Development and characterization of an innovative synbiotic fermented beverage based on vegetable soybean

Abstract Soymilk was produced from vegetable soybean and fermented by probiotics (Lactobacillus acidophilus La-5, Bifidobacterium animalis Bb-12) in co-culture with Streptococcus thermophilus. The composition of the fermented beverage and oligosaccharides content were determined. The effect of fructooligosaccharides and inulin on the fermentation time and viability of probiotic microorganisms throughout 28 days of storage at 5 °C were evaluated. The soymilk from vegetable soybeans was fermented in just 3.2 h, when pH reached 4.8. Fermentation reduced the contents of stachyose and raffinose in soymilk. Prebiotics had no effect on acidification rate and on viability of B. animalis and S. thermophilus in the fermented beverage. The viable counts of B. animalis Bb-12 remained above 108 CFU mL-1 in the fermented soymilk during 28 days of storage at 5 °C while L. acidophilus La-5 was decreased by 1 log CFU mL-1. The fermented soymilk from vegetable soybeans showed to be a good food matrix to deliver probiotic bacteria, as well as a soy product with a lower content of non-digestible oligosaccharides.

In vitro and in vivo evaluations of glass-ionomer cement containing chlorhexidine for Atraumatic Restorative Treatment

Abstract Objectives: Addition of chlorhexidine has enhanced the antimicrobial effect of glass ionomer cement (GIC) indicated to Atraumatic Restorative Treatment (ART); however, the impact of this mixture on the properties of these materials and on the longevity of restorations must be investigated. The aim of this study was to evaluate the effects of incorporating chlorhexidine (CHX) in the in vitro biological and chemical-mechanical properties of GIC and in vivo clinical/ microbiological follow-up of the ART with GIC containing or not CHX. Material and Methods: For in vitro studies, groups were divided into GIC, GIC with 1.25% CHX, and GIC with 2.5% CHX. Antimicrobial activity of GIC was analyzed using agar diffusion and anti-biofilm assays. Cytotoxic effects, compressive tensile strength, microhardness and fluoride (F) release were also evaluated. A randomized controlled trial was conducted on 36 children that received ART either with GIC or GIC with CHX. Saliva and biofilm were collected for mutans streptococci (MS) counts and the survival rate of restorations was checked after 7 days, 3 months and one year after ART. ANOVA/Tukey or Kruskal-Wallis/ Mann-Whitney tests were performed for in vitro tests and in vivo microbiological analysis. The Kaplan-Meier method and Log rank tests were applied to estimate survival percentages of restorations (p<0.05). Results: Incorporation of 1.25% and 2.5% CHX improved the antimicrobial/anti-biofilm activity of GIC, without affecting F release and mechanical characteristics, but 2.5% CHX was cytotoxic. Survival rate of restorations using GIC with 1.25% CHX was similar to GIC. A significant reduction of MS levels was observed for KM+CHX group in children saliva and biofilm 7 days after treatment. Conclusions: The incorporation of 1.25% CHX increased the in vitro antimicrobial activity, without changing chemical-mechanical properties of GIC and odontoblast-like cell viability. This combination improved the in vivo short-term microbiological effect without affecting clinical performance of ART restorations.

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.

Antimicrobial activity of ozone and NaF-chlorhexidine on early childhood caries

Abstract An early childhood carie (ECC) is an extremely destructive form of tooth decay. The aim of this study was to investigate the action of ozone (O3), and the association of sodium fluoride (NaF) with chlorhexidine (CHX) on bacteria related to ECC. Overnight culture of the bacteria was performed. On exponential phase the suspension was adjusted (101-108 CFU/mL). A drop (10μL) of each concentration of bacteria was applied on sheep blood agar plates and treated with O3 (2, 20, 200, and 2,000 ppm); after 18 hours, recovery analysis of CFU verified the reduction of bacterial activity. For NaF-CHX, sterile 96-well plates were prepared and divided into groups: G1 (150 µL TSB); G2 (20 µL of bacteria + 25 µL CHX + 25 µL NaF); and G3 (150 µL TSB + 20 µL of bacteria + 50 µL water). The plates were verified by analysis of the optical density (0, 12, 14, 16, and 18 hours). The data from O3 test were submitted to ANOVA and Tukey’s test (p < 0.05). For the data from NaF-CHX, the ANOVA 2-way and Bonferroni’s test (p < 0.05) were used. The number of CFU/mL showed death > 3log10 (99.9%) for all bacteria (ozone ≥ 20ppm), while the combination of NaF-CHX was more effective (p < 0.001) compared to each substance tested alone and the control group. The antimicrobial agents tested were able to inhibit all bacteria tested; O3 seemed to be a good alternative for controlling progression of carious lesions, while the association of NaF-CHX showed to be a good antimicrobial with easy and inexpensive application.

Effect of Lactobacillus acidophilus & epidermal growth factor on experimentally induced Clostridium difficile infection.

Background & objectives: Clostridium difficile-associated disease (CDAD) remains an important nosocomial ailment. Antimicrobial therapy used for CDAD gives inconsistent results. This experimental study was planned to investigate the beneficial effects of Lactobacillus acidophilus and epidermal growth factor (EGF) for CDAD management. Methods: Among 10 groups of BALB/c mice (6 in each), group 1 served as controls receiving no inoculum. Animals in groups 2-10 received C. difficile, those in groups 3, 6 and 9 received L. acidophilus and those in groups 4, 7 and 10 received EGF after C. difficile inoculation. Animals in groups 5-7 were pre-treated with ampicillin and those in groups 8-10 with lansoprazole prior to C. difficile. The animals were killed and investigated for colonisation by C. difficile and toxin production, myeloperoxidase (MPO) activity and histopathology. Results: Colonisation by C. difficile was found to be significantly different (P<0.001) in the various groups. C. difficile toxin titres and MPO activity were significantly lower in animals given L. acidophilus and EGF after ampicillin (groups 6 and 7) and lansoprazole (groups 9 and 10). The severity of acute inflammation was also significantly less (P<0.05) in caecal and colonic segments of animals in groups 6 and 7 compared to those in group 5. Although the severity of acute inflammation was less in the caecal and colonic segment of animals in groups 9 and 10, the reduction was not significant compared to group 8. Interpretation & conclusions: Our findings showed that the administration of L. acidophilus and EGF reduced the severity of C. difficile infection in the experimental animals.

Lactobacillus acidophilus Contributes to a Healthy Environment for Vaginal Epithelial Cells

Lactobacillus species in the female genital tract are thought to act as a barrier to infection. Several studies have demonstrated that lactobacilli can adhere to vaginal epithelial cells. However, little is known about how the adherence of lactobacilli to vaginal epithelial cells affects the acidity, cell viability, or proliferation of the lactobacilli themselves or those of vaginal epithelial cells. Lactobacillus acidophilus was co-cultured with immortalized human vaginal epithelial cells (MS74 cell line), and the growth of L. acidophilus and the acidity of the culture medium were measured. MS74 cell density and viability were also assessed by counting cell numbers and observing the cell attachment state. L. acidophilus showed exponential growth for the first 6 hr until 9 hr, and the pH was maintained close to 4.0-5.0 at 24 hr after culture, consistent with previous studies. The growth curve of L. acidophilus or the pH values were relatively unaffected by co-culture with MS74 cells, confirming that L. acidophilus maintains a low pH in the presence of MS74 cells. This co-culture model could therefore potentially be used to mimic vaginal conditions for future in vitro studies. On the other hand, MS74 cells co-cultured with L. acidophilus more firmly attached to the culture plate, and a higher number of cells were present compared to cells cultured in the absence of L. acidophilus. These results indicate that L. acidophilus increases MS74 cell proliferation and viability, suggesting that lactobacilli may contribute to the healthy environment for vaginal epithelial cells.

Comparación del crecimiento in vitro de Streptococcus mutans y Lactobacillus acidophilus con edulcorantes / In vitro comparison of the growth of Streptococcus mutans and Lactobacillus acidophilus with sweetening agents

Se realizó un estudio comparativo in vitro en el cual se analizó el crecimiento del Streptococcus mutans (S. mutans) y el Lactobacillus acidophilus (L. acidophilus) y las variaciones del pH, en un medio mínimo con edulcorantes (xilitol, sorbitol, aspartamo, sucralosa y sacarina sódica), en concentraciones del 1, 2, 3, 4 y 5 por ciento, durante 48 horas. El tipo de análisis aplicado a esta investigación fue la prueba de H. Kruskall Walls (p menor 0.01). Se encontró que el xilitol, el sorbitol y la sacarina sódica reducen el crecimiento in vitro del S. mutans y el L. acidophilus; en cambio, la sucralosa y el aspartamo son definitivamente edulcorantes que estimulan el crecimiento de S. mutans y L. acidophilus, representando mayor potencial cariogénico. Las observaciones del pH se mantuvieron constantes con todos los edulcorantes, con un valor de 6.0

Obtención de ácido láctico por fermentación con Lactobacillus delbrueckii bulgaricus / Obtention of lactic acid for fermentation with Lactobacillus delbruekii bulgaricus

El sustrato compuesto por sacarosa y suero de sangre de res, utilizado para la producción de ácido láctico, a través de Lactobacillus delbrueckii bulgaricus, ofrece al microorganismo los nutrientes necesarios para un buen crecimiento, bajo condiciones óptimas de pH(5,5 - 6,0) y temperatura de 48ºC. La velocidad máxima de crecimiento del microorganismo obtenido bajo estas condiciones es del orden del 0.068/h a un inóculo del 1,0 por ciento y disminuye hasta llegar a valores del orden de 0,024/h con inóculo 2,5 por ciento; lo contrario sucede con su crecimiento en masa celular o biomasa; esta aumenta a medida que se aumenta el porcentaje de inóculo, partiendo de rendimiento del 0,10 por ciento a inóculos del 1,0 por ciento hasta llegar a 0,65 por ciento con inóculo del 2,5 por ciento. La mayor producción que brinda este medio es del orden del 81,25 por ciento para una concentración de sacarosa de 60g/l y un inóculo del 2,5 por ciento; mientras que su mayor productividad fue de 0,57 g/lh a una concentración de sacarosa de 100g/l y un inóculo de 2,5 por ciento