Cosate Maria Raquel V, Sakamoto Tetsu, de Oliveira Mendes Tiago Antônio, Moreira Élvio C, Regis da Silva Carlos G, Brasil Bruno S A F, Oliveira Camila S F, de Azevedo Vasco Ariston, Ortega José Miguel, Leite Rômulo C, Haddad João Paulo
Instituto de Ciências Biológicas, Departamento de Bioquímica e Imunologia, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brazil.
Departamento de Medicina Veterinária Preventiva, Escola de Veterinária, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brazil.
BMC Vet Res. 2017 Jun 15;13(1):177. doi: 10.1186/s12917-017-1081-9.
Leptospirosis is caused by pathogenic spirochetes of the genus Leptospira spp. This zoonotic disease is distributed globally and affects domestic animals, including cattle. Leptospira interrogans serogroup Sejroe serovar Hardjo and Leptospira borgpetersenii serogroup Sejroe serovar Hardjo remain important species associated with this reproductive disease in livestock production. Previous studies on Brazilian livestock have reported that L. interrogans serovar Hardjo is the most prevalent leptospiral agent in this country and is related to clinical signs of leptospirosis, which lead to economic losses in production. Here, we described the isolation of three clinical strains (Norma, Lagoa and Bolivia) obtained from leptospirosis outbreaks that occurred in Minas Gerais state in 1994 and 2008.
Serological and molecular typing using housekeeping (secY and 16SrRNA) and rfb locus (ORF22 and ORF36) genes were applied for the identification and comparative analysis of Leptospira spp. Our results identified the three isolates as L. interrogans serogroup Sejroe serovar Hardjo and confirmed the occurrence of this bacterial strain in Brazilian livestock. Genetic analysis using ORF22 and ORF36 grouped the Leptospira into serogroup Sejroe and subtype Hardjoprajitno. Genetic approaches were also applied to compare distinct serovars of L. interrogans strains by verifying the copy numbers of the IS1500 and IS1533 insertion sequences (ISs). The IS1500 copy number varied among the analyzed L. interrogans strains.
This study provides evidence that L. interrogans serogroup Sejroe serovar Hardjo subtype Hardjoprajitno causes bovine leptospirosis in Brazilian production. The molecular results suggested that rfb locus (ORF22 and ORF36) could improve epidemiological studies by allowing the identification of Leptospira spp. at the serogroup level. Additionally, the IS1500 and IS1533 IS copy number analysis suggested distinct genomic features among closely related leptospiral strains.
钩端螺旋体病由钩端螺旋体属的致病性螺旋体引起。这种人畜共患病在全球范围内传播，影响包括牛在内的家畜。问号钩端螺旋体 sejroe 血清群 hardjo 血清型和博氏钩端螺旋体 sejroe 血清群 hardjo 血清型仍是与家畜生产中这种生殖疾病相关的重要菌种。此前对巴西家畜的研究报告称，问号钩端螺旋体 hardjo 血清型是该国最普遍的钩端螺旋体病原体，与钩端螺旋体病的临床症状有关，会导致生产中的经济损失。在此，我们描述了从1994年和2008年在米纳斯吉拉斯州发生的钩端螺旋体病疫情中分离出的三株临床菌株（Norma、Lagoa 和 Bolivia）。
使用管家基因（secY 和 16SrRNA）和 rfb 基因座（ORF22 和 ORF36）进行血清学和分子分型，用于钩端螺旋体属的鉴定和比较分析。我们的结果将这三株分离株鉴定为问号钩端螺旋体 sejroe 血清群 hardjo 血清型，并证实了该菌株在巴西家畜中的存在。使用 ORF22 和 ORF36 进行的遗传分析将钩端螺旋体分为 sejroe 血清群和 hardjoprajitno 亚型。还应用遗传方法通过验证 IS1500 和 IS1533 插入序列（ISs）的拷贝数来比较问号钩端螺旋体菌株的不同血清型。在分析的问号钩端螺旋体菌株中，IS1500 的拷贝数各不相同。
本研究提供了证据，表明问号钩端螺旋体 sejroe 血清群 hardjo 血清型 hardjoprajitno 亚型在巴西生产中导致牛钩端螺旋体病。分子结果表明，rfb 基因座（ORF22 和 ORF36）可以通过在血清群水平上鉴定钩端螺旋体属来改善流行病学研究。此外，IS1500 和 IS1533 IS 拷贝数分析表明密切相关的钩端螺旋体菌株之间存在不同的基因组特征。
