Dassanayake R S, Ellepola A N B, Samaranayake Y H, Samaranayak L P
Faculty of Dentistry, The University of Hong Kong, SAR, China.
APMIS. 2002 Apr;110(4):315-24. doi: 10.1034/j.1600-0463.2002.100406.x.
The emergence of drug-resistant Candida albicans in immunocompromised patients is common. A disconcerting aspect of this phenomenon is the rapid emergence of C. albicans strains that are resistant to a widely used azole drug, fluconazole (FLZ). To understand the origin of FLZ-resistant yeast isolates, we investigated molecular profiles of 20 geographically related oral C. albicans isolates using three genotyping methods: randomly amplified polymorphic DNA-PCR, with six different primers (OBU1, OBU2, OBU3 RSD6, RSD11 and RSD12); electrophoretic karyotyping by pulsed-field gel electrophoresis; and HinfI restriction fragment analysis. Of the 20 isolates studied, 10 were FLZ- resistant and originated from patients with oral candidosis with a history of FLZ therapy, and the remainder were FLZ susceptible from individuals with oral candidosis, but without a history of FLZ therapy. A composite genotype was generated for each strain by combining molecular types derived from the three independent molecular methods. The composite profiles indicated genetic diversity amongst both the FLZ-resistant as well as -sensitive isolates, and no specific features emerged distinguishing the drug-resistant and -sensitive groups. These observations cast doubt on the theory of a clonal origin of FLZ-resistant C. albicans isolates.
免疫功能低下患者中耐药白色念珠菌的出现很常见。这一现象令人不安的一个方面是,对广泛使用的唑类药物氟康唑(FLZ)耐药的白色念珠菌菌株迅速出现。为了了解耐氟康唑酵母分离株的起源,我们使用三种基因分型方法研究了20株地理相关的口腔白色念珠菌分离株的分子特征:随机扩增多态性DNA-PCR,使用六种不同引物(OBU1、OBU2、OBU3、RSD6、RSD11和RSD12);脉冲场凝胶电泳进行电泳核型分析;以及HinfI限制性片段分析。在所研究的20株分离株中,10株对氟康唑耐药,来自有氟康唑治疗史的口腔念珠菌病患者,其余来自有口腔念珠菌病但无氟康唑治疗史的个体,对氟康唑敏感。通过组合来自三种独立分子方法的分子类型,为每个菌株生成了一个复合基因型。复合图谱表明,耐氟康唑和敏感分离株之间存在遗传多样性,没有出现区分耐药组和敏感组的特定特征。这些观察结果对耐氟康唑白色念珠菌分离株的克隆起源理论提出了质疑。