Rapid identification and sequence typing of genotype VG Ⅱ of Cryptococcus gattii / 中华临床感染病杂志

ABSTRACT

Objective To establish a PCR method for rapid identification and sequence typing of VG Ⅱ allele of the intergenic spacer region (IGS) of Cryptococcus gattii.Methods Since IGS1 was of high sequence variation,multiple alignments were conducted by ClustalX 2 in IGS1 of Cryptococcus gattii and Cryptococcus neoformans,and then primer sets specific to genotype VG Ⅱ was designed for PCR analysis.The specificity of the primer pair was detected by amplification of the other genotypes in Cryptococcus gattii,Cryptococcus neoformans,and other pathogenic yeasts.The amplified fragments from VG Ⅱ genotype were sequenced and subtyped.Results Using the PCR analysis developed in this study,all VG Ⅱ genotype strains tested were amplified,whereas no amplification was obtained from other genotypes or yeast species involved herein.Three polymorphic nucleotide sites at 72,79 and 104 bp in the fragment amplified could be used to distinguish sub-genotypes within VG Ⅱ genotype.Conclusions The PCR analysis developed in this study can be used for rapid identification of genotype VG Ⅱ of Cryptococcus gattii.The sequence typing based on the amplified fragment from IGS1 may be performed for screening the highly virulent sub-genotype VGⅡ a.