Hasan Fahmi, Xess Immaculata, Wang Xiabo, Jain Neena, Fries Bettina C
Department of Microbiology, All India Institute of Medical Sciences, New Delhi, India.
Microbes Infect. 2009 Jul-Aug;11(8-9):753-61. doi: 10.1016/j.micinf.2009.04.018. Epub 2009 May 4.
Biofilm formation, an important virulence trait of Candida species was measured in 107 Candida isolates from 32 candidemic patients by XTT [2,3-bis (2-methoxy-4nitro-5-sulfo-phenyl)-2H-tetra-zolium-5-carboxanilide] activity and compared to biofilm formation of Candida isolates from oropharyngeal lesions of 19 AIDS patients. Biofilm formation by XTT varied among species and C. albicans; C. lusitaniae and C. krusei produced more biofilm than the other Candida species. C. tropicalis was the most dominant species isolated from blood followed by C. albicans, and other non-albicans species whereas only C. albicans was recovered from oral lesions. Importantly, though Biofilm formation was variable within a species it was stable in sequential isolates during chronic infection. Sequential isolates exhibited identical Karyotype pattern or RAPD patterns unless patients were co-infected with more than one strain. High biofilm formation was associated with slow growth rate but not with adherence. Murine infection studies demonstrated that, degree of in-vitro biofilm formation was associated with virulence in mice, as mice infected both with no and low biofilm formers survived longer than mice infected with high biofilm former C. albicans (p< or =0.001). We conclude that biofilm formation is a stable but strain specific characteristic that can greatly vary among C. albicans and non-albicans strains, and plays an important role in persistence of infection.
通过XTT[2,3-双(2-甲氧基-4-硝基-5-磺基苯基)-2H-四唑-5-甲酰苯胺]活性测定了32例念珠菌血症患者的107株念珠菌分离株中生物膜形成情况，这是念珠菌属的一个重要致病特性，并将其与19例艾滋病患者口腔病变处念珠菌分离株的生物膜形成情况进行了比较。通过XTT测定的生物膜形成在不同菌种以及白色念珠菌中存在差异；葡萄牙念珠菌和克鲁斯念珠菌产生的生物膜比其他念珠菌菌种更多。热带念珠菌是从血液中分离出的最主要菌种，其次是白色念珠菌和其他非白色念珠菌菌种，而从口腔病变处仅分离出白色念珠菌。重要的是，虽然生物膜形成在一个菌种内存在差异，但在慢性感染期间的连续分离株中是稳定的。除非患者同时感染了不止一种菌株，连续分离株表现出相同的核型模式或随机扩增多态性DNA模式。高生物膜形成与生长速率缓慢相关，但与黏附无关。小鼠感染研究表明，体外生物膜形成程度与小鼠体内毒力相关，因为感染无生物膜形成菌和低生物膜形成菌的小鼠比感染高生物膜形成菌白色念珠菌的小鼠存活时间更长（p≤0.001）。我们得出结论，生物膜形成是一种稳定但菌株特异性的特征，在白色念珠菌和非白色念珠菌菌株之间可能有很大差异，并且在感染持续存在中起重要作用。
