Subgingival Microbiota during Healthy Pregnancy and Pregnancy Gingivitis

BugSigDB captures patterns of differential abundance across a broad range of host-associated microbial signatures

The literature of human and other host-associated microbiome studies is expanding rapidly, but systematic comparisons among published results of host-associated microbiome signatures of differential abundance remain difficult. We present BugSigDB, a community-editable database of manually curated microbial signatures from published differential abundance studies accompanied by information on study geography, health outcomes, host body site and experimental, epidemiological and statistical methods using controlled vocabulary. The initial release of the database contains >2,500 manually curated signatures from >600 published studies on three host species, enabling high-throughput analysis of signature similarity, taxon enrichment, co-occurrence and coexclusion and consensus signatures. These data allow assessment of microbiome differential abundance within and across experimental conditions, environments or body sites. Database-wide analysis reveals experimental conditions with the highest level of consistency in signatures reported by independent studies and identifies commonalities among disease-associated signatures, including frequent introgression of oral pathobionts into the gut.

Periodontal pathogens of the interdental microbiota in a 3 months pregnant population with an intact periodontium

Steroid hormones and the oral microbiota of pregnant women both appear as cumulative risk factors for gingivitis. This cross-sectional study, using real-time PCR, investigated the composition and diversity of the microbiota in interdental spaces of 3 months pregnant women with intact periodontium according the 2018 EFP/AAP classification. Bacteria identified were belonged to the red (Porphyromonas gingivalis Treponema denticola, and Tanerella forsythia), orange (Fusobacterium nucleatum, Prevotella intermedia, Campylobacter rectus, and Parvimonas micra), and green (Eikenella corrodens and A. actinomycetencomitans) Socransky complexes. Approximatively 109.11 bacteria were counted per interdental space in pregnant women. Bacteria from the red complex represented 33.80% versus 62.81% for the orange group versus 3.39% for the green group of the total number spread over the 3 groups. Dietary habits and physical activity did not have a significant impact on interdental microbiota, although a decrease in the median amount of 9 periodontopathogens was observed when fruit and vegetable consumption increased. Pregnant women who brushed their teeth at least twice a day had lower counts of total bacteria and 9 periodontal pathogens than those who brushed less. In 3 months pregnant women at high risk of periodontal disease (>30% bleeding sites), the dendogram revealed 2 clusters of the 9 periodontopathogens. This provides further support for the "key pathogen" hypothesis, among which Porphyromonas gingivalis plays a key role, indicating that specific bacteria in limited quantities can influence the host immune system and convert the microbiota from symbiotic to dysbiotic to induce inflammatory disorder. As a result, this study reported that 3 months pregnant women with healthy periodontium had high levels of interdental bleeding and a dysbiotic microbiota with periodontal pathogens of the Socransky orange and red complexes. These subjects were therefore potentially at increased risk of developing periodontal disease and, consequently, an adverse pregnancy outcome. So, preventive oral prophylaxis measures, in particular individual interdental prophylaxis, should be implemented as soon as pregnancy is established.

Prevalence of Culturable Bacteria and Yeasts in the Nasopharynx Microbiota during the Physiological Course of Pregnancy

The aim of the study was to compare the prevalence of the nasopharyngeal carriage of culturable microorganisms in the microbiota of asymptomatic women with a physiological pregnancy (PW) and nonpregnant women (NPW). Nasopharyngeal swabs were collected from 53 PW and 30 NPW to detect bacterial and fungal colonization. Isolates were identified using the culture method and the MALDI-TOF MS technique. The nasopharyngeal microbiota (NPM) partially differed between PW and NPW. These differences in the frequency of nasopharyngeal colonization between the PW and NPW groups were not statistically significant (p > 0.05); all cases were colonized by bacteria and only two cases in the PW group were colonized by yeasts, namely, Rhodotorula spp. High levels of staphylococcal colonization, including predominantly coagulase-negative staphylococci and S. aureus in the nasopharyngeal sample, were present in both groups. The reduced number of Gram-negative rods colonized in the cases studied was seen in samples from the NPW group, particularly with Enterobacterales, and anaerobic Cutibacterium spp. were isolated only in the PW group (p < 0.05). Moreover, a higher carriage rate of Enterobacter aerogenes colonization was statistically significant (p < 0.05) and correlated with the NPW group. Pregnancy may disturb the composition of the NPM represented by commensals and opportunistic bacteria and promote yeast colonization as compared to nonpregnant women.

The Oral Microbiome Throughout Pregnancy: A Scoping Review

INTRODUCTION

Oral health is associated with systemic health, including adverse pregnancy outcomes. Understanding the oral microbiome during pregnancy may lead to targeted interventions for prevention of adverse outcomes. The purpose of this review is to examine the literature on the oral microbiome throughout pregnancy.

METHODS

We conducted a literature search with four electronic databases for original research conducted between 2012 and 2022 that examined the oral microbiome longitudinally using 16s rRNA sequencing during pregnancy.

RESULTS

We identified six studies that examined the oral microbiome longitudinally throughout pregnancy, though comparisons of oral niches, oral microbiome measures, and findings between studies were not consistent. Three studies identified alterations in alpha diversity throughout pregnancy and two studies identified increased pathogenic bacteria during pregnancy. Three studies reported no changes in the oral microbiome throughout pregnancy, and one study identified differences in the composition of the microbiome based on socioeconomic status and antibiotic exposure. Two studies examined adverse pregnancy outcomes in association with the oral microbiome, one reporting no associations and one reported difference in community gene composition in those diagnosed with preeclampsia.

CLINICAL IMPLICATIONS

There is limited research on the composition of the oral microbiome throughout pregnancy. There may be alterations in the oral microbiome during pregnancy such as increased relative abundance of pathogenic bacteria. Socioeconomic status, antibiotic use, and education may contribute to differences in the microbiome composition over time. Clinicians should evaluate oral health and educate on the importance of oral health care during the prenatal and perinatal time period.

Prevalence, Severity of Extension, and Risk Factors of Gingivitis in a 3-Month Pregnant Population: A Multicenter Cross-Sectional Study

The scope of this study was to assess the prevalence, severity of extension, and risk factors of gingivitis among pregnant women. In this cross-sectional study, 220 nulliparous women at 3 months of pregnancy were recruited in 2022 at the first obstetrical visit in Dakar, Senegal. Demographic characteristics, lifestyle habits, prenatal clinical status, and oral clinical parameters were recorded. Multivariable logistic regression modeling was used to assess relationships between gingivitis and risk factors. Eighty-eight percent of women had gingivitis, 15% were classified as moderate and 73% as severe. A total of 66.7% (95% CI [28.8-92.1]) of the sites had bleeding on interdental brushing. The odds for gingivitis decreased significantly for women consuming more than five portions of fruits and vegetables per day (OR = 0.15; 95% CI [0.03-0.66]) and increased in women who had a professional activity (OR = 6.75; 95% CI [1.27-35.87]) and high education. Concomitantly, the percentage of dental plaque (OR = 131.6; 95% CI [10.80-1619.71] and the severity of clinical attachment loss (OR = 7.70; 95% CI [3.16-18.92]) were important risk factors. Inverse associations were observed with increasing body mass index (OR = 0.76; 95% CI [0.63-0.93]). Our results underline that gingivitis cases and bleeding were particularly high among 3-month pregnant women. Literacy and adequate oral hygiene actions to modify behaviors and to achieve meticulous biofilm disorganization could make a favorable change in the gingival health outcome. Additionally, further research is necessary to precisely determine the role of biofilm-induced gingivitis and systemic-induced gingivitis in improving gingival conditions.

Characterizing the supragingival microbiome of healthy pregnant women

The ecological characteristics and changes of the supragingival plaque microbial community during pregnancy are poorly understood. This study compared the microbial community characteristics of supragingival plaque in pregnant and non-pregnant women, with the aim of identifying specific microbial lineages and genera that may be associated with pregnancy. Thirty pregnant women were randomly selected from the First Affiliated Hospital of Xinjiang Medical University and divided into groups based on pregnancy trimester: first trimester (group P1, n=10, ≤12 weeks), second trimester (group P2, n=10, 13–27 weeks), and third trimester (group P3, n=10, 28–40 weeks). Ten healthy non-pregnant women (group N) were enrolled as the control group. Supragingival plaque samples of all subjects were collected and oral microbial composition was surveyed using a 16S rRNA gene sequencing approach. Statistical analysis was performed using a nonparametric test. The Chao 1 index of P3 was significantly lower compared with that of N, P1, and P2 (P&lt;0.05). The Simpson indices of P2 and P3 were significantly higher than that of N (P&lt;0.05). The Shannon index of P2 was significantly higher compared with that of N (P&lt;0.05). Principal coordinate analysis (PCoA) showed different clustering according to the pregnancy status. Linear discriminant analysis effect size (LEfSe) revealed that the microbial species in group N that were significantly different from those of other groups were concentrated in the genus Neisseria. Species in P1 that were significantly different from those of other groups were concentrated in the genus Tannerella, while those in P2 and P3 were concentrated in the genus Leptotrichia. A total of 172 functional pathways were predicted for the bacterial communities in this study using PICRUSt2. Principal Component Analysis (PCA) showed that most predicted functional pathways clustered together in N and P1 and in P2 and P3. LEfSe analysis revealed that 11 pathways played a discriminatory role in the four groups. This work suggests a potential role of pregnancy in the formation of supragingival plaque microbiota and indicates that physiological changes during pregnancy may convert supragingival plaque into entities that could cause harm, which may be a risk factor for maternal health. Furthermore, findings from the study provide a basis for etiological studies of pregnancy-associated oral ecological disorders.

Subgingival Microbiome in Pregnancy and a Potential Relationship to Early Term Birth

Background

Periodontal disease in pregnancy is considered a risk factor for adverse birth outcomes. Periodontal disease has a microbial etiology, however, the current state of knowledge about the subgingival microbiome in pregnancy is not well understood.

Objective

To characterize the structure and diversity of the subgingival microbiome in early and late pregnancy and explore relationships between the subgingival microbiome and preterm birth among pregnant Black women.

Methods

This longitudinal descriptive study used 16S rRNA sequencing to profile the subgingival microbiome of 59 Black women and describe microbial ecology using alpha and beta diversity metrics. We also compared microbiome features across early (8-14 weeks) and late (24-30 weeks) gestation overall and according to gestational age at birth outcomes (spontaneous preterm, spontaneous early term, full term).

Results

In this sample of Black pregnant women, the top twenty bacterial taxa represented in the subgingival microbiome included a spectrum representative of various stages of biofilm progression leading to periodontal disease, including known periopathogens Porphyromonas gingivalis and Tannerella forsythia. Other organisms associated with periodontal disease reflected in the subgingival microbiome included several Prevotella spp., and Campylobacter spp. Measures of alpha or beta diversity did not distinguish the subgingival microbiome of women according to early/late gestation or full term/spontaneous preterm birth; however, alpha diversity differences in late pregnancy between women who spontaneously delivered early term and women who delivered full term were identified. Several taxa were also identified as being differentially abundant according to early/late gestation, and full term/spontaneous early term births.

Conclusions

Although the composition of the subgingival microbiome is shifted toward complexes associated with periodontal disease, the diversity of the microbiome remains stable throughout pregnancy. Several taxa were identified as being associated with spontaneous early term birth. Two, in particular, are promising targets of further investigation. Depletion of the oral commensal Lautropia mirabilis in early pregnancy and elevated levels of Prevotella melaninogenica in late pregnancy were both associated with spontaneous early term birth.

Oral microflora and pregnancy: a systematic review and meta-analysis

Understanding changes in oral flora during pregnancy, its association to maternal health, and its implications to birth outcomes is essential. We searched PubMed, Embase, Web of Science, and Cochrane Library in May 2020 (updated search in April and June 2021), and conducted a systematic review and meta-analyses to assess the followings: (1) oral microflora changes throughout pregnancy, (2) association between oral microorganisms during pregnancy and maternal oral/systemic conditions, and (3) implications of oral microorganisms during pregnancy on birth outcomes. From 3983 records, 78 studies were included for qualitative assessment, and 13 studies were included in meta-analysis. The oral microflora remains relatively stable during pregnancy; however, pregnancy was associated with distinct composition/abundance of oral microorganisms when compared to postpartum/non-pregnant status. Oral microflora during pregnancy appears to be influenced by oral and systemic conditions (e.g. gestational diabetes mellitus, pre-eclampsia, etc.). Prenatal dental care reduced the carriage of oral pathogens (e.g. Streptococcus mutans). The Porphyromonas gingivalis in subgingival plaque was more abundant in women with preterm birth. Given the results from meta-analyses were inconclusive since limited studies reported outcomes on the same measuring scale, more future studies are needed to elucidate the association between pregnancy oral microbiota and maternal oral/systemic health and birth outcomes.

The composition of microbial communities in inflammatory periodontal diseases in young adults Tatars

Host susceptibility and environmental factors are important for the development of gingivitis and periodontitis, but bacterial biofilms attached to the teeth and gingival tissues play a crucial role. We have analyzed and compared the subgingival microbial communities between subjects with dental plaque biofilm-induced generalized chronic gingivitis (CG), localized initial (Stage I) periodontitis (IP) and healthy controls (HC) of young people aged 18-19 years permanently residing in the city of Kazan (Tatarstan, Russia). The results showed that the α-diversity in groups with CG and IP was higher than in the healthy group. In a course of periodontal disease, a decrease in the relative abundance of dominates genera Rothia and Streptococcus was observed along with increase of class TM7-3 (Candidatus Saccharibacteria phylum) representatives. Also, the increase of red complex representatives Porphyromonadeceae, Treponema and Tannerella was detected together with statistically significant increase of Filifactor, Parvimonas, Peptostreptococcaceae, Veillonellaceae, Tissierelaceae and Mogibacteriaceae. Analysis of our data suggests that transition from HC to IP may be accompanied by a decrease in microbial diversity and a reduction in the abundance of family Rs-045 (Candidatus Saccharibacteria phylum), Desulfovibrionaceae Corynebacterium, Campylobacter and Selenomonas in young adults Kazan Tatars.