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ABSTRACT: Glucosyltransferases (Gtfs) catalyze the synthesis of glucans from sucrose and are produced by several species of lactic-acid bacteria. The oral bacterium produces large amounts of glucans through the action of three Gtfs. GtfD produces water-soluble glucan (WSG), GtfB synthesizes water-insoluble glucans (WIG) and GtfC produces mainly WIG but also WSG. These enzymes, especially those synthesizing WIG, are of particular interest because of their role in the formation of dental plaque, an environment where can thrive and produce lactic acid, promoting the formation of dental caries. We sequenced the , and genes from several mutans streptococcal strains isolated from the oral cavity of humans and searched for their homologues in strains isolated from chimpanzees and macaque monkeys. The sequence data were analyzed in conjunction with the available Gtf sequences from other bacteria in the genera , and to gain insights into the evolutionary history of this family of enzymes, with a particular emphasis on Gtfs. Our analyses indicate that streptococcal Gtfs arose from a common ancestral progenitor gene, and that they expanded to form two clades according to the type of glucan they synthesize. We also show that the clade of streptococcal Gtfs synthesizing WIG appeared shortly after the divergence of viviparous, dentate mammals, which potentially contributed to the formation of dental plaque and the establishment of several streptococci in the oral cavity. The two Gtfs capable of WIG synthesis, GtfB and GtfC, are likely the product of a gene duplication event. We dated this event to coincide with the divergence of the genomes of ancestral early primates. Thus, the acquisition and diversification of Gtfs predates modern humans and is unrelated to the increase in dietary sucrose consumption.
PLoS ONE 01/2013; 8(2):e56305. · 4.09 Impact Factor
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ABSTRACT: Streptococcus mutans, a member of the human oral flora, is a widely recognized etiological agent of dental caries. The cariogenic potential of S. mutans is related to its ability to metabolize a wide variety of sugars, form a robust biofilm, produce copious amounts of lactic acid, and thrive in the acid environment that it generates. The remarkable genetic variability present within the species is reflected at the phenotypic level, notably in the differences in the cariogenic potential between strains. However, the genetic basis of these differences is yet to be elucidated. In this study, we surveyed by PCR and DNA hybridization the distribution of putative virulence genes, genomic islands, and insertion sequences across a collection of 33 strains isolated from either children with severe early childhood caries (S-ECC) or those who were caries free (CF). We found this genetically diverse group of isolates to be remarkably homogeneous with regard to the distribution of the putative virulence genes and genetic elements analyzed. Our findings point to the role of other factors in the pathogenesis of S-ECC, such as uncharacterized virulence genes, differences in gene expression and/or enzymatic activity, cooperation between S. mutans strains or with other members of the oral biota, and host factors.
Journal of clinical microbiology 01/2011; 49(3):984-92. · 4.16 Impact Factor
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ABSTRACT: This article presents evidence-based clinical recommendations for use of pit-and-fissure sealants developed by an expert panel convened by the American Dental Association (ADA) Council on Scientific Affairs. The panel addressed the following clinical questions. Under what circumstances should sealants be placed to prevent caries? Does placing sealants over early (noncavitated) lesions prevent progression of the lesion? Are there conditions that favor the placement of resin-based versus glass ionomer cement sealants in terms of retention or caries prevention? Are there any techniques that could improve sealants' retention and effectiveness in caries prevention? Staff of the ADA Division of Science conducted a MEDLINE search to identify systematic reviews and clinical studies published after the identified systematic reviews.
Dental clinics of North America 02/2009; 53(1):131-47, x.
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ABSTRACT: Streptococcus mutans is one of several members of the oral indigenous biota linked with severe early childhood caries (S-ECC). Because most humans harbor S. mutans, but not all manifest disease, it has been proposed that the strains of S. mutans associated with S-ECC are genetically distinct from those found in caries-free (CF) children. The objective of this study was to identify common DNA fragments from S. mutans present in S-ECC but not in CF children. Using suppressive subtractive hybridization, we found a number of DNA fragments (biomarkers) present in 88 to 95% of the S-ECC S. mutans strains but not in CF S. mutans strains. We then applied machine learning techniques including support vector machines and neural networks to identify the biomarkers with the most predictive power for disease status, achieving a 92% accurate classification of the strains as either S-ECC or CF associated. The presence of these gene fragments in 90 to 100% of the 26 S-ECC isolates tested suggested their possible functional role in the pathogenesis of S. mutans associated with dental caries.
Journal of clinical microbiology 08/2008; 46(9):2868-73. · 4.16 Impact Factor
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ABSTRACT: This article presents evidence-based clinical recommendations for use of pit-and-fissure sealants developed by an expert panel convened by the American Dental Association Council on Scientific Affairs. The panel addressed the following clinical questions: Under what circumstances should sealants be placed to prevent caries? Does placing sealants over early (noncavitated) lesions prevent progression of the lesion? Are there conditions that favor the placement of resin-based versus. glass ionomer cement sealants in terms of retention or caries prevention? Are there any techniques that could improve sealants' retention and effectiveness in caries prevention?
Staff of the ADA Division of Science conducted a MEDLINE search to identify systematic reviews and clinical studies published after the identified systematic reviews. At the panel's request, the ADA Division of Science staff conducted additional searches for clinical studies related to specific topics. The Centers for Disease Control and Prevention also provided unpublished systematic reviews that since have been accepted for publication.
The expert panel developed clinical recommendations for each clinical question. The panel concluded that sealants are effective in caries prevention and that sealants can prevent the progression of early noncavitated carious lesions.
These recommendations are presented as a resource to be considered in the clinical decision-making process. As part of the evidence-based approach to care, these clinical recommendations should be integrated with the practitioner's professional judgment and the patient's needs and preferences. The evidence indicates that sealants can be used effectively to prevent the initiation and progression of dental caries.
Journal of the American Dental Association (1939) 04/2008; 139(3):257-68. · 1.77 Impact Factor
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ABSTRACT: Concern about inadvertently sealing over caries often prevents dentists from providing dental sealants. The objective of the authors' review was to examine the effects of sealants on bacteria levels within caries lesions under dental sealants.
The authors searched electronic databases for comparative studies examining bacteria levels in sealed permanent teeth. To measure the effect of sealants on bacteria levels, they used the log(10) reduction in mean total viable bacteria counts (VBC) between sealed and not-sealed caries and the percentage reduction in the proportion of samples with viable bacteria.
Six studies--three randomized controlled trials, two controlled trials and one before-and-after study-were included in the analysis. Although studies varied considerably, there were no findings of significant increases in bacteria under sealants. Sealing caries was associated with a 100-fold reduction in mean total VBC (four studies, 138 samples). Sealants reduced the probability of viable bacteria by about 50.0 percent (four studies, 117 samples).
The authors found that sealants reduced bacteria in carious lesions, but that in some studies, low levels of bacteria persisted. These findings do not support reported concerns about poorer outcomes associated with inadvertently sealing caries.
Practitioners should not be reluctant to provide sealants-an intervention proven to be highly effective in preventing caries-because of concerns about inadvertently sealing over caries.
Journal of the American Dental Association (1939) 04/2008; 139(3):271-8; quiz 357-8. · 1.77 Impact Factor
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The journal of evidence-based dental practice 01/2008; 7(4):155-7.
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ABSTRACT: Streptococcus mutans is the major microbial pathogen associated with dental caries in children. The objectives of this study were to design and evaluate species-specific primers for the identification of S. mutans. Validation of the best primer set, Sm479F/R, was performed using seven S. mutans reference strains, 48 ATCC non-S. mutans strains, 92 S. mutans clinical isolates, DNA samples of S. mutans-Streptococcus sobrinus or S. mutans-Streptococcus sanguinis, and mixed bacterial DNA of saliva samples from 33 18-month-old children. All of the S. mutans samples tested positive, and no PCR products were amplified from members of the other streptococci or nonstreptococci strains examined. The lowest detection level for PCR was 10(-2) ng of S. mutans DNA (c. 4.6 x 10(3) copies) in the test samples. The results of this study suggest that the Sm479F/R primer pair is highly specific and sensitive for identification of S. mutans in either purified or mixed DNA samples.
FEMS Microbiology Letters 08/2007; 272(2):154-62. · 2.04 Impact Factor
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ABSTRACT: There are suggestions that the phylogeny of Streptococcus mutans, a member of the human indigenous biota that is transmitted mostly mother to child, might parallel the evolutionary history of its human host. The relatedness and phylogeny of plasmid-containing strains of S. mutans were examined based on chromosomal DNA fingerprints (CDF), a hypervariable region (HVR) of a 5.6-kb plasmid, the rRNA gene intergenic spacer region (IGSR), serotypes, and the genotypes of mutacin I and II. Plasmid-containing strains were studied because their genetic diversity was twice as great as that of plasmid-free strains. The CDF of S. mutans from unrelated human hosts were unique, except those from Caucasians, which were essentially identical. The evolutionary history of the IGSR, with or without the serotype and mutacin characters, clearly delineated an Asian clade. Also, a continuous association with mutacin II could be reconstructed through an evolutionary lineage with the IGSR, but not for serotype e. DNA sequences from the HVR of the plasmid produced a well-resolved phylogeny that differed from the chromosomal phylogeny, indicating that the horizontal transfer of the plasmid may have occurred multiple times. The plasmid phylogeny was more congruent with serotype e than with mutacin II evolution, suggesting a possible functional correlation. Thus, the history of this three-tiered relationship between human, bacterium, and plasmid supported both coevolution and independent evolution.
Journal of Bacteriology 03/2007; 189(4):1238-43. · 3.83 Impact Factor
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Journal of the American Dental Association (1939) 12/2006; 137(11):1488-90, 1492, 1494. · 1.77 Impact Factor
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ABSTRACT: Using DNA subtractive hybridization, 49 unique gene segments were identified from a strain of Streptococcus mutans that was isolated from a patient with severe early childhood caries (S-ECC). Further hybridization with DNA from other S. mutans strains isolated from both caries-active and caries-free subjects yielded five unique sequences of DNA common to strains associated with S-ECC.
Journal of Clinical Microbiology 08/2005; 43(7):3508-11. · 4.15 Impact Factor
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ABSTRACT: By definition, dental caries is an infectious and transmissible disease because it is caused by bacteria colonizing the tooth surfaces. Unlike most infectious diseases affecting humans, caries is the result of an imbalance of the indigenous oral biota rather than a nonindigenous, exogenous pathogen. The introduction of refined sugar into modern society's diet has tipped the balance from health to disease. New insight into the natural history of the leading cariogenic bacteria, the mutans streptococci, may contribute ways to control or prevent this infectious disease. Here, we use the host-parasite model as a platform for viewing the pathogenicity of the caries process in contrast to other infectious diseases.
Compendium of continuing education in dentistry (Jamesburg, N.J.: 1995) 06/2005; 26(5 Suppl 1):10-6.
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Page W Caufield
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ABSTRACT: Dental caries is often referred to as an infectious disease, which means different things to different people. Pediatric dentists may be tempted to liken caries to other childhood diseases they encounter yet treat caries from mostly a mechanical or surgical approach. On the other end of the spectrum are clinicians who view the oral cavity as a site teaming with bacteria and think that reducing the overall microbial mass using antimicrobial agents will somehow affect this infectious disease. Here, we argue for another view, that is, to combine the most effective portion of each therapy to yield an effective outcome: the treatment and prevention of dental caries. Because primary teeth are eventually shed, pediatric dentists may be in an advantageous position to implement this approach since restorations to primary teeth need not be as durable as those made to permanent teeth. Moreover, pediatric dentists use sealants extensively and are used to working, for example, with rubber dams, especially in young patients. It may turn out that after more research is completed on the ontogeny of the oral microbial flora, changes or ecological shifts made in childhood become lifelong. More specifically, drastic reductions or eliminations of cariogenic bacteria, along with their sites for colonization in the primary dentition, may prevent or delay their transfer to the permanent dentition. Similarly, reductions in a mother's levels of cariogenic bacteria may delay or interrupt the transfer of cariogenic bacteria to her infant. Here, the goal is to discuss several concepts before their final inception into practices and to stimulate discussion of ideas, reframing the design to meet the demands of everyday practice. Ultimately, the proof will come from a large clinical trial conducted in many practices and patient populations.
The New York state dental journal 04/2005; 71(2):23-7.
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ABSTRACT: The objective of the present study was to design a PCR-generated DNA probe and determine the specificity of the probe for the identification of clinical isolates of Streptococcus sanguinis. To do this, we examined over 200 arbitrarily primed PCR (AP-PCR) amplicon patterns obtained with DNA from clinical isolates of S. sanguinis. A 1.6-kb DNA amplicon that was common to all AP-PCR profiles was extracted from agarose gels and then cloned and sequenced. A search for a similar sequence in the GenBank database with the BLASTN program revealed that the 1.6-kb DNA fragment comprised an intergenic region between two housekeeping genes, uncC (proton-translocating ATPase) and murA (UDP-N-acetylglucosamine enolpyruvyl transferase). Three digoxigenin-labeled DNA probes were synthesized on the basis of the sequence of the 1.6-kb fragment: the sequence of probe SSA-1 contained the proton-translocating ATPase (uncC) and the entire intergenic region, the sequence of probe SSA-2 contained only the intergenic region, and the sequence of probe SSA-3 contained an internal region of the murA gene. Dot blot hybridization showed that the three probes displayed signals for hybridization to both S. sanguinis strain ATCC 10556 and the S. sanguinis clinical isolates. Probe SSA-1, however, hybridized to DNA from S. oralis and S. mitis. Probe SSA-3 hybridized to DNA from S. gordonii, S. mitis, S. oralis, S. parasanguinis, and S. vestibularis. The probe SSA-2-specific intergenic region appeared to be specific for S. sanguinis. The results from this study suggest that probe SSA-2 may serve as a species-specific DNA probe for the identification of clinical isolates of S. sanguinis.
Journal of Clinical Microbiology 09/2003; 41(8):3481-6. · 4.15 Impact Factor
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ABSTRACT: In the current literature database, information on microbiological attributes to caries outcomes in African American populations is limited and scattered. Few reports have discussed MS infection and transmission from African American mothers to their children. During the past few years, the research group at the University of Alabama at Birmingham and the Jefferson County Pubic Health Department have done a series of extensive studies to systematically investigate the prevalence of MS colonization, the time of initial MS infection as defined as "the window of infectivity," the source of MS transmission as defined as "the fidelity of transmission, and the chemotherapeutic management of MS transmission and caries prevention. The objective of this report was to summarize the main significant findings generated during a period of 15 years of study. One limitation of the studies outlined in this article is that the research populations were predominately African American families. The inclusion of white and other minorities would make the conclusions more generalizable to the US population as a whole. Nevertheless, the information presented in this report can serve as baseline knowledge for future studies of caries etiology in African American and other ethnic populations.
Dental Clinics of North America 02/2003; 47(1):87-101.
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ABSTRACT: To evaluate the cares status of Sri-Lankan Veddha children in relation to the traditional risk factors. Prevalence of dental caries is still high in certain populations, studies of which may shed additional light on the complex aetiology of caries.
Using the NIDR criteria for caries diagnosis, the Strip Mutans technique (Dentocult SM), and a questionnaire administered by a native speaker, 39 children between the ages of 2-17 years were examined in a cross-sectional study.
Of the 2-9-year-olds, 33% were caries free in the primary dentition and 72% of 5-17-year-olds were caries free in the permanent dentition (mean dft = 2.7; SE = 0.61 and mean DMFT = 0.9; SE = 0.41). There was no correlation between caries and mutans streptococci levels. Excessive consumption of sugar or honey was significantly correlated with the mean dft levels (P = 0.007). The mother was the primary caregiver for all but two children and the children were breast-fed for an average of 2.8 years (SD = 0.82). The duration of breast-feeding was not correlated with the caries experience.
Lack of professional and home care and unfavourable dietary practices may be related to the high prevalence of caries observed in this population.
International Dental Journal 01/2003; 52(6):438-44. · 0.96 Impact Factor
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ABSTRACT: The aim of this investigation was to evaluate the relationship between MHC alleles at the HLA-DRB1, DQB1 and TNFa microsatellite loci and levels of oral bacteria that play a role in the etiology of dental caries, and the DMFS index in 186 AA primparous women. The average age of the cohort was 20.8 ± 3.7 years. The median DMFS index was 9 (range 0–68). High levels of S. mutans were positively associated with DRB1∗3 and DRB1∗4 presence (p ⩽ 0.005). DRB1∗8 was positively associated with higher levels of S. mutans as a percentage of total Streptococci (p = 0.04). DRB1∗1 was positively associated with high levels L. casei (p = 0.04). DQB1 alleles were not observed associated with oral bacterial levels. TNFa allele 103 was negatively associated (p = 0.04), and TNFa 117 was positively associated (p = 0.007), with high levels of L. acidophilus. No significant associations were observed between any DRB1, DQB1 or TNFa allele and the DMFS index. These results support an hypothesis of an association between host HLA class II and TNFa genetic profile and colonization of S. mutans, L. casei, and L. acidophilus thought to be pathogens involved in the etiology of dental caries.
Human Immunology 10/1999; · 2.84 Impact Factor
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ABSTRACT: A protocol that allows fast recovery and further analyses of chromosomal DNA adjacent to the Tn916 site of insertion is described. The procedure is based on single specific primer PCR amplification using restricted chromosomal
DNA ligated into a suitable vector. Two primers, one Tn916-specific and the second vector-specific, allow amplification of the chromosomal DNA flanking the site of insertion.
Biotechnology Techniques 04/1997; 11(1):51-54.
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ABSTRACT: Mutacin II is a lantibiotic that is produced by group II Streptococcus mutans. It inhibits the growth of other streptococci as well as many other gram-positive microorganisms by a hitherto unknown mechanism. Mutacin II possesses bactericidal activity against susceptible cells. It transiently depolarizes the transmembrane electrical potential (Δψ) and the transmembrane pH gradient (ΔpH) and partially inhibits amino acid transport. However, it rapidly depletes the intracellular ATP pool in glucose-energized cells and prevents the generation of ATP. It is concluded that mutacin II does not belong to the group of pore-forming lantibiotics (type A) or to the type B lantibiotics, which inhibit phospholipases or interfere with peptidoglycan biosynthesis. Mutacin II acts by inhibiting essential enzyme functions at the level of metabolic energy generation, an activity that has not yet been classified for lantibiotics.
Antimicrobial Agents and Chemotherapy 02/1995; 39(12):2656-60. · 4.84 Impact Factor
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ABSTRACT: Dental caries results from the dissolution of mineralized dental tissues by the metabolic by-products of oral bacteria colonizing the surface of teeth. The principal modality for dealing with this infectious process is through restorative treatment which removes the pathologic tissue and replaces it with a variety of inert materials. The purpose of this study was to evaluate the effect of traditional restorative treatment on select oral bacterial populations. Fifty-two females demonstrating high levels of mutans streptococci (≥ 2.5 × 104 colony forming units (cfu) per ml saliva) with no more than four missing posterior teeth were recruited for this study. Salivary levels of mutans streptococci, lactobacilli, total streptococci, and total cultivable bacteria were evaluated before, during, and after restorative treatment. Initial DMFS scores were established by two standardized examiners using bitewing radiographs and clinical examination, which was conducted under optimal conditions. All restorative treatment was completed by faculty members of the University of Alabama School of Dentistry using treatment plans developed by the DMFS examiners. The participants received a mean of 16.4 restored surfaces, which resulted in significant reductions of all the bacterial populations tested. All microbial populations monitored were predicted to return to their baseline levels within 151 days after restorative treatment in 50% of the participants. This study shows that conventional restorative treatment results in a significant reduction of bacterial populations including those associated with the dental caries process, i.e., mutans streptococci and lactobacilli. Although restorative treatment is essential for replacing form and function to the dentition, it does not appear to have a prolonged effect on any of the salivary bacterial populations monitored, including those thought responsible for dental caries. Ideally, comprehensive treatment of dental caries should address the infectious nature of this disease through modalities directed at controlling bacterial colonization as well as restoring the afflicted dentition.
Community Dentistry And Oral Epidemiology 05/1992; 20(3):138 - 143. · 1.89 Impact Factor
