Evaluation on rDNA-internal transcribed spacer regions as targets for molecular identification of clinical uncommon filamentous fungi

Objective To evaluate the internal transcribed spacer(ITS) regions as targets for molecular identification of clinical uncommon filamentous fungus,and use the method as the verification and supplementary check to the morphological identification.Methods The rDNA-ITS regions of 3 filamentous fungi were detected by polymerase chain reaction(PCR) amplification,and the PCR products were sequenced and compared with the data in GenBank.The function of BLAST in GenBank auto-generating system for phylogenetic tree and comparative indicators was helpful to determine the high homologous sequences.The results should be compared with the morphological identification and the results of ITS1,ITS2 and D1/D2 region of 26S rDNA as the targets. Results The assay successfully identified 2 strains of filamentous fungi to species,and another strain should be identified with the help of morphological characteristics of the strain since too many similar sequences in the results.It was superior to the ITS1,ITS2 and 26S rDNA D1/D2 targets in the fungal identification. Conclusions Compared with the traditional morphological identification methods,the rDNA-ITS sequence analysis is more objective and be with few influence from the experience level of operators.This method with more information has the better effect of fungus identification by comparing with other target sequences.However,this method still has its limitation,so it requires a combination of morphological identification.