Institute of Bacterial Infections and Zoonoses, Fredrich-Loeffler-Institut - Federal Research Institute for Animal Health (FLI), 07743, Jena, Germany.
Laboratory of Clinical Microbiology and Microbial Pathogenesis, School of Medicine, University of Crete, Heraklion, Crete, 71500, Greece.
BMC Infect Dis. 2023 Aug 14;23(1):529. doi: 10.1186/s12879-023-08518-z.
Brucellosis is a zoonotic disease whose causative agent, Brucella spp., is endemic in many countries of the Mediterranean basin, including Greece. Although the occurrence of brucellosis must be reported to the authorities, it is believed that the disease is under-reported in Greece, and knowledge about the genomic diversity of brucellae is lacking.
Thus, 44 Brucella isolates, primarily B. melitensis, collected between 1999 and 2009 from humans and small ruminants in Greece were subjected to whole genome sequencing using short-read technology. The raw reads and assembled genomes were used for in silico genotyping based on single nucleotide substitutions and alleles. Further, specific genomic regions encoding putative virulence genes were screened for characteristic nucleotide changes, which arose in different genotype lineages.
In silico genotyping revealed that the isolates belonged to three of the known sublineages of the East Mediterranean genotype. In addition, a novel subgenotype was identified that was basal to the other East Mediterranean sublineages, comprising two Greek strains. The majority of the isolates can be assumed to be of endemic origin, as they were clustered with strains from the Western Balkans or Turkey, whereas one strain of human origin could be associated with travel to another endemic region, e.g. Portugal. Further, nucleotide substitutions in the housekeeping gene rpoB and virulence-associated genes were detected, which were characteristic of the different subgenotypes. One of the isolates originating from an aborted bovine foetus was identified as B. abortus vaccine strain RB51.
The results demonstrate the existence of several distinct persistent Brucella sp. foci in Greece. To detect these and for tracing infection chains, extensive sampling initiatives are required.
布鲁氏菌病是一种人畜共患疾病，其病原体布鲁氏菌属在包括希腊在内的许多地中海国家流行。虽然该病的发生必须向当局报告，但据信该病在希腊的报告不足，而且对布鲁氏菌的基因组多样性知之甚少。
因此，对 1999 年至 2009 年间从希腊人类和小反刍动物中采集的 44 株布鲁氏菌分离株（主要为 B. melitensis）进行了短读长测序全基因组测序。使用原始读数和组装基因组基于单核苷酸替换和等位基因进行了基于计算机的基因分型。此外，针对编码假定毒力基因的特定基因组区域筛选了不同基因型谱系中出现的特征核苷酸变化。
基于计算机的基因分型显示，这些分离株属于东地中海基因型的三个已知亚谱系。此外，还确定了一个新的亚基因型，该亚基因型与其他东地中海亚谱系的基础不同，包括两个希腊株。由于它们与来自西巴尔干或土耳其的菌株聚类，大多数分离株可以假定为地方性起源，而源自人类的一株可以与另一个地方性地区（例如葡萄牙）的旅行有关。此外，还检测到看家基因 rpoB 和与毒力相关基因中的核苷酸替换，这些替换是不同亚基因型的特征。源自流产牛胎儿的一个分离株被鉴定为 B. abortus 疫苗株 RB51。
结果表明，希腊存在几个不同的布鲁氏菌属持久焦点。为了检测这些焦点并追踪感染链，需要进行广泛的采样计划。
