Development and characterization of an in vivo central venous catheter Candida albicans biofilm model
Development and characterization of an in vivo central venous catheter Candida albicans biofilm model
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DOI：
10.1128/iai.72.10.6023-6031.2004
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发表时间：
2004-10-01
影响因子：
3.1
通讯作者：
Pitula, A
中科院分区：
文献类型：
--
作者：
Andes, D;Nett, J;Pitula, A
生物膜代表了微生物的生态位，在那里它们受到宿主免疫系统和抗微生物疗法的保护。生物膜生长作为临床感染的一个日益增长的来源。念珠菌感染由于其持久性和相关的耐药性而难以管理。在生物膜研究中进行的观察通常限于体外模型。使用大鼠中心静脉导管模型，我们的特点是在体内白色念珠菌生物膜的发展。时程定量培养显示，在发育的前24小时，活细胞的负荷逐渐增加。荧光和扫描电子显微镜显示双层结构。在导管表面附近，酵母细胞密集地嵌入细胞外基质中。邻近导管腔的层密度较低。生物膜的最外表面包含酵母和菌丝形式，并且它们嵌入的细胞外材料呈现纤维状。这些结构特征在许多方面与体外模型中描述的结构特征相似。然而，扫描电子显微镜也显示宿主细胞嵌入生物膜基质内。药物敏感性通过使用两种测定法确定，并证明了生物膜相关的耐药表型。第一个试验证明了在超MIC抗真菌药物浓度存在下细胞的持续生长。第二个试验表明，从生物膜结构中去除后，生物膜生长的细胞的易感性降低。最后，该模型为研究与体内生物膜生长相关的差异基因表达提供了足够的核酸材料。两个氟康唑外排泵，CDR1和CDR2，在体内生物膜相关细胞中上调。最重要的是，所描述的研究为进一步研究C.白念珠菌生物膜生物学和耐药性。此外，该模型提供了一种研究新型药物疗法和器械技术的方法，旨在控制生物膜相关感染。
Biofilms represent a niche for microorganisms where they are protected from both the host immune system and antimicrobial therapies. Biofilm growth serves as an increasing source of clinical infections. Candida infections are difficult to manage due to their persistent nature and associated drug resistance. Observations made in biofilm research have generally been limited to in vitro models. Using a rat central venous catheter model, we characterized in vivo Candida albicans biofilm development. Time-course quantitative culture demonstrated a progressive increase in the burden of viable cells for the first 24 h of development. Fluorescence and scanning electron microscopy revealed a bilayered architecture. Adjacent to the catheter surface, yeast cells were densely embedded in an extracellular matrix. The layer adjacent to the catheter lumen was less dense. The outermost surface of the biofilm contained both yeast and hyphal forms, and the extracellular material in which they were embedded appeared fibrous. These architectural features were similar in many respects to those described for in vitro models. However, scanning electron microscopy also revealed host cells embedded within the biofilm matrix. Drug susceptibility was determined by using two assays and demonstrated a biofilm-associated drug resistance phenotype. The first assay demonstrated continued growth of cells in the presence of supra-MIC antifungal drug concentrations. The second assay demonstrated reduced susceptibility of biofilm-grown cells following removal from the biofilm structure. Lastly, the model provided sufficient nucleic material for study of differential gene expression associated with in vivo biofilm growth. Two fluconazole efflux pumps, CDR1 and CDR2, were upregulated in the in vivo biofilm-associated cells. Most importantly, the studies described provide a model for further investigation into the molecular mechanisms of C. albicans biofilm biology and drug resistance. In addition, the model provides a means to study novel drug therapies and device technologies targeted to the control of biofilm-associated infections.