Molecular characteristics of Brucella melitensis isolates from humans in Qinghai Province, China

• 作者: Zhao Zhi-Jun Li Ji-Quan Ma Li Xue Hong-Mei Yang Xu-Xin Zhao Yuan-Bo Qin Yu-Min Yang Xiao-Wen Piao Dong-Ri Zhao Hong-Yan Tian Guo-Zhong Li Qiang Wang Jian-Ling Tian Guang Jiang Hai Xu Li-Qing
• 来源期刊: 贫困所致传染病（英文）
• 关键词: Brucella melitensis Multiple-locus variable-number tandem repeats anal Whole-genome sequencing Single-nucleotide polymorphism
• 年，卷（期）: 2021,（2）
• 所属期刊栏目: Short Report
• 页码范围: 64-69
• 页数: 6页
• 语种: 中文
• DOI: 10.1186/s40249-021-00829-0

摘要

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 melitensis 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, IIj, 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. melitensis 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 (IIj) with an ancient origin in the eastern Mediterranean Sea.