Sousa Cláudia, Teixeira Pilar, Oliveira Rosário
Instituto de Biotecnologia e Bioengenharia, Centro de Engenharia Biológica, Universidade do Minho, Braga, Portugal.
J Basic Microbiol. 2009 Aug;49(4):363-70. doi: 10.1002/jobm.200800196.
Staphylococcus epidermidis is now well established as a major nosocomial pathogen, associated with indwelling medical devices. Its major virulence factor is related with the ability to adhere to indwelling medical devices and form biofilms. In this study, the biofilm matrix of four S. epidermidis clinical isolates was extracted and the polysaccharides and proteins content was quantified. The results were correlated with the total biofilm biomass (determined by crystal violet assay) and cellular metabolic activity (evaluated with XTT reduction assay). According to the results, the exopolymers studied play an important role not only on structure and biofilm biomass but also on cellular activity. Thus, the strain forming biofilms with the highest level of polysaccharides (S. epidermidis 1457) also formed thicker biofilms but with the lowest metabolic activity. The protein concentration also varied among strains, with the biofilm matrix of S. epidermidis 9142 presenting a higher concentration of proteins comparing to the remaining strains. This fact indicates the different levels of importance that matrix proteins can hold on biofilm composition among strains albeit overall, it is suggested that extracellular protein production it is not a determinative factor for biofilm total biomass.
表皮葡萄球菌现已被确认为一种主要的医院病原体，与植入式医疗器械有关。其主要毒力因子与粘附于植入式医疗器械并形成生物膜的能力有关。在本研究中，提取了四株表皮葡萄球菌临床分离株的生物膜基质，并对多糖和蛋白质含量进行了定量。结果与总生物膜生物量（通过结晶紫测定法确定）和细胞代谢活性（用XTT还原测定法评估）相关。根据结果，所研究的胞外聚合物不仅在生物膜结构和生物量方面发挥重要作用，而且在细胞活性方面也发挥重要作用。因此，形成多糖水平最高的生物膜的菌株（表皮葡萄球菌1457）也形成了更厚的生物膜，但代谢活性最低。不同菌株之间蛋白质浓度也有所不同，与其他菌株相比，表皮葡萄球菌9142的生物膜基质中蛋白质浓度更高。这一事实表明，尽管总体而言，基质蛋白在不同菌株的生物膜组成中的重要性程度不同，但细胞外蛋白质的产生并不是生物膜总生物量的决定性因素。
