Abstract：
Background: Brucellosis is the most important public health problem worldwide, and the annual incidence of the disease in humans is 2.1 million. The Brucella genome is highly conserved, with over 90% similarity among species. The aim of this study was to perform species-level identification of Brucella spp. strains isolated from humans diagnosed with brucellosis and to further investigate the phylogenetic relationships using multiple locus variable number of tandem repeats analysis (MLVA)-16 and 16S rRNA sequencing analysis. Materials and Methods: Brucella spp. was isolated from the blood cultures of 54 patients who tested positive for brucellosis through serological examinations. Real-time PCR was used to identify the isolates in species, and the genus level of Brucella was confirmed with 16S rRNA. All isolates were subjected to phylogenetic analysis using variable number of tandem repeat analysis with multiple loci. Results: Subsequent analysis via real-time PCR confirmed these isolates to be of the Brucella melitensis species. The 16S rRNA sequence analysis showed 100% homogeneity among the isolates. MLVA revealed the formation of five different genotypic groups. While two groups were formed based on the 16S rRNA sequence analysis, five groups were formed in the MLVA. Conclusions: The study concluded that 16S rRNA sequence analysis alone did not provide sufficient discrimination for phylogenetic analysis but served as a supportive method for identification. MLVA exhibited higher phylogenetic power. The widespread isolation of B. melitensis from human brucellosis cases highlights the importance of controlling brucellosis in small ruminants to prevent human infections.
摘要：
背景:布鲁氏菌病是世界范围内最重要的公共卫生问题。人类每年的发病率为210万。布鲁氏菌基因组是高度保守的，物种之间有90%以上的相似性。本研究的目的是进行布鲁氏菌属的种级鉴定。从诊断为布鲁氏菌病的人类分离的菌株，并使用多个基因座可变数量的串联重复序列分析（MLVA）-16和16SrRNA测序分析进一步研究系统发育关系。材料与方法:布鲁氏菌属.从通过血清学检查对布氏杆菌病检测呈阳性的54例患者的血液培养物中分离出来。采用实时荧光定量PCR技术对物种中的分离株进行鉴定,用16SrRNA确认布鲁氏菌属水平。使用具有多个基因座的可变数量的串联重复分析对所有分离物进行系统发育分析。结果：通过实时PCR进行的后续分析证实了这些分离株属于布鲁氏菌物种。16SrRNA序列分析显示分离株之间100％的同质性。MLVA揭示了五个不同基因型组的形成。虽然根据16SrRNA序列分析形成了两组，在MLVA中形成了五组。结论：该研究得出结论，单独的16SrRNA序列分析不能为系统发育分析提供足够的区分，但可以作为鉴定的支持方法。MLVA表现出更高的系统发育能力。从人类布鲁氏菌病病例中广泛分离的B.melitensis突出了控制小反刍动物布鲁氏菌病预防人类感染的重要性。
