Farrag Hala Abdallah, A-Karam El-Din Alzahraa, Mohamed El-Sayed Zeinab Galal, Abdel-Latifissa Soheir, Kamal Mona Mohamed
Drug Radiation Research Department, National Center for Radiation Research and Technology (NCRRT), Atomic Energy Authority , Nasr City, Cairo.
Int J Radiat Biol. 2015 Jun;91(6):519-27. doi: 10.3109/09553002.2015.1021959. Epub 2015 Apr 27.
Technological advances such as long-term indwelling catheters have created milieu in which infections are a major complication. Thus it is essential to be able to recognize, diagnose, and treat infections occurring in immunocompromised patients.
Adherence assay and quantitation of biofilms was performed by a spectrophotometric method, hydrophobicity was evaluated by adhesion to p-xylene. The minimum inhibitory concentration (MIC) of Nystatin was carried out by a well dilution method.
Out of 100 bladder cancer patients, 23 pathogenic yeast isolates were identified. The samples were taken from urinary catheters and urine collected from their attached drainage bags. Pathogenic yeast identified were species of Candida, Cryptococcus, Saccharomyces, Blastoschizomyces, Trichosporn, Hansenula, Prototheca and Rhodotorula. With the exception of Rhodotorula minuta, the yeast were sensitive to the antimycotic agent (Nystatin) used before and after in vitro gamma irradiation at 24.41 Gy as measured by a disc diffusion method. All tested yeast strains were slime producers and showed positive adherence reactions. There were considerable differences in adherence measurements after irradiation. An increase in adherence measurement values (using a spectrophotometric method) after irradiation were detected in four strains whereas eight other strains showed a reduction in their adherence reaction. The cell surface hydrophobicity (CSH) was evaluated by adhesion to p-xylene. Candida tropicalis showed a hydrophobic reaction with an increase in the cell surface hydrophobicity after irradiation. Scanning electron microscopy of irradiated C. tropicalis showed marked abnormalities in cell shape and size with significant reduction in adherence ability at the MIC level of Nystatin (4 μg/ml).
More basic research at the level of pathogenesis and catheter substance is needed to design novel strategies to prevent fungal adherence and to inhibit biofilm formation.
诸如长期留置导管等技术进步营造了一个感染成为主要并发症的环境。因此，能够识别、诊断和治疗免疫功能低下患者发生的感染至关重要。
采用分光光度法进行生物膜的黏附测定和定量分析，通过对二甲苯黏附评估疏水性。制霉菌素的最低抑菌浓度（MIC）采用试管稀释法测定。
在100例膀胱癌患者中，鉴定出23株致病性酵母分离株。样本取自导尿管及其连接引流袋收集的尿液。鉴定出的致病性酵母有念珠菌属、隐球菌属、酿酒酵母属、裂殖酵母属、毛孢子菌属、汉逊酵母属、原壁菌属和红酵母属。除微小红酵母外，这些酵母对体外24.41 Gyγ射线照射前后使用的抗真菌剂（制霉菌素）敏感，采用纸片扩散法测定。所有测试的酵母菌株均产生黏液且黏附反应呈阳性。照射后黏附测定存在显著差异。采用分光光度法检测发现，4株菌株照射后黏附测定值增加，而其他8株菌株黏附反应降低。通过对二甲苯黏附评估细胞表面疏水性（CSH）。热带念珠菌表现出疏水性反应，照射后细胞表面疏水性增加。照射后的热带念珠菌扫描电子显微镜显示细胞形状和大小明显异常，在制霉菌素MIC水平（4μg/ml）下黏附能力显著降低。
需要在发病机制和导管物质层面开展更多基础研究，以设计预防真菌黏附和抑制生物膜形成的新策略。
