A Study Of Genotype,population Genetic Variation And Drug Sensitivity Of Cryptococcus Neoformans In Jiangxi Province,china

Objective:1.Toexplorethegenotypecomposition,molecularepidemiological characteristics and drug sensitivity of C.neoformans in jiangxi province,and to enrich the epidemiological data of Cryptococcus in China.2.Statistics on the distribution of genotypes in the global distribution,and analysis of the genetic variation of C.neoformans in different regions of China,tracing possible transmission/mutation origin.Methods:86 isolates of C.neoformans were obtained from patients hospitalized in Jiangxi hospitals from January 2016 to November 2017.we used the MALDI-TOF MS,L-canavanine-glycine-bromothymol blue agar and the SOD1 gene to identify the isolates.The in vitro antifungal susceptibility testing of all 86 isolates of amphotericin B?AMB?,fucytosine?5FC?,fuconazole?FCA?,voriconazole?VOR?,itraconazole?ITR?was performed using the ATB^TMFUNGUS-3 kit.Polymerase chain reaction?PCR?amplification of specific product SOD1 and STE20?STE20Aa,STE20A,STE20Da and STE20D?determine genotype,serotype and mating type.Molecular genetic analysis of all strains was carried out by multilocus sequence typing?MLST?,and the results were analyzed by eBURST software.Phylogenetic analysis of the concatenated sequences of seven MLST loci was performed using MEGA version 7.0sofware.We extracted all the published genotype information for all the Chinese isolates at the seven sequenced loci from the Cryptococcus MLST database and analyzed using the GenAlEx 6.5 sofware.Results:we analyzed 86 clinical C.neoformans isolates from 14 regions in Jiangxi Province in south central China,each isolate was from a diferent patient.The majority of the total hosts?76.7%;66/86?had defcient or suppressed immune systems,and 35 of the 86?40.7%?patients were infected with HIV.Though none of the isolates was resistant to the five tested antifungal drugs,obvious diferences in their minimum inhibitory concentrations were observed,even among isolates of the same ST.All strains belonged to serotype A and mating type??MAT??.Genotyping based on DNA sequences at seven nuclear loci revealed eight sequence types?STs?among the 86 isolates,including two novel STs that have not been reported from other parts of the world,and six?ST5,ST31,ST32,ST139,ST186,and ST359?have been reported previously from other geographic areas.Population structure analysis found that these eight STs belong to the same clone group,and ST5 was the dominant Genotype?84.9%;73/86?.18 alleles at the seven loci,none was specifc to Jiangxi and all have been found elsewhere.five STs?ST5,ST186,ST359,ST31 and ST32?formed a tight cluster with each other.Our comparative analyses showed that these genotypes in Jiangxi likely originated by dispersal from other regions within and outside of China and/or mutations from another genotype within Jiangxi.Conclusion:Cryptococcosis had underlying risk factors associated with compromised immunity.ST5 was the predominant sequence type in both Jiangxi and other parts of China.Both unique STs and evidence for long distance dispersals were found among most surveyed regions in China.Continuous monitoring should be conducted to understand the changing dynamics of C.neoformans in this and other regions.