Inhibitory activity of root canal irrigants against Candida albicans, Enterococcus faecalis and Staphylococcus aureus

The present study evaluated the antimicrobial activity of three root canal irrigants against Enterococcus faecalis, Candida albicans, and Staphylococcus aureus. These microorganisms were incubated in the presence of citric acid (6 and 10 percent), EDTA (17 percent), and NaOCl (0.5, 1.0, 2.5, and 5.25 percent). Agar diffusion tests were performed and redox indicator resazurin was used to evaluate the inhibitory effect of the irrigants on the metabolic activity of these microorganisms. The mean diameters of the inhibition zones for the C. albicans cultures were 11.6 mm (17 percent EDTA), 5.5 mm (0.5 percent NaOCl), 12.9 mm (1 percent NaOCl), 22.1 mm (2.5 percent NaOCl), and 28.5 mm (5.25 percent NaOCl). The mean diameters of the inhibition zones for E. faecalis were 2.8 mm (1 percent NaOCl), 5.4 mm (2.5 percent NaOCl), and 8.3 mm (5.25 percent NaOCl). For S. aureus, the mean values were 8.0 mm (17 percent EDTA), 3.0 mm (1 percent NaOCl), 8.8 mm (2.5 percent NaOCl), and 10.0 mm (5.25 percent NaOCl). Most of the irrigant solutions presented effective antimicrobial activity against C. albicans. A high inhibitory effect on the metabolic activity of E. faecalis was detected when the microorganisms were incubated with 17 percent EDTA. The same result was reached when S. aureus was incubated in the presence of > 2.5 percent NaOCl. Altogether, these results indicate that 2.5 percent and 5.25 percent NaOCl are microbicides against S. aureus while 0.5 percent and 1 percent NaOCl are only microbiostatic against the tested bacteria. The 6 percent and 10 percent citric acid as well as 17 percent EDTA did not affect the viability of any of the assayed microorganisms.

Atividade antifúngica da clorexidina em biofilmes de Candida spp / Antifungal activity of chlorhexidine on Candida spp. biofilm

Candidíase oral é a infecção oportunista mais comum em pacientes imunocomprometidos, sendo a clorexidina um importante antimicrobiano auxiliar no seu tratamento. O objetivo do presente estudo foi avaliar o efeito antifúngico de diferentes soluções de clorexidina (Periogard®, NoPlak Max®, Noplak®, Perioxidin®, Clorexidina 0.06%, Paradontax® e Clorexidina 1%) sobre biofilmes artificiais de Candida spp.: C. albicans (ATCC36801); C. parapsilosis (ATCC22019); C. krusei (ATCC6258); C. glabrata (ATCC2001) e C. tropicalis (ATCC750). As cepas foram cultivadas em meio de cultura BHI ágar sobre fragmentos de esmalte bovino por 72 horas a 37 °C. Após o crescimento, cada fragmento de esmalte bovino foi imerso nas diferentes soluções de Clorexidina por 3 minutos. Nistatina e solução salina foram utilizadas como controle negativo e positivo, respectivamente. Para remoção das células não aderidas, os fragmentos foram então imersos em solução salina por 10 minutos e agitados em vortex. Alíquotas de 100 µL foram inoculadas em placas contendo BHI ágar por 24 horas a 37 °C para contagem de unidades formadoras de colônias (UFC). Observamos que o número de UFC de C. albicans e C. parapsilosis, apresentou um percentual de redução variando de 79 a 99% quando do uso das diferentes soluções (p < 0,001), o mesmo não foi observado para o NoPlak Max® (2,94 e 1,3%, respectivamente); Para C. krusei e C. glabrata, a solução menos efetiva foi a Nistatina (23 e 3,4%, respectivamente) enquanto que para C. tropicalis, todas as soluções apresentaram um alto percentual de redução (99 a 100%). As soluções de clorexidina foram capazes de reduzir significativamente o número de UFC provenientes de biofilme de Candida spp. in vitro.

Oral candidiasis is the most common opportunistic infection in immunocompromised patients and chlorhexidine is an important antimicrobial for its treatment. The antifungal effect of different CHX solutions (Periogard®, NoPlak Max®, Noplak®, Perioxidin®, Chlorhexidine 0.06%, Paradontax® and Chlorhexidine 1%) was evaluated on artificial biofilms of Candida spps: C. albicans (ATCC36801), C. parapsilosis (ATCC22019), C. krusei (ATCC6258), C. glabrata (ATCC2001) and Candida tropicalis (ATCC750). The strains were grown, in a BHI agar medium on bovine teeth enamel for 72 hours at 37 °C. After growth, the fragments were immersed in the CHX solutions for 3 minutes. Nystatin and saline solutions were used as positive and negative controls respectively. To remove the non-adhered cells, the fragments were inoculated in saline solution for 10 minutes, transferred to Falcon tubes containing saline solution and mixed in a vortex. Aliquots of 100 µL were inoculated on BHI agar for 24 hours at 37 °C to count the number of colony forming units (CFU). We observed that the number of (CFU) of C. albicans and C. parapsilosis, showed a reduction rate ranging from 79 to 99% with the use of different solutions (p < 0.001), except for NoPlak Max® (2.94 and 1.3%, respectively). For C. krusei and C. glabrata, nystatin was the least effective solution (23 and 3.4%, respectively); and for C. tropicalis, all the substances presented a high reduction percentage (99-100%). The chlorhexidine solutions were able to reduce the colony forming units of Candida biofilm.

Avaliacao in vitro da microdureza de cimentos de ionomero de vidro modificados por resina submetidos a biofilme de Candida albicans / In vitro evaluation of microhardness of resin-modifi ed glass ionomer cements subjected to a candida albicans biofilm

Objetivo: Analisar in vitro a influencia da presenca de um biofilme de Candida albicans na microdureza superficial de duas marcas de cimentos de ionomero de vidro modificados por resina encontrados no mercado, o Vitremer© e o Vitro Fill© LC. Metodo: Nove amostras de cada material foram confeccionadas utilizando-se moldes de plasticos, previamente padronizados. Os nove especimes de cada marca foram divididos em tresgrupos: G1 solucao salina; G2 BHI liquido sem C. albicans; G3 suspensao celular com 105 de leveduras/mL em BHI liquido e a inducao da formacao de biofilme ocorreu apos incubacao das placas a 37§C por 48 horas. Os especimes foram esterilizados atraves de oxido de etileno. Foi avaliada a microdureza Knoop (50g, 15s). Os resultados foram submeti dos a Analise de Variancia (ANOVA) e teste de Tukey (5%). Resultados: Os grupos G1 e G2 obtiveram valores medios de dureza (KHN) maiores que G3 para ambos os materiais testados. Comparando os grupos G2 e G3, os especimes de G3 apresentaram menor resistencia as indentacoes. Conclusao: Nas condicoes do estudo in vitro, o biofilme de Candida albicans apresentou potencial de reduzir a dureza superficial de dois ionomeros de vidro modificados por resina encontrados no mercado (Vitremer© e Vitro Fill LC©).

Objective: To assess in vitro the influence of the presence of a Candida albicans biofilm on the surface microhardness of two commercial brands of resin-modified glass ionomer cements, Vitremer© and Vitro Fill© LC. Method: Nine samples of each material were fabricated using standardized plastic molds. The nine specimens of each brand were assigned to three groups: G1: saline; G2: BHI broth without C. albicans; G3: cell suspension with 105 yeasts/mL in BHI broth. Induction of biofilm formation occurred after incubation of the plates at 37§C for 48 hours and the specimens were sterilized with ethylene oxide. Knoop microhardness was measured (50 g, 15 s). Data were subjected to ANOVA and Tukey test at 5% significance level. Results: G1 and G2 presented higher mean hardness values (KHN) than G3 for both tested materials. Comparing G2 and G3, G3?s specimens presented lower resistance to theindentations. Conclusion: Under the conditions of this in vitro study, the Candida albicans biofilm reduced the surface hardness of two commercially available resin-modified glass ionomer cements (Vitremer© and Vitro Fill LC©).

Effect of sphingosine and phorbol-12-myristate-13-acetate on the growth and dimethylsulfoxide-induced differentiation in the insect trypanosomatid Herpetomonas samuelpessoai

We investigated the effect of two modulators of protein kinase C, sphingosine and phorbol-12-myristate-13-acetate (PMA), on the growth and dimethylsulfoxide (DMSO)-induced differentiation in Herpetomonas samuelpessoai. Sphingosine did not stimulate the transformation of undifferentiated-promastigotes in differentiated-paramastigotes. PMA alone or in association with DMSO increased the number of paramastigotes in comparison to control cells. DMSO inhibited the parasite growth (35 percent) and several unusual morphological features resembling aberrant cell division were observed. Sphingosine did not significantly reduce the growth in contrast to PMA. Collectively, our results demonstrated that the reduction of the proliferation translates in an increase of the differentiation rate in the insect trypanosomatid H. samuelpessoai.