Pineda G, Scollo K, Santiso G, Lehmann E, Arechavala A
Unidad Micología, Hospital de Infecciosas F. J. Muñiz, Uspallata 2272 (1282) Ciudad Autónoma de Buenos Aires, Argentina.
Rev Argent Microbiol. 2008 Oct-Dec;40(4):211-7.
In order to estimate the frequence of Candida dubliniensis in clinical samples in F. J. Muñiz Infectious Diseases Hospital, a total of 388 yeasts from September 2005 to August 2007. There were 212 isolates which presented a green color on CHROMagar Candida medium and produced germ tubes and chlamidoconidiae in milk-agar; so as to distinguish whether they corresponded to Candida albicans or C. dubliniensis, different phenotypical methods were utilized. It was also evaluated the usefulness of each one in order to suggest a simple, economic and reliable identification algorithm. Each isolate was subcultured in two chromogenic media and then, the following determinations were done: chlamidospores production in Staib-agar, tomato-carrot-agar and tobacco-agar, colonies macromorphology was also studied in the last medium; opacity-test in Tween 80-CaCl2 agar (lipase activity), growing capacity at 45 degrees C, and D-xylose assimilation. Thirteen strains (6.1%) corresponded to C. dubliniensis. The difference in color between both species on chromogenic media was not so stressed as it is pointed out in some works. The more specific and sensitive tests were the ability to grow at 45 degrees C, D-xylose assimilation, color and macroscopic appearance in tobacco-agar. Between 11.6% and 15.1% of C. albicans strains produced chlamidoconidiae in the 3 differential media tested. The opacity halo (lipase) was evident in 95.6% of C. albicans isolates but 2 out of 13 C. dubliniensis also presented precipitation halo. We consider that at least 3 different phenotypical methods should be used to distinguish properly these two species since none of the tests is absolutely sensitive or specific.
为了估算穆尼兹传染病医院临床样本中都柏林念珠菌的频率，我们收集了2005年9月至2007年8月期间的388株酵母。其中212株在科玛嘉念珠菌培养基上呈现绿色，且在牛奶琼脂中产生芽管和厚垣孢子。为了区分它们是白色念珠菌还是都柏林念珠菌，我们采用了不同的表型方法。同时评估了每种方法的实用性，以提出一种简单、经济且可靠的鉴定算法。每个分离株在两种显色培养基中传代培养，然后进行以下测定：在施泰布琼脂、番茄-胡萝卜琼脂和烟草琼脂中厚垣孢子的产生情况，在最后一种培养基中还研究了菌落的宏观形态；吐温80-氯化钙琼脂中的不透明试验（脂肪酶活性）、45℃下的生长能力以及D-木糖同化。13株菌株（6.1%）为都柏林念珠菌。两种菌落在显色培养基上的颜色差异并不像一些研究中指出的那么明显。最具特异性和敏感性的试验是45℃下的生长能力、D-木糖同化、烟草琼脂中的颜色和宏观外观。在测试的3种鉴别培养基中，11.6%至15.1%的白色念珠菌菌株产生厚垣孢子。95.6%的白色念珠菌分离株出现不透明晕圈（脂肪酶），但在13株都柏林念珠菌中有2株也出现沉淀晕圈。我们认为，至少应使用3种不同的表型方法来正确区分这两个菌种，因为没有一种试验是绝对敏感或特异的。
