KTCF20: a killer agent against Candida

BULACIOS GA; BELLOMIO A; FERNÁNDEZ DE ULLIVARRI M

Córdoba

Congreso; LII Reunión Anual Sociedad Argentina de Investigación en Bioquímica y Biología Molecular; 2016

SAIB

p { margin-bottom: 0.25cm; line-height: 120%; }a:link { }Killer yeasts areable to produce proteins or glycoproteins with antimicrobial activityknown as killer toxins, and they can be used as biocontrol agentsagainst pathogens yeasts. In this study we evaluated the biocontrolpotential of killer toxins over clinical isolates of pathogenicstrains of Candida spp. A set of 15 killer yeasts was used to performa qualitative inhibition assay over lawns of 6 Candida isolates inYPD agar pH 4.5. Growth inhibition in W. anomalus Cf20 cell-freesupernatant (CFS, 2×104aU/ml), was studied at different temperaturesand NaCl concentrations. Heat-inactivated CFS (100 ºC, 15 min) wasused as control. OD600 and cell viability were measured to calculateinhibition. Fluorescence microscopy of pathogenic strains wasperformed after incubation for 16 h at 20 ºC in CFS+NaCl 1% andlive/dead staining using SYTO9 and PI as fluorescent probes. W.anomalus Cf20 was selected as the most active killer strain, while C.albicans 78 and C. tropicalis FBUNT3 were the most sensitive strains.CFS produced 74 and 80% inhibition of both strains, respectively, at20 ºC and NaCl 1%. Fluorescence microscopy and viability studiesrevealed that CFS did not killed sensitive cells. CFS was able tohighly inhibit the growth of the studied strains with fungistaticeffects. Higher concentrations should be tested to evaluate if afungicidal effect is achieved.