Image 2_Molecular epidemiology of Brucella abortus in Shandong, China: high-resolution insights from combined MLVA-16 and core genome SNP analysis.jpeg

Introduction<p>The recent identification of Brucella abortus in human clinical samples from Shandong, China, highlights an ongoing zoonotic threat.</p>Methods<p>We characterized 12 B. abortus strains isolated from human patients since 2021 using a combination of conventional biotyp...

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محفوظ في:
التفاصيل البيبلوغرافية
المؤلف الرئيسي: Chanjuan Huangfu (22481278) (author)
مؤلفون آخرون: Xiujun Ma (22481281) (author), Junjie Fan (2040463) (author), Kuo Han (1721350) (author), Ti Liu (14049918) (author), Zengqiang Kou (6746876) (author), Yan Li (23143) (author)
منشور في: 2025
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الوصف
الملخص:Introduction<p>The recent identification of Brucella abortus in human clinical samples from Shandong, China, highlights an ongoing zoonotic threat.</p>Methods<p>We characterized 12 B. abortus strains isolated from human patients since 2021 using a combination of conventional biotyping, Multiple Locus Variable-number Tandem Repeat Analysis (MLVA), and core-genome SNP (cgSNP) analysis.</p>Results<p>Epidemiological data indicated that infections primarily occurred in middle-aged men with occupational livestock exposure. Molecular typing revealed biovar 3 as the predominant type (91.7%), dominated by MLVA-8 genotype 36 and its corresponding MLVA-11 genotype 72 (66.7%). MLVA-16 distinguished 12 unique genotypes. The phylogeny based on cgSNP classified the strains into clades C1 (11 bv. 3 strains) and C2 (one bv. 1 strain). Within clade C1, nine strains in subclade C1-III exhibited ≤119 SNP differences, eight of which formed a local clonal transmission chain (≤52 SNPs) and shared MLVA-11 genotype 72. Subclade C1-I contained two strains with novel genotypes resulting from variations at the Bruce18 and Bruce43 loci. The sole C2 strain differed by only 3 SNPs from the A19 vaccine strain, suggesting a potential vaccine-related origin. Genetic links were also identified with strains from other Chinese provinces, among them Heilongjiang and Inner Mongolia, as well as from several countries, including Mongolia and Russia.</p>Discussion<p>These findings revealed a complex epidemiological pattern in Shandong, primarily characterized by local transmission chains with occasional external introductions, provided a scientific basis for targeted brucellosis control strategies.</p>