Microbiology ：用细菌来对付真菌

cao1976

原贴由wwwkkk83发表于 2010-5-9 10:24


爱尔兰科学家在5月出版的《微生物学》上撰文指出，一种能与酵母菌进行沟通的细菌可以抑制对药物耐受酵母菌的感染。这项研究为预防与医学植入有关的医院获得性感染迈出了战略性的一步。

爱尔兰科克大学的研究人员对绿脓杆菌和白色念珠菌之间的相互影响进行了研究。绿脓杆菌与严重烧伤所引起的感染有关，而白色念珠菌可以在诸如一些导管的塑料表面上生长。尽管这两种微生物非常常见，而且正常情况下对健康人也没有危害，但可以造成免疫功能低下者严重的感染。研究人员发现，绿脓杆菌所产生的一种分子能阻止白色念珠菌在硅胶导管表面的聚集生长。有趣的是，这两种微生物之间的相互作用不是依赖于叫做“群体感应”的细菌通信系统。

白色念珠菌是最常见的医院获得性感染微生物，它可以通过黏附在植入人体的塑料表面而引起疾病。这些塑料包括，导管、心脏装置和人工关节等。生物膜的形成是白色念珠菌感染的关键，同时也存在一个问题，因为生物膜常常会对治疗它们的药物产生耐受。领导这项研究的约翰莫里西博士说，“白色念珠菌可以引起敏感患者严重的深部感染，而且经常会发现它们以生物膜形式存在。因此，了解生物膜的形成过程以及如何去控制它非常重要。”

莫里西认为他的这项研究很有临床意义。“如果我们能探索到一种与绿脓杆菌同样的抑制方法，我们就能设计一种作为抗生素的药物，在生物膜形成后驱散它们，或者作为塑料表面的添加剂防止生物膜在医疗植入体上的形成。”他说。“下一步研究就是要找到绿脓杆菌所产生的这种化学物质是什么，以及这种物质在白色念珠菌上的作用靶点，这样我们就能知道开发一种用于临床的药物是否可行
原文出处：Microbiology DOI：10.1099/mic.0.037549-0

Pseudomonas aeruginosa secreted factors impair biofilm development in Candida albicansLucy J. Holcombe1,, Gordon McAlester1,, Carol A. Munro3, Brice Enjalbert3, Alistair J. P. Brown3, Neil A. R. Gow3, Chen Ding4, Geraldine Butler4, Fergal O'Gara1,2 and John P. Morrissey1

1 Department of Microbiology, University College Cork, Cork, Ireland
2 BIOMERIT Research Centre, University College Cork, Cork, Ireland
3 Institute of Medical Sciences, University of Aberdeen, Aberdeen, UK
4 School of Biomolecular and Biomedical Science, Conway Institute, University College Dublin, Dublin 4, Ireland

Signal-mediated interactions between the human opportunistic pathogens Pseudomonas aeruginosa and Candida albicans affect virulence traits in both organisms. Phenotypic studies revealed that bacterial supernatant from four P. aeruginosa strains strongly reduced the ability of C. albicans to form biofilms on silicone. This was largely a consequence of inhibition of biofilm maturation, a phenomenon also observed with supernatant prepared from non-clinical bacterial species. The effects of supernatant on biofilm formation were not mediated via interference with the yeast–hyphal morphological switch and occurred regardless of the level of homoserine lactone (HSL) produced, indicating that the effect is HSL-independent. A transcriptome analysis to dissect the effects of the P. aeruginosa supernatants on gene expression in the early stages of C. albicans biofilm formation identified 238 genes that exhibited reproducible changes in expression in response to all four supernatants. In particular, there was a strong increase in the expression of genes related to drug or toxin efflux and a decrease in expression of genes associated with adhesion and biofilm formation. Furthermore, expression of YWP1, which encodes a protein known to inhibit biofilm formation, was significantly increased. Biofilm formation is a key aspect of C. albicans infections, therefore the capacity of P. aeruginosa to antagonize this has clear biomedical implications.