Atividade antimicrobiana de probióticos comerciais frente à enterobactérias prejudiciais ao homem

Abstract

Probiotics are supplements of living microorganisms that confer benefits to the host. As a result of some change in the intestinal microbiota, probiotics are prescribed in an attempt to reverse imbalances caused by possible opportunistic pathogenic bacteria. Thus, in order to know the potential of probiotics marketed in pharmacy, Saccharomyces cerevisiae (Floratil®) Saccharomyces boulardii(Florax®) Bacillus cereus(Biovicerin®) and Bacillus clausii(Enterogermina®) was quantified in solid medium and compare with the manufacturer, to test the antimicrobial activity of probiotics individually, as well as the association of these with Lactobacillussp. (Isis ® fermented milk) in solid and liquid media against enterobacteria. The colony forming units count (UFC / mL) was performed by serial dilution and sowing in Petri dishes with Nutrient Agar (for bacteria) and Sabouraud Agar (for yeasts). The Petri dishes were incubated at 30 ° C for 24 and 48 hours for the growth of bacteria and yeasts and then quantification of the plaques that presented between 20 and 200 CFU / mL. The antimicrobial activity was evaluated from the growth of probiotics individually and their association with Lactobacillussp. in solid medium by the agar diffusion technique, which consisted in inoculating 15 mm discs onthe surface of the previously seeded Mueller Hinton agar, Escherichia coli, Salmonellasp. Klebsiellasp. and Citrobacter freundii. Antimicrobial activity of probiotic growth in liquid medium was also performed, with each probiotic extract in Mueller Hinton agar with the previously seeded bacteria. In addition, probiotic activity was also increased by the association of these with Lactobacillus sp. in liquid medium, in which, after their growth, each partner underwent two treatment conditions by placing 5 mL of the probiotic in two tubes of Falcon (15 mL) where one received ethanol (polar solvent) and the other 5 mL of acetate (apolar solvent) submitted to three hours under stirring, then 20 μl of the supernatant were pipetted from the tubes and inoculated onto the discs which were on the surface of the Mueller Hinton agar with the previously seeded test bacteria. All tests were performed in riplicates, incubated at 37ºC, with results obtained after 24 hours by the formation or not of the inhibition halo. There was no antimicrobial activity against the enterobacteria tested. Several factors should be taken into account when dealing with the metabolic action of microorganisms, under the conditions, in vitro, tested in this work.