The Application Of Polymorphic Microsatellite Markers And Repetitive Sequence-based PCR In Genotyping Of Candida Tropicalis

Objective: This study aimed to analyze polymorphic microsatellite markers(PMM)and repetitive sequence-based polymerase chain reaction(REP-PCR)in genotyping of Candida tropicalis,and to evaluate the advantages of these two analysis technologies,in order to provide technical basis for accurate typing of clinical Candida tropicalis.Methods: From August 2014 to November 2015,50 Candida tropicalis isolates were collected from four hospitals in Shanghai,including different sources such as sputum,feces,urine,blood,drainage fluid,etc.And they were used for genotyping after further identified by amplifying and sequencing with internal transcribed sequence(ITS).The first part:Polymorphic microsatellite markers(PMM),Ctrm1,Ctrm10 and Ctrm12 microsatellite markers were used for microsatellite polymorphism analysis to obtain microsmicrosatellite genotypes.The second par:In repetitive sequence PCR typing,primers Ca21,Ca22 and Com21 were used to select out the most suitable primer combination,and then REP-PCR genotypes were obtained by electrophoresis.Finally,the results of these two genotyping methods were compared.Results: Repeat sequence PCR typing was performed best by combining ca21-com21 primers.7 types were obtained from 50 strains of Candida tropicalis by REP-PCR method,and the discriminant index(DP)was 0.75.While 30 genotypes were observed with PMM method,and the discriminant index(DP)was 0.97.Subtypes were found in isolates from different sources of the same patient.Conclusions: The PMM is an effective genotyping method for Candida tropicalis isolates with higher discretionary power and fine repeatability than REP-PCR,which can be used to detect the micro-evolutionary variations between isolates from different sources of the same patient,providing theoretical basis for future research.