RESUMO
Streptococcus mutans is considered the primary etiologic agent of dental caries and contributes significantly to the virulence of dental plaque, especially in the presence of sucrose. To avoid the role of sucrose on the virulence factors of S. mutans, sugar substitutes are commonly consumed because they lead to lower or no production of acids and interfere with biofilm formation. This study aimed to investigate the contribution of sugar substitutes in the cariogenic potential of S. mutans biofilms. Thus, in the presence of sucrose, glucose, sucralose and sorbitol, the biofilm mass was quantified up to 96 h, the pH of the spent culture media was measured, the expression of biofilm-related genes was determined, and demineralization challenge experiments were conduct in enamel fragments. The presence of sugars or sugar substitutes profoundly affected the expression of spaP, gtfB, gtfC, gbpB, ftf, vicR and vicX in either biofilm or planktonic cells. The substitution of sucrose induced a down-regulation of most genes involved in sucrose-dependent colonization in biofilm cells. When the ratio between the expression of biofilm and planktonic cells was considered, most of those genes were down-regulated in biofilm cells in the presence of sugars and up-regulated in the presence of sugar substitutes. However, sucralose but not sorbitol fulfilled the purpose of reducing the cariogenic potential of the diet since it induced the biofilm formation with the lowest biomass, did not change the pH of the medium and led to the lowest lesion depth in the cariogenic challenge.
Assuntos
Biofilmes/efeitos dos fármacos , Cárie Dentária/microbiologia , Streptococcus mutans/efeitos dos fármacos , Edulcorantes/farmacologia , Proteínas de Bactérias/análise , Técnicas Bacteriológicas , Biofilmes/crescimento & desenvolvimento , Biomassa , Cariogênicos/farmacologia , Proteínas de Transporte/análise , Meios de Cultura , Esmalte Dentário/microbiologia , Perfilação da Expressão Gênica , Glucose/farmacologia , Glucosiltransferases/análise , Hexosiltransferases/análise , Humanos , Concentração de Íons de Hidrogênio , Lectinas/análise , Proteínas de Membrana/análise , Sorbitol/farmacologia , Streptococcus mutans/fisiologia , Sacarose/análogos & derivados , Sacarose/farmacologia , Fatores de Tempo , Tomografia de Coerência Óptica/métodos , Desmineralização do Dente/microbiologia , Fatores de Virulência/análiseRESUMO
Introducción: Los catéteres venosos centrales (CVC) plantean un alto riesgo de infección. La infección del sitio de salida (ISS-CVC) es la menos estudiada, y se desconoce su asociación con la bacteriemia asociada a catéter (BAC) y su impacto en la evolución del paciente. Objetivo: Evaluar la asociación entre ISS-CVC, BAC y mortalidad. Materiales y métodos: Estudio prospectivo, de observación. Pacientes internados en una Unidad de Terapia Intensiva médico/quirúrgica que requirieron la colocación de CVC desde el 01/06/2010 hasta el 01/04/2012. Se evaluaron datos epidemiológicos, BAC (según criterios de los CDC) y gérmenes. Se utilizaron media ± DE, mediana y rango intercuartílico, y porcentajes. Resultados: Durante este período, ingresaron 575 pacientes, el 98% requirió CVC. Datos de los pacientes: edad 41 ± 26 años, APACHE II 15 ± 7, 96% con ventilación mecánica, días de ventilación mecánica 41 (33-63), días de internación 43 (25-67). Todos los CVC con ISS fueron retirados y cultivados. Se observaron 51 ISS: 5,5/1000-días-catéter: 33% subclavia, 38% yugular, 29% femoral. Seis pacientes con ISS (12%) tuvieron BAC (0,65/1000-días-catéter): 3 subclavias, 2 yugulares, 1 femoral; 2 con halo y 8 con secreción purulenta. Tiempo de permanencia del CVC: 7,5 días (5-10). Clínica al momento de la ISS: shock 50%, fiebre 83%, SOFA 6 ± 3. El 83% de las infecciones fueron monomicrobianas: 83% por bacilos gramnegativos (2 Klebsiella, 2 Pseudomonas, 1 Serratia y 1 Acinetobacter), 17% por enterococos resistentes a vancomicina. La mortalidad fue del 50%. Conclusión: Aunque la ISS provocó una baja incidencia de BAC, la mortalidad fue alta. Al parecer, la ISS no es un factor predictivo de BAC.(AU)
Introduction: Central venous catheters (CVC) are widely used and pose a high risk of infection. There are few studies on insertion site infection (ISI-CVC), and both its association with catheter-associated bloodstream infection (CABSI) and the outcome of patients are unknown. Objective: To determine the association between ISI-CVC, the presence of CABSI and mortality. Materials and methods: Prospective observational study. All patients admitted to a medical/surgical Intensive Care Unit requiring CVC insertion from 06/01/2010 to 04/01/2012 were included. Epidemiological data, CABSI (according to CDC criteria) and microorganisms involved were evaluated. Mean ± SD, median and interquartile range, and percentages were used. Results: During the period study, 575 patients were admitted, 98% required CVC. Patient´s data: age 41 ± 26 years, APACHE II 15 ± 7, 96% on mechanical ventilation, days on mechanical ventilation: 41 (33-63), length of stay 43 (25-67) days. All CVCs with ISI were removed and cultured. Fifty one ISI were observed (5.5/1000-catheter-day). Six patients with ISI (12%) presented CABSI (0.65/1000-catheter-day): 3 in subclavian, 2 in jugular, 1 femoral; 2 with erythema and 8 with purulent secretion. CVC permanence: 7.5 day (5-10). Signs and/or symptoms at the moment of ISI: shock 50%, fever 83%, SOFA 6 ± 3. The 83% of infections were caused by one microorganism: 83% due to gram-negative bacilli (2 Klebsiella, 2 Pseudomonas, 1 Serratia, and 1 Acinetobacter), 17% due to vancomycin-resistant enterococci. The mortality rate was 50%. Conclusion: Although ISI-CVC presented a low incidence of CABSI, mortality rate was high. The ISI-CVC might have a little predictable value for CABSI.(AU)
Assuntos
Humanos , Bacteriemia/mortalidade , Cateteres Venosos Centrais , Infecções , MortalidadeRESUMO
Actinobacillus actinomycetemcomitans is capable of colonizing mucosa and dental plaque and plays an important role in periodontal disease in young peoples and adult. Adherence mechanisms on epithelial cells, tooth or oral bacteria and gingival invasion probably are the initial steps in the pathogenesis of gingivitis or periodontitis. In this study, the adherence of A. actinomycetemcomitans on oral epithelial cells following subculturing were examined. The adherence on oral epithelial cells showed high in all the isolates values but with differences among them and at each time of subculturing. The adherence of A. actinomycetemcomitans FDC Y4 was stable in each of the subcultures. However, adhesion values of all the tested isolates were different except for strains #1, #38 and Y4, suggesting a heterogenicity within this microbial group. Morphologic variations were observed in extracellular structures of the A. actinomycetemcomitans tested. The adhesion process on oral epithelial cells of this organism can be influenced by subcultures, but additional studies are necessary to verify the influence of subculturing on adherence or other virulence factors.
Assuntos
Aggregatibacter actinomycetemcomitans/ultraestrutura , Células Epiteliais/microbiologia , Boca/microbiologia , Aderência Bacteriana/fisiologia , Humanos , Microscopia Eletrônica , Boca/citologia , Periodontite/microbiologiaRESUMO
The aim of this investigation was to determine whether sublethal concentrations of chlorhexidine (Cx), hexetidine (Hx), cetylpyridinium chloride (Cc), sodium dodecyl sulfate (SDS), sanguinarine (Sg), sodium fluoride (NaF), and ammonium fluoride (NH4F) could affect hydrophobicity and adhesion of Streptococcus sanguis and Streptococcus mutans to saliva-coated hydroxyapatite (S-HA). Determination of the minimum inhibitory concentrations (MICs) showed that both species were susceptible to all agents tested. Growth in the presence of sub-MIC concentrations of Cx, SDS, Cc, NaF, or NH4F did not change significantly the hydrophobicity of S. sanguis cells when compared to the control which lacked any agent. However, growth in the presence of Hx or Sg resulted in a significant reduction in their hydrophobicity. Sub-MIC levels of SDS or Sg in the growth medium resulted in S. mutans cells with increased affinity for hexadecane compared with the control. The adherence of S. sanguis was changed significantly only by Hx or Sg, resulting in less cells adhering to S-HA. However, S. mutans cells previously incubated with NaF, NH4F, or Sg showed a higher adherence to S-HA than the control. The mechanisms of interference with adherence are at present not completely understood. Thus, antimicrobial agents at sub-MIC concentrations can interfere selectively with hydrophobicity and/or adhesion of oral streptococci.
Assuntos
Anti-Infecciosos Locais/farmacologia , Aderência Bacteriana/efeitos dos fármacos , Streptococcus mutans/efeitos dos fármacos , Streptococcus sanguis/efeitos dos fármacos , Adsorção , Alcaloides/administração & dosagem , Alcaloides/farmacologia , Alcanos , Compostos de Amônio , Anti-Infecciosos Locais/administração & dosagem , Benzofenantridinas , Cetilpiridínio/administração & dosagem , Cetilpiridínio/farmacologia , Clorexidina/administração & dosagem , Clorexidina/farmacologia , Placa Dentária/microbiologia , Durapatita , Fluoretos/administração & dosagem , Fluoretos/farmacologia , Hexitidina/administração & dosagem , Hexitidina/farmacologia , Humanos , Isoquinolinas , Compostos de Amônio Quaternário , Saliva/fisiologia , Dodecilsulfato de Sódio/administração & dosagem , Dodecilsulfato de Sódio/farmacologia , Fluoreto de Sódio/administração & dosagem , Fluoreto de Sódio/farmacologia , Streptococcus mutans/crescimento & desenvolvimento , Streptococcus mutans/fisiologia , Streptococcus sanguis/crescimento & desenvolvimento , Streptococcus sanguis/fisiologia , Propriedades de Superfície , ÁguaRESUMO
The purpose of this study was to evaluate the effect of acid conditioning and occlusal sealant on microbial colonization of pit and fissures submitted to ameloplasty or left intact. Human enamel blocks containing fissures prepared from the occlusal surfaces of unerupted third molars were implanted in occlusal fillings in molars of 12 patients for seven, 30, 60, and 120 days. After seven days of exposure to the oral environment, the pit and fissure blocks were removed and found to be colonized, mainly with gram-positive coccal flora. The acid-etching procedure itself reduced the number of cultivable microorganisms by about 95%. Subsequent application of occlusal sealant caused a gradual decrease of the remaining viable microorganism throughout the experiment. Despite the decrease of 100% after acid etching in most of the fissures submitted to ameloplasty, the occlusal sealant did not lead to a subsequent significant reduction.