[从临床标本中分离出的念珠菌属菌种鉴定的不同方法比较]

Cetinkaya Zafer, Altindiş Mustafa, Aktepe Orhan Cem, Karabiçak Nilgün

Kocatepe Universitesi Tip Fakültesi, Mikrobiyoloji ve Klinik Mikrobiyoloji Anabilim Dali, Afyon.

Mikrobiyol Bul. 2003 Oct;37(4):269-76.

The aim of this study was to compare the different methods for the identification of Candida strains isolated from clinical specimens. The methods of germ tube examination, chlamydospore examination formed on the rice Tween-80 (RT-80) agar and evaluation of colony morphologies on the two chromogenic agars (CHROMagar Candida, Albicans ID), were compared with a reference API 20C AUX (bioMerieux, France) automated system based on the carbohydrate assimilation, for the identification of a total 255 Candida isolates. Of them, 173 (67.8%) were identified as C. albicans, 37 (14.5%) were C. glabrata, 23 (9%) were C. krusei, 9 (3.5%) were C. tropicalis, 9 (3.5%) were C. kefyr, 2 (0.8%) were C. guillermondii and 2 (0.8%) were C. parapsilosis, by API 20C AUX system. In the view of these results, 146 (84.4%) of C. albicans strains were identified by germ tube examination, 161 (93.1%) of C. albicans strains and 208 (81.5%) of total strains were identified by chlamydospore examination. 169 (97.7%) of C. albicans strains and 231 (90.6%) of total strains were identified by CHROMagar Candida method, and 168 (97.1%) of C. albicans strains were identified by Albicans ID method, correctly. In the CHROMagar Candida medium, 169 C. albicans isolates have produced bright green colored colonies, whereas 33 (89.2%) isolates which produced dark pink/purple colored colonies were identified as C. glabrata, 7 (77.8%) isolates which produced metalical blue colored colonies were identified as C. tropicalis and 22 (95.6%) isolates which produced pale pink colored colonies were identified as C. krusei. In the Albicans ID medium, four of the 172 isolates which were evaluated as C. albicans initially by producing blue colored colonies, have been identified as C. tropicalis by API 20C AUX system. The sensitivities and specificities of germ tube examination, RT-80, CHROMagar Candida and Albicans ID methods were found as follows, respectively; 84.4% and 100%, 93.1% and 100%, 97.7% and 100%, 99.4% and 95.3 percent. In conclusion, CHROMagar Candida medium seems the most favorable rapid and practical method with high sensitivity and specificity for the identification of Candida species, but its cost-effectiveness should be kept in view.

本研究的目的是比较从临床标本中分离出的念珠菌菌株的不同鉴定方法。将芽管检查法、在米吐温80（RT-80）琼脂上形成厚壁孢子的检查法以及两种显色琼脂（科玛嘉念珠菌显色培养基、白色念珠菌鉴定琼脂）上菌落形态的评估法，与基于碳水化合物同化作用的参考API 20C AUX（法国生物梅里埃公司）自动化系统进行比较，以鉴定总共255株念珠菌分离株。其中，通过API 20C AUX系统鉴定出173株（67.8%）为白色念珠菌，37株（14.5%）为光滑念珠菌，23株（9%）为克柔念珠菌，9株（3.5%）为热带念珠菌，9株（3.5%）为解脂念珠菌，2株（0.8%）为季也蒙念珠菌，2株（0.8%）为近平滑念珠菌。根据这些结果，84.4%的白色念珠菌菌株通过芽管检查法鉴定出来，93.1%的白色念珠菌菌株和81.5%的总菌株通过厚壁孢子检查法鉴定出来。97.7%的白色念珠菌菌株和90.6%的总菌株通过科玛嘉念珠菌显色培养基法鉴定出来，97.1%的白色念珠菌菌株通过白色念珠菌鉴定琼脂法正确鉴定出来。在科玛嘉念珠菌显色培养基中，169株白色念珠菌分离株产生亮绿色菌落，而33株（89.2%）产生深粉色/紫色菌落的分离株被鉴定为光滑念珠菌，7株（77.8%）产生金属蓝色菌落的分离株被鉴定为热带念珠菌，22株（95.6%）产生淡粉色菌落的分离株被鉴定为克柔念珠菌。在白色念珠菌鉴定琼脂培养基中，最初通过产生蓝色菌落被评估为白色念珠菌的172株分离株中，有4株通过API 20C AUX系统被鉴定为热带念珠菌。芽管检查法、RT-80法、科玛嘉念珠菌显色培养基法和白色念珠菌鉴定琼脂法的敏感性和特异性分别如下：84.4%和100%、93.1%和100%、97.7%和100%、99.4%和95.3%。总之，科玛嘉念珠菌显色培养基似乎是鉴定念珠菌属最有利的快速实用方法且具有高敏感性和特异性，但应考虑其成本效益。