Sibhat Berhanu, Adamu Haileeyesus, Asmare Kassahun, Lindahl Johanna F, Magnusson Ulf, Sisay Tessema Tesfaye
Institute of Biotechnology, Addis Ababa University, Addis Ababa P.O. Box 1176, Ethiopia.
College of Veterinary Medicine, Haramaya University, Dire Dawa P.O. Box 138, Ethiopia.
Pathogens. 2024 Dec 3;13(12):1063. doi: 10.3390/pathogens13121063.
Brucellosis is a neglected zoonotic disease affecting livestock and humans that remains endemic in Ethiopia. Despite its prevalence, only a few studies have identified species circulating in livestock in the country. This study aimed to determine the species responsible for infections in livestock in the Afar region of Ethiopia and characterize the isolates using whole-genome single nucleotide polymorphism (wgSNP) analysis and in silico multi-locus sequence typing (MLST). Comparisons were made between Ethiopian and regional and global isolates to determine their phylogenetic relationships. Surveys conducted in May and October-November 2022 in six villages of the Amibara district involved the collection of vaginal swabs (n = 231) and milk samples (n = 17) from 32 sheep and 199 goats kept by 143 pastoral households reporting recent abortions in the animals. was detected in three sheep and 32 goats, i.e., 15% (35/231) of animals across 20% (29/143) of households using bacterial culture and PCR-based methods (bcsp31, AMOS, and Bruce-ladder multiplex PCR). Of the 35 positive animals, was isolated from 24 swabs, while the remaining 11 were culture-negative and detected only by PCR. The genomic DNA of the 24 isolates was sequenced using Illumina Novaseq 6000 and assembled using the SPAdes pipeline. Nine- and 21-locus MLST identified 23 isolates as genotype ST12, while one isolate could not be typed. The wgSNP-based phylogenetic analysis revealed that the Ethiopian isolates clustered within the African clade and were closely related to isolates from Somalia. Several virulence factors responsible for adhesion, intracellular survival, and regulatory functions were detected in all isolates. No antimicrobial resistance genes associated with resistance to drugs commonly used for treating brucellosis were detected. Since is prevalent in sheep and goats, vaccination with the Rev-1 vaccine is the recommended strategy in these pastoral systems to protect animal and human health.
布鲁氏菌病是一种被忽视的人畜共患病，影响家畜和人类，在埃塞俄比亚仍然流行。尽管其发病率很高，但只有少数研究确定了该国家畜中传播的布鲁氏菌物种。本研究旨在确定埃塞俄比亚阿法尔地区家畜感染的致病物种，并使用全基因组单核苷酸多态性（wgSNP）分析和计算机多位点序列分型（MLST）对分离株进行特征分析。对埃塞俄比亚分离株与区域和全球分离株进行比较，以确定它们的系统发育关系。2022年5月以及10月至11月在阿米巴拉区的六个村庄进行的调查，涉及从143个报告其动物最近流产的牧民家庭饲养的32只绵羊和199只山羊中采集阴道拭子（n = 231）和牛奶样本（n = 17）。使用细菌培养和基于PCR的方法（bcsp31、AMOS和布鲁氏菌阶梯多重PCR），在3只绵羊和32只山羊中检测到布鲁氏菌，即在20%（29/143）的家庭中的15%（35/231）的动物中检测到。在35只阳性动物中，从24份拭子中分离出布鲁氏菌，其余11份培养阴性，仅通过PCR检测到。使用Illumina Novaseq 6000对24株分离株的基因组DNA进行测序，并使用SPAdes流程进行组装。9位点和21位点MLST鉴定出23株分离株为基因型ST12，而1株分离株无法分型。基于wgSNP的系统发育分析表明，埃塞俄比亚分离株聚集在非洲分支内，并且与来自索马里的分离株密切相关。在所有分离株中检测到了几种负责黏附、细胞内存活和调节功能的毒力因子。未检测到与治疗布鲁氏菌病常用药物耐药性相关的抗菌耐药基因。由于布鲁氏菌在绵羊和山羊中流行，在这些牧区系统中，使用Rev-1疫苗进行疫苗接种是保护动物和人类健康的推荐策略。
