Steffan P, Vazquez J A, Boikov D, Xu C, Sobel J D, Akins R A
Department of Biochemistry and Molecular Biology, Wayne State University School of Medicine, Detroit, Michigan, USA.
J Clin Microbiol. 1997 Aug;35(8):2031-9. doi: 10.1128/jcm.35.8.2031-2039.1997.
We have characterized a method that produces simple yet diagnostic fingerprints that are unique to isolates of Candida species. DNA from individual colonies can be amplified from crude single-colony lysates. Randomly amplified polymorphic DNA (RAPD) fingerprints generated from a single primer correctly identified the species of most (>98%) of the isolates identified with CHROMagar Candida plates as non-Candida albicans Candida species. RAPD fingerprints were much more informative than the plates, since they distinguished between all tested species and required less time. Most (91%) of these identifications agreed with those assigned by API 20C tests. In almost every incident of species identity mismatch, electrophoretic karyotyping showed that the RAPD fingerprint was correct. This underscores the improved objectivity and reliability of this method over those of conventional diagnostic tools. The identities of approximately 30% of C. albicans isolates identified in clinical laboratories by positive germ tube tests are not verified by either testing on CHROMagar Candida plates or RAPD fingerprinting. Data suggest that clinical isolates conventionally identified as C. albicans in clinical settings are heterogeneous, consisting of both misidentified and atypical yeasts. RAPD fingerprints obtained from primary culture plate colonies allows for rapid, highly accurate determinations of Candida species, hence permitting earlier selection of appropriate antifungal agents in the clinical setting.
我们已鉴定出一种方法，该方法可产生简单却具有诊断性的指纹图谱，这些指纹图谱对于念珠菌属的分离株而言是独一无二的。来自单个菌落的DNA可从粗制的单菌落裂解物中进行扩增。由单一引物生成的随机扩增多态性DNA（RAPD）指纹图谱能够正确鉴定出大多数（>98%）经CHROMagar念珠菌平板鉴定为非白色念珠菌的念珠菌属分离株的种类。RAPD指纹图谱比平板提供的信息更多，因为它们能区分所有测试的菌种，且所需时间更短。这些鉴定结果中的大多数（91%）与API 20C测试给出的结果一致。在几乎每一例菌种鉴定不匹配的情况中，电泳核型分析表明RAPD指纹图谱是正确的。这突出了该方法相较于传统诊断工具在客观性和可靠性方面的提升。临床实验室中通过阳性芽管试验鉴定的约30%白色念珠菌分离株的身份，通过在CHROMagar念珠菌平板上进行测试或RAPD指纹图谱分析均未得到证实。数据表明，在临床环境中传统上被鉴定为白色念珠菌的临床分离株具有异质性，由误鉴定的酵母菌和非典型酵母菌组成。从原代培养平板菌落获得的RAPD指纹图谱能够快速、高度准确地鉴定念珠菌的种类，从而在临床环境中更早地选择合适的抗真菌药物。
