Silver nanoparticles as potential antibiofilm agents against Candida albicans, Candida tropicalis and Candida glabrata.

GALERA IVANA L, PÁEZ PAULINA L, PARAJE MARÍA G.

Congreso; Congreso conjunto SAMIGE-SAIB 2020; 2020

SAMIGE-SAIB

Infections caused bybiofilm-embedded pathogens decrease the efficacy of traditional treatments andincrease antimicrobial tolerance. In addition, most of the human bacterialinfections are biofilm-associated. Candidaalbicans is the yeast most frequently isolated in fungal infections,followed by Candida glabrata and Candida tropicalis. Biofilm formation isa complex process with different growth phases(early, intermediate, and maturation). Nanoparticles (NPs) are potentialcandidates to obtain an antifungal (ATF) activity, thus would preventing thefirst stages of fungal colonization and avoiding the subsequent formation ofbiofilms. The objective of this work was to evaluate the effect ofbiosynthesized silver NPs (AgNPs) against initial and mature in Candidaalbicans, Candida tropicalis and Candida glabrata biofilms.C. albicans SC5314, C. tropicalis NCPF3111, and C. glabrata ATCC 2001 werestudied. The minimum inhibitory concentration (MIC) and the minimum fungicidalconcentration (MFC) of AgNPs were determined by the microdilution methodaccording to Clinical & Laboratory Standards Institute M27-4thed. The inhibitory concentration of the biofilms (%I) was evaluated over theinitial stages of formation. The concentration of reduction of the biofilms (%R)was evaluated against the mature biofilms (48 h), being exposed toconcentrations of AgNPs (supraMIC, MIC and subMIC). Biofilmformation was achieved through the ability of microorganisms to adhere to wellsof flat-bottomed 96-wellmicroplates, and quantified by Crystal staining. The biofilmswere disrupted by sonication (40 kHz, 60 s) inorder to re-suspend and recover viablesessile cells and determined by plate counting (colony-forming units per mL, CFU mL-1). The same MIC and MFC value was found for AgNPs in C. albicans 3.7 x 10-2 pM, inC. tropicalis was 5.0 x 10-1pM and finally C. glabrata shown 1.2x 10-1 pM for AgNPs. The %I was 61 ± 8 (3.7 pM AgNPs) for C. albicans, 65 ± 3 (with 38.5 pM AgNPs)for C. tropicalis, 84 ± 4 (12.5 pM AgNPs)for C. glabrata. The %R was 53 ± 3(3.7 pM AgNPs) for C. albicans, 84 ±9 (38.5 pM AgNPs) for C. tropicalis,69 ± 9 (77 pM AgNPsfor C. glabrata. Exposure to AgNPs leads to reduction in microbial biomass andsurviving sessile cells, reduced by more than 10% in the three Candida species. This study demonstrated that AgNPs exerts anantibiofilm effect against several Candidaspecies, suggesting its potential application as an antibiofilm agent aloneor in combination with traditional antifungal agents.