Objective To understand the genotype distribution of clinical Cryptococcus neoformans var.grubii strains from China and Brazil using multilocus microsatellite typing(MLMT) method and to study the difference in their MLMT genotyping.Methods DNA was extracted from the identified 69 clinical Cryptococcus neoformans var.grubii strains.DNA fragments covering microsatellite loci(CNG1,CNG2,and CNG3) were amplified by PCR and sequenced.The number of each motif repeats in 3 microsatellite regions("TA","GA",and "CAT" repeats for CNG1,CNG2,and CNG3,respectively) was calculated.The MLMT types of 69 clinical Cryptococcus neoformans var.grubii strains were determined according to the repeat number of different motifs.Data were analyzed using SPSS 11.5 software.Results Five genotypes were identified in 33 clinical strains from China.Of these strains,29 were MLMT-17,accounting for 87.88% of the total strains.Ten genotypes were identified in 36 clinical strains from Brazil.Of the 36 strains,19 were MLMT-13,accounting for 52.78% of the total strains.Conclusion The difference is great in major genotype distributions of the clinical Cryptococcus neoformans var.grubii strains from China and Brazil.The genotype of clinical strains from Brazil is diversely distributed.

Objective Cryptococcus neoformans var.grubii isolates from 6 different cities in our country using multilocus microsatellite typing(MLMT) method were genotyped to explore the genotypic distribution of the variety.Methods The DNA of forty-three isolates of Cryptococcus neoformans var.grubii was extracted.The DNA fragments covering microsatellite loci CNG1,CNG2 and CNG3 were amplified using PCR,and then sequenced.The numbers of each motif repeat in 3 microsatellite regions("TA" repeats for CNG1,"GA" repeats for CNG2,and "CAT" repeats for CNG3) were calculated.According to the repeat numbers of these motif,the MLMT types of 43 strains of Cryptococcus neoformans var.grubii were determined.Results Out of 43 isolates,the percentage of MLMT-17 was 83.72%.In the clinical and environmental isolates,the percentages of MLMT-17 were 86.67% and 70%,respectively.Two new genotypes MLMT-39 and-40 were found.Conclusion MLMT-17 of Cryptococcus neoformans var.grubii is prevalent in both clinical and community environment in China.Implying the most clinical strains which resulted in cryptococcosis originated from indigenous environmental strains.

Objective To investigate the genetic relation between Cryptococcus neoformans var.the clinical strains in MLMT - 13 genotype and the environmental strains in MLMT - 36 genotype. Methods Multilocus microsatellite typing (MLMT) method was applied for the genotype analysis in our study.Through this method, we recognized two genotypes that distinguish a majority of clinical and environmental strains. In order to compare virulence between the two types, we chose to infect BALB/c mice (6 weeks,female) with 9 MLMT-13 strains and 10 MLMT-36 strains intravenously. Results Forty( 17 clinical and 23 environmental isolates) were analyzed. Of 17 clinical strains, 9 belonged to a major type of MLMT-13 (52.9%). They were mainly isolated from clinical specimens. About 43.5% of strains from the environment belong to a major type of MLMT-36, which are indigenous to environments and which were not isolated from clinical samples. The mortality rate and pathological changes of the above mice were observed during two months after injection. The results showed that the mortality rate of mice infected with MLMT-13 strains was 100%, while the mortality rate with MLMT-36 strains was 7. 5%. The pathological sections showed that lesions of MLMT-13 infected mice appeared in the brain, lungs, liver and kidneys, while the lesions of MLMT-36 infected mice only appeared in the brain. Most brains of MLMT-13 infected mice were distorted,and both the number and size of lesions in such brains were much larger than those of MLMT-36 infected mice. Conclusion Our study illustrated the virulent difference between MLMT-13 and MLMT-36, which are isolated from patients and environment respectively. The results inferred that some genetic changes, such ss microsatellite repeats, might occur between environmental and clinical isolates through their environmental adaptation progress.