Department of Molecular Microbiology, VIB, KU Leuven, Leuven, Belgium Laboratory of Molecular Cell Biology, Institute of Botany and Microbiology, KU Leuven, Kasteelpark Arenberg 31, B-3001 Heverlee-Leuven, Belgium.
Department of Materials Engineering, KU Leuven, Kasteelpark Arenberg 44, B-3001 Heverlee-Leuven, Belgium.
J Antimicrob Chemother. 2015 Mar;70(3):846-56. doi: 10.1093/jac/dku447. Epub 2014 Nov 17.
Biofilm studies have been mostly dedicated to the major human fungal pathogen Candida albicans, whereas much less is known about this virulence factor in Candida glabrata, certainly under in vivo conditions. This study provides a deeper understanding of the biofilm development of C. glabrata, its architecture and susceptibility profile to fluconazole and echinocandins.
In vitro and in vivo C. glabrata biofilms were developed inside serum-coated triple-lumen catheters placed in 24-well polystyrene plates or implanted subcutaneously in the back of a rat, respectively. Scanning electron microscopy and confocal scanning laser microscopy were used to visualize the biofilm architecture. Quantitative real-time PCR was used to demonstrate the expression profile of EPA1, EPA3, EPA6 and AWP1-AWP7 during in vivo biofilm formation.
Mature biofilms were observed within the first 48 h and the amount of biofilm reached its maximum by 6 days. Architecturally, mature C. glabrata biofilms consisted of a thick network of yeast cells embedded in an extracellular matrix. Moreover, in vivo biofilms were susceptible to echinocandin drugs, whereas fluconazole remained ineffective. Gene expression profiling revealed that EPA3, EPA6, AWP2, AWP3 and AWP5 were up-regulated in in vivo biofilms compared with in vitro biofilms.
C. glabrata is a unique microorganism, which, despite the lack of transition to the hyphal form, formed thick biofilms inside foreign bodies in vivo. To our knowledge, this is the first study that has described in vivo C. glabrata biofilm development and its architectural changes in detail and provides an insight into the susceptibility profile, as well as the gene expression machinery, of biofilm-associated infections.
生物膜研究主要致力于人类主要真菌病原体白色念珠菌，而对光滑念珠菌这种毒力因子的了解要少得多，特别是在体内条件下。本研究提供了对光滑念珠菌生物膜形成、结构及其对氟康唑和棘白菌素敏感性的更深入了解。
分别在涂有血清的三腔导管内和在大鼠背部皮下植入的 24 孔聚苯乙烯板中体外和体内培养光滑念珠菌生物膜。扫描电子显微镜和共聚焦扫描激光显微镜用于观察生物膜结构。定量实时 PCR 用于证明 EPA1、EPA3、EPA6 和 AWP1-AWP7 在体内生物膜形成过程中的表达谱。
在最初的 48 小时内观察到成熟的生物膜，并且在第 6 天达到生物膜的最大量。在结构上，成熟的光滑念珠菌生物膜由嵌入细胞外基质中的厚酵母细胞网络组成。此外，体内生物膜对棘白菌素类药物敏感，而氟康唑仍然无效。基因表达谱分析显示，与体外生物膜相比，体内生物膜中 EPA3、EPA6、AWP2、AWP3 和 AWP5 的表达上调。
尽管光滑念珠菌缺乏向菌丝形式的转变，但它在体内异物中形成了厚厚的生物膜，这使其成为一种独特的微生物。据我们所知，这是第一项详细描述体内光滑念珠菌生物膜形成及其结构变化的研究，并深入了解生物膜相关感染的易感性谱以及基因表达机制。
