Prospective study of potential sources of Streptococcus mutans transmission in nursery school children

Child oral health: A plea for interdisciplinarity

A child’s oral health has major implications both for their general health and for their quality of life. Even before birth, the mother’s oral health can affect the development of the baby and pregnancy outcomes. From the very first months of life, feeding habits together with non-nutritive sucking ones, early transmission of pathogenic bacteria, and oral hygiene practices prefigure the child’s future health. The aim of this article is to provide a comprehensive overview of our current knowledge regarding the main oral health issues affecting children, namely dental caries, erosive tooth wear, developmental defects of enamel, maxillofacial growth anomalies, and traumatic dental injuries. Additionally, it aims to examine the oral health prevention and promotion programs that have been implemented in France over several decades. These prevention and promotion initiatives are not only part of a national program but are also being organized at a territorial level, although, unfortunately, they often remain limited to regional, departmental, or municipal scopes. It is essential for all those involved with children, whether they are health care professionals or not, to collaborate effectively to enhance both oral health and overall well-being. This requires fostering an interdisciplinary approach that involves various contributors working together in a complementary way.

Assessment of Diversity and Fidelity of Transmission of Streptococcus mutans Genotypes in American Indian and Southeast Iowa Mother-Child Dyads

Early childhood caries (ECC) is a common chronic infectious disease of childhood with a complex etiology and many contributing risk factors. Its prevalence is greater in certain racial and ethnic minority groups and populations with low socioeconomic status. Among the species of bacteria that contribute to the progression of dental caries, Streptococcus mutans (SM) has long been considered a primary etiological agent of the disease. We report here on the genotypic diversity, commonality, and fidelity of mother-child transmission of S. mutans in mother-child dyads in two high-risk populations.

Methods

Thirty-eight mother-child dyads from a Southeast Iowa population and 40 dyads from a Northern Plains American Indian Tribe were selected for a comparison of S. mutans genotype profiles within and between populations. S. mutans was isolated from whole mouth plaque samples collected from each subject. DNA was extracted and AP-PCR using OPA2 primer was performed. Amplified DNA was electrophoresed and images of the resulting patterns were compared via GelCompar®IIv6.5 software.

Results

Thirty unique S. mutans genotypes were identified from the 1,638 S. mutans isolates analyzed. Fifteen genotypes (50%) were seen in both cohorts, while 11 were unique to the American Indian (AI) cohort and 4 were unique to the Southeast Iowa (SEI) population. Within the AI cohort, 61.5% (16/26) of the S. mutans genotypes identified were seen in ≥2 individuals and 14 of the 26 (53.8%) were seen in ≥2 dyads. In the SEI cohort, 78.9% (15/19) of the S. mutans genotypes identified were seen in ≥2 individuals and 13 of the 19 (68.4%) were present in ≥2 dyads. Fifty-seven percent of AI children and 23% of SEI children displayed fidelity of mother-child transmission of ≥1 S. mutans genotype.

Conclusion

In comparing the populations, we observed large variation in genotypic diversity and fidelity of mother-child transmission, while the amount of commonality seen in both cohorts was similarly high in both groups. This study furthers our understanding of the genotypic diversity of S. mutans in both of these populations and provides a basis for further comparison to other populations at greater risk for developing ECC.

Presence of Streptococcus mutans and interleukin-6 and -10 in amniotic fluid

AIM

To evaluate the presence of Streptococcus mutans (SM), main pathogen of dental caries, interleukin-6 and -10 in samples of amniotic fluid (AF) and clinical and oral data of the healthy pregnancy, to investigate the SM exposition in intrauterine life and to elucidate the presence of antibodies to SM in newborns' saliva (SA) with undetectable levels of this microorganism described in the previous study.

METHODS

The study involved the participation of 26 women with term deliveries and without gestational complications. General health data were collected through a questionnaire applied to the participants. The volunteers were examined orally, the caries experience (decayed, missing, and filled teeth (DMFT) scores) was calculated and unstimulated SA was collected. The acquisition of AF was performed during cesarean sections and stocked on ice. The analysis of the presence of SM-DNA was performed by real-time PCR assays with specific primers. Levels of IL-6 and IL-10 were performed by ELISA with specific kits for these interleukins in the AF samples.

RESULTS

69.2% of the AF samples had detectable SM, and 65% of the women had the bacteria in the AF and SA at the same time. There was a positive association between the presence of SM in AF and a report of not going to the dentist frequently (p<.05). There was no statistically significant difference between the frequency of AF with or without detection of MS and active caries (p>.05). However, the DMFT scores of women with positive AF for SM were higher than that of women without detectable MS (p<.05). IL-6 levels were higher than IL-10 in AF (p<.05). There were no significant differences in the levels of interleukins between samples with detectable SM or in AF and even with clinical data analysis (p>.05).

CONCLUSIONS

The AF samples have SM in quantifiable levels, probably associated with the greatest caries experience, and seen by the highest DMFT index. Interleukin levels were not related to the presence of MS. The presence of SM in AF may explain the mucosal immune stimulation of newborn children by the previous detection of salivary antibodies against SM.

Dynamic Observation of the Effect of Maternal Caries on the Oral Microbiota of Infants Aged 12-24 Months

Aim

To provide a dynamic description of the oral microbial composition in mothers with and without dental caries and their children aging 12-24 months.

Methodology

A total of 20 pairs of mothers and their children aged 12 months were included and followed up at 18 and 24 months of age. Ten mothers with dental caries(MEG) and their children(CEG) were in the exposure group, and ten caries-free mothers(MCG) and their children(CCG)in control group. Supragingival plaque biofilm samples were collected and DNA was extracted for bacterial 16S rRNA gene sequencing.

Results

A total of 18 pairs completed follow-ups. At a 3% divergence level, the number of common operational taxonomic units found between the mothers and children increased as the children aged. Proteobacteria, Bacteroidetes, Firmicutes, Fusobacteria, and Actinobacteria accounted for more than 80% phyla of each group. A microbial community structure analysis showed that the differences between mothers and children were significant in all groups except for the MEG24 and CEG24 groups.

Conclusions

Oral microbiota of children was more like their mothers' with increasing age, regardless of whether the mothers had dental caries. Mothers with dental caries may have a greater influence on the oral microbiota of children's than those without dental caries as children age.

Acquisition and establishment of the oral microbiota

Acquisition and establishment of the oral microbiota occur in a dynamic process over various stages and involve close and continuous interactions with the host and its environment. In the present review, we discuss the stages of this process in chronological order. We start with the prenatal period and address the following questions: ‘Is the fetus exposed to maternal microbiota during pregnancy?’ and ‘If so, what is the potential role of this exposure?’ We comment on recent reports of finding bacterial DNA in placenta during pregnancies, and provide current views on the potential functions of prenatal microbial encounters. Next, we discuss the physiological adaptations that take place in the newborn during the birth process and the effect of this phase of life on the acquisition of the oral microbiota. Is it really just exposure to maternal vaginal microbes that results in the difference between vaginally and Cesarian section‐born infants? Then, we review the postnatal phase, in which we focus on transmission of microbes, the intraoral niche specificity, the effects of the host behavior and environment, as well as the role of genetic background of the host on shaping the oral microbial ecosystem. We discuss the changes in oral microbiota during the transition from deciduous to permanent dentition and during puberty. We also address the finite knowledge on colonization of the oral cavity by microbes other than the bacterial component. Finally, we identify the main outstanding questions that limit our understanding of the acquisition and establishment of a healthy microbiome at an individual level.

Phenotypic and genetic characteristics of Streptococcus mutans isolates from site-specific dental plaque in China

Introduction. Streptococcus mutans is an important cariogenic microbe.Hypothesis/Gap Statement. The potential characteristics of S. mutans isolates from site-specific dental plaque are still not clear.Aim. This study aimed to investigate the phenotypic and genetic characteristics of S. mutans isolates from site-specific dental plaque in China.Methodology. We used S. mutans isolated from children with early-childhood caries (ECC) and caries-free children to compare the phenotypic and genetic characteristics of S. mutans from site-specific dental plaque samples. The ECC subjects presented two sites: a cavitated lesion and a sound surface. The caries-free subjects presented one sound surface. Growth pattern, biofilm, decrease in pH, extracellular polysaccharide, expression levels of virulence-related genes, multilocus sequence typing (MLST) and phylogenetic trees were evaluated among these three sites.Results. The phenotypes detected between the cavitated and sound surfaces of ECC children were similar. However, the capacity for biofilm formation, pH drop and expression levels of genes (gtfB and spaP) of S. mutans in the caries-free group were lower compared with those of the ECC group. We identified 44 new alleles and 77 new sequence types. More than 90 % of the children with ECC shared an identical sequence type. The distribution of sequence types among different subjects showed diversity, and child-to-child transmission was detected.Conclusions. This is the first report of MLST on site-specific dental plaques in a single subject, and indicates that S. mutans isolated from site-specific dental plaque of a single subject showed similar phenotypes as a result of the isolates were closely related.

Vertical and Horizontal Transmission of Streptococcus Mutans and Effective Factors: An In Vivo Study

Aim:

The degree of vertical (intrafamilial) and horizontal (extrafamilial) transfer of Streptococcus mutans ( S. mutans) to a child shows differences according to cultures. The wrong care habits may result in transfer of S. mutans. The aim of this study was to determine the vertical and horizontal transmission of S. mutans to a child and effective factors.

Materials and Methods:

Mothers and kindergarten staff of 37 children aged between 4 and 5 years who initially started in two kindergartens (Group 1, n = 19; Group 2, n = 18) were included in this in vivo study according to 95% reliability and 80% theoretical power. Intraoral examination of mothers and children made according to the World Health Organization criteria (dmf-t/DMF-T) was done, following which mothers were asked to fill questionnaire forms including knowledge and attitudes of them about oral/dental health care. 1 mL saliva samples received from children/mothers/staff were examined microbiologically in order to isolate and quantify S. mutans. Arbitrarily primed polymerase chain reaction analysis was done to determine the genetic characteristics of S. mutans. All examinations were repeated to evaluate the horizontal transmission in the fifth month. Parametric tests ( t-test and two-way analysis of variance) were employed for comparison of the variables that meet the normality assumption and nonparametric tests (Mann–Whitney) were also used.

Results:

It was observed that there is a statistically significant correlation between mother DMF-T values and mother–child S. mutans similarity level ( P < .05). There is a statistically positive correlation between the habits of using a common fork, spoon, glass, and mother–child similarity level.

Conclusion:

Vertical and horizontal transfers occurred in Turkish families in order to prevent the transfer of S. mutans; wrong baby care habits that may lead to the transfer of S. mutans, which is the main factor in case of tooth decay, should be avoided.

Early childhood caries prevention: non-dental health professionals' viewpoint

BACKGROUND

Dental caries can develop early in life and have harmful consequences. Objective: To examine non-dental practitioners' knowledge of early childhood caries (ECC).

METHODS

A questionnaire on oral health and caries knowledge was emailed to five types of health professional who work with young children: paediatricians, GPs, midwives, paediatric nurses and paediatric healthcare assistants. Questions concerned: when a child should first visit a dentist; at what age toothbrushing should start; aetiopathogenic factors; early diagnosis; and the effect of breastfeeding.

RESULTS

494 health professionals (79 paediatricians, 59 physicians, 217 midwives, 92 paediatric nurses and 47 paediatric healthcare assistants) participated. Although most (89.86%) discussed oral health with parents, responses on when a child should first see a dentist and when toothbrushing should start varied. Almost half of respondents said they could diagnose caries but not all were confident in this. Aetiological factors in ECC mentioned included oral hygiene, bottle feeding, sugar intake, genetics and a lack of fluoride.

CONCLUSION

Non-dental practitioners lack knowledge about ECC, so cannot help prevent it. Initiatives including interprofessional training would improve their knowledge of oral health in early childhood.

Covid-19 Pandemic: What Changes for Dentists and Oral Medicine Experts? A Narrative Review and Novel Approaches to Infection Containment

The authors performed a narrative review on Severe Acute Respiratory Syndrome- CoronaVirus-2 ( SARS-CoV-2) and all infectious agents with the primary endpoints to illustrate the most accepted models of safety protocols in dentistry and oral medicine, and to propose an easy view of the problem and a comparison (pre- vs post-COVID19) for the most common dental procedures. The outcome is forecast to help dentists to individuate for a given procedure the differences in terms of safety protocols to avoid infectious contagion (by SARS-CoV-2 and others dangerous agents). An investigation was performed on the online databases Pubmed and Scopus using a combination of free words and Medical Subject Headings (MESH) terms: "dentist" OR "oral health" AND "COVID-19" OR "SARS-CoV-2" OR "coronavirus-19". After a brief excursus on all infectious agents transmittable at the dental chair, the authors described all the personal protective equipment (PPE) actually on the market and their indications, and on the basis of the literature, they compared (before and after COVID-19 onset) the correct safety procedures for each dental practice studied, underlining the danger of underestimating, in general, dental cross-infections. The authors have highlighted the importance of knowing exactly the risk of infections in the dental practice, and to modulate correctly the use of PPE, in order to invest adequate financial resources and to avoid exposing both the dental team and patients to preventable risks.

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.

Dental Health Status and Oral Health Care in Nursery School-Aged Children and their Parents Living in Poznan (Poland)

OBJECTIVES

The aim of this study was to evaluate the dental health status of nursery age children and parents. The use of dental services was assessed.

SUBJECTS AND METHODS

The study was performed in nursery schools located in Poznan, Western Poland. Clinical examination was carried out in 157 children (48.41% males and 51.59% females), aged 10-42 months. Dental health status (the number of teeth with caries, fillings and extracted) of their parents was determined on the basis of data obtained from a questionnaire. The questions also concerned information on child's and parents' dental check-ups and opinion on their predisposition to dental caries.

RESULTS

Clinical examination revealed that 21.05% of boys and 18.51% of girls had dental caries. Most mothers had from 1 to 5 either carious and/or filled teeth (47.13%) or extracted teeth due to carious process (61.15%); the fathers' values were similar at 46.50 and 66.24%, respectively. More mothers (84.71%) than fathers (72.62%) had regular dental check-ups (p = 0.02). The analysis of mother-father-child triads showed that when both parents visited the dentist regularly, more children were free of caries (56.68%) in comparison to those with the disease (13.38%; p < 0.001).

CONCLUSIONS

This study showed that the dental health status, as well as oral care of nursery school children and their parents, is unsatisfactory. Therefore, there is a need to introduce an intensive dental educational program focusing on dental prophylaxis for nursery age children and their parents or caregivers.

Streptococcus mutans detection in saliva and colostrum samples

Objective

To detect Streptococcus mutans in colostrum and saliva of neonates and compare with its detection in saliva of mothers.

Methods

Forty-three healthy women, full-term gestations with no complications, submitted to elective Cesarean section, and their newborns were included in the study. Samples were investigated by polymerase chain reaction to detect S. mutans in genetic material from the samples.

Results

Approximately 16% of colostrum samples showed S. mutans , but not correlated with the presence of the bacteria in both samples of saliva. S. mutans was detected in 49 and 30% of saliva samples of mothers and neonates, respectively. There was a positive correlation in S. mutans detection between types of saliva. The number of maternal samples of saliva with detectable S. mutans was smaller in women receiving dental treatment during pregnancy. Tooth brushing, three times a day, influenced the detection of S. mutans in both the saliva and the colostrum.

Conclusion

Although maternal saliva may present S. mutans , few samples of colostrum present the bacteria. The presence of bacteria in neonate saliva may be related to contact before birth. Dental treatment and hygiene habits seem to influence the detection of S. mutans in samples of maternal saliva and colostrum.

Plaque biofilm microbial diversity in infants aged 12 months and their mothers with or without dental caries: a pilot study

Background

A number of studies on oral microbial diversity of early childhood caries (ECC) have tended to focus on mid- or late-stage of ECC, with a lack of research into early stage of tooth eruption and maternal influence. The aims of this study are to compare the supragingival plaque biofilm microbiota diversity between mothers with or without dental caries and their 12-month-old infants, and to explore the relationship of microbial diversity between infants and their mothers, using sequencing analysis.

Methods

Supragingival plaque biofilm samples were collected from 20 pairs of mothers and their infants aged 12 months (10 mothers with dental caries and their 10 infants vs. 10 caries-free mothers and their 10 infants). The basic information of the mothers and infants had been collected through self-completed questionnaire. Pooled plaque biofilm DNA was extracted and DNA amplicons of the V4-V5 hypervariable region of the bacterial 16S rRNA gene were generated. Ilumina Miseq PE300 was used for 16S rRNA sequencing.

Results

The results showed that high bacterial diversity was noted in the plaque biofilm of infants and their mothers with or without dental caries (dental caries mothers vs. caries-free mothers: 774 operational taxonomical units (OTUs) vs. 761 OTUs at a 3% divergence; infants whose mothers have dental caries vs. infants whose mothers are caries-free: 815 OTUs vs. 684 OTUs at 3% divergence). The Shannon microbial diversity index showed no statistically significant differences both on infants and their mothers between two groups (p > 0.05). Mother’s microbial diversity was higher than infants’ based on Shannon index (p < 0.05). Significant positive correlations were found between mothers’ and their infants’ Shannon index (r = 0.656, p = 0.002).

Conclusion

Oral microbial diversity is significantly different between mothers and infants regardless of dental caries status, but no significant difference was found between mothers with and without dental caries or between their infants. Mother’s oral microbial diversity has an overall impact on the infants aged 12 months.

Electronic supplementary material

The online version of this article (10.1186/s12903-018-0699-8) contains supplementary material, which is available to authorized users.

Streptococcus mutans in Umbilical Cord Blood, Peripheral Blood, and Saliva from Healthy Mothers

The aims of this study were to analyze the presence of Streptococcus mutans (SM)-DNA in cord blood (CB), maternal peripheral blood (PB), and maternal saliva (SA) and compare with data collected in health surveys. Sixty-four healthy women with pregnancies to term and without complications attending for elective cesarean section in the Clinical Hospital of Ribeirao Preto, Sao Paulo were included. Samples of PB and unstimulated SA were obtained on the day of hospitalization and samples of CB were collected after the delivery section. Samples were investigated using polymerase chain reaction for the presence of SM-DNA using specific primers. The results show over 50% of the sample of PB and CB showed SM-DNA detectable. There was a positive correlation between the SM detection in PB/CB and SA (P < 0.05). Pregnant women, who reported tooth brushing more than three times a day, often showed detectable SM-DNA in PB and CB (P < 0.05). In conclusion, the majority of children can have contact with SM-DNA during the intrauterine life by the CB. SM probably transferred from salivary habitat to PB and CB. The tooth brushing can be associated to S. mutans detection in blood samples.

Transmission patterns of Streptococcus mutans demonstrated by a combined rep-PCR and MLST approach

OBJECTIVE

Clinical typing methods of the oral pathogen Streptococcus mutans with molecular analysis can be very specific, but expensive. Repetitive extragenic palindromic PCR (rep-PCR) is a relatively inexpensive pre-screening alternative for isolate selection for additional analyses. This study evaluated the prediction accuracy of using rep-PCR to identify S. mutans multilocus sequence typing (MLST) sequence types (ST) among children and their family members. Potential S. mutans strain sources were evaluated for evidence of transmission.

MATERIAL AND METHODS

Ten dendrograms (rep-PCR), with 20 isolates each of the 10 most common S. mutans genotypes, were generated from different subjects. Using a cut-off of 98% similarity, 7-11 isolates of each genotype were selected for MLST analysis to determine ST match/no-match.

RESULTS

Overall, rep-PCR was 75% effective at determining MLST ST match/no-match and 90% effective when applied to related individuals. Most genotypes were further differentiated by MLST. MLST ST diversity was greatest for one genotype (genotype 12, G12) and evidence of transmission among children and their family members was identified by rep-PCR and MLST. Younger children (6 months to 4 years old) shared ST with their mothers but 50% of older children (5-9 years old) had ST not identified in their mother. Six ST were shared between different families and probable source members were identified.

CONCLUSION

This study confirms that rep-PCR offers an affordable option to predict diverse isolates for downstream applications.

CLINICAL RELEVANCE

Using a combined rep-PCR and MLST approach, it is possible to track probable transmission and strain sources for S. mutans genotypes.

Salivary intercellular adenosine triphosphate testing in primary caretakers: An examination of statistical significance versus diagnostic predictability

A primary caretaker is a potential reservoir of bacteria for an infant child and can be evaluated during a child's caries risk assessment. The aim of this study was to investigate an indirect method for assessing Streptococcus mutans and Streptococcus sobrinus (MS) and lactobacillus (LB) levels in a caretaker's saliva. Thirty-eight primary caretakers participated in the study to determine whether a 2-step method to assess the intracellular adenosine triphosphate (ATP) levels in saliva (saliva i-ATP method) predicted higher MS and LB levels. This method was tested against a 1-step swab-based total ATP testing of dental plaque (plaque t-ATP method). Receiver operating characteristic (ROC) curves were used to examine the relationship between specificity and sensitivity of the two diagnostic tests. Although the area under the ROC curves of both the saliva i-APT (0.823) and the plaque t-ATP (0.774) methods were shown to be statistically different (p < .05) than the null hypothesis test of a random coin flip, the diagnostic predictability of the ATP tests to assess high levels of MS and LB remained low. The optimal cutoff, which was defined by the Youden index, for the saliva i-ATP method produced a sensitivity/specificity of 60.7/100.0 for MS and 78.6/88.9 for LB. Applying these results to populations of low or high bacterial level prevalence produced undesirable positive and negative predictive values for future potential patients. A pair-wise comparison of both area under the ROC curve values of the saliva i-ATP and plaque t-ATP did not find a statistically significant difference in using one test over the other (MS, p = .629; LB, p = .737). The findings of this study can educate dental clinicians that diagnostic tests, such as the 2-step saliva i-ATP method, can be found to be statistically significant but not ideal for patient use in terms of diagnostic predictability.

Genetic Diversity and Evidence for Transmission of Streptococcus mutans by DiversiLab rep-PCR

This two-part study investigated the genetic diversity and transmission of Streptococcus mutans using the DiversiLab repetitive extragenic palindromic PCR (rep-PCR) approach. For children with S. mutans and participating household members, analysis for evidence of unrelated child-to-child as well as intra-familial transmission was evaluated based on commonality of genotypes. A total of 169 index children and 425 household family members from Uniontown, Alabama were evaluated for genetic diversity using rep-PCR. Thirty-four unique rep-PCR genotypes were observed for 13,906 S. mutans isolates. For transmission, 117 child and household isolates were evaluated for shared genotype (by child and by genotype cases, multiple matches possible for each child). Overall, children had 1-9 genotypes and those with multiple genotypes were 2.3 times more likely to have caries experience (decayed, missing and filled teeth/surfaces>0). Only 28% of children shared all genotypes within the household, while 72% had at least 1 genotype not shared with anyone in the household. Children had genotype(s) not shared with any household members in 157 cases. In 158 cases children and household members shared a genotype in which 55% (87/158 cases) were shared with more than one family member. Children most frequently shared genotypes with their mothers (54%; 85/158), siblings (46%; 72/158) and cousins (23%; 37/158). A reference library for S. mutans for epidemiological surveillance using the DiversiLab rep-PCR approach is detailed. The genetic diversity of S. mutans in this population demonstrated frequent commonality of genotypes. Evidence for both child-to-child and intra-familial transmission of S. mutans was observed by rep-PCR.

Secondhand smoke and incidence of dental caries in deciduous teeth among children in Japan: population based retrospective cohort study

STUDY QUESTION

Does maternal smoking during pregnancy and exposure of infants to tobacco smoke at age 4 months increase the risk of caries in deciduous teeth?

METHODS

Population based retrospective cohort study of 76 920 children born between 2004 and 2010 in Kobe City, Japan who received municipal health check-ups at birth, 4, 9, and 18 months, and 3 years and had information on household smoking status at age 4 months and records of dental examinations at age 18 months and 3 years. Smoking during pregnancy and exposure of infants to secondhand smoke at age 4 months was assessed by standardised parent reported questionnaires. The main outcome measure was the incidence of caries in deciduous teeth, defined as at least one decayed, missing, or filled tooth assessed by qualified dentists without radiographs. Cox regression was used to estimate hazard ratios of exposure to secondhand smoke compared with having no smoker in the family after propensity score adjustment for clinical and lifestyle characteristics.

STUDY ANSWER AND LIMITATIONS

Prevalence of household smoking among the 76 920 children was 55.3% (n=42 525), and 6.8% (n=5268) had evidence of exposure to tobacco smoke. A total of 12 729 incidents of dental caries were observed and most were decayed teeth (3 year follow-up rate 91.9%). The risk of caries at age 3 years was 14.0% (no smoker in family), 20.0% (smoking in household but without evidence of exposure to tobacco smoke), and 27.6% (exposure to tobacco smoke). The propensity score adjusted hazard ratios of the two exposure groups compared with having no smoker in the family were 1.46 (95% confidence interval 1.40 to 1.52) and 2.14 (1.99 to 2.29), respectively. The propensity score adjusted hazard ratio between maternal smoking during pregnancy and having no smoker in the family was 1.10 (0.97 to 1.25).

WHAT THIS STUDY ADDS

Exposure to tobacco smoke at 4 months of age was associated with an approximately twofold increased risk of caries, and the risk of caries was also increased among those exposed to household smoking, by 1.5-fold, whereas the effect of maternal smoking during pregnancy was not statistically significant.

FUNDING, COMPETING INTERESTS, DATA SHARING

This study was supported by a grant in aid for scientific research 26860415. The authors have no competing interests or additional data to share.

Genotypic characterization of initial acquisition of Streptococcus mutans in American Indian children

Background

Severe-early childhood caries (S-ECC) is one of the most common infectious diseases in children and is prevalent in lower socio-economic populations. American Indian children suffer from the highest levels of S-ECC in the United States. Members of the mutans streptococci, Streptococcus mutans, in particular, are key etiologic agents in the development of caries. Children typically acquire S. mutans from their mothers and early acquisition is often associated with higher levels of tooth decay.

Methods

We have conducted a 5-year birth cohort study with a Northern Plains Tribe to determine the temporality and fidelity of S. mutans transmission from mother to child in addition to the genotypic diversity of S. mutans in this community. Plaque samples were collected from 239 mother/child dyads at regular intervals from birth to 36 months and S. mutans were isolated and genotyped by arbitrarily primed-polymerase chain reaction (AP-PCR).

Results

Here we present preliminary findings from a subset of the cohort. The focus for this paper is on initial acquisition events in the children. We identified 17 unique genotypes in 711 S. mutans isolates in our subset of 40 children, 40 mothers and 14 primary caregivers. Twelve of these genotypes were identified in more than one individual. S. mutans colonization occurred by 16 months in 57.5% of the children and early colonization was associated with higher decayed, missing and filled surface (DMFS) scores (p=0.0007). Children colonized by S. mutans shared a common genotype with their mothers 47.8% of the time. While multiple genotypes were common in adults, only 10% of children harbored multiple genotypes.

Conclusion

These children acquire S. mutans at an earlier age than the originally described ‘window of infectivity’ and often, but not exclusively, from their mothers. Early acquisition is associated with both the caries status of the children and the mothers.

Mother-to-child transmission of mutans streptococci

Mutans streptococci (MS) are the major group of pathogens implicated in dental caries. Like other infectious diseases, transmission of the causative microorganisms is the initial and essential step that should be understood relative to disease control and prevention. This review summarizes current knowledge regarding MS transmission, especially from mothers to their children. Included are methods used to study transmission, sources of MS, initial acquisition, factors concerning transmission and prevention of transmission. Information accumulated over many decades showed the involvement of MS transmission in the pathogenesis of caries, hence several preventive measurements have been proposed. Nevertheless, some essential aspects remain to be elucidated for more benefits of practical application.

Mother-to-child transmission of Streptococcus mutans: a systematic review and meta-analysis

OBJECTIVES

A systematic review was performed with the aim of determining whether there is scientific evidence of the transmission of Streptococcus mutans from mother to child.

DATA

The eligibility criteria, based on the PECO strategy, were the following: observational human studies whose subjects were mother and child pairs (P) contaminated by S. mutans (E); comparison according to the presence or absence of S. mutans (C); and whether there is transmission (O). The qualitative analysis was performed by assessing the risk of bias of the included studies, while quantitative synthesis was performed through comprehensive Meta-Analysis software (p<0.05).

SOURCES

Two reviewers performed the database search of studies published between January 1950 and May 2014. The strategy included observational studies that assessed the vertical transmission of S. mutans from mothers to children through analyzing genetic strains.

STUDY SELECTION

It was found 166 non-duplicated studies. However, after reviewing the articles in full and applying the eligibility criteria, 36 papers were selected for qualitative analysis and 19 for quantitative analysis. The cumulative meta-analysis demonstrated vertical transmission of S. mutans from mother to child (p<0.001).

CONCLUSIONS

The present systematic review and meta-analysis demonstrated evidence of vertical transmission of S. mutans from mother to child because there was an association between S. mutans n mothers and their respective children.

CLINICAL SIGNIFICANCE

The knowledge of the S. mutans strains is important because the virulence of the microorganisms is varied; also, the virulence affects the dental caries evolution rate, being more or less aggressive.

Increased number of teeth predict acquisition of mutans streptococci in infants

This longitudinal study of 194 very-low birthweight (VLBW) and 184 normal birthweight (NBW) infants hypothesized that the causal pathway between birth group (VLBW or NBW) and mutans streptococci (MS) acquisition (presence) at 18-20 months is mediated by biological, behavioral, and caregiver MS levels. Biological (number of teeth at 8 and 18-20 months and enamel hypoplasia) and behavioral (brushing/cleaning, sweet snacks, breastfeeding, and dental access) factors were assessed using dental examinations and caregiver questionnaire responses at 8 and 18-20 months. Infant MS acquisition and caregiver MS levels were assessed from saliva and plaque samples collected at 8 and 18-20 months. Structural equation modeling evaluated the causal pathway with latent variables for biology and behavior. Mutans streptococci presence was similar between birth groups at 18-20 months (40% in VLBW infants and 49% in NBW infants), but was significantly higher for NBW infants at 8 months. Increased number of teeth at 8 and 18-20 months was associated with biological risk. Infants whose caregivers had a 1-point higher score on MS had a significantly (1.5) higher odds of MS presence. Caregiver behavior was not associated with MS presence. Early-intervention efforts should focus on delaying initial acquisition and improving caregiver awareness of taking care of erupting primary teeth.

Salivary antibody response to streptococci in preterm and fullterm children: a prospective study

OBJECTIVES

Secretory immunoglobulins present in mucosa surfaces represent the first line of defense of the adaptive immune system against infectious challenges. Preterm (PT) neonates' humoral immunity is diminished compared to full-term (FT) newborns. The identification of important antigens (Ags) of virulence of oral species may help in the investigation of the mechanisms of antigenic stimulation and the development of the mucosal immune response. In the present study, we measured saliva levels of immunoglobulins A (IgA) and M (IgM) and characterized the specificity of IgA against Ags of several streptococcal species found early in life.

METHODS

This was a prospective observational study. Salivary IgA (sIgA) antibody responses to bacterial species that are prototypes of pioneer (Streptococcus mitis, S. sanguinis, S. gordonii) and pathogenic (Streptococcus mutans) microorganisms of the oral cavity were studied in FT and PT children in two visits: at birth (T0) and at 3 months of age (T3). Salivas from 123 infants (72 FT and 51 PT) were collected during the first 10h after birth (T0) and again at 3 months of age (T3). Salivary levels of IgA and IgM antibodies were analysed by enzyme-linked immunosorbent assay (ELISA). A subgroup of 26 FT and 24 PT children were compared with respect to patterns of antibody specificities against different streptococci Ags using Western blot assays.

RESULTS

No significant differences (P>0.05) in salivary levels of IgA and IgM between FT and PT babies were found at birth. At T3, mean sIgA values were similar between groups and sIgM levels were significantly higher in PT than FT (P<0.05). Western blot assays identified positive IgA response to streptococci in the majority of children, especially in the FT group. There were some differences between groups in relation to the frequency of children with positive response to Ags and intensity of IgA response. In general, oral streptococci Ags were more frequently detected and bands were more intense in FT than in PT, especially in T3. Prospective analysis of patterns of sIgA against Ags of different streptococcal species revealed an increase in complexity of the sIgA antibody response from the first day of birth (T0) to T3 in PT and FT.

CONCLUSION

The patterns of sIgA response to streptococci Ags appear to be influenced by the gestational age, which might reflect the level of immunological maturity of the mucosal immune system.

Levels and complexity of IgA antibody against oral bacteria in samples of human colostrum

Streptococcus mutans (SM) have three main virulence antigens: glucan binding protein B (gbpB), glucosyltransferase (Gtf) and antigens I/II (Ag I/II) envolved in the capacity of those bacteria to adhere and accumulate in the dental biofilm. Also, the glycosyltransferases 153 kDa of Streptococcus gordonii (SGO) and 170kDa of Streptococcus sanguinis (SSA) were important antigens associated with the accumulation of those bacterias. Streptococcus mitis (SMI) present IgA1 protease of 202 kDa. We investigated the specificity and levels IgA against those antigens of virulence in samples of human colostrum. This study involved 77 samples of colostrum that were analyzed for levels of immunoglobulian A, M and G by Elisa. The specificity of IgA against extracts of SM and initials colonizators (SSA, SMI, SGO) were analyzed by the Western blot. The mean concentration of IgA was 2850.2 (±2567.2) mg/100 mL followed by IgM and IgG (respectively 321.8±90.3 and 88.3±51.5), statistically different (p<0.05). Results showed that the majority of samples had detectable levels of IgA antibodies to extracts of bacteria antigens and theirs virulence antigens. To SM, the GbpB was significantly lower detected than others antigens of SM (p<0.05). High complexities of response to Ags were identified in the samples. There were no significant differences in the mean number of IgA-reactive Ags between the antigens (p>0.4). So, the breast milk from first hours after birth presented significant levels of IgA specific against important virulence of antigens those oral streptococci, which can disrupt the installation and accumulation process of these microorganisms in the oral cavity.

Characteristics of Streptococcus mutans genotypes and dental caries in children

This longitudinal cohort study evaluated the diversity, commonality, and stability of Streptococcus mutans genotypes associated with dental caries history. Sixty-seven 5- and 6-yr-old children, considered as being at high caries risk, had plaque collected from baseline through 36 months for S. mutans isolation and genotyping using repetitive extragenic palindromic-PCR (4,392 total isolates). Decayed, missing, or filled surfaces (dmfs (primary teeth)/DMFS (secondary teeth)) for each child were recorded at baseline. At baseline, 18 distinct genotypes were found among 911 S. mutans isolates from 67 children (diversity), and 13 genotypes were shared by at least two children (commonality). The number of genotypes per individual was positively associated with the proportion of decayed surfaces (p-ds) at baseline. Twenty-four of the 39 children who were available at follow-up visits maintained a predominant genotype for the follow-up periods (stability) and this was negatively associated with the p-ds. The observed diversity, commonality, and stability of S. mutans genotypes represent a pattern of dental caries epidemiology in this high-caries-risk community, which suggests that fewer decayed surfaces are significantly associated with lower diversity and higher stability of S. mutans genotypes.

Mode of delivery, mutans streptococci colonization, and early childhood caries in three- to five-year-old Thai children

OBJECTIVE

To investigate whether mode of delivery is associated with mutans streptococci (MS) colonization and early childhood caries (ECC) in preschool Thai children.

METHODS

Three hundred and fifty mothers and their 3- to 5-year-old children (184 born vaginally and 166 born by Caesarean section) participated in the study. Data included a dental examination, MS colonization assessed by the Dentocult(®) SM Strip Mutans method, and a questionnaire survey of family socio-demographic information, as well as children's birth history, dietary habits, and oral health practices.

RESULTS

Overall, ECC prevalence was 56% in 3-year-old and 78% in 5-year-old Thai children. Compared to children delivered by C-section, vaginally born children experienced increased ECC prevalence (73.8% versus 59.6%; P = 0.009) and were more likely to have higher MS scores (OR = 1.8, 95% CI = 1.1-2.9), adjusting for mother's gestational age, MS score, feeding practice habits; child's age and tooth brushing habits. Children's MS scores were highly correlated with their mothers' MS scores (P < 0.001). Additionally, children's age, MS colonization, and mothers' prechewing feeding habits were the most significant risk indicators for ECC in Thai children.

CONCLUSION

Our findings suggest that mode of delivery is significantly correlated with MS colonization and caries outcomes in young Thai children. Future studies are needed to further understand the possible biological mechanisms linking mode of child delivery to the colonization of cariogenic microbiota and development of ECC.

Five questions about Streptococcus mutans: theoretical study of its transmission and colonisation

PURPOSE

This theoretical study aimed to identify the decisive (and controllable) factors involved in Streptococcus mutans (Sm) infection through addressing questions about (i) the time and prevalence pattern (including the raison d'etre of the discrete period for the infection or WI) of initial Sm colonisation and (ii) the infant's selection of bacterial types and their diversity, which are not yet definitely answered by empirical works.

METHOD

A model of Sm infection (within-host type) was developed. For questions (i): using the basic model, stochastic simulation was performed to reproduce longitudinal observations of the initial colonisation time. A symmetrical or right-skewed gamma distribution was assumed for the maximum colonisable area (K(max)) and transmission rate (mx). Additionally, 3 or 4 developmental modes of colonisable area [K(t)] were assigned based on the K(max) value. For (ii): by extending the basic model to the two-bacterial type model, intraspecific competition analysis focusing on the differences in mx (received by the infancy) and colonisation ability (θD) was performed.

RESULTS

The basic model simulation showed that mx and K(t) played a pivotal role in determining the individual time of initial colonisation and their variations among infants in forming its prevalence patterns (with or without WI). The competition model simulation showed that higher mx could be more advantageous in competitive colonisation than higher θD under repeated invasions. Accordingly, it played a decisive role in infant's selection of initially, persistently and transiently colonising bacterial types, and thus in their diversity.

CONCLUSIONS

(i) The mx is the primary and controllable (risk) factor that extensively affects various aspects of the Sm infection process. (ii) Also, the growing carrying capacity, i.e., K(t) is another important factor when considering how to effectively delay the onset of the colonisation. (iii) Thus, currently, the most feasible and effective control measure for the infection should be microbiological interventions in the primary host with concurrent oral hygiene and dietary control in the exposed child.

Salivary IgA antibody responses to Streptococcus mitis and Streptococcus mutans in preterm and fullterm newborn children

OBJECTIVES

The intensities and specificities of salivary IgA antibody responses to antigens of Streptococcus mutans, the main pathogen of dental caries, may influence colonization by these organisms during the first 1.5 year of life. Thus, the ontogeny of salivary IgA responses to oral colonizers continues to warrant investigation, especially with regard to the influence of birth conditions, e.g. prematurity, on the ability of children to efficiently respond to oral microorganisms. In this study, we characterised the salivary antibody responses to two bacterial species which are prototypes of pioneer and pathogenic microorganisms of the oral cavity (Streptococcus mitis and Streptococcus mutans, respectively) in fullterm (FT) and preterm (PT) newborn children.

METHODS

Salivas from 123 infants (70 FT and 53 PT) were collected during the first 10h after birth and levels of IgA and IgM antibodies and the presence of S. mutans and S. mitis were analysed respectively by ELISA and by chequerboard DNA-DNA hybridization. Two subgroups of 24 FT and 24 PT children were compared with respect to patterns of antibody specificities against S. mutans and S. mitis antigens, using Western blot assays. Cross-adsorption of 10 infant's saliva was tested to S. mitis, S. mutans and Enterococcus faecalis antigens.

RESULTS

Salivary levels of IgA at birth were 2.5-fold higher in FT than in PT children (Mann-Whitney; P<0.05). Salivary IgA antibodies reactive with several antigens of S. mitis and S. mutans were detected at birth in children with undetectable levels of those bacteria. Adsorption of infant saliva with cells of S. mutans produced a reduction of antibodies recognizing S. mitis antigens in half of the neonates. The diversity and intensity of IgA responses were lower in PT compared to FT children, although those differences were not significant.

CONCLUSION

These data provide evidence that children have salivary IgA antibodies shortly after birth, which might influence the establishment of the oral microbiota, and that the levels of salivary antibody might be related to prematurity.

Genotypic diversity of Streptococcus mutans and Streptococcus sobrinus in 3-4-year-old children with severe caries or without caries

BACKGROUND.  The genotypic diversity of both Streptococcus mutans and Streptococcus sobrinus in children with different caries experience remains unclear. AIM.  To investigate the genotypic diversity of S. mutans and S. sobrinus in children with severe early childhood caries (SECC) and in caries-free (CF) children. METHODS.  Stimulated saliva of 87 SECC and 91 CF children aged 3-4 years was collected and submitted to cultivation, and MS colonies were enumerated. The genomic fingerprint analysis of S. mutans and S. sobrinus was carried out using AP-PCR. RESULTS.  One to five genotypes of S. mutans were colonized in an oral cavity of SECC and CF children; 85.5% SECC children and 57.9% CF children harboured more than one genotype of S. mutans. One to three genotypes of S. sobrinus were detected from each SECC child; 31.25% SECC children harboured more than one genotype of S. sobrinus. And one genotype was colonized in each CF child. S. mutans isolates from different individuals displayed distinctive DNA fingerprints. CONCLUSIONS.  DNA fingerprints of S. mutans and S. sobrinus isolates from 3- to 4-year-old children displayed genetic polymorphism, and S. mutans has greater genetic diversity than S. sobrinus. SECC children harboured more genotypes of S. mutans and S. sobrinus than CF children.