Analysis of the antimicrobial and anti-caries effects of TiF4 varnish under microcosm biofilm formed on enamel

Abstract Titanium tetrafluoride (TiF4) is known for interacting with enamel reducing demineralization. However, no information is available about its potential antimicrobial effect. Objectives This study evaluated the antimicrobial and anti-caries potential of TiF4 varnish compared to NaF varnish, chlorhexidine gel (positive control), placebo varnish and untreated (negative controls) using a dental microcosm biofilm model. Material and Methods A microcosm biofilm was produced on bovine enamel previously treated with the varnishes, using inoculum from human saliva mixed with McBain saliva, under 0.2% sucrose exposure, for 14 days. All experiments were performed in biological triplicate (n=4/group in each experiment). Factors evaluated were: bacterial viability (% dead and live bacteria); CFU counting (log10 CFU/mL); and enamel demineralization (transverse microradiography - TMR). Data were analysed using ANOVA/Tukey's test or Kruskal-Wallis/Dunn's test (p<0.05). Results Only chlorhexidine significantly increased the number of dead bacteria (68.8±13.1% dead bacteria) compared to untreated control (48.9±16.1% dead bacteria). No treatment reduced the CFU counting (total microorganism and total streptococci) compared to the negative controls. Only TiF4 was able to reduce enamel demineralization (ΔZ 1110.7±803.2 vol% μm) compared to both negative controls (untreated: ΔZ 4455.3±1176.4 vol% μm). Conclusions TiF4 varnish has no relevant antimicrobial effect. Nevertheless, TiF4 varnish was effective in reducing enamel demineralization under this model.

Cymbopogon citratus essential oil: effect on polymicrobial caries-related biofilm with low cytotoxicity

Abstract The objective of this study was to evaluate the effects of Cymbopogon citratus essential oil and its main compound (citral) against primary dental colonizers and caries-related species. Chemical characterization of the essential oil was performed by gas chromatography/mass spectroscopy (GC/MS), and the main compound was determined. Antimicrobial activity was tested against Actinomyces naeslundii, Lactobacillus acidophilus, S. gordonii, S. mitis, S. mutans, S. sanguinis and S. sobrinus. Minimum inhibitory and bactericide concentrations were determined by broth microdilution assay for streptococci and lactobacilli reference, and for clinical strains. The effect of the essential oil on bacterial adhesion and biofilm formation/disruption was investigated. Negative (without treatment) and positive controls (chlorhexidine) were used. The effect of citral on preformed biofilm was also tested using the same methodology. Monospecies and microcosm biofilms were tested. ANOVA or Kruskal-Wallis tests were used (α=0.05). Cytotoxicity of the essential oil to human keratinocytes was performed by MTT assay. GC/MS demonstrated one major component (citral). The essential oil showed an inhibitory effect on all tested bacterial species, including S. mutans and L. acidophilus. Essential oil of C. citratus (10X MIC) reduced the number of viable cells of lactobacilli and streptococci biofilms (p < 0.05). The essential oil inhibited adhesion of caries-related polymicrobial biofilm to dental enamel (p < 0.01). Citral significantly reduced the number of viable cells of streptococci biofilm (p < 0.001). The essential oil showed low cytotoxicity to human keratinocytes. Based on these findings, this study can contribute to the development of new formulations for products like mouthwash, against dental biofilms.

A study on ß-defensin-2 and histatin-5 as a diagnostic marker of early childhood caries progression

BACKGROUND: Recently, a continuous growth of interest has been observed in antimicrobial peptides (AMPs) in the light of an alarming increase in resistance of bacteria and fungi against antibiotics. AMPs are used as biomarkers in diagnosis and monitoring of oral cavity pathologies. Therefore, the determination of specific protein profiles in children diagnosed with early childhood caries (ECC) might be a basis for effective screening tests and specialized examinations which may enable progression of disease. METHODS: The objective of the studies was to determine the role of histatin-5 and ß-defensing-2 as a diagnostic marker of early childhood caries progression. In this work, results of concentration determination of two salivary proteins (histatin-5 and ß-defensin-2) were presented. In addition, bacterial profiles from dental plaque in various stages of ECC and control were marked. The assessment of alteration in the concentration of these two proteins in a study group of children with various stages of ECC and a control group consisting of children with no symptoms was performed by enzyme-linked immunosorbent assays. RESULTS: The statistical analysis showed a significant increase in the concentration of histatin-5 and ß-defensin-2 in the study group compared to the control group and correlated with the progression of the disease. CONCLUSIONS: The confirmation of concentration changes in these proteins during the progression of dental caries may discover valuable disease progression biomarkers.

Survey of canine tick-borne diseases in Lábrea, Brazilian Amazon: ‘accidental’ findings of Dirofilaria immitis infection / Pesquisa de agentes transmitidos por carrapatos em cães de Lábrea, Amazonas: achados “acidentais” de Dirofilaria immitis

Blood samples were collected from 99 domestic dogs from the urban and rural areas of the Lábrea municipality, state of Amazonas, Brazil. Canine serum samples were tested by immunofluorescence assay against Rickettsia spp., which revealed that only 3.0% (1/33) and 7.6% (5/66) of the dogs from urban and rural areas, respectively, reacted positively to at least one Rickettsia species. DNA was extracted from canine blood and tested by a battery of PCR assays targeting protozoa of the genera Babesia and Hepatozoon, and bacteria of the genera Rickettsia and Ehrlichia and family Anaplasmataceae. All samples were negative in the PCR assays targeting the genera Babesia, Hepatozoon, Ehrlichia and Rickettsia. For Anaplasmataceae, 3% (1/33) and 39.4% (26/66) of the urban and rural dogs, respectively, yielded amplicons that generated DNA sequences 100% identical to the corresponding sequence of Wolbachia endosymbiont of Dirofilaria immitis. Because of these results, all canine DNA samples were further tested in a PCR assay targeting filarial nematodes, which was positive for 18.2% (6/33) and 57.6% (38/66) urban and rural dogs, respectively. Filarial-PCR products generated DNA sequences 100% identical to D. immitis. While tick-borne infections were rare in Lábrea, D. immitis infection rates were among the highest reported in South America.

Amostras de sangue foram coletadas de 99 cães domésticos de áreas urbana e rural do município de Lábrea, estado do Amazonas. Soros caninos foram testados pela técnica de imunofluorescência indireta contra Rickettsia spp., resultando em apenas 3,0% (1/33) e 7,6% (5/66) de cães soropositivos nas áreas urbana e rural, respectivamente. DNA foi extraído do sangue canino e testado por diferentes protocolos da PCR para detecção de protozoários dos gêneros Babesia e Hepatozoon, e bactérias dos gêneros Rickettsia e Ehrlichia e da família Anaplasmataceae. Todas as amostras foram negativas nos protocolos de PCR para os gêneros Babesia, Hepatozoon, Ehrlichia e Rickettsia. Para Anaplasmataceae, 3% (1/33) e 39,4% (26/66) dos cães de áreas urbana e rural, respectivamente, geraram sequências de DNA 100% idênticas ao endosimbionte Wolbachia de Dirofilaria immitis. Posteriormente, as amostras foram testadas pela PCR para nematódeos filarídeos, resultando em 18,2% (6/33) e 57,6% (38/66) de amostras positivas nas áreas urbana e rural, respectivamente. Os produtos geraram sequências de DNA 100% idênticas a D. immitis. Em contraste com várias outras regiões do Brasil, infecções transmitidas por carrapatos foram raras em Lábrea. Por outro lado, as frequências de infecção por D. immitis estiveram entre as mais altas relatadas na América do Sul.

Influence of lingual bracket position on microbial and periodontal parameters in vivo

OBJECTIVE: Lingual orthodontics is becoming more popular in dental practice. The purpose of the present investigation was to compare plaque formation on teeth bonded with the same bracket onto buccal or lingual surface, with non-bonded control teeth, via an in vivo growth experiment over a 30-day period. MATERIAL AND METHODS: A randomized controlled trial with split-mouth design was set up enrolling 20 dental students. Within each subject sites with buccal and lingual brackets and control sites were followed. Clinical periodontal parameters (periodontal pocket depth: PPD; bleeding on probing: BOP) were recorded at baseline and on days 1, 7 and 30. Microbiological samples were taken from the brackets and the teeth on days 1, 7 and 30 to detect colony-forming units (CFU). Total CFU, streptococci CFU and anaerobe CFU were measured. RESULTS: No significant differences (P>0.05) were found between buccal and lingual brackets in terms of clinical periodontal parameters and microbiological values. Conclusion: Bracket position does not have significant impact on bacterial load and on periodontal parameters.

Microbial colonization in orthodontic mini-implants

Peri-implant inflammation contributes for loss of secondary stability of orthodontic mini-implants. The investigation of microbial colonization in this area would benefit its control, and consequently favor the long-term success of mini-implants. Therefore, the aim of this study was to determine the establishment and the evolution of microbial colonization process in orthodontic mini-implants for 3 months, since the time of their installation. One-hundred and fifty samples collected from 15 mini-implants were investigated from baseline up to 3 months. The biological material was obtained from peri-implant area using paper points. Nonspecific, Streptococcus spp, Lactobacillus casei and Candida spp colonizations were analyzed by cell growth methods. Porphyromonas gingivalis colonization was observed by 16S rDNA-directed polymerase chain reaction. Data from cell growth were submitted to the Wilcoxon sign rank test and results from molecular analysis were presented in a descriptive way. There was no significant difference in the microbial colonization among the examined time intervals, except for Streptococcus spp, between baseline and 24 h, which characterized the initial colonization in this time interval. Lactobacillus casei and Candida spp colonizations were insignificant. No Porphyromonas gingivalis was detected among the analyzed samples. The microbial colonization of mini-implants did not significantly change during the study. However, it should be monitored by orthodontists, since it is an important factor for mini-implants success.

A inflamação peri-implantar contribui para a perda da estabilidade secundária dos mini-implantes ortodônticos. A investigação da colonização microbiana desta área beneficiaria o seu controle e, consequentemente, favoreceria o sucesso dos mini-implantes a longo prazo. Portanto, o objetivo dos autores foi determinar o estabelecimento e evolução do processo de colonização microbiana em mini-implantes ortodônticos por três meses desde a instalação. Cento e cinquenta amostras coletadas de 15 mini-implantes foram investigadas desde o tempo inicial até 3 meses. O material biológico foi obtido da área peri-implantar com auxílio de cones de papel absorvente. As colonizações inespecíficas de Streptococcus spp, Lactobacillus casei e Candida spp foram analisadas por métodos de crescimento celular. A colonização por Porphyromonas gingivalis foi observada por meio da reação em cadeia da polimerase 16S rDNA. Os dados do crescimento celular foram submetidos ao teste de Wilcoxon sign rank e os resultados da biologia molecular foram apresentados de modo descritivo. Não houve diferença estatisticamente significante da colonização microbiana entre os intervalos de tempo avaliados, exceto para Streptococcus spp entre os tempos inicial e 24 h, o que caracterizou o início da colonização neste intervalo de tempo. As colonizações por Lactobacillus casei e Candida spp foram insignificantes. Não foi detectada a presença de Porphyromonas gingivalis nas amostras analisadas. A colonização microbiana nos mini-implantes não se alterou significativamente durante o estudo. No entanto, deve ser monitorada por ortodontistas, uma vez que é um fator importante para o sucesso dos mini-implantes.

Effect of a probiotic mixed culture on texture profile and sensory performance of Minas fresh cheese in comparison with the traditional products / Efeito de uma cultura probiótica mista sobre o perfil de textura e o desempenho sensorial de queijo Minas frescal, em comparação aos produtos tradicionais

The effect of a mixed probiotic culture on instrumental texture, and on sensorial and related properties of Minas fresh cheese during refrigerated storage was investigated. Three cheese-making trials were prepared: T1, with the traditional type O starter culture (Lactococcus lactis subsp. lactis + L. lactis subsp. cremoris), T2 with only lactic acid and T3, with lactic acid and the probiotic ABT culture (Lactobacillus acidophilus La-5 + Bifidobacterium animalisBb-12 + Streptococcus thermophilus). Instrumental texture profile analysis and related properties were monitored during storage for up to 21 days. Lb. acidophilus and B. animalis were present in high levels throughout storage of cheeses T3, above 6 log cfu.g-1, threshold required for probiotic activity, and stimulation of the La-5 growth was observed. Cheeses with added probiotic ABT culture, as well as those made adding lactic acid only, showed to be less brittle and with more favorable sensorial features, due to higher pH values. Results indicated that the use of probiotic ABT culture complementary to lactic acid for the purpose of substituting the type O (Lc. lactis subsp. lactis + Lc. lactis subsp. cremoris) culture, traditionally employed for Minas cheese production, is advantageous.

Efeito de uma cultura probiótica mista sobre o perfil de textura e o desempenho sensorial de queijo Minas frescal, em comparação aos produtos tradicionais. O presente trabalho investigou o efeito de uma cultura probiótica mista sobre a textura instrumental, as características sensoriais e as propriedades relacionadas de queijoMinas frescal durante seu armazenamento refrigerado. Três variáveis de elaboração de queijo Minas frescal foram estudadas: T1, empregando-se a cultura lática mesofílica tradicional tipo O (Lactococcus lactis subsp. lactis + L. lactis subsp. cremoris), T2,produzido somente com ácido lático e T3, empregando-se ácido lático e a cultura probiótica ABT (Lactobacillus acidophilus La-5 + Bifidobacterium animalis Bb-12 + Streptococcus thermophilus). O perfil de textura instrumental e as propriedades relacionadas foram monitorados durante 21 dias de armazenamento dos queijos. As populações de Lb. acidophilus e de B. animalis estiveram elevadas durante o armazenamento do queijo T3, acima de 6 log UFC.g-1,população mínima requerida para apresentar efeito probiótico, e foiobservado um estímulo da multiplicação de La-5. Os queijos produzidos com a cultura probiótica ABT, assim como aqueles somente com ácido lático, apresentaram-se menos frágeis e com atributos sensoriais mais favoráveis, devido ao pH mais elevado. Os resultados indicaram ser vantajoso o emprego da cultura probiótica ABT complementarmente ao ácido lático para o propósito de substituição da cultura tipo O (Lc. lactis subsp. lactis + Lc. lactis subsp. cremoris), tradicionalmenteempregada para a produção de queijo Minas frescal.

Evaluación de la actividad de cultivos probióticos sobre Listeria monocytogenes durante la producción y almacenamiento de yogur / Evaluation of the activity of probiotic cultures over Listeria monocytogenes during the production and storage of yogurt

The effect of probiotic cultures over Listeria monocytogenes during the production and storage of yogurt was evaluated. A yogurt mixture (10.6 per cent non-fat solid liquids, 3 per cent fat and 0.3 per cent gelatin) was prepared, homogenized and pasteurized. Yogurt was inoculated with 0, 10(2), 10(4) and 10(6) CFU/mL of L. monocytogenes and 0.02 per cent of traditional lactic culture YC 180 (Streptococcus thermophilus and Lactobacillus bulgaricus) and probiotic culture ABY-1 (Bifidobacterium longum, B. bifidum, B, infantis, Lactobacillus acidophilus, Streptococcus thermophilus y Lactobacillus delbrueckii subsp. bulgaricus). It was incubated for 3 h at 43 degrees C until pH reached an approximate value of 4.8, followed by refrigeration at 5 degrees C for 21 days. During fermentation, samples were taken every hour, and during storage every 3 days, analyzing pH and lactic, bifidobacteria and pathogen count for each time. It was demonstrated that there was no significant simple effect for the type of culture used (ABY-1 and YC 180) (p = 0.684) over the amount of L. monocytogenes present in yogurt during the fermentation and storage periods. The presence of bifidobacteria in the ABY-1 culture did not present a significant effect over L. monocytogenes. Neither the effect of time presented a significant effect over L. monocytogenes (p = 0.448). In this case, the ABY-1 and YC 180 cultures present a bacteriostatic effect over the pathogen. The probiotic cultures had a bacteriostatic but not bactericidal effect over L. monocytogenes. This is not related to the protective effect of these cultures in bowel, since in-vivo conditions favor the production of antimicrobial substances, such as bacteriocins that act over pathogens.

Consideraciones sobre el aislamiento en exudados vaginales de Streptococcus morbillorum / The isolation of Streptococcus morbillorum from vaginal exudates

De el estudio de 195 exudados vaginales enviados por el Servicio de Ginecologia de este hospital, durante el periodo 1988-1990, hemos seleccionado aquellos en los que el cultivo fue positivo para estreptococos, 58 (30 por ciento) de los cuales 26 (44.8 por ciento) correspondia a Streptococcus morbillorum, 9 (15.5 por ciento) a Gardnerella vaginalis, 5 (8.6 por ciento) a Enterococcus faecalis-durans, y a Streptococcus agalactiae, 3 (5.1 por ciento) a Streptococcus mitis y Styreptococcus milleri, 2 (3.4 por ciento) a Streptococcus bovis y Streptococcus cremoris y 1 (1.7 por ciento) a Streptococcus salivarius, Streptococcus equinus y Strptococcus sanguis II respectivamente. En todos los casos se observó antecedentes de actuacción medicoquirurjica en el tracto genital, y en el 52,8 por ciento de los casos fuè concomitante con el diagnostico clinico-micologico de candidiasis vaginal. La identificacción bacteriologica se realizó mediante el sistema API 20 STREP (sistema api bioMérieux GmbH, Nüttingen, Alemania) dando un patron tipico ("excelente identificacción") para el Streptococcus morbillorum.

Effect of growth medium on the production of streptolysin S

The effect of growth medium on the production of Streptolysin S [SLS] was examined. Two media, Brain heart infusion broth [BHIB] from different sources [Oxoid and Difco] were used for comparative studies of SLS. Two strains, strain C203S and strain 55903M were tested and it was observed that both strains under investigation grew to high cell density in either Oxoid or Difco BHIB but only cells grown in Difco culture medium gave high yields of SLS

The effect of subminimal inhibitory concentrations of penicillin on growth rate and haemolysin activity of group G Streptococcus

The influence of the subminimal inhibitory concentrations (1/3 and 1/4 of the MIC) of penicillin on growth rate and on haemolysin production of a strain of group G Streptococcus was studied. It was shown that 1/3 of the MIC almost completely inhibited the bacterial growth, but it was not able to inhibit haemolysin activity in the culture supernate. The generation time of bacteria grown in 1/4 of the MIC was approximately twice longer than that of the control culture. In all cultures, the haemolysin, after being produced (or liberated), reached a peak and decreased to low levels, which could suggest that group G Streptococcus produces some end products of metabolism that are able to inhibit haemolysin activity

Cones de prata: avaliaçäo in vitro do poder bacteriostático

Cones de prata de diversos calibres, empregados na obturaçäo de canais radiculares, tiveram sua açäo antimicrobiana testada, através da verificaçäo do halo de inibiçäo de crescimento de cepas de três diferentes bactérias (Staphylococcus aureus, Streptococcus viridans e Pseudomonas aeruginosa) em ágar nutritivo. Confirmou-se o poder bacteriostático. Consideraçöes sobre a utilizaçäo dos cones de prata como material obturador de canais radiculares foram feitas respaldadas em conflitante revisäo bibliográfica