Department of Bacteriology and Parasitology, Laboratory for Bacterial Zoonosis and Molecular Diagnostics of Bacterial Diseases, Croatian Veterinary Institute, Savska street 143, Zagreb, Croatia.
French Agency for Food, Environmental & Occupational Health Safety (ANSES), Bacterial Zoonoses Unit - Animal Health Laboratory, National & OIE/FAO Animal Brucellosis Reference Laboratory, EU Reference Laboratory for Brucellosis, 14 rue Pierre et Marie Curie, Maisons-Alfort, Cedex, France.
BMC Vet Res. 2021 Mar 20;17(1):126. doi: 10.1186/s12917-021-02833-w.
A novel Brucella strain closely related to Brucella (B.) melitensis biovar (bv) 3 was found in Croatian cattle during testing within a brucellosis eradication programme.
Standardised serological, brucellin skin test, bacteriological and molecular diagnostic screening for Brucella infection led to positive detection in one dairy cattle herd. Three isolates from that herd were identified to species level using the Bruce ladder method. Initially, two strains were typed as B. melitensis and one as B. abortus, but multiplex PCR based on IS711 and the Suis ladder showed that all of them to belong to B. melitensis, and the combination of whole-genome and multi-locus sequencing as well as Multi-Locus Variable numbers of tandem repeats Analysis (MLVA) highlighted a strong proximity within the phylogenetic branch of B. melitensis strains previously isolated from Croatia, Albania, Kosovo and Bosnia and Herzegovina. Two isolates were determined to be B. melitensis bv. 3, while the third showed a unique phylogenetic profile, growth profile on dyes and bacteriophage typing results. This isolate contained the 609-bp omp31 sequence, but not the 723-bp omp31 sequence present in the two isolates of B. melitensis bv. 3.
Identification of a novel Brucella variant in this geographic region is predictable given the historic endemicity of brucellosis. The emergence of a new variant may reflect a combination of high prevalence among domestic ruminants and humans as well as weak eradication strategies. The zoonotic potential, reservoirs and transmission pathways of this and other Brucella variants should be explored.
在一项布鲁氏菌病根除计划的检测中，在克罗地亚牛群中发现了一种与布鲁氏菌（B.）melitensis 生物型（bv）3 密切相关的新型布鲁氏菌菌株。
对布鲁氏菌感染的标准化血清学、布鲁氏菌素皮肤试验、细菌学和分子诊断筛查导致一个奶牛场呈阳性检测。使用 Bruce 梯法从该牛群中鉴定出三种分离株到种水平。最初，两种菌株被分型为 B. melitensis，一种为 B. abortus，但基于 IS711 和 Suis 梯的多重 PCR 显示它们均属于 B. melitensis，全基因组和多位点测序以及多位点可变数串联重复分析（MLVA）的组合突出了在先前从克罗地亚、阿尔巴尼亚、科索沃和波斯尼亚和黑塞哥维那分离的 B. melitensis 菌株的系统发育分支内的密切关系。两种分离株被确定为 B. melitensis bv. 3，而第三种分离株显示出独特的系统发育特征、染料生长特征和噬菌体分型结果。该分离株含有 609-bp 的 omp31 序列，但不含有存在于两种 B. melitensis bv. 3 分离株中的 723-bp omp31 序列。
鉴于布鲁氏菌病的历史流行情况，在该地理区域鉴定出一种新型布鲁氏菌变种是可以预测的。新变种的出现可能反映了家养反刍动物和人类中的高流行率以及薄弱的根除策略的结合。应探索这种和其他布鲁氏菌变种的人畜共患病潜力、宿主和传播途径。
