Departman of Veterinary Microbiology, Fakulty of Veterinary Medicine, Siirt University, Siirt, Türkiye.
Departman of Veterinary Microbiology, Fakulty of Veterinary Medicine, Harran University, Şanlıurfa, Türkiye.
BMC Infect Dis. 2024 Oct 30;24(1):1220. doi: 10.1186/s12879-024-09921-w.
Brucellosis, a zoonotic disease in Türkiye, which has significant direct and indirect impacts on the healthcare system and livestock. This study, which aimed to investigate the differences among Brucella spp. isolates originating from different regions of Türkiye, for implications for public health and veterinary medicine.
Twenty-one isolates from ruminants and two isolates from humans obtained from various regions of Türkiye were utilized in the study. The isolates were identified and biotyped using traditional microbiological procedures, and whole-genome sequencing (WGS) was performed. This was followed by single nucleotide polymorphism (SNP)--based phylogenetic analysis and WGS-based analysis of virulence and resistance genes. Additionally, phenotypic antimicrobial resistance and phage susceptibilities were determined. The obtained data were then compared for concordance, ensuring the validity and reliability of the results.
Our study, employing culture methods, polymerase chain reaction (PCR), and WGS analyses, identified 11 Brucella melitensis (bv 3 (n = 9), one each bv 1 and bv 2) and 12 B. abortus (bv 3 (n = 11), bv 9 (n = 1)) isolates All B. abortus isolates were of bovine origin, while the B. melitensis isolates were from sheep (n = 7), goat (n = 1), ram (n = 1), and humans (n = 2). In the whole-genome SNP-based phylogenetic tree, all B. melitensis strains were found to be of the IIb subtype of genotype II associated with the Eastern Mediterranean lineage. Ten different genotypes were identified in the SNP analysis of the isolates, with a maximum SNP difference of 278 and a minimum SNP difference of 4 among these genotypes. According to the WGS-SNP-based phylogenetic tree of B. abortus isolates, they were grouped in clade C1. In the SNP analysis, where ten different genotypes were identified, the SNP difference among these genotypes was a maximum of 316 and a minimum of 6. In the in silico MLST analysis performed with WGS data, B. melitensis isolates were identified as ST8 and ST102 genotypes, while B. abortus isolates were identified as ST2 and ST3 genotypes. The dominant genotypes were ST8 for B. melitensis and ST2 for B. abortus, respectively. Virulence gene analysis conducted based on WGS data of the 23 B. abortus and B. melitensis isolates revealed 43 virulence gene-associated regions in all strains, irrespective of species, host, or isolation year. Although classical resistance-related genes were not detected by WGS-based antimicrobial resistance gene analysis, phenotypic resistance analysis revealed resistance to azithromycin, rifampin, and trimethoprim/sulfamethoxazole in B. abortus and B. melitensis isolates.
Both B. melitensis and B. abortus were circulating species in animals and human. The dominant genotypes were ST8 for B. melitensis and ST2 for B. abortus, respectively. All B. melitensis strains were found to be of the IIb subtype of genotype II associated with the Eastern Mediterranean lineage, while B. abortus isolates, they were grouped in clade C1. Further, a comprehensive study with a sufficient number of isolates covering all regions of Türkiye would provide more accurate information about the current epidemiological situation in the country.
布氏杆菌病是一种人畜共患的疾病，在土耳其对医疗保健系统和畜牧业都有重大的直接和间接影响。本研究旨在调查起源于土耳其不同地区的布鲁氏菌属分离株之间的差异，为公共卫生和兽医医学提供依据。
从土耳其不同地区的 21 株来自反刍动物和 2 株来自人类的分离株进行了研究。通过传统的微生物学程序对分离株进行鉴定和生物型分型，并进行全基因组测序（WGS）。然后进行单核苷酸多态性（SNP）-基于系统发育分析和基于 WGS 的毒力和耐药基因分析。此外，还测定了表型抗菌药物耐药性和噬菌体敏感性。对获得的数据进行一致性比较，以确保结果的有效性和可靠性。
我们的研究采用培养方法、聚合酶链反应（PCR）和 WGS 分析，鉴定出 11 株贝氏杆菌属（bv 3（n = 9），1 株 bv 1 和 1 株 bv 2）和 12 株流产布氏杆菌（bv 3（n = 11），bv 9（n = 1））分离株。所有流产布氏杆菌分离株均来自牛，而贝氏杆菌分离株则来自绵羊（n = 7）、山羊（n = 1）、公羊（n = 1）和人类（n = 2）。在全基因组 SNP 基于系统发育树中，所有贝氏杆菌属菌株均属于与东地中海谱系相关的 IIb 亚型基因型 II。在分离株的 SNP 分析中，鉴定出 10 种不同的基因型，这些基因型之间的最大 SNP 差异为 278，最小 SNP 差异为 4。根据流产布氏杆菌分离株的 WGS-SNP 基于系统发育树，它们被分为 C1 群。在 SNP 分析中，鉴定出 10 种不同的基因型，这些基因型之间的 SNP 差异最大为 316，最小为 6。在使用 WGS 数据进行的体外 MLST 分析中，贝氏杆菌分离株被鉴定为 ST8 和 ST102 基因型，而流产布氏杆菌分离株被鉴定为 ST2 和 ST3 基因型。优势基因型分别为 ST8 用于贝氏杆菌属和 ST2 用于流产布氏杆菌属。基于所有 23 株流产布氏杆菌和贝氏杆菌分离株的 WGS 数据进行的毒力基因分析显示，所有菌株中均存在 43 个与毒力相关的基因区域，与物种、宿主或分离年份无关。尽管基于 WGS 的抗菌药物耐药基因分析未检测到经典的耐药相关基因，但表型耐药分析显示贝氏杆菌和流产布氏杆菌分离株对阿奇霉素、利福平、和磺胺甲恶唑/甲氧苄啶耐药。
贝氏杆菌属和流产布氏杆菌属均在动物和人类中流行。优势基因型分别为 ST8 用于贝氏杆菌属和 ST2 用于流产布氏杆菌属。所有贝氏杆菌属菌株均属于与东地中海谱系相关的 IIb 亚型基因型 II，而流产布氏杆菌分离株，它们被分为 C1 群。进一步，对覆盖土耳其所有地区的足够数量的分离株进行全面研究，将为该国当前的流行病学情况提供更准确的信息。
