Estudo in vitro da açäo antimicrobiana de cimentos protetores do complexo dentina-polpa sobre os microorganismos S. mutans e S. sanguis / In vitro study of the antimicrobial action of dentin-pulp complex protector cements on S. mutans e S. sanguis

Os autores utilizaram o teste de difusäo em ágar, para verificar a açäo antimicrobiana dos cimentos protetores do complexo dentina-polpa, sobre o S. mutans e S. sanguis. Nas condiçöes do trabalho, dos oito cimentos estudados in vitro, Vitrebond, Hydro C, XR-Ionomer e Life Improved mostraram ter açäo antimicrobiana, enquanto Ketac-Bond, Renew Light, Shofu Lining Cement e Timeline näo revelaram açäo antimicrobiana

Efecto del control del streptococcus mutans en niños de 2 y 3 años de edad / Effect of streptococcus mutans control in 2 and 3-year-old children

Se realizó el estudio del efecto del control del Streptococcus mutans en 612 niños de dos y tres años de 10 círculos infantiles del municipio Habana Vieja y se les realizó el examen bucal y la determinación del grado de infección en saliva (Técnica de Matsukubo et al) y los niños altamente infectados recibieron aplicaciones semestrales de laca-flúor clorhexidine durante dos años. Al finalizar el período experimental se volvieron a realizar el examen bucal y los análisis de saliva. Se halló que en esas edades, el 36,1 % de los niños estaban infectados y el 14,7 % presentaba alta infección, lo cual tiende a aumentar con la edad; el 5,4 % estaba afectado por caries, aunque todos padecían una alta infección. El tratamiento impuesto logró eliminar o reducir la infección por el S. mutans en los niños con alta infección previa, además de reducir la actividad cariogénica, lo cual prueba la eficacia del tratamiento. Se concluye que este tratamiento preventivo es primordial en los niños altamente infectados, pero debe de ir aparejado con el tratamiento curativo de los que estén afectados

Efecto de la leche sobre los estreptococos orales de la placa bacteriana en niños / Effect of milk on dental plaque oral streptococci in children

Se procura establecer si la ingesta de leche sin el añadido de azúcar, suministrada antes de dormir y después de realizado el cepillado de los dientes, actúa inhibiendo los estreptococos de la placa bacteriana en niños. Se trabajó con 12 niños de ambos sexos, de edades comprendidas entre 3 y 11 años. Los mismos fueron divididos en un grupo problema, al que se le hizo ingerir medio vaso de leche bovina pasteurizada, y un grupo testigo, que no tomó leche después de las cinco de la tarde. Se realizó una primera toma de muestra de placa bacteriana a la noche después de cenar y haberse cepillado los dientes. A la mañana siguiente, antes de la higiene bucal y previo al desayuno, se obtuvieron muestras nuevamente en ambos grupos. La experiencia se extendió a 15 días. Al cabo de ese tiempo se repitió el control microbiológico. Los resultados indicaron que en los pacientes que tomaron leche, al cabo de 15 días, se produce una disminución en el número de microorganismos total y en el pocentaje de estreptococos. En los pacientes testigo, el número de microorganismos aumentó en las muestras de la mañana. El porcentaje de estreptococos se mantuvo constante

Efecto de la leche sobre los estreptococos orales de la placa bacteriana en niños / Effect of milk on dental plaque oral streptococci in children

Se procura establecer si la ingesta de leche sin el añadido de azúcar, suministrada antes de dormir y después de realizado el cepillado de los dientes, actúa inhibiendo los estreptococos de la placa bacteriana en niños. Se trabajó con 12 niños de ambos sexos, de edades comprendidas entre 3 y 11 años. Los mismos fueron divididos en un grupo problema, al que se le hizo ingerir medio vaso de leche bovina pasteurizada, y un grupo testigo, que no tomó leche después de las cinco de la tarde. Se realizó una primera toma de muestra de placa bacteriana a la noche después de cenar y haberse cepillado los dientes. A la mañana siguiente, antes de la higiene bucal y previo al desayuno, se obtuvieron muestras nuevamente en ambos grupos. La experiencia se extendió a 15 días. Al cabo de ese tiempo se repitió el control microbiológico. Los resultados indicaron que en los pacientes que tomaron leche, al cabo de 15 días, se produce una disminución en el número de microorganismos total y en el pocentaje de estreptococos. En los pacientes testigo, el número de microorganismos aumentó en las muestras de la mañana. El porcentaje de estreptococos se mantuvo constante (AU)

Quantitative determination of the intracellular concentration of the various forms of HPr, a phosphocarrier protein of the phosphoenolpyruvate: sugar phosphotransferase system in growing cells of oral streptococci.

A simple procedure for quantitative estimation of the different phosphorylated forms of the phosphocarrier protein HPr in growing cells of oral streptococci is described. The growth of the cells was rapidly stopped by acidification of the medium and concomitant addition of the ionophore Gramicidin D. This procedure inactivated Enzyme I, HPr(Ser) kinase, HPr(Ser-P) phosphatase, and the enzymes involved in the metabolism of the allosteric effectors as well as the substrates of HPr phosphorylation. The cellular concentrations of HPr (His approximately P), HPr (Ser-P), HPr (His approximately P) (Ser-P), and free HPr were then determined by crossed immunoelectrophoresis.

Binding of a Streptococcus mutans cationic protein to kidney in vitro.

An 8-kDa protein, with binding activity for heparin and heparan sulfate of basal laminae of animal tissues, was isolated from Streptococcus mutans MT703 and purified to homogeneity. Binding of radioiodinated 8-kDa protein to rabbit kidney tissue in vitro showed a high degree of specificity, as indicated by saturation kinetics, time dependence, and competitive inhibition by unlabeled protein. Binding activity for kidney tissue was competitively inhibited by selected glycosaminoglycans and polyanions in the following order: heparin greater than dextran sulfate greater than heparan sulfate greater than chondroitin sulfate greater than lipoteichoic acid greater than keratan sulfate greater than hyaluronic acid. Binding of the streptococcal protein to rabbit kidney tissue was also strongly inhibited by protamine sulfate, polylysine, and a random copolymer of lysine and alanine. Among the monosaccharides tested at 50 mM, glucosamine 2,3- or 2,6-disulfate, glucuronic acid, glucose 6-phosphate, and glucose 6-sulfate inhibited 50% or more of the binding activity, whereas N-acetylglucosamine 3-sulfate, glucosamine 6-sulfate, N-acetyl-glucosamine, N-acetylgalactosamine, N-acetylneuraminic acid, and a selection of neutral sugars were not inhibitory. The heparin-binding protein was detected on the cell wall of S. mutans and in the culture medium following growth. Several other species of streptococci produce an immunologically related protein of similar size.

Characterization of leukocyte chemotactic activity of bacteriocin from Streptococcus mutans Rm-10.

Bacteriocins have several biological activities in addition to their antibacterial effect. We investigated the chemotactic properties and mode of action of purified streptococcal bacteriocin. Bacteriocin purified from a culture supernatant of Streptococcus mutans (S. mutans) Rm-10 induced chemotaxis of human polymorphonuclear leukocytes and monocytes. Following purification, leukocyte migration appeared in one bacteriocin fraction, and this migration was dependent on the concentration gradient in dilution ranges from 1/960 to 1/15. Chemotactic activity of the bacteriocin was heat labile and trypsin sensitive. Moreover, preincubation of bacteriocin with varying dilutions of its antiserum prepared in rabbits resulted in a significant loss of the chemotactic activity.

[Oral Streptococci - a scheme for the identification of Streptococcus mutans]. / Orale Streptokokken - Ein Beitrag zur Identifizierung von Streptococcus mutans.

A reliable simple scheme for the rapid identification of certain species of oral streptococci has been developed and compared with biochemical and physiological results of 45 well known clinical isolates and stock strains. Moreover, a method for the determination of H2O2 production was tested. With selected reactions as for instance acid formation in mannitol and raffinose broth, hydrolysis of arginine and esculin, the production of peroxidase, and the resistance of bacitracin the species S. rattus, S. sobrinus, S. mutans, S. cricetus, S. ferus, S. milleri, S. mitis, S. sanguis, S. mitior, and S. salivarius were differentiated.

Relationship of microbiological, social, and environmental variables to caries status in young children.

This study was undertaken to investigate the significance of social, environmental, and biological variables in relation to caries status in a group of young children, and to determine whether incorporating data on social and environmental variables into a multivariate model could improve the accuracy of a screening approach that relies solely on quantifying levels of salivary Streptococcus mutans. Data regarding fluoride status and sociodemographic characteristics were collected from the dental records of 89 children who ranged in age from 10-71 months, and who had been screened previously for S. mutans. Multivariate analyses (logit) revealed that the probability of having clinically or radiographically detectable caries was associated with 1) higher levels of salivary S. mutans, 2) residing in a single-parent household, 3) having suboptimal levels of fluoride in the drinking water and 4) not being covered by a dental insurance plan. The findings attest to the importance of considering social and environmental factors, in addition to biological variables, when evaluating caries status in young children.

Preliminary characterization of four bacteriocins from Streptococcus mutans.

The various properties of the inhibitory substances produced by Streptococcus mutans strains C67-1, Ny257-S, Ny266, and T8, and the fact that inhibitory zones produced could not be associated with lactic acid (or other organic acids), bacteriophages, or hydrogen peroxide indicate that these substances can be classified as mutacins. The substances produced by strains C67-1, Ny266, and T8 possessed similar properties. They were shown to be thermoresistant (100 degrees C, 30 min), low molecular weight (less than 3500) substances sensitive to proteolytic enzymes (chymotrypsin, papain, pronase E, proteinase K, and trypsin) and they were active against most of the Gram-positive bacteria tested but not against most of the Gram-negative bacteria. The substance produced by strain Ny257-S differs from the other three by its narrower activity spectrum, its lower thermoresistance (80 degrees C, 30 min), and its higher molecular weight (8,000-14,000). The gene or the genes coding for the mutacins are probably located on the chromosome since no plasmid DNA could be detected in these four producing strains. Restriction-fragment patterns of C67-1 and T8 suggest that these strains are closely related, as supported by the strong similarity observed between the properties of their mutacins.

Purification of a Streptococcus mutans protein that binds to heart tissue and glycosaminoglycans.

Proteins of Streptococcus mutans MT703 were isolated by differential filtration from chemically defined culture medium following growth of the bacteria. Incubation of this preparation with cryostat-cut sections of fresh rabbit cardiac muscle resulted in deposition of streptococcal components on basement membranes of sarcolemmal sheaths and capillary walls, as indicated by indirect immunofluorescence assay. Binding of radioiodinated streptococcal proteins to heart in vitro was time dependent and saturable. Unlabeled S. mutans proteins competitively inhibited 72% of heart binding by the radiolabeled proteins, indicating a high level of binding specificity. A selection of components common to tissue basement membranes was tested for their abilities to inhibit the binding of streptococcal proteins to heart tissue. Of the glycosaminoglycans, heparin was the most effective inhibitor, followed by heparan sulfate and chondroitin sulfate. Hyaluronic acid was not inhibitory. Of the glycoproteins tested, laminin and collagen type IV were weakly inhibitory, whereas fibronectin was ineffective. A single polypeptide was purified to homogeneity by affinity chromatography on a column of heparin-agarose. Gel filtration chromatography of the purified protein under nondissociating conditions showed a single component at 31 kilodaltons (kDa), whereas in sodium dodecyl sulfate-polyacrylamide gel electrophoresis one band appeared at 8 kDa. This indicates that the tissue-binding protein may either be a linear polypeptide or be released into the environment by the bacterium as a tetramer of the 8-kDa polypeptide. The purified protein had an isoelectric point of 9.5 and showed binding activity for basement membranes in thin sections of heart. Chemical analyses of the purified binding protein showed it to have high contents of lysine and alanine and to be devoid of half-cystine, methionine, tyrosine, histidine, and both neutral and amino sugars.

[Effects of orthodontic treatment on individual caries risk parameters]. / Der Einfluss kieferorthopädischer Behandlung auf Parameter des individuellen Kariesrisikos.

Systemic and microbiological caries risk factors were assessed in 49 children and adolescents, age 11-14. The subjects were divided into three groups with similar age profiles. At the time of investigation members of test group 1 (n = 19) were receiving orthodontic therapy with removable appliances. Members of test group 2 (n = 15) were treated with fixed appliances and the control group (n = 15) had not been subjected to any kind of orthodontic treatment at all. The results demonstrate, that patients undergoing orthodontic treatment with fixed appliances harbor significantly more salivary S. mutans and therefore are at a higher microbiological risk to develop caries than patients being treated with removable appliances or individuals receiving no orthodontic treatment at all.

Some salivary factors in insulin-dependent diabetics.

The aim of the study was to compare salivary flow rate, salivary pH, buffer capacity of the saliva, salivary glucose content, and number of Candida albicans, lactobacilli, and Streptococcus mutans in the saliva in age- and sex-matched adult long- and short-duration insulin-dependent diabetics and non-diabetics. Ninety-four long-duration and 86 short-duration diabetics and 86 non-diabetics, aged 20-70 years, participated in the study. Paraffin-stimulated whole saliva was collected. Both long- and short-duration diabetics had a decreased salivary flow rate and an increased salivary glucose content compared with non-diabetics. However, the differences were small. There were no significant differences between the groups in salivary pH, buffer capacity, or bacterial counts.

[Characterization of fatty acid composition in the cytoplasmic membrane of Streptococcus mutans].

The present study was performed to investigate the role of the fatty acid composition of cytoplasmic membranes in bacterial differentiation and the appearance of cariogenic properties of Streptococcus mutans. Bacterial fatty acid composition was effective for differentiation of Streptococcus mutans from the other oral streptococci. The composition obtained from the reference strains and the clinical isolates involved five groups and was useful as a rapid screening index for Streptococcus mutans. Compositional changes in membrane lipids played important roles in synthesis and secretion of extracellular glucosyltransferase for Streptococcus mutans. A characteristic property of Streptococcus mutans, resistance to 40% sucrose in the medium, is ascribable to compositional changes in membrane lipids, especially the glycolipids, of Streptococcus mutans.

Molecular surface characterization of oral streptococci by Fourier transform infrared spectroscopy.

In order to characterize the molecular composition of oral streptococci, infrared transmission spectroscopy on freeze-dried cells dissolved in KBr was used. All infrared spectra show similar absorption bands for the strains studied with the most important absorption bands located at 2930 cm-1 (CH), 1653 cm-1 (AmI), 1541 cm-1 (AmII) and two bands at 1236 cm-1 and 1082 cm-1, which were assigned to phosphate and sugar groups. However, calculation of absorption band ratios normalized with respect to the integrated intensity of the CH stretching region around 2930 cm-1, show significant differences between the strains. Both Streptococcus mitis strains possess high AmI/CH and AmII/CH absorption band ratios compared to the other strains. Streptococcus salivarius HBC12, a mutant strain devoid of all proteinaceous surface appendages, shows significantly lower AmI/CH and AmII/CH band ratios with respect to its parent strain S. salivarius HB. Two positive relationships could be established both between the AmII/CH absorption band ratio and the N/C elemental surface concentration ratio of the strains previously, determined from X-ray photoelectron spectroscopy (XPS) and also between AmI/CH and the fraction of carbon atoms at the surface involved in amide bonds, determined by XPS as well. From this comparison, it is concluded that transmission infrared spectroscopy can be employed as a technique to study the molecular surface composition of freeze-dried microorganisms.

Identification of viridans streptococci by pyrolysis-gas chromatography.

An isothermal method of pyrolysis-gas chromatography (Py-GC) was used for the identification of viridans streptococci. Pyrograms from 104 reference strains were subjected to a discriminant analysis to produce classification coefficients for the identification of 74 test organisms. Five groups representing recognised species were discriminated but Streptococcus milleri strains could not be distinguished from S. sanguis. If S. milleri and S. sanguis are regarded as a single pyrogroup, only three strains out of 74 were incorrectly identified by Py-GC. A multidimensional scaling analysis of the Py-GC data produced a similar species grouping, but this statistical method was less satisfactory for pyrogram data than discriminant analysis. While Py-GC was moderately successful for the identification of viridans streptococci, this study indicated that the technique has limited use in diagnostic medical microbiology because it is time-consuming and lacks flexibility.

Determination of viridans streptococci surface lipoteichoic acid by enzyme linked immune sorbent assay.

An enzyme linked immune sorbent assay (ELISA) was developed to measure bacterial surface lipoteichoic acid (LTA). Numerous strains of oral streptococci belonging to the 'viridans' group were examined on three separate occasions. The results show that, under these cultural conditions, oral streptococci do not normally express LTA on the cell surface. Occasionally strains produced amounts of LTA detectable using the ELISA but this was not a reproducible phenomenon.

[Gas chromatographic analysis of the S. mutans product spectrum from glucose turnover]. / Gaschromatographische Analyse des Produktspektrums von S. mutans aus Glucose.

In addition to other acids lactate was detected as prevailing end product in glucose containing broth of 8 S. mutans strains. The total acid amounts differed depending on the microbial origin. Further quantitative and qualitative differences existed between acidic products of the pH-stat controlled reaction with glucose as substrate and defined germ suspensions. S. mutans LM 7 showed the most strongly heterofermentative pathway.

Semi-purification of an immunosuppressor substance secreted by Streptococcus mutans that plays a role in the protection of the bacteria in the host.

Crude extracellular products of Streptococcus mutans (CEP-Sm) suppress the proliferative response to phytohaemagglutinin of human peripheral blood mononuclear cells and the primary immune response of C57BL/6 mice to sheep erythrocytes. This immunosuppressive effect favours the survival of the microorganism, and the bacteria lose the ability to secrete immunosuppressor substance if previously subcultured several times. Cells incubated with CEP-Sm and subsequently washed recover the ability to proliferate. Traces of CEP-Sm or to short a time of contact between CEP-Sm and the target immune system induced higher proliferative ratios or higher in vivo immune responses than controls, respectively. The proliferative values of cultures supplemented with CEP-Sm were parallel to the control values up to a certain time, after which they dropped abruptly. This drop is followed by a proliferation, and the higher the amount of CEP-Sm added to the cultures, the shorter the time until the proliferation. CEP-Sm was fractionated by means of ion exchange chromatography followed by double preparative isoelectrofocusing, ending in a subfraction of isoelectric point between 3.9 and 4.2, containing a heat-unstable material stainable by Coomassie blue but unstainable by periodic acid Schiff or methylene blue, and having a maximum optical density of 280 nm.