阅读方式:

Silicone colonization by non-Candida albicans Candida species in the presence of urine.
尿液中非白色念珠菌的念珠菌种硅胶定植

出处: J Med Microbiol   2010   Jul   59 (Pt 7) :747-54

作者:Silva S;Negri M;Henriques M;Oliveira R;Williams D;Azeredo J

PMID:20299506

Urinary tract infections (UTIs) are the most common nosocomial infections and 80 % are related to the use of urinary catheters. Furthermore, Candida species are responsible for around 15 % of UTIs and an increasing involvement of non-Candida albicans Candida (NCAC) species (e.g. Candida glabrata, Candida tropicalis and Candida parapsilosis) has been recognized. Given the fact that silicone is frequently used in the manufacture of urinary catheters, the aim of this work was to compare both the adhesion and biofilm formation on silicone of different urinary clinical isolates of NCAC species (i.e. C. glabrata, C. tropicalis and C. parapsilosis) in the presence of urine. Several clinical isolates of NCAC species recovered from patients with UTIs, together with reference strains of each species, were examined. Adhesion and biofilm formation were performed in artificial urine and the biofilm biomass was assessed by crystal violet staining. Hydrophobicity and surface charge of cells was determined by measuring contact angles and zeta potential, respectively. The number of viable cells in biofilms was determined by enumeration of c.f.u. after appropriate culture. The biofilm structure was also examined by confocal laser scanning microscopy (CLSM). The results showed that all isolates adhered to silicone in a species- and strain-dependent manner with C. parapsilosis showing the lowest and C. glabrata the highest levels of adhesion. However, these differences in adhesion abilities cannot be correlated with surface properties since all strains examined were hydrophilic and exhibited a similar zeta potential. Despite a higher number of cultivable cells being recovered after 72 h of incubation, stronger biofilm formation was not observed and CLSM showed an absence of extracellular polymeric material for all isolates examined. In summary, this work demonstrated that all tested NCAC species were able to adhere to and survive on silicone in the presence of urine. Furthermore, C. glabrata strains presented higher colonization abilities than C. tropicalis and C. parapsilosis strains, a fact that might explain the larger role of C. glabrata colonization and disseminated infections in hospitalized and catheterized patients.

泌尿道感染 (Urinary tract infections,UTIs)是最常见的医院交叉感染,80%与应用尿管有关。而且,约15%的UTIs与念珠菌种有关,现已发现非白色念珠菌的念珠菌 (non-Candida albicans Candida,NCAC) 属(例如光滑假丝酵母菌,热带念珠菌和近平滑念珠菌) 感染不断上升。考虑到尿管的生产过程中常用到硅胶,本研究的目的旨在比较不同尿液的NCAC临床分离株(例如光滑假丝酵母菌,热带念珠菌和近平滑念珠菌) 在尿液中对硅胶的粘附和生物被膜形成。检测从UTIs感染患者中得到的几种NCAC临床分离株,以及各菌种的参考菌株。在人造尿中进行粘附和生物被膜形成试验,用结晶紫染色法评价生物被膜的生物量。分别通过测量接触角和zeta电位来确定细胞的疏水性和表面电荷。适当培养后用菌落形成单位(c.f.u.)计数测定生物膜中的存活细胞数量。用共聚焦激光扫描显微镜 (confocal laser scanning microscopy,CLSM)测定生物膜的结构。结果表明,所有分离株都以菌种和菌株依赖性方式粘附于硅胶上,其中近平滑念珠菌粘附能力最低,光滑假丝酵母菌粘附能力最强。然而,粘附能力的差异与表面特性无关,因为所有检测的菌株都是亲水性的,具有近似的zeta电位。虽然孵育72h后获得的可培养细胞数量较多,但并未观察到较强的生物膜形成。CLSM 可见所有检测的分离株均无胞外聚合物。总之,这项研究证实,所有检测的NCAC种都有能力在尿液中粘附并生存于硅胶上。此外,光滑假丝酵母菌株表现出的定植能力较热带念珠菌株和近平滑念珠菌株高,这也许可以解释住院和插管患者中光滑假丝酵母菌定植和播散感染发生较多的原因。