Malcok Hilal Kuzucu, Aktas Esin, Ayyildiz Ahmet, Yigit Nimet, Yazgi Halil
Atatürk Universty, Faculty of Medicine, Department of Microbiology and Clinical Microbiology, Erzurum, Turkey.
Ataturk Universty, Health Services Vocational Training School, Department of Medical Laboratory, Erzurum, Turkey.
Eurasian J Med. 2009 Aug;41(2):95-8.
The aim of this study was to evaluate the in vitro hemolytic activities of 107 Candida strains isolated from different clinical samples in liquid medium, and to examine the impact of glucose on this activity.
A total of 107 Candida isolates representing seven species (C. albicans, n=28; C. glabrata, n=23; C. tropicalis, n=17; C. parapsilosis, n=16; C. kefyr, n=14; C. krusei, n=5; C. guilliermondii, n=4) were included in the study. The hemolytic activities of the strains were tested on two different Sabouraud dextrose liquid media (SDB) containing 7% defibrinated human blood, one of which is supplemented with 3% glucose and the other without glucose. Cultures were evaluated at the end of a 48-hour incubation. The hemolysis in the media was detected spectrophotometrically by measuring the amount of released hemoglobin and compared with a standard hemolysate which was prepared prior to testing. The degree of hemolysis (percentage value) by an individual strain was calculated according to the following formula below: (Absorbance of supernatant media at 540 nm / Absorbance of standard hemolysate at 540 nm X 100).
In the liquid medium without glucose, strains generally produced hemolysis at low levels. The degree of hemolysis produced by all species increased noticeably in the liquid medium with glucose. Strains of C. albicans and C.kefyr had demonstrated significant hemolytic activity, whereas others had lower activity. C. parapsilosis exerted very little hemolytic activity in the medium with glucose and showed no activity in the medium without glucose.
The hemolytic activities of most Candida species was found to be higher in the human blood-enriched SDB medium containing 3% additive glucose than in the one free from additives. This result indicates that increased blood glucose concentration may contribute to increased hemolytic activity in Candida species, and it suggests a parallel with possible pathogenesis of Candida in patients with diabetes mellitus.
本研究旨在评估从不同临床样本中分离出的107株念珠菌在液体培养基中的体外溶血活性，并研究葡萄糖对该活性的影响。
本研究共纳入代表7个菌种的107株念珠菌分离株（白色念珠菌，n = 28；光滑念珠菌，n = 23；热带念珠菌，n = 17；近平滑念珠菌，n = 16；克柔念珠菌，n = 14；克鲁斯念珠菌，n = 5；季也蒙念珠菌，n = 4）。在两种不同的含7%去纤维蛋白人血的沙氏葡萄糖液体培养基（SDB）上测试菌株的溶血活性，其中一种添加3%葡萄糖，另一种不添加葡萄糖。培养48小时后对培养物进行评估。通过测量释放的血红蛋白量，用分光光度法检测培养基中的溶血情况，并与测试前制备的标准溶血产物进行比较。根据以下公式计算单个菌株的溶血程度（百分比值）：（540nm处上清培养基的吸光度/540nm处标准溶血产物的吸光度×100）。
在无葡萄糖的液体培养基中，菌株通常产生低水平的溶血。在含葡萄糖的液体培养基中，所有菌种产生的溶血程度均显著增加。白色念珠菌和克柔念珠菌的菌株表现出显著的溶血活性，而其他菌株的活性较低。近平滑念珠菌在含葡萄糖的培养基中溶血活性极低，在无葡萄糖的培养基中无活性。
发现大多数念珠菌种在含3%添加葡萄糖的富含人血的SDB培养基中的溶血活性高于无添加剂的培养基。该结果表明血糖浓度升高可能导致念珠菌种的溶血活性增加，这提示与糖尿病患者念珠菌可能的发病机制存在平行关系。
