Identification of candida, trichosporon, geotrichum and rhodotorula strains that are isolated from the clinical samples by DNA sequencing analysis method

It has been determined that yeasts are the most commonly encountered fungal pathogens in immunosuppressive patients and the Candida are the most dominant ones among these pathogens. Also it is stated that there has been an increase in infections related to yeast-like fungi such as Trichosporon, Geotrichum, Rhodotorula, Saccharomyces in recent years in addition to Candida. Though genus level identification might be sufficient for many yeasts, species level identification of certain yeasts which are resistant particularly for antifungal agent is significantly needed.The aim of our study is the application of DNA sequencing analysis method and comparison of the results in order to identify Candida, Trichosporon, Geotrichum and Rhodotorula strains that are isolated from clinical samples and identified through conventional methods.So as to achieve this aim, 45 yeast origins and five reference origins isolated from clinical samples, which were sent to Gazi University, Faculty of Medicine, Medical Microbiology Department?s Mycology Laboratory between the years 2010-2012, have been included in the study. When the DNA sequencing analysis results of ITS and D1-D2 area and the results of the conventional method ID 32C and cornmeal-tween 80 agar are compared; all origins belonging to C.krusei, C.parapsilosis, C.lusitaniae, C.kefyr, T.asahii, C.pelliculosa, C.tropicalis, G.capitatum, T.inkin and R.muciloginosa have been identified identically, by means of the all methods.As for the nine C.glabrata origins, it is found out that except for two, seven origins have been identified correctly on the basis of variety by means of the ID 32C method. Two origins, which we identify as C.glabrata through the ID 32C method, have been identified as Candida pelliculosa and Pichiakluyveri respectively, in accordance with the result of the DNA sequencing analysis method. In cornmeal-tween 80 agar, two origins have been observed to have inconsistent morphology with C.glabrata.It is concluded that the DNA sequencing analysis method can be used for the identification of rarely encountered yeast strains that are difficult to identify through conventional methods or when a rather quick identification is required.