Multilocus Sequence Typing Of Candida Albicans

ObjectiveTo assess the clonality of Candida albicans (C. albicans)isolates using Multilocus Sequence Typing and compare results of ABC (ATP-binding cassette) classification and randomLy amplified polymorphic DNA(RAPD).Ascertain whether different characteristics (fluconazole or itraconazole resistance, patient or hospital origin, source) can be attributed to certain specific MLST ST.To build the domestic C. albicans MLST database.Methods1Collect clinical strains of C. albicans. Determine the susceptibility of clinical isolates to fluconazole(FLU) and itraconazole(ICZ).Select10fluconzole-resistant strains and23fluconzole-sensitive strains.Extract the DNA of33C. albicans isolates.2. Seven house-keeping genes were selected as target genes. The PCR products were sequenced. The sequences were compared with data in the central database and STs were identified. ABC types and RAPD were determined by PCR and agarose gel electrophoresis.3. The sequences were analyzed by MEGA version4.0. Study the relationship of ST,stains characters, ABC-typing and RAPD results by the unweightedpair group method with arithmetic averages (UPGMA) and Minimum spanning trees.Results1. For the33clinical isolates,33STs were defined by MLST,3types by ABC-typing,13types by RAPD-12,11types by RAPD-OPE-18.2. Select a p-distance difference of0.0025by UPGMA analysis. STs were divided into8clades. The diversity of MLST types could be showed by Minimum spanning trees.Conclusion1.The MLST method had higher discrimination power. It could be used to study the diversity of C. albicans and be applied to epidemiological research.2. The DNA type of each isolate was patient specific and associated with ABC type and decade of isolation, but not associated with, anatomical source of isolation, hospital origin,RAPD type or fluconazole resistance patterns.3. The domestic MLST method and C. albicans MLST database was established.