Size-dependent activity of silver nanoparticles on the morphological switch and biofilm formation of opportunistic pathogenic yeasts

BMC Microbiology

article

Szerencsés, Bettina¹  Vágvölgyi, Csaba¹  Kónya, Zoltán²  Pfeiffer, Ilona¹  Kiricsi, Mónika⁴  Igaz, Nóra⁴  Tóbiás, Ákos⁴  Prucsi, Zsombor⁴  Rónavári, Andrea²  Bélteky, Péter²  Madarász, Dániel²  Papp, Csaba¹  Makra, Ildikó⁴ 

[1] Department of Microbiology, University of Szeged;Department of Applied and Environmental Chemistry, University of Szeged;HAS-USZ Reaction Kinetics and Surface Chemistry Research Group;Department of Biochemistry and Molecular Biology, Faculty of Science and Informatics, University of Szeged

关键词: Pathogenic yeasts;    Silver nanoparticles;    Morphological switch;    Biofilm formation;    Human keratinocytes;    Toxicity;   

DOI  :  10.1186/s12866-020-01858-9

学科分类：放射科、核医学、医学影像

来源: BioMed Central

【 摘 要 】

Dimorphism and biofilm formation are important virulence factors of some opportunistic human pathogenic yeasts. Such species commensally colonize skin or mucosal surfaces generally in yeast form, but under particular circumstances, convert into virulent hyphae and disseminate internal organs or cause mucocutaneous infections. The yeast-to-hypha shape-conversion promotes the development of a biofilm, a thick extracellular matrix with sessile cells within. The biofilm is capable to prevent the penetration of antifungal drugs, rendering the surviving biofilm-resident cells intrinsic sources of recurrent infections. The aim of this study was to evaluate the ability of silver nanoparticles (AgNPs) to attenuate the morphological switch and biofilm formation of several opportunistic pathogenic yeasts and to determine whether this feature depends on the nanoparticle size. AgNPs in three different sizes were prepared by chemical reduction approach and characterized by transmission electron microscopy, ultraviolet–visible spectroscopy and dynamic light scattering. The antifungal activity was evaluated by the microdilution method, the inhibitory capacity on biofilm formation and the biofilm degradation ability of differently sized AgNPs was assessed by viability assay. The morphological state of opportunistic pathogenic yeast cells in monoculture and in co-culture with human keratinocytes in the presence of AgNPs was examined by flow cytometry and scanning electron microscopy. All the three AgNPs inhibited the growth of the examined opportunistic pathogenic yeasts, nevertheless, AgNPs with the smallest diameter exhibited the most prominent toxic activities. AgNPs attenuated the biofilm formation in a nanoparticle size-dependent manner; however, their biofilm destruction capacity was negligible. AgNPs with the smallest size exerted the most significant effect on suppressing the morphological change of pathogens in monoculture as well as in a co-culture with keratinocytes. Our results confirm that AgNPs are capable to hinder yeast-to-hypha morphological conversion and biofilm formation of opportunistic pathogens and this biological effect of AgNPs is size-dependent.

【 授权许可】

CC BY|CC0