Prevalence of Candida albicans and Candida dubliniensis in caries-free and caries-active children in relation to the oral microbiota-a clinical study

Interactions between non-albicans Candida and Streptococcus mutans enhance cariogenic potential of dual-species interkingdom biofilms

Background

Non-albicans Candida species (NACs) are commonly found in carious lesions, yet their specific role in caries progression remains unclear. Hence, we conducted an in vitro study to explore how NACs interactions with Streptococcus mutans affect cariogenicity.

Materials and Methods

Dual-species interkingdom biofilms were developed with S.mutans and six Candida species, C.albicans and the NACs: C.dubliniensis, C.glabrata, C.krusei, C.parapsilosis and C.tropicalis. Biofilm mass, viable cell counts, and pH were evaluated in mono- and dual-species biofilms. Quantitative RT-PCR was used to assess the expression of S.mutans genes associated with cariogenicity.

Results

Co-culturing S.mutans with either C.albicans, C.glabrata, or C.tropicalis significantly increased biofilm mass. While S.mutans numbers either increased or remained stable in dual-species biofilms, C.krusei, C.parapsilosis, and in particular C.tropicalis numbers significantly increased. All dual-species biofilms exhibited a pH below the critical demineralization level of enamel, akin to S.mutans mono-species biofilms. The expression of a battery of cariogenic genes in S.mutans was upregulated, particularly in dual-species biofilms with C.krusei and with C.tropicalis.

Conclusion

NACs influence the biofilm production and the cariogenic gene expression of S.mutans. The dual-species biofilm of S.mutans and NACs, particularly C.tropicalis, likely possess heightened cariogenic potential. Further research is warranted to unravel these intriguing interactions within interkingdom biofilms.

Antibiofilm potential of plant extracts: inhibiting oral microorganisms and Streptococcus mutans

Introduction

A range of disinfectant mouthwashes are available for oral hygiene. The gold standard is Chlorhexidine digluconate (CHX), which, like other available products, cannot be used without side effects in the long term. However, in recent years, therapy with herbal products, often considered antiquated, has regained considerable interest. Therefore, the search for plant compounds as an alternative to existing oral disinfectants is meaningful.

Methods

In this study, eleven Mediterranean plant extracts were tested for their antimicrobial effect in vitro. Methanol extracts of the following plants were produced by the pharmaceutical faculty of the University of Athens: Mentha aquatica, Mentha longifolia, Sideritis euboea, Sideritis syriaca, Stachys spinosa, Satureja parnassica, Satureja thymbra, Lavandula stoechas, Achillea taygetea, Phlomis cretica, and Vaccinium myrtillus. The extracts were dissolved for microdilution experiments at concentrations ranging from 10 to 0.019 mg/ml. The oral pathogens tested were Streptococcus mutans, Streptococcus oralis, Streptococcus sobrinus, Prevotella intermedia, Fusobacterium nucleatum, Parvimonas micra, Porphyromonas gingivalis, and Candida albicans. Enterococcus faecalis, Staphylococcus aureus, and Escherichia coli were used as references.

Results

All extracts, except the methanol extract of V. myrtillus, showed an antibacterial effect at concentrations ranging from 10 to 0.15 mg/ml. None of the extracts exhibited a significant antifungal effect. In general, the anaerobic pathogens could be inhibited and killed at lower concentrations compared to the aerobic pathogens. S. oralis also showed good susceptibility to the extracts. Additionally, the extracts' ability to inhibit biofilm formation by S. mutans was tested. L. stoechas at a concentration of 0.3 mg/ml showed a moderate inhibitory effect. The extracts of L. stoechas, S. thymbra, S. parnassica, and the methanol extract of V. myrtillus were effective at concentrations up to 1.25 mg/ml. P. cretica was able to inhibit and kill S. mutans at a concentration of 0.6 mg/ml, but its effectiveness in biofilm inhibition significantly decreased at 2.5 mg/ml.

Discussion

The study's hypothesis that all extracts would exhibit an antimicrobial effect was thus confirmed.

Oral Candida-biome and Early Childhood Caries: A Systematic Review and Meta-Analysis

OBJECTIVE

Candida is a common fungal pathogen in the oral cavity, with Candida albicans being the most prevalent species. Some studies report a correlation between Candida prevalence and dental caries experience in preschoolers, while others report no such association. This systematic review and meta-analysis aimed to evaluate the association of Candida-biome with Early Childhood Caries (ECC) in preschool children.

METHODS

Seven databases were searched for studies evaluating the correlation between Candida and ECC in healthy preschool children under 71 months of age. Dual independent screening, data extraction, bias risk assessment, meta-analysis, and quality evaluation of evidence were conducted.

RESULTS

The review included 20 studies with 12 reporting a positive association between Candida prevalence and ECC. The prevalence of Candida albicans in ECC ranged from 60%-84% across sample sites. Certain specific species, including C. dubliniensis and atypical non-albicans Candida (NAC), were also associated with caries severity in preschoolers. The pooled odds ratio (OR) estimate was 7.98 (95%CI; 3.84-16.58) for Candida-biome in plaque samples (I² = 84%), and 9.42 (95%CI: 4.15- 21.40) for Candida-biome in saliva sample (I² = 50%). These results suggest that children with Candida-biome in plaque and saliva have higher odds of having ECC than caries-free children.

CONCLUSIONS

Children with Candida-biome in plaque and saliva samples have a higher risk of Early Childhood Caries, predominantly associated with Candida albicans. Standardised methodologies for evaluating and comparing data on Candida species and ECC are recommended for future studies.

Adaptation to Sodium Hypochlorite and Potassium Permanganate May Lead to Their Ineffectiveness Against Candida albicans

Background/Objectives: Adaptation can reduce or completely eliminate the effectiveness of antibiotics and antiseptics at clinical concentrations. To our knowledge, no studies have examined fungal adaptation to antiseptics. This study aimed to preliminarily investigate the potential for Candida albicans adaptation to eight antiseptics. Methods: The minimal inhibitory concentration (MIC), drug susceptibility, adaptation to antiseptics, and Karpinski Adaptation Index (KAI) of C. albicans strains were assessed. Results: The antiseptics with the most effective MICs activity against C. albicans were octenidine dihydrochloride (OCT), chlorhexidine digluconate (CHX), and polyhexamethylene biguanide (polyhexanide, PHMB). Sodium hypochlorite (NaOCl) and ethacridine lactate (ET) demonstrated moderate activity, while boric acid (BA), povidone-iodine (PVI), and potassium permanganate (KMnO4) showed the weakest activity. The MIC values for NaOCl and KMnO4 were close to or equal to the clinical concentrations used in commercial products. The studied strains were susceptible to econazole, miconazole, and voriconazole. Resistance to other drugs occurred in 10-30% of the strains. Antifungal resistance remained unchanged after antiseptic adaptation testing. The lowest KAI values, indicating very low resistance risk, were observed for CHX, OCT, and PHMB. PVI and BA presented a low risk, ET a moderate risk. KMnO4 and NaOCl had the highest KAI values, indicating high and very high resistance risk in Candida yeasts. Conclusions:C. albicans strains can adapt to antiseptics to varying extents. For most antiseptics, adaptation does not significantly affect their clinical efficacy. However, due to adaptation, NaOCl and KMnO4 may become ineffective against C. albicans strains even at clinical concentrations.

Role of socioeconomic factors and interkingdom crosstalk in the dental plaque microbiome in early childhood caries

Early childhood caries (ECC) is influenced by microbial and host factors, including social, behavioral, and oral health. In this cross-sectional study, we analyze interkingdom dynamics in the dental plaque microbiome and its association with host variables. We use 16S rRNA and ITS1 amplicon sequencing on samples collected from preschool children and analyze questionnaire data to examine the social determinants of oral health. The results indicate a significant enrichment of Streptococcus mutans and Candida dubliniensis in ECC samples, in contrast to Neisseria oralis in caries-free children. Our interkingdom correlation analysis reveals that Candida dubliniensis is strongly correlated with both Neisseria bacilliformis and Prevotella veroralis in ECC. Additionally, ECC shows significant associations with host variables, including oral health status, age, place of residence, and mode of childbirth. This study provides empirical evidence associating the oral microbiome with socioeconomic and behavioral factors in relation to ECC, offering insights for developing targeted prevention strategies.

The Associations between Snack Intake and Cariogenic Oral Microorganism Colonization in Young Children of a Low Socioeconomic Status

Cariogenic microorganisms are crucial pathogens contributing to the development of early childhood caries. Snacks provide fermentable carbohydrates, altering oral pH levels and potentially affecting microorganism colonization. However, the relationship between snack intake and cariogenic microorganisms like Candida and Streptococcus mutans in young children is still unclear. This study aimed to assess this association in a prospective underserved birth cohort. Data from children aged 12 to 24 months, including oral microbial assays and snack intake information, were analyzed. Sweet and non-sweet indices based on the cariogenic potential of 15 snacks/drinks were created. Mixed-effects models were used to assess the associations between sweet and non-sweet indices and S. mutans and Candida carriage. Random forest identified predictive factors of microorganism carriage. Higher non-sweet index scores were linked to increased S. mutans carriage in plaques (OR = 1.67, p = 0.01), potentially strengthening with age. Higher sweet index scores at 12 months were associated with increased Candida carriage, reversing at 24 months. Both indices were top predictors of S. mutans and Candida carriage. These findings underscore the associations between snack intake and cariogenic microorganism carriage and highlight the importance of dietary factors in oral health management for underserved young children with limited access to dental care and healthy foods.

The Evolving Microbiome of Dental Caries

Dental caries is a significant oral and public health problem worldwide, especially in low-income populations. The risk of dental caries increases with frequent intake of dietary carbohydrates, including sugars, leading to increased acidity and disruption of the symbiotic diverse and complex microbial community of health. Excess acid production leads to a dysbiotic shift in the bacterial biofilm composition, demineralization of tooth structure, and cavities. Highly acidic and acid-tolerant species associated with caries include Streptococcus mutans, Lactobacillus, Actinomyces, Bifidobacterium, and Scardovia species. The differences in microbiotas depend on tooth site, extent of carious lesions, and rate of disease progression. Metagenomics and metatranscriptomics not only reveal the structure and genetic potential of the caries-associated microbiome, but, more importantly, capture the genetic makeup of the metabolically active microbiome in lesion sites. Due to its multifactorial nature, caries has been difficult to prevent. The use of topical fluoride has had a significant impact on reducing caries in clinical settings, but the approach is costly; the results are less sustainable for high-caries-risk individuals, especially children. Developing treatment regimens that specifically target S. mutans and other acidogenic bacteria, such as using nanoparticles, show promise in altering the cariogenic microbiome, thereby combatting the disease.

Evaluation of Changes in Oral Microflora in Children with Early Childhood Caries after Full Mouth Rehabilitation

Aim

To evaluate the change in microflora in children suffering from severe early childhood caries (ECC) after full mouth rehabilitation.

Materials and methods

A total of 60 children, aged 3-5 years suffering from severe ECC who fulfilled the inclusion and exclusion criteria were included in the study. Pooled plaque samples were taken and subjected to quantitative reverse transcriptase polymerase chain reaction (PCR) to obtain baseline mean values of Streptococcus mutans (S. mutans), Streptococcus sobrinus (S. sobrinus), Candida albicans (C. albicans), and Candida dubliniensis (C. dubliniensis) before full mouth rehabilitation was done under general anesthesia. Posttreatment samples were collected at 6, 12, and 18 months. Wilcoxon signed-rank test was used to compare the mean values of S. mutans, S. sobrinus, C. albicans, and C. dubliniensis before and after full mouth rehabilitation.

Results

A total of 60 patients recruited for the study were present at the follow-up at 6 and 12 months. At 18 months, 55 patients returned, and five were lost due to follow-up. A statistically significant reduction was seen in all microorganisms at 6, 12, and 18 months compared to baseline values. At 18 months a slight increase in S. mutans, S. sobrinus, and C. albicans was seen. C. dubliniensis was not detected in any cases after full mouth rehabilitation. Caries recurrence was seen in four patients at 18 months.

Conclusion

Significant reduction of S. mutans, S. sobrinus, C. albicans, and C. dubliniensis was seen at 6, 12, and 18 months. A complete reduction of only C. dubliniensis was seen. A significant but not permanent reduction of S. mutans, S. sobrinus, and C. albicans. Caries recurrence was seen in 7.27% of patients at 18 months.

How to cite this article

Mathew MG, Jeevanandan G, Rathod NN. Evaluation of Changes in Oral Microflora in Children with Early Childhood Caries after Full Mouth Rehabilitation. Int J Clin Pediatr Dent 2024;17(1):21-25.

Supragingival mycobiome of HIV-exposed-but-uninfected children reflects a stronger correlation with caries-free-associated taxa compared to HIV-infected or uninfected children

IMPORTANCE

Globally, caries is among the most frequent chronic childhood disease, and the fungal component of the microbial community responsible is poorly studied despite evidence that fungi contribute to increased acid production exacerbating enamel demineralization. HIV infection is another global health crisis. Perinatal HIV exposure with infection are caries risk factors; however, the caries experience in the context of perinatal HIV exposure without infection is less clear. Using high-throughput amplicon sequencing, we find taxonomic differences that become pronounced during late-stage caries. Notably, we show a stronger correlation with health-associated taxa for HIV-exposed-but-uninfected children when compared to unexposed and uninfected children. This aligns with a lower incidence of caries in primary teeth at age 6 or less for exposed yet uninfected children. Ultimately, these findings could contribute to improved risk assessment, intervention, and prevention strategies such as biofilm disruption and the informed design of pro-, pre-, and synbiotic oral therapies.

Effects of Nystatin oral rinse on oral Candida species and Streptococcus mutans among healthy adults

OBJECTIVES

To examine the effect of Nystatin oral rinse on oral Candida species and Streptococcus mutans carriage.

MATERIALS AND METHODS

Twenty healthy adults with oral candidiasis participated in the single-arm clinical trial and received Nystatin oral rinse for 7 days, 4 applications/day, and 600,000 International Units/application. Demographic-socioeconomic-oral-medical conditions were obtained. Salivary and plaque Candida species and Streptococcus mutans were assessed at baseline and 1-week and 3-month follow-ups. Twenty-four salivary cytokines were assessed. Candida albicans isolates underwent Nystatin susceptibility test.

RESULTS

Half of participants (10/20) were free of salivary C. albicans after using Nystatin rinse. Salivary S. mutans was significantly reduced at 3-month follow-up (p < 0.05). Periodontal status reflected by bleeding-on-probing was significantly improved at 1-week and 3-month follow-ups (p < 0.05). Plaque accumulation was significantly reduced at 1-week follow-up (p < 0.05). Interestingly, the responses to Nystatin oral rinse were not associated with race, gender, age, oral hygiene practice, adherence to Nystatin rinse, or sweet consumption (p > 0.05). No C. albicans isolates were resistant to Nystatin. Furthermore, salivary cytokine eotaxin and fractalkine were significantly reduced at 3-month follow-up among participants who responded to Nystatin rinse (p < 0.05).

CONCLUSIONS

The study results indicate that oral antifungal treatment had an effect on S. mutans salivary carriage. Future clinical trials are warranted to comprehensively assess the impact of antifungal treatment on the oral flora other than S. mutans and Candida.

CLINICAL RELEVANCE

Due to the potential cariogenic role of oral Candida species, antifungal approaches shed new light on the prevention and management of dental caries from a fungal perspective.

Cell Wall Mannan of Candida Attenuates Osteogenic Differentiation by Human Dental Pulp Cells

INTRODUCTION

Candida spp. has recently been introduced to interact with conventional carious bacteria, leading to dental caries progression and virulence ability. Evidence regarding the influence of Candida spp. on human dental pulp cell response remains unknown. This study aimed to investigate the effects of Candida albicans mannans on cytotoxicity, cell proliferation, osteogenic differentiation, and inflammatory-related gene expression in human dental pulp cells (hDPCs).

METHODS

hDPCs were treated with cell wall mannans isolated from C. albicans, Candida krusei, Candida glabrata, Candida tropocalis, Candida parapsilosis, and Candida dubliniensis. Cell viability was performed using a 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazolium bromide assay. Osteogenic differentiation- and inflammatory-related gene expression were determined using a real-time polymerase chain reaction. Mineralization was examined using alizarin red S staining.

RESULTS

The treatment of mannans isolated from C. albicans, C. krusei, C. glabrata, C. tropocalis, C. parapsilosis, and C. dubliniensis at concentrations ranging from 10-100 μg/mL did not affect cytotoxicity or cell proliferation. Mannans isolated from C. albicans, C. glabrata, and C. tropocalis significantly attenuated mineralization. However, cell wall mannans isolated from C. krusei, C. parapsilosis, and C. dubliniensis did not significantly influence mineral deposition in hDPCs. C. albicans cell wall mannans significantly attenuated osteogenic differentiation-related gene expression (RUNX2, ALP, and ENPP1). Interestingly, IL12 messenger RNA expression was significantly upregulated when treated with C. albicans cell wall mannans. The addition of recombinant IL12 significantly decreased mineralization in hDPCs.

CONCLUSIONS

C. albicans cell wall mannans attenuated osteogenic differentiation in hDPCs and up-regulated inflammatory-related gene IL12 expression.

Candida species and selected behavioral factors co-associated with severe early childhood caries: Case-control study

Severe Early Childhood Caries (sECC) is a multifactorial disease associated with the occurrence of specific oral microorganisms and other environmental, behavioral, and genetic factors. This study aimed to construct a multivariable model including the occurrence of Candida spp. and selected behavioral factors (length of breastfeeding, serving sweet beverages and beginning of brushing child's teeth) to determine their relationships to the occurrence of sECC. In this case-control study 164 children with sECC and 147 children without dental caries were included. MALDI-TOF MS and multiplex qPCR were used to identify Candida spp. and selected bacteria in dental plaque samples, respectively. A questionnaire on oral hygiene, diet, and children's health was filled in by the parents. The constructed multivariable logistic regression model showed an independent influence of the microbial and behavioral factors in sECC etiopathogenesis. The occurrence of C. albicans and C. dubliniensis was associated with higher odds of sECC development (odds ratio, OR: 9.62 and 16.93, respectively), together with breastfeeding of 6 months or less (OR: 2.71), exposure to sweet beverages (OR: 3.77), and starting to brush child's teeth after the 12th month of age (OR: 4.10), all statistically significant (p < 0.01). Considering the high occurrence of C. albicans and C. dubliniensis in dental plaque in children with sECC, we propose them as "keystone pathogens" and risk factors for sECC. The models showed that presence of specific species of Candida in dental plaque may be a better descriptor of sECC than the mentioned behavioral factors.

Characterization of Supragingival Plaque and Oral Swab Microbiomes in Children With Severe Early Childhood Caries

The human oral cavity harbors one of the most diverse microbial communities with different oral microenvironments allowing the colonization of unique microbial species. This study aimed to determine which of two commonly used sampling sites (dental plaque vs. oral swab) would provide a better prediction model for caries-free vs. severe early childhood caries (S-ECC) using next generation sequencing and machine learning (ML). In this cross-sectional study, a total of 80 children (40 S-ECC and 40 caries-free) < 72 months of age were recruited. Supragingival plaque and oral swab samples were used for the amplicon sequencing of the V4-16S rRNA and ITS1 rRNA genes. The results showed significant differences in alpha and beta diversity between dental plaque and oral swab bacterial and fungal microbiomes. Differential abundance analyses showed that, among others, the cariogenic species Streptococcus mutans was enriched in the dental plaque, compared to oral swabs, of children with S-ECC. The fungal species Candida dubliniensis and C. tropicalis were more abundant in the oral swab samples of children with S-ECC compared to caries-free controls. They were also among the top 20 most important features for the classification of S-ECC vs. caries-free in oral swabs and for the classification of dental plaque vs. oral swab in the S-ECC group. ML approaches revealed the possibility of classifying samples according to both caries status and sampling sites. The tested site of sample collection did not change the predictability of the disease. However, the species considered to be important for the classification of disease in each sampling site were slightly different. Being able to determine the origin of the samples could be very useful during the design of oral microbiome studies. This study provides important insights into the differences between the dental plaque and oral swab bacteriome and mycobiome of children with S-ECC and those caries-free.

Oral Mycobiome Differences in Various Spatial Niches With and Without Severe Early Childhood Caries

Purpose: Severe early childhood caries (S-ECC) is a microbe-mediated disease with tooth hard tissue destruction. However, the role of the fungal community in various ecological niches of deciduous dental caries has not been fully elucidated. This study aimed to analyze the differences of mycobiome in diverse spatial niches with and without S-ECC. Method: A total of 48 samples were obtained from 8 S-ECC children (SE group) and 8 caries-free children (CF group) aged 4-5 years. Unstimulated saliva (S), healthy supragingival plaque (FMIX), mixed plaque from decayed teeth (SMIX) and carious lesion (DMIX) samples were collected. The ITS2 region of the fungi was amplified and sequenced using the Ion S5™XL platform. Results: A total of 281 species were identified. Candida albicans showed relatively higher abundance in S-ECC children, while Alternaria alternata and Bipolaris sorokiniana were more enriched in CF group. In this study, the relative abundance of C. albicans in CF.FMIX (0.4%), SE.FMIX (12.5%), SE.SMIX (24.0%), and SE.DMIX (37.2%) increased successively. Significant differences of fungal species richness and diversity were observed between SE.FMIX-SE.SMIX, SE.FMIX-SE.DMIX (P < 0.05). Conclusions: The diversity of fungal communities in S-ECC children showed significant differences in various spatial niches of primary teeth. The richness of C. albicans was closely related to the caries states and depth, suggesting that it may play a crucial role in caries pathogenicity.

Oral microbiome in down syndrome and its implications on oral health

Introduction: The oral cavity harbors an abundant and diverse microbial community (i.e. the microbiome), whose composition and roles in health and disease have been the focus of intense research. Down syndrome (DS) is associated with particular characteristics in the oral cavity, and with a lower incidence of caries and higher incidence of periodontitis and gingivitis compared to control populations. However, the overall composition of the oral microbiome in DS and how it varies with diverse factors like host age or the pH within the mouth are still poorly understood. Methods: Using a Citizen-Science approach in collaboration with DS associations in Spain, we performed 16S rRNA metabarcoding and high-throughput sequencing, combined with culture and proteomics-based identification of fungi to survey the bacterial and fungal oral microbiome in 27 DS persons (age range 7–55) and control samples matched by geographical distribution, age range, and gender.

Results: We found that DS is associated with low salivary pH and less diverse oral microbiomes, which were characterized by lower levels of Alloprevotella, Atopobium, Candidatus Saccharimonas, and higher amounts of Kingella, Staphylococcus, Gemella, Cardiobacterium, Rothia, Actinobacillus, and greater prevalence of Candida.

Conclusion: Altogether, our study provides a first global snapshot of the oral microbiome in DS. Future studies are required to establish whether the observed differences are related to differential pathology in the oral cavity in DS.

Critically Appraising the Significance of the Oral Mycobiome

Recent efforts to understand the oral microbiome have focused on its fungal component. Since fungi occupy a low proportion of the oral microbiome biomass, mycobiome studies rely on sequencing of internal transcribed spacer (ITS) amplicons. ITS-based studies usually detect hundreds of fungi in oral samples. Here, we review the oral mycobiome, critically appraising the significance of such large fungal diversity. When harsh lysis methods are used to extract DNA, 2 oral mycobiome community types (mycotypes) are evident, each dominated by only 1 genus, either Candida or Malassezia. The rest of the diversity in ITS surveys represents low-abundance fungi possibly acquired from the environment and ingested food. So far, Candida is the only genus demonstrated to reach a significant biomass in the oral cavity and clearly shown to be associated with a distinct oral ecology. Candida thrives in the presence of lower oral pH and is enriched in caries, with mechanistic studies in animal models suggesting it participates in the disease process by synergistically interacting with acidogenic bacteria. Candida serves as the main etiological agent of oral mucosal candidiasis, in which a Candida-bacteriome partnership plays a key role. The function of other potential oral colonizers, such as lipid-dependent Malassezia, is still unclear, with further studies needed to establish whether Malassezia are metabolically active oral commensals. Low-abundance oral mycobiome members acquired from the environment may be viable in the oral cavity, and although they may not play a significant role in microbiome communities, they could serve as opportunistic pathogens in immunocompromised hosts. We suggest that further work is needed to ascertain the significance of oral mycobiome members beyond Candida. ITS-based surveys should be complemented with other methods to determine the in situ biomass and metabolic state of fungi thought to play a role in the oral environment.

Candida and dental caries in children, adolescents and adults: A systematic review and meta-analysis

OBJECTIVE

This systematic review and meta-analysis aimed to investigate whether the presence of fungi of the genus Candida in oral cavity is associated with dental caries in children and adolescents (from 6 to 18 years) or in adults (older than 18 years).

DESIGN

Electronic search was carried out in MEDLINE, EMBASE and LILACS databases. Studies that evaluated the presence of Candida spp. and dental caries on those individuals were included. Data extraction and evidence quality assessment were performed by two independent investigators. Prevalence ratio (PR) was calculated considering 95 % confidence interval (CI). Meta-analysis was performed using random effect Mantel-Haenszel model.

RESULTS

Thirty out of 123 publications selected for full-reading were included in the systematic review. Prevalence of Candida spp. in the oral cavity ranged from 7.7 % to 78 %. Prevalence of dental caries in individuals harbouring Candida spp. ranged from 27.2%-100% and was higher than in individuals not harbouring Candida spp. (PR = 1.72 [1.46-2.02]). Prevalence of dental caries was 2.3 times higher in individuals harbouring Candida spp. in mucosa. Moreover, dental caries prevalence was 80 % and 48 % higher in children/adolescents and adults harbouring Candida spp., respectively (95 % CI [1.44-2.25] and [1.20-1.83]). The quality of evidence of most studies (n = 21) was graded as fair.

CONCLUSIONS

These results suggest that, regardless of age or sample site, individuals with the presence of Candida spp. have a higher prevalence of dental caries when compared to individuals without these microorganisms in the oral cavity.

Site-Specific Profiling of the Dental Mycobiome Reveals Strong Taxonomic Shifts during Progression of Early-Childhood Caries

Dental caries is one of the most common diseases worldwide. Bacteria and fungi are both commensals in the oral cavity; however, most research regarding caries has focused on bacterial impacts. The oral fungal mycobiome associated with caries is not well characterized, and its role in disease is unclear. ITS1 amplicon sequencing was used to generate taxonomic profiles from site-specific supragingival plaque samples (n = 82) obtained from 33 children with different caries status. Children were either caries free (CF), caries active with enamel lesions (CAE), or caries active with dentin lesions (CA). Plaque samples were collected from caries-free surfaces (PF) and from enamel (PE) and dentin (PD) lesions. Taxonomic profiles representing the different categorizations (CF-PF, CAE-PF, CAE-PE, CA-PF, CA-PE, and CA-PD) were used to characterize the mycobiome and its change through disease progression. A total of 139 fungal species were identified. Candida albicans was the most abundant species, followed by Candida dubliniensis We found that severely progressed plaque communities (CA-PD) were significantly different from healthy plaque communities (CF-PF). A total of 32 taxa were differentially abundant across the plaque categories. C. albicans, C. dubliniensis, Nigrospora oryzae, and an unclassified Microdochium sp. were correlated with caries, whereas 12 other taxa were correlated with health. C. dubliniensis increased steadily as caries progressed, suggesting that C. dubliniensis may play an important role in caries pathogenicity. In contrast, four health-associated fungal taxa have the potential to antagonize the cariogen Streptococcus mutans via xylitol production, suggesting a possible fungal mechanism that could contribute to maintenance of dental health.IMPORTANCE Early-childhood caries is one of the most prevalent diseases in children worldwide and, while preventable, remains a global public health concern. Untreated cavities are painful and expensive and can lead to tooth loss and a lower quality of life. Caries are driven by acid production via microbial fermentation of dietary carbohydrates, resulting in enamel erosion. While caries is a well-studied disease, most research has focused on bacterial impacts, even though fungi are commensal organisms living within the plaque biofilm. There is very little known about how fungi impact caries pathogenicity. The elucidation of fungal taxa involved in caries disease progression is necessary for a more holistic view of the human oral microbiome. Data from this study will improve our understanding of how the fungal community changes as disease progresses and provide insight into the complex etiology of dental caries, which is necessary for the development of treatment plans and preventative measures.

Spatial Design of Polymicrobial Oral Biofilm in Its Native Disease State

Biofilms are structured microbial communities adhered to surfaces that cause many human infections. The study of oral biofilms has revealed complex composition, spatial organization, and phenotypic/genotypic diversity of the resident microbiota at the various sites in the mouth. Yet, knowledge about the spatial arrangement, positioning, and function of the polymicrobial community across the intact biofilm architecture remains sparse. Using multiple length scale imaging and computational analysis, we discovered unique spatial designs comprising mixed interbacterial species and interkingdom communities within intact biofilms formed on teeth of toddlers with caries. Intriguing structural patterns ranging from intermixed communities with extensive coaggregation (including bacterial-fungal clustering) to spatially segregated species forming a multilayered architecture were found. Among them, a distinctive 3-dimensional structure exhibited densely clustered cariogenic pathogens that were surrounded by outer layers of mixed bacterial communities in juxtaposition, forming a highly ordered spatial organization. These findings are particularly relevant as we approach the postmicrobiome era whereby studying the spatial structure of the pathogen and commensal microbiota may be important for understanding the microbiome function at the infection site to coordinate the disease process in situ.

Sex-Based Diverse Plaque Microbiota in Children with Severe Caries

Severe early childhood caries (S-ECC) is a multifactorial disease that can lead to suffering and reduced oral health-related quality of life in young children. The bacterial and fungal composition of dental plaque and how children's sex is associated with S-ECC are largely unknown. In this study, V4-16S rRNA and ITS1 rRNA gene amplicon sequencing was used to compare the plaque bacteriome and mycobiome of children <72 mo of age: 40 with S-ECC (15 males, 25 females) and 40 caries-free (19 males, 21 females). Health- and nutrition-related questionnaire data were also investigated. This study aimed to analyze potential sex-based differences in the supragingival plaque microbiota of young children with S-ECC and those caries-free. Behavioral and nutritional habit differences were observed between children with S-ECC and those caries-free and between male and female children. Overall, higher levels of Veillonella dispar, Streptococcus mutans, and other bacterial species were found in the S-ECC group as compared with caries-free controls (P < 0.05). A significant difference in the abundance of Neisseria was observed between males and females with S-ECC (P < .05). Fungal taxonomic analysis showed significantly higher levels of Candida dubliniensis in the plaque of children with S-ECC as compared with those caries-free (P < 0.05), but no differences were observed with Candida albicans (P > 0.05). Significant differences in the relative abundance of Mycosphaerella, Cyberlindnera, and Trichosporon fungal species were also observed between the caries-free and S-ECC groups (P < 0.05). Machine learning analysis revealed the most important bacterial and fungal species for classifying S-ECC versus caries-free. Different patterns of crosstalk between microbial species were observed between male and female children. Our work demonstrates that plaque microbiota and sex may be important determinants for S-ECC and could be factors to consider for inclusion in caries risk assessment tools.

Oral health and Candida carriage in socioeconomically disadvantaged US pregnant women

Background

Despite the well-documented associations between poor maternal oral health and increased risk for adverse birth outcomes and dental caries in children after birth, prenatal oral health care is under-utilized, especially among the underserved population. In addition, oral Candida has recently been suggested as a potential culprit for children’s dental caries, with evident maternal contributions. Therefore, this study aimed to obtain epidemiological data on the oral health and oral Candida carriage in a cohort of underserved US pregnant women, and reveal factors associated with their oral Candida carriage.

Methods

Demographic-medical-oral hygiene practice data were collected. Comprehensive oral examination was conducted. Caries status and plaque index were recorded. Oral samples (saliva, plaque and swab) were processed to identify Candida species and Streptococcus mutans by culturing-dependent and -independent methods. Multiple logistic regression analyses were used to identify factors associated with oral Candida carriage and caries severity.

Results

Eighty-two socioeconomically disadvantaged women (48 pregnant and 34 non-pregnant) were enrolled. More pregnant women (79.1%) had > = 1 untreated decayed tooth when compared to their non-pregnant counterparts (47.1%) (p = 0.01). The average number of decayed teeth in pregnant and non-pregnant women was 3.9 and 3.1 (p > 0.05). Caries severity was positively associated with race (African American vs. white), plaque index and salivary Candida albicans level. C. albicans was the most predominant/abundant Candida strain, with cheek and tonsil as the most common colonized sites. The detection of C. albicans was 56%/56% in saliva and 40%/47% in plaque of the pregnant and non-pregnant groups, respectively. Study women’s oral Candida carriage is positively associated with hypertension [p = 0.03, odds ratio = 14.47(1.28, 163.51)], decayed teeth number [p = 0.04, odds ratio = 1.31 (1.01,1.69)] and salivary S. mutans level [p = 0.03, odds ratio = 4.80 (1.18–19.43)].

Conclusions

Socioeconomically disadvantaged US women are in need of improved prenatal oral health, a large proportion of them have untreated decayed teeth and high carriage of oral Candida. Due to the observed significant association between the decayed teeth number and oral Candida carriage, providing oral health care during pregnancy (including limiting decayed teeth) will not only improve women’s oral health, but also present as a promising approach to reduce oral Candida carriage in women.

Combined Candida dubliniensis and Candida albicans Keratitis following a Chemical Injury

Candida dubliniensis is an uncommon source of ocular infections and has only been reported in a single previous case of keratitis. This report documents the course of a combined Candida dubliniensis and Candida albicans keratitis following a chemical injury. Antifungal sensitivities of the two different Candida species are also demonstrated.

Phenotypic and genotypic detection of Candida albicans and Candida dubliniensis strains isolated from oral mucosa of AIDS pediatric patients

The aim of this study was to assess a collection of yeasts to verify the presence of Candida dubliniensis among strains isolated from the oral mucosa of AIDS pediatric patients which were initially characterized as Candida albicans by the traditional phenotypic method, as well as to evaluate the main phenotypic methods used in the discrimination between the two species and confirm the identification through genotypic techniques, i.e., DNA sequencing. Twenty-nine samples of C. albicans isolated from this population and kept in a fungi collection were evaluated and re-characterized. In order to differentiate the two species, phenotypic tests (Thermotolerance tests, Chromogenic medium, Staib agar, Tobacco agar, Hypertonic medium) were performed and genotypic techniques using DNA sequencing were employed for confirmation of isolated species. Susceptibility and specificity were calculated for each test. No phenotypic test alone was sufficient to provide definitive identification of C. dubliniensis or C. albicans, as opposed to results of molecular tests. After amplification and sequencing of specific regions of the 29 studied strains, 93.1% of the isolates were identified as C. albicans and 6.9% as C. dubliniensis. The Staib agar assay showed a higher susceptibility (96.3%) in comparison with other phenotypic techniques. Therefore, genotypic methods are indispensable for the conclusive identification and differentiation between these species.

Prevalence of Candida albicans and carriage of Candida non-albicans in the saliva of preschool children, according to their caries status

OBJECTIVE

This study was conducted to establish associations among the Candida carriage rate, the diversity of Candida species carried and the different caries status of preschool children.

MATERIALS AND METHODS

Sixty-one children between 2 and 5 years of age were examined by a single expert examiner and were divided into three groups, the caries-free, moderate caries and severe caries groups, according to the criteria of the International Caries Detection and Assessment System II (ICDAS). Saliva samples were obtained from the members of each group and were plated on Sabouraud agar plates to assess the Candida carriage rates. CHROMagar Candida medium was used for the preliminary screening. Biochemical testing or PCR/sequencing was conducted to identify the different Candida species in the samples. The differences observed were considered significant if the p value was <0.05.

RESULTS

The Candida carriage rate and the number of species of this fungus carried were higher in the group with the highest level of caries severity (p < 0.05). Whereas Candida albicans was the most predominant Candida species in the saliva of all of the children, C. dubliniensis was identified only in the most caries-affected group in addition to other rare species of Candida non-albicans.

CONCLUSIONS

A high salivary Candida carriage rate and the presence of specific species of this fungus (such as C. albicans and C. dubliniensis) appear to be related to the severity of caries experienced by preschool children.