Biofilm production in vitro on Candida spp strains recovered from genitourinary infections

Abstract

Background: Biofilms (BF) impacts on many aspects of our lives. The pathogenesis of diverse infections is related to the presence of originating microorganisms, including Candida yeast, which could play a role in the immunoapathogenesis, persistence and lack of response to treatment. The purpose of this work was to investigate the in vitro capacity for developing BF via Candida albicans (Ca), Candida troplicalis (Ct) and Candida glabrata sl (Cg) strains, obtained from genitourinary infections. Methods & Materials: 12 strains were studied from each species through the 96 well microtiter plate method on a flat background. They were planted and incubated on agar Sabouraud for 24hs at 37 • C. Afterwards, the inoculum were prepared and adjusted to a final concentration corresponding to a 0.5 Mc Farland scale. 100 ml of inoculum were placed in each well and 100 ml of Sabouraud broth was added at double concentration, on an overnight culture at 37 • C, recovering nutrients after 24hs. 12 wells were left apart as a target reaction. After that, the broth was removed, cleansing each well 3 times with PBS. Then they were fixed by methanol and proceeded to the coloring with safranin. After 15 minutes we cleaned 3 times to remove any coloring residue and the colored BP were eluted with acetic acid. These determinations were performed 3 times per strain, nonsimultaneous. 450 nm readings were performed, and the absence of BF was considered to the average absorbance white readings, acoording to Stepanovic. Results: Of the 12 Ca strains, 2 didn't develop any BF, 7 had a weak production and 3 on a moderate amount. For the 12 Cg, 1 didn't develop any BF, 2 had a moderate production and 9 had a strong BF. All Ct strains formed BF, 3 were moderate and 9 strong. Conclusion: We conclude from the results, that the use of this simple technique will allow us to evaluate the in vitro resistance to antifungal probiotics, prebiotics, natural compounds and chemicals on Candida strains, considering the BF formation as a pathogenesis factor related to failed treatment