Dorneles Elaine Maria Seles, Santana Jordana Almeida, Alves Telma Maria, Pauletti Rebeca Barbosa, Mol Juliana Pinto da Silva, Heinemann Marcos Bryan, Lage Andrey Pereira
Laboratório de Bacteriologia Aplicada, Departamento de Medicina Veterinária Preventiva, Escola de Veterinária, Universidade Federal de Minas Gerais, Av, Antônio Carlos, 6627, Caixa Postal 567, 31270-901 Belo Horizonte, MG, Brazil.
BMC Microbiol. 2014 Jul 11;14:186. doi: 10.1186/1471-2180-14-186.
Brucellosis caused by Brucella abortus is one of the most important zoonoses in the world. Multiple-locus variable-number tandem repeat analysis (MLVA16) has been shown be a useful tool to epidemiological traceback studies in B. abortus infection. Thus, the present study aimed (i) to evaluate the genetic diversity of B. abortus isolates from a brucellosis outbreak, and (ii) to investigate the in vivo stability of the MLVA16 markers.
Three-hundred and seventy-five clinical samples, including 275 vaginal swabs and 100 milk samples, were cultured from a brucellosis outbreak in a cattle herd, which adopted RB51 vaccination and test-and-slaughter policies. Thirty-seven B. abortus isolates were obtained, eight from milk and twenty-nine from post-partum/abortion vaginal swabs, which were submitted to biotyping and genotyping by MLVA16. Twelve B. abortus isolates obtained from vaginal swabs were identified as RB51. Twenty four isolates, seven obtained from milk samples and seventeen from vaginal swabs, were identified as B. abortus biovar 3, while one isolate from vaginal swabs was identified as B. abortus biovar 1. Three distinct genotypes were observed during the brucellosis outbreak: RB observed in all isolates identified as RB51; W observed in all B. abortus biovar 3 isolates; and Z observed in the single B. abortus biovar 1 isolate. Epidemiological and molecular data show that the B. abortus biovar 1 genotype Z strain is not related to the B. abortus biovar 3 genotype W isolates, and represents a new introduction B. abortus during the outbreak.
The results of the present study on typing of multiple clinical B. abortus isolates from the same outbreak over a sixteen month period indicate the in vivo stability of MLVA16 markers, a low genetic diversity among B. abortus isolates and the usefulness of MLVA16 for epidemiological studies of bovine brucellosis.
由流产布鲁氏菌引起的布鲁氏菌病是世界上最重要的人畜共患病之一。多位点可变数目串联重复序列分析（MLVA16）已被证明是流产布鲁氏菌感染流行病学追溯研究的有用工具。因此，本研究旨在（i）评估布鲁氏菌病暴发中流产布鲁氏菌分离株的遗传多样性，以及（ii）研究MLVA16标记在体内的稳定性。
从一个采用RB51疫苗接种和检测与屠宰政策的牛群布鲁氏菌病暴发中采集了375份临床样本，包括275份阴道拭子和100份乳样。获得了37株流产布鲁氏菌分离株，8株来自乳样，29株来自产后/流产阴道拭子，对这些分离株进行了生物分型和MLVA16基因分型。从阴道拭子中获得的12株流产布鲁氏菌分离株被鉴定为RB51。24株分离株，7株来自乳样，17株来自阴道拭子，被鉴定为流产布鲁氏菌生物变种3，而1株来自阴道拭子的分离株被鉴定为流产布鲁氏菌生物变种1。在布鲁氏菌病暴发期间观察到三种不同的基因型：在所有鉴定为RB51的分离株中观察到RB型；在所有流产布鲁氏菌生物变种3分离株中观察到W型；在单个流产布鲁氏菌生物变种1分离株中观察到Z型。流行病学和分子数据表明，流产布鲁氏菌生物变种1基因型Z菌株与流产布鲁氏菌生物变种3基因型W分离株无关，并且代表了暴发期间新引入的流产布鲁氏菌。
本研究对同一暴发中16个月内多个临床流产布鲁氏菌分离株进行分型的结果表明，MLVA16标记在体内具有稳定性，流产布鲁氏菌分离株之间的遗传多样性较低，以及MLVA16在牛布鲁氏菌病流行病学研究中的有用性。
