Chemical and structural composition of black pigmented supragingival biofilm of bovines with periodontitis / Composição química e estrutural do biofilme supragengival pigmentado de bovinos com periodontite

Bovine periodontitis is a multifactorial disease primarily associated with a potentially pathogenic microbiota housed in the oral biofilm of animals. Biofilms are organized structures, in which the constituents coexist in symbiosis, already described as a predisposing factor to periodontitis in other species. The objective of the present study was to characterize the structure and chemical aspects of the bovine black pigmented supragingival biofilm using scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS), respectively, and determine its relationship with bovine periodontitis. Eleven premolar teeth from different animals were evaluated; five non-pigmented samples and six samples with black pigmented biofilms were initially submitted to SEM, and three areas of these samples were selected for EDS. The structure of the pigmented biofilm was more complex and irregular because of a higher content of mineral elements. The semi-quantitative EDS data indicated an association of iron (p<0.014) and magnesium (p<0.001) with the occurrence of periodontitis, whereas carbon, phosphorus, calcium, manganese, sodium, and potassium were not associated with the disease. Carbon (p<0.039), manganese (p<0.007), and iron (p<0.015) were associated with pigmentation, whereas phosphorus, calcium, and magnesium were not associated with it. Spearman correlation test showed the relationships between calcium and phosphorus, and iron and silicon. The strong association of iron in the pigmented supragingival biofilm and with the occurrence of periodontitis suggests the presence of microorganisms that use this element in their metabolism and that are also associated with bovine periodontitis. This study suggests that the pigmented deposits in the crown of the teeth of cattle are an true biofilm with the deposition of iron, and it indicates that the presence of iron and magnesium in these formations may be involved in the metabolism of some microorganisms associated with the etiology of bovine periodontitis.(AU)

A periodontite bovina é uma infecção multifatorial associada primariamente à microbiota potencialmente patogênica presente no biofilme bucal. Biofilmes são estruturas organizadas, nas quais os constituintes convivem em simbiose, descritos em outras espécies como um fator predisponente à periodontite. O objetivo do presente estudo foi caracterizar estrutural e quimicamente o biofilme supragengival pigmentado de preto em bovinos, utilizando-se as técnicas de microscopia eletrônica de varredura (MEV) e espectroscopia de dispersão de energia (EDS), respectivamente, correlacionando os elementos identificados à ocorrência de periodontite e pigmentação. Foram avaliados 11 dentes primeiro-molares; cinco amostras sem pigmentação visível e seis amostras com biofilme pigmentado de preto, que foram submetidas inicialmente à MEV; posteriormente foram selecionadas três áreas aleatórias de cada dente para realização da EDS. A estrutura do biofilme pigmentado revelou formações irregulares e mais complexas, provavelmente devido ao maior acúmulo de elementos minerais. Os resultados semi-quantitativos da EDS apontaram associações entre a presença de ferro (p<0,014) e magnésio (p<0,001) com a ocorrência de periodontite. Carbono, fósforo, cálcio, manganês, sódio e potássio não apresentaram associação com a periodontite. Em relação à pigmentação, carbono (p<0,039), manganês (p<0,007) e ferro (p<0,015) foram os elementos estatisticamente significantes, enquanto fósforo, cálcio e magnésio não apresentaram associação com a pigmentação. O teste de correlação de Spearman demonstrou associações entre os elementos cálcio e fósforo, e ferro e silício. A forte associação do ferro presente no biofilme supragengival com a ocorrência de periodontite, sugere a presença de micro-organismos que utilizam este elemento em seu metabolismo e que possivelmente tenham envolvimento com o desenvolvimento da periodontite bovina. Os resultados inéditos do presente trabalho sugerem que os depósitos pigmentados que se formam na coroa dos dentes de bovinos são um biofilme verdadeiro com deposição de ferro, e indicam que a presença de ferro e magnésio nestas formações pode estar envolvida no metabolismo de alguns dos principais micro-organismos associados à etiologia da periodontite bovina.(AU)

Antimicrobial activity of mouth rinses against bacteria that initially colonizes dental's surface / Atividade antimicrobiana de enxaguatórios bucais sobre bactérias que iniciam a colonização das superfícies dentais

Abstract Introduction Much advertising in mouthwash is conveyed in all media appealing to the anti-plaque effect and rendering a disservice to the community. Mouth rinses are available over-the-count and differ on their compositions and antimicrobial effectiveness. Objective In this study, we evaluated the antimicrobial activity of 35 widely available mouth rinses against bacterial species involved in initiation of dental biofilm - Streptococcus gordonii, Streptococcus mitis, Streptococcus oralis, Streptococcus salivarius, and Streptococcus sanguinis. Material and method The Minimum Inhibitory Concentration (MIC) and the Minimum Bactericidal Concentration (MBC) of the evaluated mouth rinses were determined according to the Clinical & Laboratory Standards Institute protocols. Data were submitted to Kruskal-Wallis test and Mann-Whitney post hoc (α=0.05). Result About 70% of the mouth rinses achieved high antibacterial activity and 30%, a low antibacterial activity against all the species tested. The most ineffective mouth rinse showed antibacterial activity (MIC) at 1:1 dilution, while the most effective showed activity even at 1:2048 dilution, which may imply prolonged effect in the mouth. About 51% of mouth rinses showed bactericidal activity, and it was verified that cetylpyridinium chloride or chlorhexidine digluconate containing in the formulation were associated with the highest activity. Conclusion Most - but not all - mouth rinses commercially available are effective in inhibiting in vitro initial colonizers of dental surfaces.

Resumo Introdução Muita publicidade sobre enxaguatórios bucais é veiculada em todos os meios de comunicação apelando para o efeito anti-placa e prestando um desserviço à comunidade. Grande quantidade de enxaguatórios bucais está disponível no mercado e estes diferem em suas composições e eficácia antimicrobiana. Objetivo Neste estudo, avaliamos a atividade antimicrobiana de 35 enxaguatórios bucais amplamente disponíveis contra espécies bacterianas envolvidas na iniciação do biofilme dental - Streptococcus gordonii, Streptococcus mitis, Streptococcus oralis, Streptococcus salivarius e Streptococcus sanguinis. Material e método A Concentração Inibitória Mínima (CIM) e a Concentração Bactericida Mínima (CBM) dos enxaguatórios avaliados foram determinadas de acordo com os protocolos do Clinical & Laboratory Standards Institute. Os dados foram submetidos ao teste Kruskal-Wallis e Mann-Whitney post hoc (α=0,05). Resultado Aproximadamente 70% dos enxaguatórios bucais alcançaram alta atividade antibacteriana e 30%, baixa atividade antibacteriana contra todas as espécies testadas. O enxaguatório bucal mais ineficaz mostrou atividade antibacteriana (CIM) na diluição de 1:1, enquanto a mais eficaz mostrou atividade mesmo na diluição de 1:2048, o que pode implicar em efeito prolongado na boca. Cerca de 51% dos enxaguatórios bucais apresentaram atividade bactericida, e verificou-se que formulações contendo cloreto de cetilpiridíneo ou digluconato de clorexidina estavam associados à maior atividade. Conclusão A maior parte - mas não todos - dos enxaguatórios bucais comercialmente disponíveis são eficazes na inibição de colonizadores iniciais de superfícies dentárias in vitro.

Dynamics of the seasonal airborne propagation of Staphylococcus aureus in academic dental clinics

Abstract Objective Staphylococcus aureus strains can be disseminated during dental treatments and occasionally lead to the contamination and infection of patients and dentists, which is an important public health problem. The dynamics of the airborne propagation and the genetic diversity of S. aureus isolated in an academic dental clinic environment were investigated using isoenzyme typing. Material and Methods The isoenzymes of 44 previously reported isolates were obtained from fresh cultures and extracted using glass beads. Nine isoenzymes were investigated using multilocus enzyme electrophoresis (MLEE). The genetic diversity and relationship among the strains (electrophoretic type - ET) were determined using statistics previously described by Nei25 (1972) and the SAHN grouping method (UPGMA algorithm). Results Clonal pattern analyses indicated a high level of genetic polymorphism occurring among the 33 ETs, which were grouped into five taxa. Each taxon presented one or more clusters that were moderately related and that contained two or more identical/highly related isolates, revealing seasonal airborne propagation in these dental clinic environments. Conclusions These data suggest the occurrence of active microevolutionary processes in S. aureus as well as the possibility of environmental propagation during a 14-month time span. Such findings are important to show that multiuser academic dental clinics can retain certain strains that are spreadable to different niches.

Isoenzyme genotyping and phylogenetic analysis of oxacillin-resistance Staphylococcus aureus isolates

Aim: The propagation of S. aureus in hospital and dental environments is considered an important public health problem since resistant strains can cause serious infections in humans. The genetic variability of 99 oxacillin-resistant S. aureus isolates (ORSA) from the dental patients (oral cavity) and environments (air) was studied by isoenzyme genotyping. Methods: S. aureus isolates were studied using isoenzyme markers (alcohol dehydrogenase, sorbitol dehydrogenase, mannitol-1-phosphate dehydrogenase, malate dehydrogenase, glucose dehydrogenase, D-galactose dehydrogenase, glucose-6-phosphate dehydrogenase, catalase and α/ß-esterase) and genetic (Nei's statistics) and cluster analysis (UPGMA algorithm). Results: A highly frequent polyclonal pattern was observed in this population of ORSA isolates, suggesting various sources of contamination or microbial dispersion. Genetic relationship analysis showed a high degree of polymorphism between the strains, and it revealed three taxa (A, B and C) distantly genetically related (0.653≤dij≤1.432) and fifteen clusters (I to XV) moderately related (0.282≤dij<0.653). These clusters harbored two or more highly related strains (0≤dij<0.282), and the existence of microevolutionary processes in the population of ORSA. Conclusion: This research reinforces the hypothesis of the existence of several sources of contamination and/or dispersal of ORSA of clinical and epidemiologically importance, which could be associated with carriers (patients) and dental environmental (air) (AU)

Antifungal activity of the ethanolic extracts of Punica granatum L. and evaluation of the morphological and structural modifications of its compounds upon the cells of Candida spp.

Ethanolic crude extracts prepared from the arils and seeds, pericarp, peels and from the whole fruit of Punica granatum, known as pomegranate, had their antifungal activity tested against Candida spp. The ethanolic crude extracts were analyzed by Mass Spectrometry and yielded many compounds such as punicalagin and galladydilacton. The extracts from the pericarp and peel showed activity against Candida spp., with MICs of 125 µg/mL. The effect of pericarp and peel extracts upon the morphological and structure of C. albicans and C. krusei were examined by scanning and transmission electron microscopy, with the visualization of an irregular membrane and hyphae, formation of vacuoles and thickening of the cell wall. The data obtained revealed potential antimicrobial activity against yeasts cells of the Candida genus, and the bioactive compounds could be responsible for changes in cell morphology and structure. The data obtained open new perspectives for future research in continuation to this study, where information such as determination of the site of action of the compounds could contribute to an alternative therapy against these organisms.

Avaliação in vitro da atividade de fosfolipase e proteinase de cepas de candida albicans isolada da cavidade bucal de pacientes diabéticos / In vitro evaluation of phospholipase and proteinase of candida albicans isolated from oral cavity of diabetic patients

Leveduras do gênero Candida são comuns na cavidade bucal e podem causar candidose na presença de fatores predisponentes, especialmente em paciente diabético, o qual é caracterizado por um aumento anormal da glicose no sangue. A manifestação da doença está relacionada a este conjunto de fatores locais, tais como a presença de próteses dentárias, pH salivar, fluxo salivar e tabaco. A redução da saliva é um dos principais fatores de risco para o aparecimento de infecção e o controle glicêmico inadequado causado por diabetes, em associação com todos estes fatores, pode aumentar a incidência de infecções. Os objetivos deste estudo foram: 1) isolar e identificar cepas de Candida albicans da mucosa bucal de pacientes diabéticos 2) avaliar os fatores de virulência: proteinase e fosfolipase. Amostras microbiológicas foram coletadas a partir de locais da mucosa bucal e semeadas em CHROMagar para posterior identificação de C. albicans por PCR. Foram realizados testes da atividade de proteinase e fosfolipase para todos os isolados de C. albicans. Neste estudo, 22 isolados foram identificados como C. albicans. Em relação às atividades de proteinases, todas as cepas de C. albicans foram capazes de produzir proteinase, enquanto que para fosfolipase, apenas 4,5% dos isolados não produziram esta exoenzima. Portanto, C. albicans presente na cavidade bucal de pacientes diabéticos tem potencial patogênico e pode participar de processos infecciosos e inflamatórios, causando lesões e invadindo os tecidos orais.

Candida yeasts are common in the oral cavity and can cause candidosis in the presence of predisposing factors, especially diabetes, which is characterized by an abnormal increasing in blood glucose concentration. The manifestation of the disease is related to a set of local factors such as the presence of dental prostheses, salivary pH, salivary flow and tobacco. The reduction in saliva is a major risk factor for the onset of infection and poor glycemic control caused by diabetes in association with all these factors further increases the incidence of candidosis. The objectives of this study were: 1) to isolate and identify Candida albicans strains from oral mucosa sites of diabetic patients 2) to evaluate the virulence factors: proteinase and phospholipase. Thus, microbial samples were collected from oral mucosa sites and seeded in CHROMagar for subsequent identification of C. albicans by PCR. For the phenotypic tests, all strains of C. albicans were evaluated for their proteinase and phospholipase productions. In this study, 22 isolates were identified as C. albicans. In regard to the proteinase activities, all strains of C. albicans were able to produce proteinase, while only 4.5% from those isolates were not able to produce phospholipase activity. In conclusion, C. albicans present in the oral cavity of diabetic patients is potentially pathogenic and can participate in infectious and inflammatory processes, causing injury and invading oral tissues.

Typing Candida albicans oral isolates from healthy Brazilian schoolchildren using multilocus enzyme electrophoresis reveals two highly polymorphic taxa

The genetic diversity of C. albicans oral isolates from 75 healthy schoolchildren from eight schools located in different geographic areas of Piracicaba city, São Paulo state, Brazil, was established using isoenzymes marker (Multilocus Enzyme Electrophoresis - MLEE) and cluster analysis. Patterns of monoclonal and polyclonal oral colonization by C. albicans within and between groups of schoolchildren were identified. However, significant divergence between the observed and the expected genotypic frequencies (Hardy-Weinberg equilibrium test) was not detected in the geographically adjacent groups, suggesting the hypothesis that populations of healthy schoolchildren do not correspond to the selection factor (differential survival) of strains. Two highly polymorphic and distantly genetically related taxa (A and B) were identified within the total population of yeasts, each contained subgroups (A1, A2, A3, A4, B1 and B2) and clusters of moderately related strains (from I to X), suggesting the existence of strains restricted or not to certain groups of geographically limited, healthy students. However, the coexistence of identical strains in healthy schoolchildren from the same school (geographically related) reinforces the hypothesis of oral transmission, where the sources of propagation could be explored. Furthermore, this could also be used in current and retrospective analyses of C. albicans isolated from immunocompetent and immunocompromised people, in order to detect commensal or potentially pathogenic yeast groups, predominantly in candidiasis, and in the development of strategies to prevent transmission or human propagation.

Conventional and alternative antifungal therapies to oral candidiasis

Candida-associated denture stomatitis is the most common form of oral candidal infection, with Candida albicans being the principal etiological agent. Candida adheres directly or via an intermediary layer of plaque-forming bacteria to denture acrylic. Despite antifungal therapy to treat denture stomatitis, infection is reestablished soon after the treatment ceases. In addition, many predisposing factors have been identified as important in the development of oral candidiasis, including malnourishment, common endocrine disorders, such as diabetis mellitus, antibacterial drug therapy, corticosteroids, radiotherapy and other immunocompromised conditions, such as acquired immunodeficiency syndrome (AIDS). These often results in increased tolerance to the most commonly used antifungals. So this review suggests new therapies to oral candidiasis.

Evidências científicas da colonização de Candida spp. em bolsas periodontais / Scientific evidence of Candida spp. colonization in periodontal pockets

Objetivo: o objetivo do presente trabalho é apresentar uma breve revisão de literatura a respeito da colonização de Candida spp. em bolsas periodontais, seus principais fatores de virulência e possível influência sobreas doenças periodontais. Revisão de Literatura: Apesar de a mucosa bucal ser considerada o principal reservatóriode Candida spp, este micro-organismo pode estar coagregado a bactérias do biofilme dental, sendo considerado um fator importante para o processo decolonização de bolsas periodontais. Além disso, possui vários fatores de virulência relevantes na patogênese dadoença periodontal, tais como a capacidade de aderir ao epitélio e invadir o tecido conjuntivo gengival. Também pode inibir a função de neutrófilos polimorfonucleares, bem como produzir enzimas como colagenases e proteinases, que são capazes de degradar imunoglobulinas.Considerações finais: Os fatores de virulência de Candida spp. associada à suscetibilidade do hospedeiro poderiam desempenhar um papel importante nasalterações inflamatórias associadas com as doenças periodontais destrutivas

The role of immune system in the development of periodontal disease: a brief review / O papel do sistema imune no desenvolvimento da doença periodontal: uma breve revisão

Periodontitis is a highly complex and multi-factorial disease. This review summarizes some immunological factors involved in the development and control of this oral disease, such as: the participation of inflammatory cells in local inflammation, the synthesis of chemotaxis proteins with activation of the complement system and a range of antimicrobial peptides, such as defensins, cathelicidin and saposins. The integration of pathogen-associated molecular patterns (PAMPs) from microorganisms with their surface receptors in the immune cells, induces the production of several cytokines and chemokines that presents either a pro- and/or anti-inflammatory role by stimulating the secretion of a great variety of antibody subtypes and the activation of mechanisms of controlling the disease, such as the regulatory T cells. Although several studies have tried to clarify some of the immune mechanisms involved in periodontal disease, more studies must be conducted to understand its development and progression and consequently to discover new alternatives for the prevention and treatment of this severe inflammatory disease.

A periodontite é uma doença altamente complexa e multifatorial. Esta breve revisão reúne alguns fatores imunológicos envolvidos no desenvolvimento e controle desta doença oral, tais como: a participação de células inflamatórias no local da inflamação, a síntese de proteínas quimiotáticas através da ativação do sistema complemento e a presença de alguns dos peptídeos antimicrobianos, como defensinas, catelicidinas e saposinas. A interação de padrões moleculares associados à patógenos (PAMPs) de microrganismos com seus receptores de superfície, em células imunológicas, induz a produção de várias citocinas e quimiocinas que apresentam função pró- e/ou anti-inflamatória estimulando a secreção de uma grande variedade de subtipos de anticorpos e a ativação de mecanismos de controle da doença, como as células T reguladoras. Embora vários trabalhos tentem esclarecer alguns dos mecanismos imunológicos envolvidos na doença periodontal, estudos adicionais são necessários para ampliar conhecimentos sobre o desenvolvimento, a progressão e, consequentemente, para se descobrir novas alternativas de prevenção e tratamento desta grave doença inflamatória.

Molecular fingerprinting methods for studies involving oral Candida albicans: [review] / Métodos de caracterização molecular para estudos envolvendo Candida albicans de origem bucal: [revisão]

OBJECTIVE: This review was aimed to discuss the literature concerning the fingerprint methods for epidemiological studies of oral-borne Candida albicans. DISCUSSION: Interest in obtaining a better understanding of the pathogenesis, epidemiology, genetics and evolution of Candida albicans has led to the development of innumerable investigations. These studies have employed fingerprinting systems, such as multilocus enzyme electrophoresis, electrophoretic karyotyping, randomly amplified polymorphic DNA, and restriction length fragment polymorphism, with and without hybridization. The efficacy of these systems has been examined at different levels of discrimination. A validation strategy has been delineated which compares two or more unrelated methods. Moreover, the different fingerprinting patterns produced could be registered in database programs and submitted to comparison with parameters of the host and characteristics of the pathogen. These procedures permit urrent and retrospective comparison of a selection of clinical and epidemiologically important strains, which could show one or several characteristics of the host or pathogen. Additionally, the sum of this growing amount of information could contribute even more to the understanding of the dynamics of infectious organisms in human populations, the complex relationship between commensalism and infection, and genetic and evolutionary mechanisms. CONCLUSIONS: Multiple molecular systems are available for studies involving C. albicans. This growing amount of information contributes to the understanding of the dynamics of this fungus in human populations.

OBJETIVO: Esta revisão discute as informações existentes acerca dos métodos de caracterização para estudos epidemiológicos envolvendo Candida albicans de origem bucal. DISCUSSÃO: O interesse no melhor entendimento da patogênese, epidemiologia, genética e evolução de C. albicans tem levado os pesquisadores à condução de inúmeras investigações. Esses estudos empregam sistemas de caracterização molecular como eletroforese de enzimas multilocus, cariotipagem por eletroforese, amplificação do DNA polimórfico ao acaso e polimorfismo dos fragmentos de restrição com e sem hidridização. A eficácia desses sistemas tem sido avaliada nos seus diferentes níveis de discriminação. Uma estratégia de validação foi delineada, a qual compara dois ou mais métodos não relacionados. Ainda, os diferentes padrões de caracterização molecular produzem dados que podem ser avaliados por programas computacionais e permite a comparação comparâmetros do hospedeiro e características do patógeno. Tais procedimentos permitem comparações correntes e retrospectivas de cepas clínicas e epidemiologicamente importantes, que podem mostrar uma ou mais características do hospedeiro ou do patógeno. A somatória do montante de informação pode contribuir para o entendimento da dinâmica dos organismos infecciosos em populações humanas, as relações complexas entre comensalismo e infecção, e mecanismos genéticos e evolutivos. CONCLUSÕES: Vários sistemas de caracterização molecular estão disponíveis para estudos envolvendo C. albicans. Este aumento de informação contribui na compreensão da dinâmica deste fungo em populações humanas.

Enhanced susceptibility of Candida albicans to chlorhexidine under anoxia

Aim: Periodontal pockets can be colonized not only by bacteria, but also by Candida albicans. However, its role in periodontitis is unknown. This study evaluated the inhibitory performance of chlorhexidine digluconate under normoxic and anoxic conditions against 16 strains of C. albicans from periodontal pockets and other 20 from the oral mucosa. Methods: Strains were grown in normoxia and anoxia to adapt themselves to the different atmospheric conditions. Microdilution-based assays were carried out to determine the minimum concentrations of chlorhexidine that may restrain the conditioned candidal strains, in normoxia (normoxic MIC) and anoxia (anoxic MIC). The Mann-Whitney U test was used to evaluate the antimicrobial effect of chlorhexidine on C. albicans under normoxic and anoxic conditions (α = 0.05). Results: The normoxic MIC of chlorhexidine varied broadly from 150 to 1200 µg/mL, whereas its anoxic MIC varied narrower from 2.34 to 37.5 µg/mL. Regarding the origins of strains, no statistically significant differences (p > 0.05) were found. Conclusions: These results indicate that anoxic environmental conditions, compatible with periodontal pockets, tend to enhance C. albicans susceptibility to chlorhexidine.

Fundamental mechanisms of immune response to oral bacteria and the main perspectives of a vaccine against dental caries: a brief review / Mecanismos fundamentais de resposta imune contra bactérias bucais e as principais perspectivas para uma vacina anticárie: uma breve revisão

Dental caries may be defined as a complex multifatorial disease in that a broad group of biological, socio-economic and cultural factors interact directly or indirectly in the establishment and colonization of cariogenic microorganisms within the microbial community of the dental biofilm. Innate and adaptative immunity are two fundamental aspects of the immune system response against infections, such as dental caries. Besides, the majority of pathogenic infectious agents enter the organisms by the oral route. Consequently, the mucosal tissue, associated exocrine glands and saliva contributes to the protection of the oral cavity because contain cells responsible for antigen internalization and antibodies specific to oral bacteria. Macrophages are phagocytic cells that can internalize and kill bacteria by several mechanisms of internalization, including endocytosis, macropinocytosis and phagocytosis. Streptococcus mutans is the major pathogen of dental caries due to its ability to adhere and accumulate on tooth surfaces, using different virulence factors (AgI/II, Gtf, Gbps). Recent studies demonstrated protection against experimentally induced dental caries for vaccines containing intact or peptides from antigen I/II, Gtf or Gbp and vaccines containing a combination of antigens. The present review summarizes the fundamental mechanisms of host immune responses to oral bacteria and the main perspectives of a vaccine against dental caries.

A cárie dentária pode ser definida como uma doença complexa multifatorial causada por fatores biológicos, socioeconômicos e culturais que interagem direta ou indiretamente na colonização e estabelecimento de microrganismos cariogênicos na comunidade microbiana do biofilme dentário. As imunidades inata e adaptativa são os dois aspectos fundamentais de resposta do sistema imune contra infecções, como a cárie dentária. Além disso, a maioria dos agentes infecciosos patogênicos entra no organismo por via oral. Consequentemente, o tecido mucoso, associado com as glândulas exócrinas e a saliva contribuem para a proteção da cavidade bucal por conterem células responsáveis pela internalização de antígenos ou anticorpos contra as bactérias bucais. Os macrófagos são células fagocíticas que podem internalizar e eliminar bactérias por diversos mecanismos de internalização, como a endocitose, macropinocitose e fagocitose. Streptococcus mutans é o principal patógeno da cárie dentária por sua habilidade em aderir e acumular nas superfícies dentárias, usando diferentes fatores de virulência (AgI/II, Gtf e Gbps). Estudos recentes têm demonstrado proteção contra cárie induzida experimentalmente utilizando vacinas contendo antígenos intactos ou peptídeos a partir de AgI/II, Gtf ou Gbps ou uma combinação de antígenos. A presente revisão sumariza os mecanismos fundamentais de resposta imune contra bactérias bucais e as principais perspectivas de uma vacina anticárie.

Genetic polymorphism of Streptococcus mutans strains associated with incomplete caries removal

Aim: Despite the antibacterial properties of dental materials, the survival of residual bacteria under restorations has been demonstrated after incomplete caries removal. The aim of this study was to evaluate the genetic polymorphism of Streptococcus mutans strains isolated from deep dentinal lesions before and three months after incomplete caries removal. Methods: Samples of carious dentin were collected from 33 primary and/or permanent molars before and after indirect pulp treatment and processed for microbiological isolation of mutans streptococci (MS). After three months of the dental treatment, positive cultures for MS were detected in only ten of these teeth. DNA of MS isolates were obtained and subjected to polymerase chain reaction (PCR) for identification of S mutans. The arbitrary primed-PCR method (primer OPA-13) was used to detect the genetic polymorphism of S. mutans strains. Results: Identical or highly related S. mutans genotypes were observed in each tooth, regardless of the collect. Considering each tooth separately, a maximum of nine genotypic patterns were found in each tooth from all the collects. In addition, at least one genotypic pattern was repeated in the three collects. Genetic diversity was observed among the S. mutans isolates, obtained from different teeth after three months of the dental treatment. Conclusions: The persistence of identical genotypic patterns and the genetic similarity among the isolates, from the same tooth in distinct collects, showed the resistance of some S. mutans strains after incomplete caries removal treatment.

Evidence of Heterokaryon compatibility on Candida albicans biofilm

Aims: Candida species, especially Candida albicans, are frequently found associated with biomaterials and immunosuppressed patients, and have been described as the most virulent yeasts in human fungi diseases. These yeasts have recently been isolated from periodontal pockets, revealing the penetration of hyphae into the periodontal connective tissue. Methods: In this study, 7 periodontal C. Albicans strains were applied individually in biofilm development on titanium discs and the samples were thereafter analyzed as for the number of colony forming units per milliliter (CFU/mL), dry-weight and scanning electron microscopy (SEM). Results: Counting of CFU/ mL and determination of dry-weight showed that all samples formed biofilm. SEM analysis showed the development of a polymorphic network in the biofilms and the presence of hyphal anastomosis in the sites where fusion between the hyphae occurred. Conclusion: periodontal C. albicans strains present heterokaryon compatibility.

Susceptibility of Candida spp. Oral isolates for azolic antifungals and amphotericin B

Aims: Among the oral infections, candidosis may be considered the most frequent, and C. albicans the most prevalent species. Meanwhile, the non-albicans species may also be related to other infections processes and be able to affect the oral cavity, including periodontal disease. In this sense, understanding the relationship between Candida spp. and host, it is necessary and justified the search of mechanisms modulators of infections and treatments against diseases associated with these yeasts. Methods: Nineteen patients with periodontal disease were involved in this study. The aim was evaluate the susceptibility to azoles antifungals fluconozole, itraconazole, ketoconazole and the polienic anfotericin B against Candida spp isolated from three different sites of the oral cavity from these patients (periodontal disease, being periodontal pocket, oral mucosa and ridge gingival), by the minimum inhibitory concentration method – MIC. Results: Among the samples of C. albicans, 88% showed susceptibility depending on the concentration (SCD) and 3.6 % were resistant to at least one antifungal azole studied. Among the others species, 57% presented SDC and 42.8% showed resistance to at least one of the antifungal azole tested. Regarding to Anfotericin B, 90% of the C. albicans isolates and 3% of the nonalbicans showed resistance. There was no occurrence of resistance to the fluconazole and only 3.6% of C. albicans and 40% of the non-albicans were SDC to this antifungal. Conclusions: Patients with periondontal disease showed relevant levels of colonization by Candida spp, mainly at the oral mucosa and periodontal pocket showing important occurrence of SDC and resistance to the antifungals drugs tested.

Clonal characterization of Streptococcus mutans strains by multilocus enzyme electrophoresis

Vinte e uma cepas de Streptococcus mutans foram agrupadas pela eletroforese de enzimas codificadas por multilocus (MLEE). Seis isoenzimas apresentaram forte poder discriminatório (M1P, MPI, PLP, NSP, GOT e LAP). A MLEE é uma técnica robusta que pode ser empregada no estudo da diversidade clonal de cepas de S. mutans, em estudos epidemiológicos.

In vitro bacterial plaque suppression and recolonization by S. mutans and S. sobrinus

O estudo in vitro das interações entre S. mutans e S. sobrinus pode ser importante na determinação do papel desses microrganismos na formação de biofilmes nas estruturas dentais e seu potencial em induzir lesões cariosas. O objetivo da presente pesquisa foi estudar a supressão da formação da placa dental e sua recolonização por S. mutans rifampicina-resistentes e S. sobrinus estreptomicina-resistentes in vitro. Para avaliar as relações de competitividade entre essas espécies, cepas que foram previamente padronizadas foram incubadas em meio de cultura contendo diferentes carboidratos fermentáveis. Em intervalos de tempo determinados, amostras de S. mutans e S. sobrinus foram coletadas a partir de culturas mistas, diluídas e semeadas em placas com meio BHI-ágar contendo rifampicina ou estreptomicina para determinação do número de células viáveis de cada espécie por contagem de unidades formadoras de colônia. Para a avaliação da colonização bacteriana e recolonização da placa bacteriana in vitro, três experimentos foram realizados: I - co-cultivo de S. mutans e S. sobrinus; II - inoculação de S. mutans em placa bacteriana pré-formada por S. sobrinus; e III - placa bacteriana pré-formada por S. mutans dispersada e plaqueada em meio BHI-ágar contendo estreptomicina ou rifampicina para determinação do número de células viáveis para cada espécie. Os resultados indicaram uma predominância de S. mutans em relação ao S. sobrinus, demonstrando a capacidade do S. mutans em inibir a formação de placa por S. sobrinus e recolonizar a superfície dentária.

Biotyping and genotypic diversity among oral Candida albicans strains from caries-free and caries-active healthy children

Cepas orais de Candida albicans coletadas de crianças saudáveis cárie ativas e livres de cárie com idade variando de 24 a 36 meses, foram estudadas. O propósito do estudo foi determinar a atividade da proteinase e da fosfolipase produzida por Candida albicans nos dois grupos e comparar com a diversidade genotípica usando o método AP-PCR. As cepas identificadas como C. albicans por testes morfológicos e de fermentação, foram cultivadas em meio ágar proteinase e fosfolipase a 37ºC por 7 e 4 dias, respectivamente. Após o período de incubação, a atividade enzimática das cepas proteinase e fosfolipase positiva foram medidas. Todas as cepas foram submetidas a técnica genotípica AP-PCR, usando o primer arbitrário AP-3. A análise enzimática demonstrou que não há diferença entre os dois grupos estudados. O método AP-PCR foi eficiente em demonstrar o polimorfismo genético de C. albicans intra indivíduos demonstrando uma maior diversidade clonal em crianças cárie ativas em relação as livres de cárie. Dendogramas de similaridade demonstraram semelhança na linhagem clonal apenas intra-indivíduos. Os resultados sugerem que o perfil enzimático não depende das características genotípicas das cepas.

Candida albicans proteinases

Candida species are ubiquitous commensal yeast that usually reside as part of an individual´s normal mucosal microflora and can be detected in approximately 50% of the population in this form. However, if the balance of the normal flora is disrupted or the immune defences are compromised, Candida species can invade mucosal surfaces and cause disease manifestations. Determining exactly how this transformation from commensal to pathogen takes place and how it can be prevented is a continuing challenger for the medical mycology field. Attributes that contribute to Candida albicans virulence include adhesion, hyphal formation, phenotypic switching and extra cellular hydrolytic enzyme production. The extra cellular hydrolytic enzyme, especially the secreted aspartyl proteinases (Saps), are one a few gene products that have been shown to directly contribute to C. albicans pathogenicity. Given the limited number of suitable and effective antifungal drugs, the continuing increase in the incidence of Candida infections, together with increasing drug resistance, highlights the need to discover new and better agents that target fundamental biological processes and or pathogenic determinants of C. albicans.