Department of Mycology, Faculty of Medical Sciences, Tarbiat Modares University, Tehran 14115-331, Iran.
Folia Microbiol (Praha). 2011 Nov;56(6):527-34. doi: 10.1007/s12223-011-0078-1. Epub 2011 Nov 15.
In the present study, genetic diversity and mycotoxin profiles of Aspergillus flavus isolated from air (indoors and outdoors), levels (surfaces), and soils of five hospitals in Southwest Iran were examined. From a total of 146 Aspergillus colonies, 63 isolates were finally identified as A. flavus by a combination of colony morphology, microscopic criteria, and mycotoxin profiles. No Aspergillus parasiticus was isolated from examined samples. Chromatographic analyses of A. flavus isolates cultured on yeast extract-sucrose broth by tip culture method showed that approximately 10% and 45% of the isolates were able to produce aflatoxin B(1) (AFB(1)) and cyclopiazonic acid (CPA), respectively. Around 40% of the isolates produced sclerotia on Czapek-Dox agar. The isolates were classified into four chemotypes based on the ability to produce AF and CPA that majority of them (55.5%) belonged to chemotype IV comprising non-mycotoxigenic isolates. Random amplified polymorphic DNA (RAPD) profiles generated by a combination of four selected primers were used to assess genetic relatedness of 16 selected toxigenic and non-toxigenic isolates. The resulting dendrogram demonstrated the formation of two separate clusters for the A. flavus comprised both mycotoxigenic and non-toxigenic isolates in a random distribution. The obtained results in this study showed that RAPD profiling is a promising and efficient tool to determine intra-specific genetic variation among A. flavus populations from hospital environments. A. flavus isolates, either toxigenic or non-toxigenic, should be considered as potential threats for hospitalized patients due to their obvious role in the etiology of nosocomial aspergillosis.
在本研究中，对来自伊朗西南部五家医院的空气（室内和室外）、水平（表面）和土壤中的黄曲霉进行了遗传多样性和霉菌毒素分析。从总共 146 株曲霉属菌落中，最终通过菌落形态、显微镜标准和霉菌毒素图谱的组合，鉴定出 63 株为黄曲霉属。从检查的样本中未分离出寄生曲霉。通过尖端培养法对在酵母提取物-蔗糖肉汤中培养的黄曲霉属分离物进行色谱分析表明，大约 10%和 45%的分离物分别能够产生黄曲霉毒素 B1（AFB1）和环匹阿尼酸（CPA）。大约 40%的分离物在察氏琼脂上产生菌核。根据产生 AF 和 CPA 的能力，将分离物分为四个化学型，其中大多数（55.5%）属于包含非产毒分离物的化学型 IV。通过组合使用四个选定的引物生成的随机扩增多态性 DNA（RAPD）图谱用于评估 16 个选定的产毒和非产毒分离物的遗传相关性。生成的聚类图显示，由产毒和非产毒分离物组成的黄曲霉属形成了两个独立的聚类，随机分布。本研究的结果表明，RAPD 图谱是确定医院环境中黄曲霉种群种内遗传变异的一种很有前途和有效的工具。由于它们在医院获得性曲霉菌病的病因学中的明显作用，产毒或非产毒的黄曲霉属分离物都应被视为住院患者的潜在威胁。
