ABSTRACT

Melissococcus plutonius

is a bacterial pathogen that causes epidemic outbreaks of European foulbrood (EFB) in honey bee populations. The pathogenicity of a bacterium depends on its virulence, and understanding the mechanisms influencing virulence may allow for improved disease control and containment. Using a standardized in vitro assay, we demonstrate that virulence varies greatly among sixteen M. plutonius isolates from five European countries. Additionally, we explore the causes of this variation. In this study, virulence was independent of the multilocus sequence type of the tested pathogen, and was not affected by experimental co-infection with Paenibacillus alvei, a bacterium often associated with EFB outbreaks. Virulence in vitro was correlated with the growth dynamics of M. plutonius isolates in artificial medium, and with the presence of a plasmid carrying a gene coding for the putative toxin melissotoxin A. Our results suggest that some M. plutonius strains showed an increased virulence due to the acquisition of a toxin-carrying mobile genetic element. We discuss whether strains with increased virulence play a role in recent EFB outbreaks.

中文翻译：

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假定的致病力是决定性的决定因素，即构成蜜蜂中欧洲臭脚的细菌。

摘要

布鲁氏菌

是一种细菌病原体，可导致蜜蜂种群中欧洲臭蝇（EFB）流行。细菌的致病性取决于其毒力，了解影响毒力的机制可能会改善疾病的控制和遏制。使用标准化的体外测定方法，我们证明了来自五个欧洲国家的16个分枝杆菌的毒力差异很大。此外，我们探索了这种差异的原因。在这项研究中，毒力与所测试病原体的多基因座序列类型无关，并且不受与肺炎Paenibacillus alvei（一种经常与EFB暴发相关的细菌）的实验性共感染的影响。体外毒力用的生长动态相关M. plutonius菌株在人工培养基，并用携带基因编码推定的毒素melissotoxin A.质粒的存在我们的研究结果表明，一些M. plutonius菌株显示提高的毒力因收购携带毒素的移动遗传元件 我们讨论了毒力增加的菌株是否在最近的EFB暴发中起作用。