|Year : 2017 | Volume
| Issue : 3 | Page : 205-209
Association between Streptococcus mutans and Candida albicans among 3–5-year-old children with early childhood caries: A cross-sectional study
F Farhanaz1, R Yashoda1, ML Kalayadhav2, Manjunath P Puranik1
1 Department of Public Health Dentistry, Government Dental College and Research Institute, Bengaluru, Karnataka, India
2 Department of Microbiology, Bangalore Medical College and Research Institute, Bengaluru, Karnataka, India
|Date of Web Publication||18-Sep-2017|
Department of Public Health Dentistry, Government Dental College and Research Institute, Bengaluru, Karnataka
Source of Support: None, Conflict of Interest: None
Introduction: Streptococcus mutans infection has been identified as an important microbial factor for early childhood caries (ECC). Candida species has been shown to enhance the adherence of S. mutans to the oral biofilm and carious tooth substance. However, there is a paucity of the literature regarding the association between S. mutans and Candida albicans related to the ECC. Aim: To assess and compare the levels of S. mutans and C. albicans among 3–5-year-old preschool children with and without ECC and to determine the association between them. Materials and Methods: A cross-sectional study was conducted among 30 children with ECC (ECC group) and 30 children without ECC (non-ECC group). Dental caries was assessed, and unstimulated saliva samples were collected. S. mutans and C. albicans counts were determined using Mutans-Sanguis agar and CHROMagar, respectively. Chi-square test and logistic regression were used. Significance levels were set at 5%. Results: There was a significant difference between ECC group and non-ECC group for S. mutans (P = 0.04) and C. albicans (P = 0.02) levels. There was no significant association between S. mutans and C. albicans in ECC and non-ECC groups. Children with ECC were more likely to have high levels of S. mutans and C. albicans when compared to non-ECC group. Conclusion: Children with ECC presented higher levels of S. mutans and C. albicans compared to children without ECC. High affinity between S. mutans and C. albicans suggests interaction between these diverse species that may mediate cariogenic development.
Keywords: Candida albicans, early childhood caries, preschool children, saliva, Streptococcus mutans
|How to cite this article:|
Farhanaz F, Yashoda R, Kalayadhav M L, Puranik MP. Association between Streptococcus mutans and Candida albicans among 3–5-year-old children with early childhood caries: A cross-sectional study. J Indian Assoc Public Health Dent 2017;15:205-9
|How to cite this URL:|
Farhanaz F, Yashoda R, Kalayadhav M L, Puranik MP. Association between Streptococcus mutans and Candida albicans among 3–5-year-old children with early childhood caries: A cross-sectional study. J Indian Assoc Public Health Dent [serial online] 2017 [cited 2018 Jul 20];15:205-9. Available from: http://www.jiaphd.org/text.asp?2017/15/3/205/215069
| Introduction|| |
Early childhood caries (ECC) is a major public health problem, being the most common chronic infectious childhood disease, which is difficult to control. The global prevalence of ECC has been reported to range from 1% to 70%. While not life-threatening, its impact on individuals and communities is considerable, resulting in pain, impairment of function, deleterious influence on the child's growth rate, body weight, and ability to thrive, thus reducing the quality of life.
ECC is defined as the presence of one or more decayed teeth (noncavitated or cavitated), missing (due to caries), or filled teeth (dmft) surfaces in any primary tooth in a child 71 months of age or younger. Some of the well-documented factors implicated in the development of ECC include high level of cariogenic microorganisms such as mutans streptococci, susceptible host, and fermentable carbohydrates. Other risk factors include socioeconomic status, parental attitudes, feeding, and oral hygiene practices in children with chronic illness or with special health-care needs and frequent use of sweetened medication.
Candida albicans are common inhabitants of the normal oral microbiota, thus do not cause any symptoms in healthy individuals. Among Candida species, the most prevalent in the oral cavity is C. albicans that varies with age: 24% in premature newborns, 4% in 4–5-day-old babies, and 30% in children aged 3–12 years. Some studies have reported higher cariogenic potential in C. albicans when compared to mutans when it is in contact with a hydroxyapatite substrate. It is possible that this potential is attributed to the ability of Candida to produce increased levels of pyruvate and acetate which, in turn, contribute to an acidic environment and to consequent caries process.
However, studies proving the association between the Candida levels in the oral cavity and caries are scarce. Since caries are caused by microorganisms, knowledge about the relationship between microorganisms and ECC is important for its prevention. Hence, there is a need to evaluate the levels of Streptococcus mutans and C. albicans in children with and without ECC and to determine the association between S. mutans and C. albicans in these groups. It was hypothesized that there is no association between S. mutans and C. albicans in children with and without ECC.
| Materials and Methods|| |
A cross-sectional study was conducted among 3–5-year-old children in Bengaluru for a period of 2 months from September 2016 to October 2016. Ethical clearance was obtained from the institutional ethics committee before commencing the study. Permissions were obtained from the authorities of Anganwadis/preschools. Informed consent was obtained from the parents.
Sample size was calculated through online calculator, considering minimum odds ratio (OR) 5, percentage exposed among controls 30%, power 80%, number of controls per case 1, and alpha risk 5%; the estimated sample size was 27 pairs which was rounded off to 30 pairs so the total sample size was 60: 30 children with ECC (ECC group) and 30 children without ECC (non-ECC group)].
A list of Anganwadi schools were obtained from the Integrated Child Development Services office and a list of play homes were obtained from the website; from this list, four Anganwadis and four preschools were selected randomly by lottery method. The study participants were recruited based on eligibility criteria: children aged 3–5 years old were included. Children who gave a history of prolonged antibiotic treatment, fungal infection, chronic diseases, immunocompromised, and those with any other developmental abnormalities were excluded from the study.
Data collection was done using structured pro forma at their respective Anganwadis/preschools, by a single-calibrated investigator. General information such as demographic profile, oral hygiene practices, and dental history were obtained from the parents. Dental caries was assessed as per the WHO 1997 criteria. The clinical oral examination was followed by collection of saliva.
Whole saliva (unstimulated saliva) that pools in the floor of the mouth was used. A sample of 2 ml saliva was collected by making the child to drool into sterile containers for 10 min between 10:00 am to 12:00 pm during the study.
Salivary samples were serially labeled as ECC/non-ECC before subjecting for microbiological investigations. Saliva samples were aseptically plated within 2 h on Mutans-Sanguis agar and CHROMagar for S. mutans and C. albicans, respectively. Plates were aerobically incubated at 37°C for 48–72 h. S. mutans were expressed in terms of colony-forming unit [Figure 1] and C. albicans were checked for its presence. Candida species are identified according to the different colors of colonies on the agar medium. C. albicans appeared as green-colored smooth colonies [Figure 2].
The data were entered into Microsoft Excel spread sheet and analyzed using the Statistical Package for the Social Sciences (SPSS) version 22.0 (IBM SPSS statistics for windows Armonk, NY: IBM Corp). Descriptive statistics were computed. Statistical significance was considered at 5% (P < 0.05) (confidence interval [CI] of 95%). Chi-square test was used to find out association between S. mutans and C. albicans. Logistic regression analysis was performed to find out the odds of occurrence of S. mutans and C. albicans together in study groups.
| Results|| |
Majority of the children were aged 5 years and were males in both the groups [Table 1]. Mean age of the children was 4.90 ± 0.92 years. Most of the children in ECC group used toothpaste (86.6%) and toothbrush (73.3%) and cleaned their teeth in circular direction (56.6%) once a day before meals (100%). However, slightly higher proportion of children in non-ECC group used toothpaste (90%) and toothbrush (83.3%) to clean their teeth. Relatively lower proportion of children both in ECC (13.3%) and non-ECC groups (3.3%) visited a dentist. Among those who visited the dentist for the main reason of pain, restorations and extractions were the treatments availed.
The mean caries experience (dmft) among ECC group was 4.17 ± 2.32 with dt being predominant (3.90 ± 2.15) [Table 2]. The proportion of children with higher levels of S. mutans (>105) was more among ECC group compared to non-ECC group, and the difference between the groups was statistically significant (P = 0.04) [Table 3]. The proportion of children with C. albicans was higher in ECC group compared to non-ECC group, and the difference between the groups was statistically significant (P = 0.02) [Table 4].
There was no significant association between S. mutans and C. albicans in both the groups. According to logistic regression, children with ECC were 10 times more likely to have high levels of S. mutans and C. albicans (OR = 10.54, 95% CI 1.22–90.6) (P = 0.032) compared to non-ECC group [Table 5].
|Table 5: Association between Streptococcus mutans and Candida albicans in study groups|
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| Discussion|| |
ECC is a common chronic childhood disease. It is a transmissible and biofilm-dependent infectious disease. It is an extremely expensive disease to treat and constitutes a major challenge in public health. Hence, understanding the acquisition of cariogenic microbes is important for the development of improved preventive strategies.
Previous studies have considered age group from 12 to 71 months.,,,,,,,, In the present study, the age ranged from 3 to 5 years which is in line with most of the studies reported in the literature.,, Caries experience in earlier studies ranged from 5.8 to 10.8 which is higher than the present study (4.17).
Earlier studies have evaluated the association between S. mutans and C. albicans using stimulated/unstimulated saliva, plaque, carious dentine, or sterile tooth pick. The present study assessed the levels of S. mutans and C. albicans using unstimulated saliva.
Level of S. mutans in children with ECC ranged from 84% to 100% when compared to 19%–53% in non-ECC group in the previous studies.,,, The current study is in accordance with earlier studies with S. mutans detected in all the children with ECC (100%) and about one-third in children without ECC. Higher levels (>105) of S. mutans were four times more among children with ECC than non-ECC group.
S. mutans has been ascribed as the primary microbial cause of ECC through its heavy presence in the biofilms formed on the tooth surface. Many attribute virulence of S. mutans solely to its ability to produce acid and to tolerate an acidic environment. The key virulence factor of S. mutans resides in its ability to convert dietary sucrose into a diverse range of soluble and, particularly, insoluble extracellular polysaccharides (EPSs) through exoenzymes such as glucosyltransferases (GTFs). The EPSs are the prime building blocks of cariogenic biofilms. They promote the colonization of the tooth surface by S. mutans and the recruitment of additional microorganisms into dental plaque, while forming the scaffold core or matrix of the biofilm.
The levels of C. albicans in children with ECC ranged from 12% to 93% when compared to 12%–33% in non-ECC group in earlier studies.,,, The present study is in agreement with earlier studies with C. albicans detected more than two times in children with ECC compared to non-ECC children. C. albicans in the ECC-affected children is more common than in caries-free children. Carious teeth may constitute an ecologic niche for the progression and dissemination of C. albicans in oral cavity. C. albicans has a high collagenolytic activity and can adhere to the intact and denatured collagen exposed from dentine. This process may contribute to the persistence of C. albicans on the surface of dissolved hydroxyl apatite because of high adherence capacity of this yeast to collagen.
Although there was no significant association between S. mutans and C. albicans within the groups, it was observed that children with ECC were more likely to have higher levels of S. mutans and C. albicans when compared to non-ECC group. It is possible that C. albicans enhanced co-colonization and proliferation in the oral cavity of ECC children which could be explained by the ecological plaque hypothesis. In the context of ECC, which is characterized by diet and dietary practices rich in fermentable carbohydrates, the acidogenic microorganisms can rapidly acidify the plaque microenvironment. In turn, the acidic pH conditions would favor the growth of acid-tolerant (aciduric) organisms, such as C. albicans and S. mutans, providing an ecological advantage compared to many other oral microbes. Hence, the likelihood of finding higher levels of S. mutans and C. albicans is manifold in children with ECC than their counterparts as shown in this study.
Interaction between these diverse species is subject of debate since long. In the oral cavity, the coadhesion between C. albicans and oral bacteria is crucial for C. albicans colonization and persistence. When sucrose is available, C. albicans could interact and develop biofilms with S. mutans, which greatly enhances the colonization by these organisms on apatitic surfaces. A major mechanism involved in this cross-kingdom association appears to be linked with the S. mutans-derived exoenzyme GTF B (GTFB), a key exopolysaccharides (EPSs) producer. GTFB can bind to the surface of C. albicans cells in an active form and produce EPS locally that provide enhanced binding sites for S. mutans, which in turn promote the formation of biofilms containing elevated EPS amounts and high numbers of S. mutans and C. albicans. Once together within a diffusion-limiting EPS-rich matrix, it is conceivable that coexistence of S. mutans and C. albicans could induce each other's growth and further enhance acid production in the biofilm (as the fungus is highly acidogenic and aciduric).
The study has some limitations such as cross-sectional study design, sample size, and varying caries experience in ECC group. Hence, generalization should be done with caution. Further longitudinal studies with large sample size are recommended to elucidate the possible interaction between these species in the initiation and progression of dental caries.
The presence of C. albicans in the oral environment can be considered as an additional factor that needs to be taken into account in evaluating risks to caries. Hence, salivary Candida levels may be used to assess caries risk in children and thus use of antifungal agents may represent a strategy for prevention of caries.
| Conclusion|| |
Children with ECC presented higher levels of S. mutans and C. albicans compared to children without ECC. However, there was no significant association between the S. mutans and C. albicans. High affinity between S. mutans and C. albicans among children with ECC suggests interaction between these diverse species that may mediate cariogenic development.
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Conflicts of interest
There are no conflicts of interest.
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[Figure 1], [Figure 2]
[Table 1], [Table 2], [Table 3], [Table 4], [Table 5]