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1.
J Clin Periodontol ; 44 Suppl 18: S5-S11, 2017 03.
Artículo en Inglés | MEDLINE | ID: mdl-28266109

RESUMEN

BACKGROUND AND AIMS: The scope of this working group was to review (1) ecological interactions at the dental biofilm in health and disease, (2) the role of microbial communities in the pathogenesis of periodontitis and caries, and (3) the innate host response in caries and periodontal diseases. RESULTS AND CONCLUSIONS: A health-associated biofilm includes genera such as Neisseria, Streptococcus, Actinomyces, Veillonella and Granulicatella. Microorganisms associated with both caries and periodontal diseases are metabolically highly specialized and organized as multispecies microbial biofilms. Progression of these diseases involves multiple microbial interactions driven by different stressors. In caries, the exposure of dental biofilms to dietary sugars and their fermentation to organic acids results in increasing proportions of acidogenic and aciduric species. In gingivitis, plaque accumulation at the gingival margin leads to inflammation and increasing proportions of proteolytic and often obligately anaerobic species. The natural mucosal barriers and saliva are the main innate defence mechanisms against soft tissue bacterial invasion. Similarly, enamel and dentin are important hard tissue barriers to the caries process. Given that the present state of knowledge suggests that the aetiologies of caries and periodontal diseases are mutually independent, the elements of innate immunity that appear to contribute to resistance to both are somewhat coincidental.


Asunto(s)
Biopelículas , Caries Dental/microbiología , Salud Bucal , Periodontitis/microbiología , Interacciones Huésped-Patógeno , Humanos
2.
Clin Oral Investig ; 21(5): 1769-1776, 2017 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-27660160

RESUMEN

OBJECTIVE: The aim of this study was to evaluate the acidogenicity of dual-species biofilms of bifidobacteria and Streptococcus mutans. MATERIALS AND METHODS: The following strains were tested: Bifidobacterium dentium DSM20436, Parascardovia denticolens DSM10105, and Scardovia inopinata DSM10107. Streptococcus mutans UA159 and Lactobacillus acidophilus ATCC4356 were used as control. Bifidobacteria were studied planktonically as they were not able to form monospecies biofilm, they were grown in biofilms associated with S. mutans. Endogenous polysaccharide reserves of cultures at log phase were depleted. Standardized suspensions of the microorganisms were incubated in growth media supplemented with 10 mM glucose, lactose, raffinose, glucose, or xylitol. S. mutans biofilms were grown on glass cover slips for 24 h to which bifidobacteria were added. After 24 h, the dual-species biofilms were exposed to the same carbon sources, and after 3 h, the pH of spent culture media and concentrations of organic acids were measured. Statistical analyses were carried out using ANOVA and Tukey's test (α = 0.05). RESULTS: A higher pH drop was observed when S. mutans was associated with P. denticolens or S. inopinata, in either planktonic or biofilm cultures, than with S. mutans alone. Bifidobacteria showed a higher pH drop in the presence of raffinose than S. mutans or L. acidophilus. CONCLUSIONS: Dual-species biofilms of bifidobacteria and S. mutans produced more acid and greater pH drops than biofilms of S. mutans alone. CLINICAL RELEVANCE: New insights on the complex process of caries pathogenicity contribute to the establishment of preventive and therapeutic measures, in particular in specific cases, such as in early childhood caries.


Asunto(s)
Bifidobacterium/crecimiento & desarrollo , Biopelículas/crecimiento & desarrollo , Streptococcus mutans/crecimiento & desarrollo , Animales , Técnicas de Cultivo de Célula , Medios de Cultivo , Concentración de Iones de Hidrógeno , Lactobacillus acidophilus
3.
Periodontol 2000 ; 70(1): 80-92, 2016 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-26662484

RESUMEN

Saliva plays a major role in determining the composition and activity of the oral microbiota, via a variety of mechanisms. Molecules, mainly from saliva, form a conditioning film on oral surfaces, thus providing receptors for bacterial attachment. The attached cells use saliva components, such as glycoproteins, as their main source of nutrients for growth. Oral bacteria work sequentially and in a concerted manner to catabolize these structurally complex molecules. Saliva also buffers the pH in the biofilm to around neutrality, creating an environment which is conducive to the growth of many oral bacteria that provide important benefits to the host. Components of the adaptive and innate host defences are delivered by saliva, and these often function synergistically, and at sublethal concentrations, so a complex relationship develops between the host and the resident microbiota. Dysbiosis can occur rapidly if the flow of saliva is perturbed.


Asunto(s)
Microbiota/fisiología , Boca/microbiología , Saliva/microbiología , Saliva/fisiología , Humanos , Saliva/química , Proteínas y Péptidos Salivales/metabolismo , Proteínas y Péptidos Salivales/fisiología
4.
Eur J Oral Sci ; 124(3): 251-8, 2016 06.
Artículo en Inglés | MEDLINE | ID: mdl-27061393

RESUMEN

There is growing interest in the use of probiotic bifidobacteria for enhancement of the therapy, and in the prevention, of oral microbial diseases. However, the results of clinical studies assessing the effects of bifidobacteria on the oral microbiota are controversial, and the mechanisms of actions of probiotics in the oral cavity remain largely unknown. In addition, very little is known about the role of commensal bifidobacteria in oral health. Our aim was to study the integration of the probiotic Bifidobacterium animalis subsp. lactis Bb12 and of oral Bifidobacterium dentium and Bifidobacterium longum isolates in supragingival and subgingival biofilm models and their effects on other bacteria in biofilms in vitro using two different in vitro biofilms and agar-overlay assays. All bifidobacteria integrated well into the subgingival biofilms composed of Porphyromonas gingivalis, Actinomyces naeslundii, and Fusobacterium nucleatum and decreased significantly only the number of P. gingivalis in the biofilms. The integration of bifidobacteria into the supragingival biofilms containing Streptococcus mutans and A. naeslundii was less efficient, and bifidobacteria did not affect the number of S. mutans in biofilms. Therefore, our results suggest that bifidobacteria may have a positive effect on subgingival biofilm and thereby potential in enhancing gingival health; however, their effect on supragingival biofilm may be limited.


Asunto(s)
Bifidobacterium/fisiología , Biopelículas , Porphyromonas gingivalis/crecimiento & desarrollo , Streptococcus mutans/crecimiento & desarrollo , Fusobacterium nucleatum , Encía/microbiología , Humanos
5.
Clin Oral Investig ; 20(8): 2149-2160, 2016 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-26856712

RESUMEN

OBJECTIVES: The presence of opportunistic pathogens such as Propionibacterium acnes (P. acnes) may contribute to the endodontic pathology. The presence of P. acnes may be influenced by different endodontic conditions. The aims of the study were firstly, to identify P. acnes within the whole cultivable microbiota of primary endodontic infections, to investigate which P. acnes phylotypes predominate in such infections and secondly to determine if the presence of an "open" communication (e.g. a sinus) can be associated with the isolation of P. acnes from the root canal. MATERIAL AND METHODS: The predominant cultivable microbiota of 15 primary endodontic lesions (7 without communication with the oral environment and 8 with an open communication) were identified using partial 16S ribosomal RNA (rRNA) gene sequence analysis. The identification of the organism was determined by interrogating the Human Oral Microbiome Database. The P. acnes isolates were typed on the basis of the recA gene sequence comparison. A neighbor-joining tree was constructed using MEGA 4.1 with the inclusion of known recA sequences. RESULTS: There was no difference in the number of species identified from lesions without communication (5.86 ± 3.7) and those with communication (5.37 ± 3.6) (P > 0.05). PCR-based 16S rRNA gene sequencing revealed P. acnes as the most prevalent isolate recovered from lesions with communication. recA gene sequencing revealed two phylogenetic lineages present in lesion with communication, with mainly type I (further split into type IA and type IB) and type II. CONCLUSIONS: The presence of P. acnes as opportunistic pathogens has been confirmed and may sustain the traits observed in specific clinical presentations. CLINICAL RELEVANCE: Clinical management of open lesions may require further disinfection to eliminate opportunistic bacteria.


Asunto(s)
Infecciones por Bacterias Grampositivas/microbiología , Infecciones Oportunistas/microbiología , Fístula Oral/microbiología , Propionibacterium acnes/aislamiento & purificación , Pulpitis/microbiología , Absceso/microbiología , Adolescente , Adulto , Técnicas de Tipificación Bacteriana , Femenino , Humanos , Masculino , Microbiota , Propionibacterium acnes/clasificación
6.
Mol Biol Evol ; 30(4): 881-93, 2013 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-23228887

RESUMEN

Streptococcus mutans is widely recognized as one of the key etiological agents of human dental caries. Despite its role in this important disease, our present knowledge of gene content variability across the species and its relationship to adaptation is minimal. Estimates of its demographic history are not available. In this study, we generated genome sequences of 57 S. mutans isolates, as well as representative strains of the most closely related species to S. mutans (S. ratti, S. macaccae, and S. criceti), to identify the overall structure and potential adaptive features of the dispensable and core components of the genome. We also performed population genetic analyses on the core genome of the species aimed at understanding the demographic history, and impact of selection shaping its genetic variation. The maximum gene content divergence among strains was approximately 23%, with the majority of strains diverging by 5-15%. The core genome consisted of 1,490 genes and the pan-genome approximately 3,296. Maximum likelihood analysis of the synonymous site frequency spectrum (SFS) suggested that the S. mutans population started expanding exponentially approximately 10,000 years ago (95% confidence interval [CI]: 3,268-14,344 years ago), coincidental with the onset of human agriculture. Analysis of the replacement SFS indicated that a majority of these substitutions are under strong negative selection, and the remainder evolved neutrally. A set of 14 genes was identified as being under positive selection, most of which were involved in either sugar metabolism or acid tolerance. Analysis of the core genome suggested that among 73 genes present in all isolates of S. mutans but absent in other species of the mutans taxonomic group, the majority can be associated with metabolic processes that could have contributed to the successful adaptation of S. mutans to its new niche, the human mouth, and with the dietary changes that accompanied the origin of agriculture.


Asunto(s)
Evolución Molecular , Metagenómica , Streptococcus mutans/genética , Adaptación Biológica/genética , Metabolismo de los Hidratos de Carbono/genética , Caries Dental/microbiología , Frecuencia de los Genes , Genoma Bacteriano , Humanos , Funciones de Verosimilitud , Desequilibrio de Ligamiento , Modelos Genéticos , Polimorfismo de Nucleótido Simple , Recombinación Genética , Selección Genética
7.
Gerodontology ; 31(4): 265-73, 2014 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-23347075

RESUMEN

BACKGROUND: The oral health needs of older adults present increasing challenges to dental services. OBJECTIVES: To examine the clinical oral health status of dentate older people living in the community and attending dental services. METHODS: One hundred and eighty-six dentate adults, aged ≥60 years, underwent clinical examination (DMFS, Plaque and Gingival Indexes), salivary analysis and completed a questionnaire. RESULTS: Participants had an average of 21.4 (±6.2) teeth present and 1.2 (±3.0) decayed, 51.0 (±28.8) missing and 32.6 (±20.5) restored surfaces. Individuals living in the most deprived areas had significantly lower numbers of teeth than those in the least deprived areas (19.1 ± 7.5 cf 23.8 ± 4.1; p < 0.001). Whilst there were no significant differences in DMFS score, residents in the most deprived areas had significantly more missing and fewer filled surfaces than those in the least deprived areas (p = 0.001 and p < 0.001, respectively). Participants with ≥21 teeth (64%) had lower plaque scores, fewer decayed root surfaces, higher stimulated saliva flow rates and lower salivary lactobacilli and yeast counts than those with <21 teeth (p < 0.05 for all). CONCLUSIONS: The findings highlight differences in clinical oral health by age and deprivation status and underline the importance of saliva and retaining a functional dentition.


Asunto(s)
Cuidado Dental para Ancianos/estadística & datos numéricos , Necesidades y Demandas de Servicios de Salud/estadística & datos numéricos , Vida Independiente , Salud Bucal/estadística & datos numéricos , Factores de Edad , Anciano , Anciano de 80 o más Años , Carga Bacteriana , Estudios Transversales , Índice CPO , Caries Dental/epidemiología , Índice de Placa Dental , Restauración Dental Permanente/estadística & datos numéricos , Femenino , Humanos , Lactobacillus/aislamiento & purificación , Londres/epidemiología , Masculino , Persona de Mediana Edad , Índice Periodontal , Caries Radicular/epidemiología , Saliva/química , Saliva/microbiología , Tasa de Secreción/fisiología , Streptococcus mutans/aislamiento & purificación , Pérdida de Diente/epidemiología , Poblaciones Vulnerables/estadística & datos numéricos
8.
Int J Paediatr Dent ; 23(1): 32-8, 2013 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-22309226

RESUMEN

BACKGROUND: Salivary levels of Bifidobacteria have been shown to be significantly correlated with caries experience in adults but not as yet in children. HYPOTHESIS: Salivary levels of Bifidobacteria are positively associated with caries experience in children. AIM: To compare the salivary concentrations of Bifidobacteria of caries-free and caries-active children. DESIGN: Saliva was collected using the tongue-loop method from 38 caries-active children and from 22 clinically caries-free children, and the numbers of Bifidobacteria, mutans streptococci, lactobacilli and yeasts were determined. Additionally, the age and gender of the children, a plaque index, sugar amount in diet, sugar frequency in diet, hygiene practice and fluoride toothpaste usage were recorded. RESULTS: Bifidobacteria were isolated from 95% of the caries-active children and from only 9% of the caries-free children (P < 0.001). Salivary levels of Bifidobacteria were significantly correlated with amount of sugar in the diet, frequency of sugar consumption and oral hygiene practice. The significant variables that discriminated between the caries-free and caries-active subjects were salivary levels of Bifidobacteria, salivary levels of mutans streptococci and oral hygiene practice (χ(2) = 72.57, P < 0.001) and overall 90.0% of cases were correctly classified. CONCLUSIONS: Salivary levels of Bifidobacteria are significantly associated with caries experience in children. The salivary levels of this genus may be a useful marker of caries risk.


Asunto(s)
Bifidobacterium/aislamiento & purificación , Caries Dental/microbiología , Saliva/microbiología , Carga Bacteriana , Cariostáticos/uso terapéutico , Niño , Preescolar , Recuento de Colonia Microbiana , Susceptibilidad a Caries Dentarias , Índice de Placa Dental , Dentición Mixta , Sacarosa en la Dieta/administración & dosificación , Femenino , Fluoruros/uso terapéutico , Humanos , Lactobacillus/aislamiento & purificación , Masculino , Streptococcus mutans/aislamiento & purificación , Diente Primario/microbiología , Cepillado Dental/métodos , Pastas de Dientes/uso terapéutico , Levaduras/aislamiento & purificación
9.
Microorganisms ; 11(2)2023 Jan 19.
Artículo en Inglés | MEDLINE | ID: mdl-36838222

RESUMEN

The aim of this study was to investigate and clarify the ambiguous taxonomy of Actinomyces naeslundii and its closely related species using state-of-the-art high-throughput sequencing techniques, and, furthermore, to determine whether sub-clusters identified within Actinomyces oris and Actinomyces naeslundii in a previous study by multi locus sequence typing (MLST) using concatenation of seven housekeeping genes should either be classified as subspecies or distinct species. The strains in this study were broadly classified under Actinomyces naeslundii group as A. naeslundii genospecies I and genospecies II. Based on MLST data analysis, these were further classified as A. oris and A. naeslundii. The whole genome sequencing of selected strains of A. oris (n = 17) and A. naeslundii (n = 19) was carried out using Illumina Genome Analyzer IIxe and Roche 454 allowing paired-end and single-reads sequencing, respectively. The sequences obtained were aligned using CLC Genomic workbench version 5.1 and annotated using RAST (Rapid Annotation using Subsystem Technology) release version 59 accessible online. Additionally, genomes of seven publicly available strains of Actinomyces (k20, MG1, c505, OT175, OT171, OT170, and A. johnsonii) were also included. Comparative genomic analysis (CGA) using Mauve, Progressive Mauve, gene-by-gene, Core, and Pan Genome, and finally Digital DNA-DNA homology (DDH) analysis was carried out. DDH values were obtained using in silico genome-genome comparison. Evolutionary analysis using ClonalFrame was also undertaken. The mutation and recombination events were compared using chi-square test among A. oris and A. naeslundii isolates (analysis methods are not included in the study). CGA results were consistent with previous traditional classification using MLST. It was found that strains of Actinomyces k20, MG1, c505, and OT175 clustered in A. oris group of isolates, while OT171, OT170, and A. johnsonii appeared as separate branches. Similar clustering to MLST was observed for other isolates. The mutation and recombination events were significantly higher in A. oris than A. naeslundii, highlighting the diversity of A. oris strains in the oral cavity. These findings suggest that A. oris forms six distinct groups, whereas A. naeslundii forms three. The correct designation of isolates will help in the identification of clinical Actinomyces isolates found in dental plaque. Easily accessible online genomic sequence data will also accelerate the investigation of the biochemical characterisation and pathogenesis of this important group of micro-organisms.

10.
Caries Res ; 51(5): I-II, 2017.
Artículo en Inglés | MEDLINE | ID: mdl-29040975
11.
PLoS Genet ; 5(12): e1000785, 2009 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-20041198

RESUMEN

Bifidobacteria, one of the relatively dominant components of the human intestinal microbiota, are considered one of the key groups of beneficial intestinal bacteria (probiotic bacteria). However, in addition to health-promoting taxa, the genus Bifidobacterium also includes Bifidobacterium dentium, an opportunistic cariogenic pathogen. The genetic basis for the ability of B. dentium to survive in the oral cavity and contribute to caries development is not understood. The genome of B. dentium Bd1, a strain isolated from dental caries, was sequenced to completion to uncover a single circular 2,636,368 base pair chromosome with 2,143 predicted open reading frames. Annotation of the genome sequence revealed multiple ways in which B. dentium has adapted to the oral environment through specialized nutrient acquisition, defences against antimicrobials, and gene products that increase fitness and competitiveness within the oral niche. B. dentium Bd1 was shown to metabolize a wide variety of carbohydrates, consistent with genome-based predictions, while colonization and persistence factors implicated in tissue adhesion, acid tolerance, and the metabolism of human saliva-derived compounds were also identified. Global transcriptome analysis demonstrated that many of the genes encoding these predicted traits are highly expressed under relevant physiological conditions. This is the first report to identify, through various genomic approaches, specific genetic adaptations of a Bifidobacterium taxon, Bifidobacterium dentium Bd1, to a lifestyle as a cariogenic microorganism in the oral cavity. In silico analysis and comparative genomic hybridization experiments clearly reveal a high level of genome conservation among various B. dentium strains. The data indicate that the genome of this opportunistic cariogen has evolved through a very limited number of horizontal gene acquisition events, highlighting the narrow boundaries that separate commensals from opportunistic pathogens.


Asunto(s)
Adaptación Fisiológica/genética , Bifidobacterium/genética , Genoma Bacteriano/genética , Boca/microbiología , Secuencia de Bases , Bifidobacterium/metabolismo , Bifidobacterium/patogenicidad , Transporte Biológico/genética , Fimbrias Bacterianas/genética , Perfilación de la Expresión Génica , Regulación Bacteriana de la Expresión Génica , Genes Bacterianos/genética , Sitios Genéticos/genética , Variación Genética , Humanos , Secuencias Repetitivas Esparcidas/genética , Análisis de Secuencia por Matrices de Oligonucleótidos , Alineación de Secuencia , Análisis de Secuencia de ADN , Transcripción Genética , Factores de Virulencia/genética , Factores de Virulencia/metabolismo
12.
Int J Syst Evol Microbiol ; 61(Pt 1): 25-29, 2011 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-20139283

RESUMEN

Six strains of anaerobic, pleomorphic Gram-positive bacilli, isolated from the human oral cavity and an infected arm wound, were subjected to a comprehensive range of phenotypic and genotypic tests and were found to comprise a homogeneous group. 16S rRNA gene sequence analysis revealed that the isolates were most closely related to Scardovia inopinata CCUG 35729(T) (94.8-94.9 % 16S rRNA gene sequence similarity). The isolates were saccharolytic and produced acetic and lactic acids as end products of fermentation. The major fatty acids were C(16 : 0) (49.8 %) and C(18 : 1)ω9c (35.8 %). Polar lipid analysis revealed a variety of glycolipids, diphosphatidylglycerol, an unidentified phospholipid and an unidentified phosphoglycolipid. No respiratory quinones were detected. The peptidoglycan was of the type A4α L-Lys-Thr-Glu, with L-lysine partially replaced by L-ornithine. The DNA G+C content of one of the strains, C1A_55(T)(,) was 55 mol%. A novel species, Scardovia wiggsiae sp. nov., is proposed to accommodate the six isolates, with the type strain C1A_55(T) (=DSM 22547(T)=CCUG 58090(T)).


Asunto(s)
Actinobacteria/clasificación , Actinobacteria/aislamiento & purificación , Infecciones por Bacterias Grampositivas/microbiología , Boca/microbiología , Ácido Acético/metabolismo , Actinobacteria/genética , Actinobacteria/fisiología , Composición de Base , Análisis por Conglomerados , ADN Bacteriano/química , ADN Bacteriano/genética , ADN Ribosómico/química , ADN Ribosómico/genética , Ácidos Grasos/análisis , Fermentación , Humanos , Ácido Láctico/metabolismo , Datos de Secuencia Molecular , Peptidoglicano/química , Fosfolípidos/análisis , Filogenia , Quinonas/análisis , ARN Ribosómico 16S/genética , Análisis de Secuencia de ADN
13.
J Clin Microbiol ; 48(11): 3859-69, 2010 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-20739494

RESUMEN

The predominant cultivable microbiota from 20 refractory endodontic lesions (9 with abscesses and 11 without abscesses) were determined, and Propionibacterium acnes and Staphylococcus epidermidis were among the most predominant organisms. The number of species identified from lesions with abscesses (14.1 ± 2.6) was significantly greater (P < 0.001) than the number from lesions without abscesses (7.4 ± 5.9). Comparison of perioral isolates using repetitive extragenic palindromic PCR of the same species from the same subjects demonstrated that the endodontic and skin populations were significantly different. The P. acnes isolates were typed on the basis of recA gene sequence comparison, and only three types (types I, II, and III) were identified among 125 isolates examined. However, we found that type I (type IA and IB) isolates were primarily isolated from the skin, while types II and III were significantly more likely to be isolated from the endodontic lesions (P < 10(-10)). We found that the robustness of the recA phylotypes was not strong by comparing the partial gene sequences of six putative virulence determinants, PAmce, PAp60, PA-25957, PA-5541, PA-21293, and PA-4687. The resulting neighbor-joining trees were incongruent, and significant (phi test; P = 2.2 × 10(-7)) evidence of recombination was demonstrated, with significant phylogenetic heterogeneity being apparent within the clusters. P. acnes and S. epidermidis isolated from refractory endodontic infections, with or without periapical abscesses, are likely to be nosocomial infections.


Asunto(s)
Infecciones por Bacterias Grampositivas/microbiología , Infecciones Oportunistas/microbiología , Propionibacterium acnes/aislamiento & purificación , Pulpitis/microbiología , Staphylococcus epidermidis/aislamiento & purificación , Absceso/microbiología , Técnicas de Tipificación Bacteriana , Análisis por Conglomerados , Genotipo , Humanos , Boca/microbiología , Filogenia , Propionibacterium acnes/clasificación , Propionibacterium acnes/genética , Rec A Recombinasas/genética , Piel/microbiología
15.
Appl Environ Microbiol ; 74(20): 6457-60, 2008 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-18723652

RESUMEN

Bifidobacteriaceae were isolated from saliva and infected dentine by using a mupirocin-based selective medium. Of the saliva samples, 94% harbored bifids. The mean concentration (+/- the standard error) was 4.46 (+/-0.12) log(10)(CFU per ml + 1), and the predominant isolates were Bifidobacterium dentium, B. longum, Scardovia inopinata, Parascardovia denticolens, and Alloscardovia omnicolens.


Asunto(s)
Actinobacteria/clasificación , Actinobacteria/aislamiento & purificación , Saliva/microbiología , Adulto , Antibacterianos/farmacología , Técnicas de Tipificación Bacteriana , Recuento de Colonia Microbiana , Medios de Cultivo/química , Dermatoglifia del ADN , ADN Bacteriano/genética , Dentina/microbiología , Genotipo , Humanos , Mupirocina/farmacología
16.
FEMS Microbiol Lett ; 288(2): 156-62, 2008 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-18823396

RESUMEN

Actinomyces spp., predominant members of human oral biofilms, may use extracellular sialidase to promote adhesion, deglycosylate immunoglobulins and liberation of nutrients. Partial nanH gene sequences (1,077 bp) from Actinomyces oris (n=74), Actinomyces naeslundii (n=30), Actinomyces viscosus (n=1) and Actinomyces johnsonii (n=2) which included the active-site region and the bacterial neuraminidase repeats (BNRs) were compared. The sequences were aligned and each species formed a distinct cluster with five isolates having intermediate positions. These five isolates (two A. oris and three A. naeslundii) exhibited interspecies recombination. The nonsynonymous/synonymous ratio was <1 for both A. oris and A. naeslundii indicating that nanH in both species is under stabilizing selective pressure; nonsynonymous mutations are not selected. However, for A. oris significant negative values in tests for neutral selection suggested the rate of mutation in A. oris was greater than in A. naeslundii but with selection against nonsynonymous mutations. This was supported by the observation that the frequency of polymorphic sites in A. oris, which were monomorphic in A. naeslundii was significantly greater than the frequency of polymorphic sites in A. naeslundii which were monomorphic in A. oris (chi(2)=7.011; P=0.00081). The higher proportions of A. oris in the oral biofilm might be explained by the higher mutation rate facilitating an increased ability to respond successfully to environmental stress.


Asunto(s)
Actinomyces/enzimología , Actinomyces/genética , Neuraminidasa/genética , Recombinación Genética , Actinomyces/aislamiento & purificación , Actinomicosis/microbiología , Proteínas Bacterianas/genética , Placa Dental/microbiología , Humanos , Datos de Secuencia Molecular , Boca/microbiología , Análisis de Secuencia de ADN , Especificidad de la Especie
17.
J Pain Symptom Manage ; 35(5): 508-14, 2008 May.
Artículo en Inglés | MEDLINE | ID: mdl-18242047

RESUMEN

Oral candidosis is a significant cause of morbidity in patients with advanced cancer. The objectives of the study were to determine the epidemiology, etiology, clinical features, and microbiological aspects of oral candidosis among community-based patients. The subjects were recruited from hospice day centers in England. The clinical component involved completion of a study questionnaire, assessment of performance status, clinical examination of the oral cavity, measurement of unstimulated whole salivary flow rate, measurement of stimulated whole salivary flow rate, and performance of an oral rinse. Oral swabs were taken from subjects with appearances indicative of oral candidosis. The laboratory component involved standard procedures to isolate, enumerate, and identify yeasts from the clinical specimens. Three hundred ninety patients participated in the study. Two hundred seventy-two (70%) patients had oral yeast carriage, and 51 (13%) patients had combined clinical and microbiological evidence of oral candidosis. On univariate analysis, the presence of oral candidosis was associated with poor Eastern Cooperative Oncology Group performance status, presence of a denture, usage of a systemic corticosteroid, the severity of xerostomia, a low unstimulated whole salivary flow rate, and a low stimulated whole salivary flow rate. Multivariate analysis identified poor Eastern Cooperative Oncology Group performance status, presence of a denture, usage of a systemic corticosteroid, and the severity of xerostomia as being independently associated with the presence of oral candidosis. Oral candidosis is relatively common in community-based patients with advanced cancer. Hence, such patients should be screened for oral candidosis and should also be screened for reversible factors that predispose to oral candidosis, such as poor dental hygiene and salivary gland dysfunction.


Asunto(s)
Candidiasis Bucal/epidemiología , Neoplasias/complicaciones , Adulto , Anciano , Anciano de 80 o más Años , Candida albicans , Candidiasis Bucal/patología , Candidiasis Bucal/terapia , Centros de Día , Inglaterra/epidemiología , Femenino , Hospitales para Enfermos Terminales , Humanos , Masculino , Persona de Mediana Edad , Estudios Prospectivos
18.
Dent Mater J ; 26(3): 388-92, 2007 May.
Artículo en Inglés | MEDLINE | ID: mdl-17694749

RESUMEN

MDPB, 12-methacryloyloxydodecylpyridinium bromide, was tested for its ability to inhibit the growth of organisms associated with active root caries lesions and to modify the growth characteristics of these organisms at sub-MICs. MICs and MBCs of MDPB for independent isolates (n=5) of the following taxa: Streptococcus mutans, Streptococcus oralis, Streptococcus salivarius, Actinomyces naeslundii, Actinomyces israelii, Actinomyces gerensceriae, Actinomyces odontolyticus, Lactobacillus spp., and Candida albicans were determined, and the effects at sub-MIC on microbial growth kinetics were assessed. All isolates were sensitive to inhibition by MDPB. The median MICs and MBCs of MDPB for these organisms were in the range of 3.13 to 25.0 microg/ml and 6.25 to 50.0 microg/ml, respectively. As for the influence of pH, inhibition was sensitive to acidic pH. Even at sub-MICs, the growth of all strains, measured as cell yield and doubling time, was significantly reduced. Based on the results of this study, MDPB exhibited the potential to inhibit the growth of microbiota associated with active root caries lesions.


Asunto(s)
Antibacterianos/farmacología , Compuestos de Piridinio/farmacología , Caries Radicular/microbiología , Actinomyces/efectos de los fármacos , Animales , Candida albicans/efectos de los fármacos , Caballos , Lactobacillus/efectos de los fármacos , Pruebas de Sensibilidad Microbiana , Caries Radicular/tratamiento farmacológico , Streptococcus/efectos de los fármacos
19.
Oral Oncol ; 42(7): 698-702, 2006 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-16527512

RESUMEN

The objectives of the study were to determine the epidemiology, aetiology, clinical features and microbiological aspects of oral candidosis in a cohort of cancer patients receiving specialist palliative care. One hundred and twenty patients participated in the study. Seventy-nine (66%) of the patients had microbiological evidence of oral yeast carriage, whilst 36 (30%) of the patients had combined clinical and microbiological evidence of oral candidosis. Oral candidosis was associated with a poor performance status, the presence of xerostomia, and the presence of dentures; oral candidosis was not associated with the use of oral/parenteral antibiotics, or the use of oral/parenteral corticosteroids. Candida albicans was the predominant organism isolated from the oral swabs of patients with oral candidosis. However, non-C. albicans species were the predominant organism in 25% cases, and a contributing organism in a further 19% cases.


Asunto(s)
Candidiasis Bucal/complicaciones , Neoplasias/complicaciones , Infecciones Oportunistas/complicaciones , Adulto , Anciano , Anciano de 80 o más Años , Candida/clasificación , Candida/aislamiento & purificación , Candidiasis Bucal/diagnóstico , Candidiasis Bucal/microbiología , Femenino , Humanos , Masculino , Persona de Mediana Edad , Infecciones Oportunistas/diagnóstico , Infecciones Oportunistas/microbiología , Cuidados Paliativos , Estudios Prospectivos , Factores de Riesgo , Índice de Severidad de la Enfermedad , Estomatitis Subprotética/complicaciones , Estomatitis Subprotética/microbiología , Xerostomía/complicaciones
20.
Community Dent Oral Epidemiol ; 33(4): 248-55, 2005 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-16008631

RESUMEN

The involvement of the oral biofilm in the caries process requires re-evaluation. The essential role of mutans streptococci (Streptococcus mutans and Streptococcus sobrinus) in the caries process is not proven. Acid production by dental plaque is not dependent upon the presence of mutans streptococci; caries occurs in the absence of these species and their presence does not necessarily indicate caries activity. Other oral bacteria, non-mutans streptococci, Actinomyces spp. and Bifidobacterium spp., are acidogenic and aciduric. They outnumber mutans streptococci in dental plaque, and there are data which support a role for these bacteria in the initiation and progression of caries. Molecular studies demonstrate the great diversity and complexity of the flora associated with caries. Many taxa identified have not been cultured and the role of these taxa is not known. We have, in mutans streptococci, good markers of disease but not necessarily the aetiological agents of the disease. Considerably more research is required to investigate the transition of tooth surfaces from being intact and sound to the white spot lesion stage. A combination of conventional and molecular approaches are required to elucidate the involvement of an individual taxon and of microbial populations with particular traits in the caries process.


Asunto(s)
Caries Dental/microbiología , Ácidos/metabolismo , Actinomyces/metabolismo , Actinomyces/fisiología , Animales , Bifidobacterium/metabolismo , Bifidobacterium/patogenicidad , Recuento de Colonia Microbiana , ADN Bacteriano/análisis , Placa Dental/genética , Placa Dental/metabolismo , Placa Dental/microbiología , Humanos , Concentración de Iones de Hidrógeno , Streptococcus mutans/metabolismo , Streptococcus mutans/patogenicidad , Streptococcus oralis/metabolismo , Streptococcus oralis/patogenicidad
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