Department of Biochemistry, Faculty of Medical Science, Naresuan University, 65000 Phitsanulok, Thailand.
Division of Clinical Microbiology and Parasitology, Department of Medical Technology, School of Allied Health Sciences, University of Phayao, 56000 Phayao, Thailand.
J Mycol Med. 2019 Dec;29(4):325-330. doi: 10.1016/j.mycmed.2019.08.001. Epub 2019 Aug 6.
Candidemia is one of the most common fungal nosocomial infections worldwide. It causes high mortality and morbidity rate with significant hospital costs due to increased length of hospital stay and costs for anti-fungal treatment. This study aims to investigate anti-fungal drug susceptibility, enzymatic activity and biofilm formation of the Candida spp. isolated from blood cultures. In 2016, a total of 84 clinical Candida isolates were analyzed for minimum inhibitory concentration (MIC) against fluconazole and amphotericin B by agar diffusion E-test (E-strips). Three enzymatic activity tests for phospholipase, proteinase and esterase were performed by using egg yolk agar, bovine serum albumin medium and Tween 80 opacity medium, respectively. Biofilm formation was determined by crystal violet staining. To describing the various Candida distributions cultured, C. albicans was the most frequent species (n=37, 44.1%), followed by C. tropicalis (n=30, 35.7%), C. parapsilosis (n=8, 9.5%), C. glabrata (n=6, 7.1%) and C. guilliermondii (n=3, 3.6%). Regarding anti-fungal drug susceptibility, C. albicans was susceptible to fluconazole (100%). In addition, all clinical Candida isolates were fully susceptible to amphotericin B (100%). The predominant enzyme activity of C. albicans included medium to high levels of phospholipase, proteinase and esterase activities. C. tropicalis displayed esterase activity, while C. glabrata and C. guilliermondii had no phospholipase and proteinase activity. Non-albicans Candida (NAC) i.e. C. tropicalis formed a biofilm at a higher rate than C. albicans. This study revealed the production of virulent factors in Candida strains from candidemia patients.
念珠菌血症是全球最常见的真菌性医院获得性感染之一。由于住院时间延长和抗真菌治疗费用增加，念珠菌血症导致死亡率和发病率高，医院花费巨大。本研究旨在调查从血培养中分离的念珠菌属的抗真菌药物敏感性、酶活性和生物膜形成。2016 年，共分析了 84 株临床念珠菌分离株，采用琼脂扩散 E 试验（E 试条）测定氟康唑和两性霉素 B 的最小抑菌浓度（MIC）。分别用蛋黄琼脂、牛血清白蛋白培养基和吐温 80 不透明度培养基进行三种酶活性试验，用于磷脂酶、蛋白酶和酯酶。通过结晶紫染色法测定生物膜形成。为了描述培养的各种念珠菌分布，白色念珠菌是最常见的物种（n=37，44.1%），其次是热带念珠菌（n=30，35.7%）、近平滑念珠菌（n=8，9.5%）、光滑念珠菌（n=6，7.1%）和季也蒙念珠菌（n=3，3.6%）。关于抗真菌药物敏感性，白色念珠菌对氟康唑（100%）敏感。此外，所有临床念珠菌分离株均对两性霉素 B（100%）完全敏感。白色念珠菌的主要酶活性包括中等到高水平的磷脂酶、蛋白酶和酯酶活性。热带念珠菌显示酯酶活性，而光滑念珠菌和季也蒙念珠菌没有磷脂酶和蛋白酶活性。非白色念珠菌（NAC），即热带念珠菌，比白色念珠菌形成生物膜的速度更快。本研究揭示了念珠菌血症患者念珠菌株产生毒力因子的情况。
