Distribution of anaerobic bacteria among pregnant periodontitis patients who experience preterm delivery

Small, but smelly: the importance of Solobacterium moorei in halitosis and other human infections

Solobacterium moorei (S. moorei) has been described as Gram-positive, non spore forming, obligate anaerobic bacillus from human feces. The traditional culture and identification of these strains is very difficult (as the strains are often not cultivable or they grow only relatively slowly, in addition to producing only a very few positive biochemical reactions in commercially available identification kits); thus, reliable identification may only be carried out using methods, such as matrix-assisted laser desorption/ionization time-of-flight mass spectrometry and DNA sequencing. Regarding its pathogenic role, the relevance of S. moorei in halitosis (oral malodor) has a good standing, as it has been suggested by multiple studies, while the isolation of these bacteria from invasive infections is very rare; there are only a few reports available in the literature, regarding infections outside the oral cavity. Based on these reports, affected patients are predominantly characterized compromised immunity and are frequently associated with a dental focus of infection. The aim of our present review is to summarize the currently available knowledge on the pathogenic role of S. moorei in halitosis and other infections and to emphasize the relevance of this neglected anaerobic pathogen.

Maternal periodontitis and preterm birth: Systematic review and meta-analysis

AIM

To assess the association between periodontitis and preterm birth in women of childbearing age.

MATERIALS AND METHODS

This review included analytical case-control studies and prospective cohort studies evaluating the association between maternal periodontitis and preterm birth. Of the 3104 screened articles, 31 met the inclusion criteria for the review, and 20 met the quality criteria. The selected studies included a total of 10 215 women.

RESULTS

Twenty articles contributed to the meta-analysis; 16 used a case-control design, and 4 were prospective cohort studies. The study heterogeneity was low (Q = 24.2464; P = 0.1869; I²  = 21.63%). A positive association between maternal periodontitis and preterm birth was found in 60% of the studies. Under the random-effects model, meta-analysis gave an odds ratio (OR) of 2.01 (95% CI 1.71, 2.36), representing a significant positive association between the explanatory and outcome variables.

CONCLUSION

Pregnant mothers with periodontitis double the risk of preterm birth. There is a lack of international consensus for diagnosing maternal periodontitis.

Bi-directional relationship between pregnancy and periodontal disease

During pregnancy profound perturbations in innate and adaptive immunity impact the clinical course of a number of infectious diseases, including those affecting periodontal tissues. Conversely, it has been suggested that periodontal infections may increase the risk of adverse pregnancy outcomes. In this review, a summary of the literature associated with the bidirectional relationship between pregnancy and periodontal disease as well as the possible mechanisms behind this interaction were examined.

Detection of periodontopathogenic bacteria in pregnant women by traditional anaerobic culture method and by a commercial molecular genetic method

To culture facultative and strict anaerobic bacteria is a well-established method for analyzing subgingival plaque samples. Micro-IDent and micro-IDent Plus (HAIN Lifescience GmbH, Nehren, Germany) tests are two commercially available rapid PCR-based methods for the identification and quantification of putative periodontopathogen bacteria. In this study, we compared these commercial PCR-based hybridization methods with conventional anaerobic culture technique. A total of 36 subgingival plaque samples were collected from periodontal pockets of pregnant women with chronic localized periodontitis. Aliquots of these samples were evaluated with species-specific probes provided by micro-IDent and micro-IDent Plus tests simultaneously, and from the same samples anaerobic and capnophylic bacteria were cultured on selective media. The overall agreement between both methods was excellent for Eubacterium nodatum, Tannerella forsythia and Porphyromonas gingivalis (97-92%), fair for Capnocytophaga sp, Eikenella corrodens, Actinobacillus actinomycetemcomitans, and Prevotella intermedia (91-89%) and poor for Fusobacterium nucleatum, Parvimonas micra (Micromonas micros), and Campylobacter rectus (86-78%). Discrepancies in the results may be explained by inability of culture method to distinguish between closely related taxa (e.i P. intermedia/Prevotella. nigrescens), and problems of keeping periodontopathogen bacteria viable, which is required for successful detection by standard culture method. Nucleic acid-based methods may replace cultivation method as frequently used methods in microbiological diagnosis of progressive periodontitis, thus micro-IDent and micro-IDent Plus tests can be recommended where culture of periodontopathogenic bacteria is not performed in routine microbiology laboratories to analyze subgingival plaque samples.

Vaginal and oral microbes, host genotype and preterm birth

Preterm birth (PTB) is a leading cause of infant mortality and morbidity in the US and across the globe. Infection and associated inflammation are important initiators for PTB pathways; an estimated 40% of PTBs are attributed to amniochorionic-decidual or systemic inflammation. Historically, intrauterine infections have been implicated in PTB; recent evidence suggests that infections remote from the fetal site may also be causative. There is strong epidemiological evidence that bacterial vaginosis and periodontitis--two syndromes characterized by perturbations in the normal vaginal and oral bacterial microflora, respectively--are linked to infection-associated PTB. Oral and vaginal environments are similar in their bacterial microbiology; identical bacterial species have been independently isolated in periodontitis and bacterial vaginosis. Periodontitis and bacterial vaginosis also share many behavioral and sociodemographic risk factors suggesting a possible common pathophysiology. Genetic polymorphisms in host inflammatory responses to infection are shared between bacterial vaginosis, periodontitis and PTB, suggesting common mechanisms through which host genotype modify the effect of abnormal bacterial colonization on preterm birth. We review the state of knowledge regarding the risk of PTB attributable to perturbations in bacterial flora in oral and vaginal sites and the role of host genetics in modifying the risk of infection-related PTB. We posit that bacterial species that are common in perturbed vaginal and oral sites are associated with PTB through their interaction with the host immune system.

Benefits of Periodontal Therapy When Preterm Birth Threatens

There is growing evidence that chronic periodontitis may be a risk factor for pre-term birth. The goal of this intervention study was to determine the effect of periodontal treatment on the pregnancy outcome in women with threatening pre-term birth and initial localized chronic periodontitis. Forty-one women with a singleton pregnancy were enrolled in the study. For this treatment group, oral hygiene instruction and periodontal therapy were provided in the third trimester, while those in the control group (42 persons) did not receive any periodontal treatment. In the treatment group, the mean weight of newborns was 3079.0 g, compared with the control group mean of 2602.4 g. The incidence of pre-term birth and low birthweight in the treatment group was significantly less than in the control group ( p = 0.015). Periodontal treatment completed before the 35th week appeared to have a beneficial effect on birth weight and time of delivery.

The vaginal microflora in relation to gingivitis

BACKGROUND

Gingivitis has been linked to adverse pregnancy outcome (APO). Bacterial vaginosis (BV) has been associated with APO. We assessed if bacterial counts in BV is associated with gingivitis suggesting a systemic infectious susceptibilty.

METHODS

Vaginal samples were collected from 180 women (mean age 29.4 years, SD +/- 6.8, range: 18 to 46), and at least six months after delivery, and assessed by semi-quantitative DNA-DNA checkerboard hybridization assay (74 bacterial species). BV was defined by Gram stain (Nugent criteria). Gingivitis was defined as bleeding on probing at >or= 20% of tooth sites.

RESULTS

A Nugent score of 0-3 (normal vaginal microflora) was found in 83 women (46.1%), and a score of > 7 (BV) in 49 women (27.2%). Gingivitis was diagnosed in 114 women (63.3%). Women with a diagnosis of BV were more likely to have gingivitis (p = 0.01). Independent of gingival conditions, vaginal bacterial counts were higher (p < 0.001) for 38/74 species in BV+ in comparison to BV- women. Counts of four lactobacilli species were higher in BV- women (p < 0.001). Independent of BV diagnosis, women with gingivitis had higher counts of Prevotella bivia (p < 0.001), and Prevotella disiens (p < 0.001). P. bivia, P. disiens, M. curtisii and M. mulieris (all at the p < 0.01 level) were found at higher levels in the BV+/G+ group than in the BV+/G- group. The sum of bacterial load (74 species) was higher in the BV+/G+ group than in the BV+/G- group (p < 0.05). The highest odds ratio for the presence of bacteria in vaginal samples (> 1.0 x 104 cells) and a diagnosis of gingivitis was 3.9 for P. bivia (95% CI 1.5-5.7, p < 0.001) and 3.6 for P. disiens (95%CI: 1.8-7.5, p < 0.001), and a diagnosis of BV for P. bivia (odds ratio: 5.3, 95%CI: 2.6 to 10.4, p < 0.001) and P. disiens (odds ratio: 4.4, 95% CI: 2.2 to 8.8, p < 0.001).

CONCLUSION

Higher vaginal bacterial counts can be found in women with BV and gingivitis in comparison to women with BV but not gingivitis. P. bivia and P. disiens may be of specific significance in a relationship between vaginal and gingival infections.

Epidemiology and environmental factors in preterm labour

An epidemiological and environmental approach is the appropriate starting point to understanding preterm labour. Although there are multiple aetiologies it seems likely that anthropometric and environmental risk factors in combination with inherent genetic susceptibilities contribute to an increased risk of preterm labour for certain women. Poct 2pulation-based studies identifying risk factors and quantifying outcomes facilitate informed counselling and provide a framework for developing prediction tools. Carefully conducted case-control and cohort studies identify associations that may contribute to an understanding of causation. A combined approach encompassing epidemiology, pathophysiology and clinical research is required to understand the aetiologies, prevention and optimal management of preterm labour. This review focuses on the epidemiology of preterm labour and the role of environmental factors.

Maternal oral health status and preterm low birth weight at Muhimbili National Hospital, Tanzania: a case-control study

Background

The study examined the relationship between oral health status (periodontal disease and carious pulpal exposure (CPE)) and preterm low-birth-weight (PTLBW) infant deliveries among Tanzanian-African mothers at Muhimbili National Hospital (MNH), Tanzania.

Methods

A retrospective case-control study was conducted, involving 373 postpartum mothers aged 14–44 years (PTLBW – 150 cases) and at term normal-birth-weight (TNBW) – 223 controls), using structured questionnaire and full-mouth examination for periodontal and dentition status.

Results

The mean number of sites with gingival bleeding was higher in PTLBW than in TNBW (P = 0.026). No significant differences were observed for sites with plaque, calculus, teeth with decay, missing, filling (DMFT) between PTLBW and TNBW. Controlling for known risk factors in all post-partum (n = 373), and primiparaous (n = 206) mothers, no significant differences were found regarding periodontal disease diagnosis threshold (PDT) (four sites or more that had probing periodontal pocket depth 4+mm and gingival bleeding ≥ 30% sites), and CPE between cases and controls. Significant risk factors for PTLBW among primi- and multiparous mothers together were age ≤ 19 years (adjusted Odds Ratio (^aOR) = 2.09, 95% Confidence interval (95% CI): 1.18 – 3.67, P = 0.011), hypertension (^aOR = 2.44, (95% CI): 1.20 – 4.93, P = 0.013) and being un-married (^aOR = 1.59, (95% CI): 1.00 – 2.53, P = 0.049). For primiparous mothers significant risk factors for PTLBW were age ≤ 19 years (^aOR = 2.07, 95% CI: 1.13 – 3.81, P = 0.019), and being un-married (^aOR = 2.58, 95% CI: 1.42 – 4.67, P = 0.002).

Conclusions

These clinical findings show no evidence for periodontal disease or carious pulpal exposure being significant risk factors in PTLBW infant delivery among Tanzanian-Africans mothers at MNH, except for young age, hypertension, and being unmarried. Further research incorporating periodontal pathogens is recommended.

Possible association between mother's periodontal status and preterm delivery

BACKGROUND

A case-control study was undertaken to detect whether initial chronic localized periodontitis could be a risk factor for preterm birth (PB) and foetal growth restriction.

METHODS

A PB case was defined if a patient had a threatening premature event during pregnancy pre-term premature rupture of membranes, or spontaneous pre-term delivery, before the 37th week of pregnancy, and/or the weight of the newborn was <2500 g. Into the PB (case) group, 77 women were allocated, while 84 were included in the control group, all of whom had delivery after the 37th gestational week and with a newborn weighing >or=2500 g.

RESULTS

A significant association was found between PB and initial chronic localized periodontitis, the criteria being bleeding at >or=50% of the examined teeth and having at least at one site at >or=4 mm probing depth (p=0.0001). The adjusted odds ratio for initial chronic localized periodontitis was 3.32, 95% CI: 1.64-6.69. The average weight of newborns of mothers with periodontitis was significantly less than that of the women without periodontitis (p=0.002).

CONCLUSIONS

The results support the hypothesis that initial chronic localized periodontitis of pregnant women could lead to PB, and birth-weight reduction.