Attachment to and biofilm formation on abiotic surfaces by Acinetobacter baumannii:: involvement of a novel chaperone-usher pili assembly system
Attachment to and biofilm formation on abiotic surfaces by Acinetobacter baumannii:: involvement of a novel chaperone-usher pili assembly system
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DOI：
10.1099/mic.0.26541-0
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发表时间：
2003-12-01
期刊：
影响因子：
2.8
通讯作者：
Actis, LA
中科院分区：
文献类型：
--
作者：
Tomaras, AP;Dorsey, CW;Actis, LA
鲍曼不动杆菌会导致患者的严重感染，在医院环境中的非生物表面生存，并在不同的医疗设备上定居。在这项研究中，对原型菌19606参与表面附着和生物膜形成的过程进行了分析。这种菌株附着在塑料和玻璃表面上并形成生物膜结构，特别是在停滞培养的培养物的液气界面上。细胞聚集体是在不同培养条件下形成的，在铁限制条件下，细胞聚集体的数量显著增加。电子显微镜和荧光显微镜显示菌毛和胞外多糖是该菌株形成的细胞聚集体的一部分。两个缺乏附着和生物膜形成的插入衍生物的电子显微镜显示，菌毛状结构消失，DNA测序分析表明，转座子插入中断了与铜绿假单胞菌、恶臭假单胞菌和副溶血性弧菌的假设基因最相似的基因。尽管这些基因的产物被命名为csuC和csuE，功能尚不清楚，但它们位于一个多顺反子操纵子内，其中包括另外四个基因，其中两个编码与伴侣相关的蛋白质，并在其他细菌中引导参与菌毛组装的蛋白质。CsuE亲本基因拷贝的导入恢复了csuE突变体的黏附表型和细胞表面菌毛的存在，但不恢复csuC衍生物的黏附表型和菌毛的存在。这些结果表明，伴侣-引座者分泌系统的表达对于菌毛的形成和伴随的塑料表面的附着以及随后鲍曼不动杆菌细胞生物膜的形成是必需的，其中一些成分似乎是从无关来源获得的。
Acinetobacter baumannii causes severe infections in compromised patients, survives on abiotic surfaces in hospital environments and colonizes different medical devices. In this study the analysis of the processes involved in surface attachment and biofilm formation by the prototype strain 19606 was initiated. This strain attaches to and forms biofilm structures on plastic and glass surfaces, particularly at the liquid-air interface of cultures incubated stagnantly. The cell aggregates, which contain cell stacks separated by water channels, formed under different culture conditions and were significantly enhanced under iron limitation. Electron and fluorescence microscopy showed that pili and exopolysaccharides are part of the cell aggregates formed by this strain. Electron microscopy of two insertion derivatives deficient in attachment and biofilm formation revealed the disappearance of pili-like structures and DNA sequencing analysis showed that the transposon insertions interrupted genes with the highest similarity to hypothetical genes found in Pseudomonas aeruginosa, Pseudomonas putida and Vibrio parahaemolyticus. Although the products of these genes, which have been named csuC and csuE, have no known functions, they are located within a polycistronic operon that includes four other genes, two of which encode proteins related to chaperones and ushers involved in pili assembly in other bacteria. Introduction of a copy of the csuE parental gene restored the adherence phenotype and the presence of pili on the cell surface of the csuE mutant, but not that of the csuC derivative. These results demonstrate that the expression of a chaperone-usher secretion system, some of whose components appear to be acquired from unrelated sources, is required for pili formation and the concomitant attachment to plastic surfaces and the ensuing formation of biofilms by A. baumannii cells.