Badiee Parisa, Arastefar Amir, Jafarian Hadis
Professor Alborzi Clinical Microbiology Research Center, Shiraz University of Medical Sciences, Shiraz, Iran.
Iran J Microbiol. 2013 Dec;5(4):406-10.
The aim of this study was to compare direct microscopic examination with culture and PCR for the diagnosis of Mucorales infection in blood and tissue specimens.
Blood samples and tissue specimens were obtained from 28 patients (total 58 samples) with suspected invasive fungal infection and cultured on proper media. Direct smear of tissue samples was done with potassium hydroxide, hematoxylin and eosin, and methenamine silver staining. DNA extracted from blood and tissue specimens were used for semi-nested PCR targeting 18S rDNA of Mucorales species.
Mucormycosis was documented in 7/28 (25%) of tissue specimens with positive findings by direct smear, of which PCR and culture were positive in 6 (86%) and 5 (70%) specimens, respectively. The etiologic agents were Mucor spp. and Rhizopus spp. However, culture and PCR results for all blood specimens were negative.
As the orders of Mucorales do not have well growth in culture media, PCR with tissue specimens is more sensitive than tissue or blood culture methods. Unfortunately, there is no alternative method for direct smear, which is an invasive method. Molecular methods may be helpful in these cases.
本研究旨在比较直接显微镜检查与培养及聚合酶链反应（PCR）在血液和组织标本中毛霉目感染诊断中的应用。
从28例疑似侵袭性真菌感染患者中获取血液样本和组织标本（共58份样本），并在合适的培养基上进行培养。组织样本进行氢氧化钾、苏木精和伊红以及六胺银染色直接涂片。从血液和组织标本中提取的DNA用于针对毛霉目物种18S rDNA的半巢式PCR。
在28份组织标本中有7份（25%）通过直接涂片发现阳性结果，确诊为毛霉病，其中PCR和培养分别在6份（86%）和5份（70%）标本中呈阳性。病原体为毛霉属和根霉属。然而，所有血液标本的培养和PCR结果均为阴性。
由于毛霉目在培养基中生长不佳，组织标本的PCR比组织或血液培养方法更敏感。遗憾的是，直接涂片没有替代方法，而这是一种侵入性方法。分子方法在这些病例中可能会有帮助。
