Background:The prevalence of human brucellosis in Qinghai Province of China has been increasing rapidly,with confirmed cases distributed across 31 counties.However,the epidemiology of brucellosis transmission has not ...Background:The prevalence of human brucellosis in Qinghai Province of China has been increasing rapidly,with confirmed cases distributed across 31 counties.However,the epidemiology of brucellosis transmission has not been fully elucidated.To characterize the infecting strains isolated from humans,multiple-locus variable-number tandem repeats analysis(MLVA)and whole-genome single-nucleotide polymorphism(SNP)-based approaches were employed.Methods:Strains were isolated from two males blood cultures that were confirmed Brucella m elitensis positive following biotyping and MLVA.Genomic DNA was extracted from these two strains,and whole-genome sequencing was performed.Next,SNP-based phylogenetic analysis was performed to compare the two strains to 94 B.melitensis strains(complete genome and draft genome)retrieved from online databases.Results:The two Brucella isolates were identified as B.melitensis biovar 3(QH2019001 and QH2019005)following conventional biotyping and were found to have differences in their variable number tandem repeats(VNTRs)using MLVA-16.Phylogenetic examination assigned the 96 strains to five genotype groups,with QH2019001 and QH2019005 assigned to the same group,but different subgroups.Moreover,the QH2019005 strain was assigned to a new subgenotype,llj,within genotype II.These findings were then combined to determine the geographic origin of the two Brucella strains.Conclusions:Utilizing a whole-genome SNP-based approach enabled differences between the two B.m elitensis strains to be more clearly resolved,and facilitated the elucidation of their different evolutionary histories.This approach also revealed that QH2019005 is a member of a new subgenotype(Hj)with an ancient origin in the eastern Mediterranean Sea.展开更多
基金supported by National Key R&D Program of China(Grant No.2020YFA0907101)Major Infectious Diseases such as AIDS and Viral Hepatitis Prevention and Control Technology Major Projects(2018ZX10201002)the National Natural Scientific Foundation of China(81860588).
文摘Background:The prevalence of human brucellosis in Qinghai Province of China has been increasing rapidly,with confirmed cases distributed across 31 counties.However,the epidemiology of brucellosis transmission has not been fully elucidated.To characterize the infecting strains isolated from humans,multiple-locus variable-number tandem repeats analysis(MLVA)and whole-genome single-nucleotide polymorphism(SNP)-based approaches were employed.Methods:Strains were isolated from two males blood cultures that were confirmed Brucella m elitensis positive following biotyping and MLVA.Genomic DNA was extracted from these two strains,and whole-genome sequencing was performed.Next,SNP-based phylogenetic analysis was performed to compare the two strains to 94 B.melitensis strains(complete genome and draft genome)retrieved from online databases.Results:The two Brucella isolates were identified as B.melitensis biovar 3(QH2019001 and QH2019005)following conventional biotyping and were found to have differences in their variable number tandem repeats(VNTRs)using MLVA-16.Phylogenetic examination assigned the 96 strains to five genotype groups,with QH2019001 and QH2019005 assigned to the same group,but different subgroups.Moreover,the QH2019005 strain was assigned to a new subgenotype,llj,within genotype II.These findings were then combined to determine the geographic origin of the two Brucella strains.Conclusions:Utilizing a whole-genome SNP-based approach enabled differences between the two B.m elitensis strains to be more clearly resolved,and facilitated the elucidation of their different evolutionary histories.This approach also revealed that QH2019005 is a member of a new subgenotype(Hj)with an ancient origin in the eastern Mediterranean Sea.
