquid antibiotics on Streptococcus mutans growth and biofilm formation.

STUDY DESIGN

A 24 hour culture of S. mutans was treated with various concentrations of liquid medications commonly prescribed to children for odontogenic or fungal infections- amoxicillin, penicillin VK, clindamycin, and nystatin. The study was conducted in sterile 96-well flat bottom microtiter plates. The minimum inhibitory and biofilm inhibitory concentrations (MIC/MBIC) of S. mutans were determined for each medication. S. mutans was cultured with and without the test drugs, the amount of total growth measured, the biofilms washed, fixed, and stained with crystal violet. The absorbance was determined to evaluate biofilm formation.

RESULTS

Higher concentrations of amoxicillin, penicillin VK and clindamycin had decreased biofilm and overall growth than the control. The MICs were 1:2,560 (1.95 ug/ml), 1:2,560 (1.95 ug/ml) and 1:40 (9.375 ug/ml), while the MBIC were 1:640 (7.8 ug/ml), 1:1,280 (3.9 ug/ml) and 1:20 (18.75 ug/ml), respectively. Lower concentrations provided increased biofilm and overall growth. Nystatin induced significantly more biofilm and overall growth than the control at all concentrations.

CONCLUSION

At high concentrations, approximately at the levels expected to be present in the oral cavity of children, amoxicillin, penicillin, and clindamycin inhibited S. mutans biofilm and overall growth due to their antibiotic activity, while at lower concentrations the three antibiotics demonstrated an increase in biofilm and growth. The increase in S. mutans biofilm and overall growth is most likely attributed to the sugar content in the medications. Nystatin provided an increase in biofilm and growth at each concentration tested.

Oral Microbiota in Infants Fed a Formula Supplemented with Bovine Milk Fat Globule Membranes - A Randomized Controlled Trial

Background

In a recent study, supplementation of infant formula with milk fat globule membranes (MFGM) decreased the incidence of otitis media in infants <6 months of age.

Objectives

The aim of the present study was to characterize the oral microbiota in infants fed MFGM-supplemented formula and compare it to that of infants fed standard formula or breast milk.

Methods

In a prospective double-blinded randomized controlled trial, exclusively formula-fed infants <2 months of age were randomized to be fed experimental formula (EF, n = 80) with reduced energy and protein and supplemented with a bovine MFGM concentrate, or standard formula (SF, n = 80) until 6 months of age. A breast-fed reference (BFR, n = 80) group was also recruited. The oral microbiota was analyzed at 4 (n = 124) and 12 (n = 166) months of age using Illumina MiSeq multiplex sequencing and taxonomic resolution against the HOMD 16S rDNA database of oral bacteria.

Results

Species richness in the oral samples did not differ between the EF and SF groups, but partial least square modeling identified a few taxa that were significantly associated with being in either group, e.g. lower level of Moraxella catarrhalis in the EF group. Infants in the BFR group had significantly lower species richness at 4 months of age and their microbiota pattern differed markedly from the formula-fed groups.

Conclusions

Supplementation of infant formula with MFGM yielded moderate effects on the oral microbiome. Moraxella catarrhalis was less prevalent in infants fed EF than in those fed SF and may be associated with the decrease in otitis media seen in the same group.

Breastfeeding Duration and Childhood Caries: A Cohort Study

This cohort study was conducted in Khon Kaen, Thailand, to test the hypothesis that a longer breastfeeding duration increases the risk for dental caries in primary teeth. We collected information on infant feeding practices and potential confounders using a structured questionnaire to interview mothers or caregivers during the second trimester of pregnancy and after birth at 21 days and at 3, 12, 18, 24, and 36 months. Regardless of other liquids and foods, full breastfeeding was defined as feeding breast milk but not formula, while any breastfeeding was feeding breast milk with or without formula. Two calibrated dentists measured dental caries when the children were 3-4 years of age using the decayed, missing, and filled surfaces (dmfs) index following the World Health Organization criteria. Negative binomial regression with a generalized linear model was used to estimate relative risks (RRs) and 95% confidence intervals (CIs) using dmfs as an outcome. Log-binomial regression was performed to model the caries prevalence. Of 556 children, 88.1% had dental caries with a mean dmfs of 14.2. Full breastfeeding for 6-11 months was significantly associated with a lower dmfs (adjusted RR 0.77, 95% CI 0.63, 0.93) and a lower caries prevalence (adjusted RR 0.45, 95% CI 0.22, 0.90). The frequency of sleeping while breast- or bottle-feeding increased the caries risk in a dose-response manner. There was no association between duration of any breastfeeding and dental caries. In conclusion, full breastfeeding for 6-11 months may protect against dental caries in primary teeth. Prolonged breastfeeding was not associated with dental caries in this population.

Characterization and in vitro properties of oral lactobacilli in breastfed infants

Background

Lactobacillus species can contribute positively to general and oral health and are frequently acquired by breastfeeding in infancy. The present study aimed to identify oral lactobacilli in breast and formula-fed 4 month-old infants and to evaluate potential probiotic properties of the dominant Lactobacillus species detected. Saliva and oral swab samples were collected from 133 infants who were enrolled in a longitudinal study (n=240) examining the effect of a new infant formula on child growth and development. Saliva was cultured and Lactobacillus isolates were identified from 16S rRNA gene sequences. Five L. gasseri isolates that differed in 16S rRNA sequence were tested for their ability to inhibit growth of selected oral bacteria and for adhesion to oral tissues. Oral swab samples were analyzed by qPCR for Lactobacillus gasseri.

Results

43 (32.3%) infants were breastfed and 90 (67.7%) were formula-fed with either a standard formula (43 out of 90) or formula supplemented with a milk fat globule membrane (MFGM) fraction (47 out of 90). Lactobacilli were cultured from saliva of 34.1% breastfed infants, but only in 4.7% of the standard and 9.3% of the MFGM supplemented formula-fed infants. L. gasseri was the most prevalent (88% of Lactobacillus positive infants) of six Lactobacillus species detected. L. gasseri isolates inhibited Streptococcus mutans binding to saliva-coated hydroxyapatite, and inhibited growth of S. mutans, Streptococcus sobrinus, Actinomyces naeslundii, Actinomyces oris, Candida albicans and Fusobacterium nucleatum in a concentration dependent fashion. L. gasseri isolates bound to parotid and submandibular saliva, salivary gp340 and MUC7, and purified MFGM, and adhered to epithelial cells. L. gasseri was detected by qPCR in 29.7% of the oral swabs. Breastfed infants had significantly higher mean DNA levels of L. gasseri (2.14 pg/uL) than infants fed the standard (0.363 pg/uL) or MFGM (0.697 pg/uL) formula.

Conclusions

Lactobacilli colonized the oral cavity of breastfed infants significantly more frequently than formula-fed infants. The dominant Lactobacillus was L. gasseri, which was detected at higher levels in breastfed than formula-fed infants and displayed probiotic traits in vitro.

Oral microbial profile discriminates breast-fed from formula-fed infants

OBJECTIVES

Little is known about the effect of diet on the oral microbiota of infants, although diet is known to affect the gut microbiota. The aims of the present study were to compare the oral microbiota in breast-fed and formula-fed infants, and investigate growth inhibition of streptococci by infant-isolated lactobacilli.

METHODS

A total of 207 mothers consented to participation of their 3-month-old infants. A total of 146 (70.5%) infants were exclusively and 38 (18.4%) partially breast-fed, and 23 (11.1%) were exclusively formula-fed. Saliva from all of their infants was cultured for Lactobacillus species, with isolate identifications from 21 infants. Lactobacillus isolates were tested for their ability to suppress Streptococcus mutans and S sanguinis. Oral swabs from 73 infants were analysed by the Human Oral Microbe Identification Microarray (HOMIM) and by quantitative polymerase chain reaction for Lactobacillus gasseri.

RESULTS

Lactobacilli were cultured from 27.8% of exclusively and partially breast-fed infants, but not from formula-fed infants. The prevalence of 14 HOMIM-detected taxa, and total salivary lactobacilli counts differed by feeding method. Multivariate modelling of HOMIM-detected bacteria and possible confounders clustered samples from breast-fed infants separately from formula-fed infants. The microbiota of breast-fed infants differed based on vaginal or C-section delivery. Isolates of L plantarum, L gasseri, and L vaginalis inhibited growth of the cariogenic S mutans and the commensal S sanguinis: L plantarum >L gasseri >L vaginalis.

CONCLUSIONS

The microbiota of the mouth differs between 3-month-old breast-fed and formula-fed infants. Possible mechanisms for microbial differences observed include species suppression by lactobacilli indigenous to breast milk.