PCR Detection of Streptococcus Mutans and Streptococcus Sobrinus in Dental Plaque Samples from Low, Moderate, and High Caries Risk Children PDF Download

Author: Ajit A. Patel
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ISBN:
Category :
Languages : en
Pages : 72

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Author: Chanika Manmontri
Publisher:
ISBN:
Category :
Languages : en
Pages : 53

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Mutans streptococci (MS), e.g., Streptococcus mutans (Sm) and Streptococcus sobrinus (Ss), are associated with dental caries. Quantification of MS has been shown to predict caries risk. Traditional culture methods are problematic, especially because consistently maintaining the viability of bacteria is difficult. A new technology using PCR has the potential to streamline and improve MS quantification compared to traditional culture methods. Purpose: To use real-time quantitative PCR (qPCR) and standard plate counting (SPC) for detection and quantification of levels of Sm, Ss and total streptococci (TS) in clinical samples from high-caries-risk children (no regular access to dental care) and to evaluate the correlation of these results to caries prevalence. Methods: Saliva and plaque samples were collected from school-aged children for SYBR Green based qPCR using primers specific for Sm, Ss and TS from DNA extracted. UA159 genomic DNA was used as standard from which "copy number" (CN/ml) of MS and TS was computed. For comparison, samples were also processed and quantified for "colony forming unit" (CFU/ml) of MS and TS using SPC. Calibrated examiners performed oral examinations (DMFT/DMFS/dmft/dmfs). Pearson's analysis and T-test assessed correlations between level of Sm and ratio of Sm to TS to caries using SAS V9.2. Results: Fifty-eight subjects (mean age=9.8 years, DMFS/dmfs=7.0) had samples collected. By qPCR Sm was detected in 98.1% of samples while SPC was 72.9%. Ss was only found in 4 qPCR samples (none by SPC). Mean qPCR CN/ml of samples were: Sm (2.54x106), Ss (5.27x102) and TS (2.34x109). Mean SPC CFU/ml of samples were: Sm (9.4x105), Ss (0) and TS (1.0x107). Significant correlations were found between level of Sm and ratio of Sm/TS from oral samples to prevalence of dental caries. Conclusion: The levels of Sm and ratio of Sm/TS by qPCR and SPC were correlated to dental caries. Correlations between mean levels of Sm and ratio of Sm/TS to caries experience from qPCR are comparable to SPC. Given the similar correlations found, the more streamlined method of qPCR is a suitable outcome measure in epidemiological studies.

Author: Jungyi Alexis Liu
Publisher:
ISBN:
Category :
Languages : en
Pages : 47

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Streptococcus mutans (Sm) and Streptococcus sobrinus (Ss), are considered the major bacterium associated with dental caries. However, recent findings identify Scardovia species (Sc) is associated with early childhood caries, with or without the presence of Sm or Ss. This IRB approved study quantified the presence of Sm and Sc in saliva by real-time quantitative PCR (qPCR) in relation to caries. Saliva samples were collected from 72 preschool children in a high-caries risk community in rural Alabama. SYBR Green-based qPCR using extracted DNA and primers specific for Sm, Ss, Sc and total bacteria determined the copy number (CN/ml). Twenty two subjects (30.6%) were in caries-free group (DMFS/dmfs=0), whereas 50 (69.4%) subjects in caries-experience group (DMFS/dmfs>0). The detection limited for quantification was determined to be 1000 CN/ml. Sc was detected in 72.8% in the caries-free group and 80% of subjects in the caries-experience group. Sm was ubiquitous (approached 100%) in both groups. None of the samples had quantitatable levels of Ss. Generally, the level of Sm was much higher than Sc. Although the caries-experience group had higher mean ratio of Sm/total bacteria and Sc/total bacteria than children in caries-free group, the only significant difference between the two groups was found in the mean ratio of Sc/total bacteria (p=0.022). No statistical difference was found in detection frequency between caries-experience and caries-free group in the three different bacterial combination groups (Sc negative+ Sm negative, Sc negative+ Sm positive, Sc positive+ Sm positive). The overall results indicated that Sc was highly detected in caries-experience group and the ratio of Sc/total bacteria was significantly associated with caries history. Although the presence of Sm, Sc or the combination of both bacteria didn't show correlation to caries, other factors (e.g., diet & dietary practices, ethnicity, oral hygiene factors, socioeconomic influences, host factors and general health conditions, medications) must also be considered since caries is a multifactorial disease.

Author: Satu Alaluusua
Publisher:
ISBN:
Category : Dental caries
Languages : en
Pages : 110

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Author:
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Category : Dental caries
Languages : en
Pages : 68

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Author: Peter Carlsson
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ISBN:
Category : Dental caries
Languages : en
Pages : 112

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Author: Brent David Johnson
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Category : Streptococcus mutans
Languages : en
Pages : 32

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Abstract: Nested PCR using a newly-developed oligonucleotide primer specific to the 16S- 23S ribosomal DNA Intergenic Spacer Region for Streptococcus mutans was used to determine the prevalence of Streptococcus mutans in 112 supragingival plaque samples obtained from 55 children and adolescents with and without caries experience. In all, twenty-two children with primary dentition under the age of 30 months, sixteen children with severe caries in the primary dentition, and seventeen children and adolescents ages eight to sixteen were sampled; subjects with caries experience provided samples from intact enamel, enamel whitespots, cavitated enamel, and dentin lesions. Some subjects were sampled multiple times longitudinally. Development and testing of the newly-developed oligonucleotide primer using MacVector software and genomic sequence data obtained from GenBank enabled analysis of the primer's specificity for Streptococcus mutans. Overall, 91% of the subjects contained Streptococcus mutans in at least one of their plaque samples. In addition, over 92% of caries-free subjects contained plaque with Streptococcus mutans, and subjects with caries demonstrated from 73% to 95% prevalence of Streptococcus mutans depending on the sample location. These levels of prevalence are similar to other reports of Streptococcus mutans prevalence in the young primary and primary dentition.

Author: Catarina Wallman
Publisher:
ISBN:
Category : Chlorhexidine
Languages : en
Pages : 104

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Author: Aaron Bottner
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Category :
Languages : en
Pages : 0

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Within dental plaque, Streptococcus mutans produces acids from fermentable carbohydrates, decreasing the biofilm pH, causing enamel demineralization. S. mutans produces persisters, dormant variants of cells that survive lethal antibiotic concentrations without developing antibiotic resistance. Persisters have been associated with infection chronicity. We hypothesized that phenotypic heterogeneity of S. mutans is directly associated with cariogenicity. S. mutans were isolated from plaque collected from caries-free (CF) children and children with Severe Early Childhood Caries (S-ECC). For each identified genotype, an acid tolerance analysis was performed and persisters were quantified. In S-ECC patients with >1 strain, the dominant strain exhibited higher cell survival following exposure to pH 3.2, whereas in CF patients, survival was similar. S. mutans isolates from S-ECC patients produced ~15x more persisters than isolates from CF patients. S. mutans exhibits phenotypic diversity. The ability of S. mutans to produce high levels of persisters may be a hallmark of cariogenicity.

Author: Jan Doekes de Stoppelaar
Publisher:
ISBN:
Category : Dental caries
Languages : en
Pages : 82

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