Park Bo Rae G, Kim Tae-Hyoung, Kim Hye Ryoun, Lee Mi-Kyung
Departments of 1Laboratory Medicine, Chung-Ang University College of Medicine, Seoul, Korea.
Ann Clin Lab Sci. 2011 Summer;41(3):251-6.
The goal of this study was to determine the time to detection of Candida species isolates using the two most commonly used automated blood culture systems, and to evaluate rapid, widely available methods for the presumptive identification of C. albicans. Candidemia models of eight commonly detected Candida species were prepared using ATCC standards. The times to detection were evaluated using the BACTEC 9240 (Becton Dickinson) and BacT/Alert 3D (bioMerieux) automated blood culture systems. The presence of pseudohyphae clusters was examined by Gram staining and wet preparation. Germ tube tests were performed directly from blood culture bottles. All samples were cultured on blood agar plates and macroscopically examined for the presence of an irregular margin (spiking). Most Candida species (6/8) except C. glabrata and C. krusei grew more rapidly in aerobic than in anaerobic conditions. Clusters of pseudohyphae were observed in cultures of C. albicans and C. tropicalis. All culture bottles positive for C. albicans were positive by the germ tube test and macroscopically showed 'spiking.' Aerobic and anaerobic blood culture systems can effectively detect candidemia. Furthermore, the direct germ tube test may be the most useful available morphological presumptive identification method for C. albicans.
本研究的目的是确定使用两种最常用的自动化血培养系统检测念珠菌属分离株的时间，并评估用于白色念珠菌初步鉴定的快速、广泛可用的方法。使用美国典型培养物保藏中心（ATCC）标准制备了八种常见检测念珠菌属的念珠菌血症模型。使用BACTEC 9240（贝克顿·迪金森公司）和BacT/Alert 3D（生物梅里埃公司）自动化血培养系统评估检测时间。通过革兰氏染色和湿片制备检查假菌丝团的存在。直接从血培养瓶中进行芽管试验。所有样本均接种于血琼脂平板上，并进行肉眼检查以确定是否存在不规则边缘（尖刺状）。除光滑念珠菌和克柔念珠菌外，大多数念珠菌属（6/8）在需氧条件下比在厌氧条件下生长更快。在白色念珠菌和热带念珠菌培养物中观察到假菌丝团。所有白色念珠菌阳性的培养瓶芽管试验均为阳性，肉眼观察显示“尖刺状”。需氧和厌氧血培养系统均可有效检测念珠菌血症。此外，直接芽管试验可能是白色念珠菌最有用的现有形态学初步鉴定方法。
