Inibição in vitro da aderência de enteropatógenos pelo xilitol

Xylitol, a five-carbon polyalcohol, has several clinical applications such as the anti-adherent action on many bacteria. Currently,with the emergence of microorganisms resistant to conventional antibiotics, researches for new strategies are necessary, aimingat preventing and/or treating diseases caused by the presence of such pathogens. The present study aimed to evaluate xylitol’santimicrobial and anti-adherence activities on the strain Shigella flexneri ATCC 12022 and on the clinical strains (isolated frompatients) Shigella flexneri and Salmonella enterica serotype Typhimurium. In vitro, the antimicrobial and anti-adherent activitieswere tested using 0.5%, 2.5% and 5.0% xylitol. The slides of anti-adherent activity were analyzed by scanning electron microscopy(SEM). It was found that xylitol does not have antimicrobial properties on the strains tested. However, it was demonstrated, bySEM microphotographs, the inhibition of microbial adherence in slides treated with xylitol, and this is probably the mechanismof action of this compound. This study gives xylitol a greater added value, turning it into an appropriate biomolecule for useas an adjuvant therapeutic, alternative to the use of conventional antibiotics, for the treatment of recurrent infections of thegastrointestinal tract.O xilitol, um poli-álcool de cinco átomos de carbono, possui diversas aplicações clínicas, destacando-se a ação antiaderentesobre diversas bactérias. Com o surgimento de microorganismos resistentes aos antimicrobianos convencionais, torna-seessencial a intensificação de pesquisas de novas estratégias para se prevenirem e (ou) tratarem doenças ocasionadaspela presença desses patógenos. O presente trabalho teve como objetivo avaliar a atividade antimicrobiana e antiaderentedo xilitol sobre a cepa Shigella flexneri ATCC 12022 e as cepas clínicas (isoladas de pacientes) Shigella flexneri e Salmonellaenterica sorotipo Typhimurium. Foram realizados ensaios in vitro de atividade antimicrobiana e de atividade antiaderente,sendo, em ambos, o xilitol empregado nas concentrações de 0,5%; 2,5% e 5,0% (p/v). As lamínulas, usadas como corpos deprova no teste de atividade antiaderente, foram analisadas por microscopia eletrônica de varredura (MEV). Foi constatadoque o xilitol não possui propriedade antimicrobiana sobre as cepas testadas; no entanto, as microfotografias obtidas pelaMEV revelaram a inibição da aderência microbiana nas lamínulas tratadas com xilitol, sendo esse o provável mecanismode ação desse composto. Este trabalho confere ao xilitol um maior valor agregado, tornando-o uma biomolécula adequadapara ser usada como adjuvante terapêutico, alternativo ao uso dos antibióticos convencionais, para o tratamento deinfecções recorrentes do trato gastrintestinal

Revista de Ciências Médicas e Biológicas

Keywords: Xylitol – Bacterial adhesion – Gastrointestinal tract – Bacteria – Prevention and control.Abstract Xylitol, a five-carbon polyalcohol, has several clinical applications such as the anti-adherent action on many bacteria. Currently, with the emergence of microorganisms resistant to conventional antibiotics, researches for new strategies are necessary, aiming at preventing and/or treating diseases caused by the presence of such pathogens. The present study aimed to evaluate xylitol’s antimicrobial and anti-adherence activities on the strain Shigella flexneri ATCC 12022 and on the clinical strains (isolated from patients) Shigella flexneri and Salmonella enterica serotype Typhimurium. In vitro, the antimicrobial and anti-adherent activities were tested using 0.5%, 2.5% and 5.0% xylitol. The slides of anti-adherent activity were analyzed by scanning electron microscopy (SEM). It was found that xylitol does not have antimicrobial properties on the strains tested. However, it was demonstrated, by SEM microphotographs, the inhibition of microbial adherence in slides treated with xylitol, and this is probably the mechanism of action of this compound. This study gives xylitol a greater added value, turning it into an appropriate biomolecule for use as an adjuvant therapeutic, alternative to the use of conventional antibiotics, for the treatment of recurrent infections of the gastrointestinal tract.Salvado

In vitro inhibition of adhesion of Escherichia coli strains by Xylitol

The present study aimed to evaluate xylitol's antimicrobial and anti-adherence activities on Escherichia coli (ATCC 8739) and on another clinical strain enteropathogenic E. coli (EPEC). In vitro minimum inhibitory concentration (MIC) test and adhesion assays were performed using 0.5, 2.5 and 5.0% xylitol. It was found that xylitol did not have antimicrobial properties on these strains. The scanning electron microscopy (SEM) demonstrated that the slides treated with xylitol had a significant reduction in the number of bacilli and the inhibition of microbial adhesion was probably the xylitol's mechanism of action. Xylitol could be a possible alternative on the control of E. coli infections

Cellulase Production by Trichosporon laibachii

The ability of twenty-three yeast strains isolated from decayed wood and the fungus garden of attine ants to produce hemi- and cellulolytic hydrolases in a chemically defined medium was screened. Xylanase, β-glucosidase and cellulase activities were found in yeasts strains in the genera Cryptococcus, Trichosporon, Debaryomyces and Pichia. Among the isolated microorganisms, two strains of Trichosporon laibachii MG270406-1A14 strain showed higher cellulase titers. Several biochemical and physiological parameters were investigated for optimum cellulase production under submerged fermentation. Enzyme induction was also examined using different carbon and nitrogen sources. Cellobiose and ammonium sulphate were found best carbon (C) and nitrogen (N) sources to enhance carboxymethylcellulase production. A 22- factorial design with center points was developed to optimize enzyme production, and data analysed by the response surface method. Maximal enzyme titres (0.3 U mL-1) occurred at initial pH 6.0, C/N ratio 9.0 and 5 days. DOI: http://dx.doi.org/10.17807/orbital.v9i4.1024</p