Akyol Volkan, Cerikçioğlu Nilgün
Marmara Üniversitesi Tıp Fakültesi, Tıbbi Mikrobiyoloji Anabilim Dalı, İstanbul, Türkiye.
Mikrobiyol Bul. 2010 Oct;44(4):605-17.
In recent years there is an increase in frequency of systemic candidiasis cases caused by Candida parapsilosis. However there isn't any standardized genotyping method to be used in epidemiology of those infections. In this study we aimed to determine utility of morphotyping instead of genotyping to study the epidemiology of 53 C.parapsilosis strains isolated from blood (n= 40) and urine (n= 13) cultures of inpatients at Marmara University Hospital, Istanbul, Turkey. The isolates were morphotyped according to their surface and color properties on Sabouraud-triphenyltetrazolium agar (STTZ) and surface characteristics on malt extract agar (MA) media and 10 different subgroups were obtained. In order to genotype the strains, RAPD-PCR (Random Amplified Polymorphic DNA-Polymerase Chain Reaction) method was used and three different genotypes were obtained comprising mostly type II (90.6%). One of the putative virulence factors investigated in the isolates was phospholipase activity. Phospholipase production was not detected in any of the strains on egg-yolk agar (pH: 4.2). Esterase activity of the strains on Tween-80 agar was negative except for one. In order to observe acid proteinase activity, bovine serum albumin containing (pH: 5.0) agar was used and in 11.3% of the strains no acid proteinase activity was seen while in 75.5% moderate (+), in 13.2% strong (++) activity was detected. Slime production was investigated in 8% glucose containing Sabouraud broth (SB) medium and 67.9 % of the strains were found to be negative; while 20.7% were weakly (+), 7.5% were moderately (++) and 3.7% were strongly (+++) positive. Hydrophobicity of the strains was evaluated by using hexadecane hydrocarbon adherence assay and one isolate was weakly hydrophobic while the remaining strains were found to be moderately hydrophobic. We could not observe superiority of morphotyping over genotyping. Additionally no property was found to associate with a certain morphotype, in terms of virulence factors.
近年来，由近平滑念珠菌引起的系统性念珠菌病病例频率有所增加。然而，在这些感染的流行病学研究中，没有任何标准化的基因分型方法可供使用。在本研究中，我们旨在确定形态分型而非基因分型在研究从土耳其伊斯坦布尔马尔马拉大学医院住院患者的血液（n = 40）和尿液（n = 13）培养物中分离出的53株近平滑念珠菌菌株流行病学中的效用。根据分离株在沙氏-三苯基四氮唑琼脂（STTZ）上的表面和颜色特性以及在麦芽提取物琼脂（MA）培养基上的表面特征进行形态分型，获得了10个不同的亚组。为了对菌株进行基因分型，使用了随机扩增多态性DNA - 聚合酶链反应（RAPD - PCR）方法，获得了三种不同的基因型，其中大部分为II型（90.6%）。在分离株中研究的一种假定毒力因子是磷脂酶活性。在蛋黄琼脂（pH：4.2）上，未在任何菌株中检测到磷脂酶产生。除一株外，菌株在吐温80琼脂上的酯酶活性均为阴性。为了观察酸性蛋白酶活性，使用了含牛血清白蛋白（pH：5.0）的琼脂，11.3%的菌株未观察到酸性蛋白酶活性，而75.5%为中度（+），13.2%为强（++）活性。在含8%葡萄糖的沙氏肉汤（SB）培养基中研究了黏液产生，发现67.9%的菌株为阴性；20.7%为弱阳性（+），7.5%为中度阳性（++），3.7%为强阳性（+++）。通过十六烷烃黏附试验评估菌株的疏水性，一株分离株为弱疏水性，其余菌株为中度疏水性。我们未观察到形态分型优于基因分型。此外，就毒力因子而言，未发现任何特性与特定形态型相关。
