Chawjiraphan Wireeya, Sonthayanon Piengchan, Chanket Phanita, Benjathummarak Surachet, Kerdsin Anusak, Kalambhaheti Thareerat
Southeast Asian J Trop Med Public Health. 2016 Nov;47(6):1270-87.
Although brucellosis outbreaks in Thailand are rare, they cause abortions and infertility in animals, resulting in significant economic loss. Because Brucella spp display > 90% DNA homology, multilocus sequence typing (MLST) was employed to categorize local Brucella isolates into sequence types (STs) and to determine their genetic relatedness. Brucella samples were isolated from vaginal secretion of cows and goats, and from blood cultures of infected individuals. Brucella species were determined by multiplex PCR of eight loci, in addition to MLST based on partial DNA sequences of nine house-keeping genes. MLST analysis of 36 isolates revealed 78 distinct novel allele types and 34 novel STs, while two isolates possessed the known ST8. Sequence alignments identified polymorphic sites in each allele, ranging from 2-6%, while overall genetic diversity was 3.6%. MLST analysis of the 36 Brucella isolates classified them into three species, namely, B. melitensis, B. abortus and B. suis, in agreement with multiplex PCR results. Genetic relatedness among ST members of B. melitensis and B. abortus determined by eBURST program revealed ST2 as founder of B. abortus isolates and ST8 the founder of B. melitensis isolates. ST 36, 41 and 50 of Thai Brucella isolates were identified as single locus variants of clonal cluster (CC) 8, while the majority of STs were diverse. The genetic diversity and relatedness identified using MLST revealed hitherto unexpected diversity among Thai Brucella isolates. Genetic classification of isolates could reveal the route of brucellosis transmission among humans and farm animals and also reveal their relationship with other isolates in the region and other parts of the world.
尽管泰国布鲁氏菌病疫情爆发较为罕见，但这些疫情会导致动物流产和不孕，造成重大经济损失。由于布鲁氏菌属的DNA同源性超过90%，因此采用多位点序列分型（MLST）方法将当地布鲁氏菌分离株分类为序列类型（STs），并确定它们的遗传相关性。从奶牛和山羊的阴道分泌物以及感染个体的血培养物中分离出布鲁氏菌样本。除了基于9个管家基因的部分DNA序列进行MLST外，还通过对8个基因座的多重PCR来确定布鲁氏菌的种类。对36株分离株的MLST分析揭示了78种不同的新等位基因类型和34种新的STs，而有两株分离株具有已知的ST8。序列比对确定了每个等位基因中的多态性位点，范围为2%-6%，而总体遗传多样性为3.6%。对这36株布鲁氏菌分离株的MLST分析将它们分为三个种，即羊种布鲁氏菌、牛种布鲁氏菌和猪种布鲁氏菌，这与多重PCR结果一致。通过eBURST程序确定的羊种布鲁氏菌和牛种布鲁氏菌ST成员之间的遗传相关性表明，ST2是牛种布鲁氏菌分离株的始祖，ST8是羊种布鲁氏菌分离株的始祖。泰国布鲁氏菌分离株的ST 36、41和50被鉴定为克隆群（CC）8的单一位点变体，而大多数STs则各不相同。使用MLST确定的遗传多样性和相关性揭示了泰国布鲁氏菌分离株之间迄今未曾预料到的多样性。分离株的基因分类可以揭示布鲁氏菌病在人类和家畜之间的传播途径，还可以揭示它们与该地区及世界其他地区其他分离株的关系。
