Departamento de Análises Clínicas, Toxicológicas e Bromatológicas, Faculdade de Ciências Farmacêuticas de Ribeirão Preto - USP, Av. do Café, s/n, Ribeirão Preto, SP, 14040-903, Brazil.
Fundação Oswaldo Cruz - FIOCRUZ, Pavilhão Rocha Lima, Av. Brasil, 4365, Rio de Janeiro, RJ, 21040-900, Brazil.
Braz J Microbiol. 2020 Jun;51(2):497-509. doi: 10.1007/s42770-019-00156-5. Epub 2019 Nov 8.
Salmonella Dublin is a strongly adapted serovar that causes enteritis and/or systemic disease with high rates of mortality in cattle and occasionally infects humans. Despite the importance of this serovar, there is a lack of studies in Brazil. The aim of this study was to characterize the genetic diversity of 112 S. Dublin strains isolated from humans and animals in Brazil by CRISPR and CRISPR-MVLST and the relatedness among strains by MLST. In addition, the frequency of some important virulence genes was verified. The strains studied belonged to nine different sequence types, being all of them single- or double-locus variants of the ST10. CRISPR discriminated the strains into 69 subtypes with a similarity ≥ 84.4% and CRISPR-MVLST into 72 subtypes with a similarity ≥ 84.7%. The virulence genes ratB, lpfA, mgtC, avrA, sopB, sopE2, sifA, sseA, ssrA, csgA, fliC, and sinH were found in all the strains studied, while spvB, spvC, sodCl, rpoS, sipA, sipD, invA, and hilA were detected in ≥ 93.7% of the strains. In conclusion, the high similarity among the strains reinforces the clonal nature of the strains of this serovar that may have descended from a common ancestor that little differed over 33 years in Brazil. CRISPR and CRISPR-MVLST showed to be good alternatives to type S. Dublin strains. MLST suggested that S. Dublin strains from Brazil were phylogenetically related to strains from other parts of the globe. Moreover, the high frequency of virulence genes among the strains studied reinforces the capacity of S. Dublin to cause invasive diseases.
都柏林沙门氏菌是一种适应能力很强的血清型，可引起牛的肠炎和/或全身性疾病，死亡率很高，偶尔也会感染人类。尽管这种血清型很重要，但在巴西却缺乏相关研究。本研究旨在通过 CRISPR 和 CRISPR-MVLST 对 112 株从巴西人和动物中分离出的都柏林沙门氏菌进行遗传多样性特征分析，并通过 MLST 分析菌株之间的亲缘关系。此外，还验证了一些重要毒力基因的频率。所研究的菌株属于 9 个不同的序列型，均为 ST10 的单或双基因座变体。CRISPR 将菌株分为 69 个相似度≥84.4%的亚型，CRISPR-MVLST 将菌株分为 72 个相似度≥84.7%的亚型。所有研究菌株均携带 ratB、lpfA、mgtC、avrA、sopB、sopE2、sifA、sseA、ssrA、csgA、fliC 和 sinH 毒力基因，而 spvB、spvC、sodCl、rpoS、sipA、sipD、invA 和 hilA 毒力基因则在≥93.7%的菌株中检测到。总之，菌株之间的高相似度证实了该血清型菌株的克隆性质，这些菌株可能起源于一个共同的祖先，在巴西 33 年间差异很小。CRISPR 和 CRISPR-MVLST 显示是鉴定都柏林沙门氏菌血清型的良好替代方法。MLST 表明，巴西的都柏林沙门氏菌菌株与来自全球其他地区的菌株在系统发育上有关。此外，研究菌株中高频率的毒力基因证实了都柏林沙门氏菌引起侵袭性疾病的能力。
