Veterinary Research Institute, Hudcova 70, 621 00 Brno, Czech Republic.
BMC Microbiol. 2009 Dec 19;9:268. doi: 10.1186/1471-2180-9-268.
Salmonella is a highly successful parasite of reptiles, birds and mammals. Its ability to infect and colonise such a broad range of hosts coincided with the introduction of new genetic determinants, among them 5 major pathogenicity islands (SPI1-5), into the Salmonella genome. However, only limited information is available on how each of these pathogenicity islands influences the ability of Salmonella to infect chickens. In this study, we therefore constructed Salmonella Enteritidis mutants with each SPI deleted separately, with single individual SPIs (i.e. with the remaining four deleted) and a mutant with all 5 SPIs deleted, and assessed their virulence in one-day-old chickens, together with the innate immune response of this host.
The mutant lacking all 5 major SPIs was still capable of colonising the caecum while colonisation of the liver and spleen was dependent on the presence of both SPI-1 and SPI-2. In contrast, the absence of SPI-3, SPI-4 or SPI-5 individually did not influence virulence of S. Enteritidis for chickens, but collectively they contributed to the colonisation of the spleen. Proinflammatory signalling and heterophil infiltration was dependent on intact SPI-1 only and not on other SPIs.
SPI-1 and SPI-2 are the two most important pathogenicity islands of Salmonella Enteritidis required for the colonisation of systemic sites in chickens.
沙门氏菌是一种高度成功的爬行动物、鸟类和哺乳动物寄生虫。它能够感染和定殖如此广泛的宿主，这与新的遗传决定因素的引入同时发生，其中包括 5 个主要的致病性岛（SPI1-5）进入沙门氏菌基因组。然而，关于这些致病性岛中的每一个如何影响沙门氏菌感染鸡的能力，只有有限的信息。在这项研究中，我们因此分别构建了缺失每个 SPI 的沙门氏菌肠炎突变体，缺失单个 SPI（即其余四个 SPI 缺失）和缺失所有 5 个 SPI 的突变体，并评估了它们在 1 日龄鸡中的毒力，以及宿主的固有免疫反应。
缺失所有 5 个主要 SPI 的突变体仍能在盲肠中定植，而肝脏和脾脏的定植则依赖于 SPI-1 和 SPI-2 的存在。相比之下，单独缺失 SPI-3、SPI-4 或 SPI-5 并不影响肠炎沙门氏菌对鸡的毒力，但它们共同有助于脾脏的定植。促炎信号和嗜中性粒细胞浸润仅依赖于完整的 SPI-1，而不依赖于其他 SPI。
SPI-1 和 SPI-2 是肠炎沙门氏菌定殖鸡全身部位所必需的两个最重要的致病性岛。
