Influence of glucose supplementation on biofilm formation of Candida albicans and Candida glabrata isolated from diabetic and non-diabetic individuals

Abstract

Objective: This study evaluated the effect of different glucose concentration on biofilm formation of Candida albicans and Candida glabrata strains isolated from diabetic and non-diabetic individuals.

Methods: The study was divided into two stages: (I) selection and identification of 48 C. albicans and C. glabrata strains by polymerase chain reaction followed by restriction fragment length polymorphism analysis (PCR/RFLP); (II) evaluation of biofilm formation by means of viability rates (colony-forming units), biofilm dry matter (mg) and biofilm-covered areas (μm²). Statistical comparisons were performed through nonparametric analysis of longitudinal data in factorial experiments with pairwise comparisons using Friedman Conover's test (α = 0.05).

Results: All the Candida spp. had their identifications confirmed by PCR/RFLP. C. albicans biofilm of strains from diabetic individuals cultivated in different glucose concentration showed higher viability rates than strains from non-diabetic individuals. No difference was observed on viability of C. glabrata biofilm. Regarding biofilm dry matter, C. albicans biofilm of strains from diabetic individuals cultivated in different glucose concentration showed lower amount in weight than strains from non-diabetic individuals. In C. glabrata strains, this result was only observed in biofilms cultivated with no glucose supplementation. With regard to biofilm-covered areas, only glucose supplementation and non-diabetic condition showed a positive effect on C. albicans biofilm development, and no condition affected C. glabrata biofilm formation.

Conclusion: The strain type (C. albicans and C. glabrata) isolated from diabetic and non-diabetic individuals influenced on biofilm formation, but glucose supplementation did not.

Keywords: Biofilm; Candidiasis; Diabetes mellitus; Glucose; Saliva.