Department of Veterinary Science and Microbiology, The University of Arizona, Tucson, Arizona, USA.
Appl Environ Microbiol. 2012 Apr;78(8):2867-73. doi: 10.1128/AEM.07456-11. Epub 2012 Feb 3.
The consumption of raw oysters is an important risk factor in the acquisition of food-borne disease, with Salmonella being one of a number of pathogens that have been found in market oysters. Previous work by our lab found that Salmonella was capable of surviving in oysters for over 2 months under laboratory conditions, and this study sought to further investigate Salmonella's tissue affinity and mechanism of persistence within the oysters. Immunohistochemistry was used to show that Salmonella was capable of breaching the epithelial barriers, infecting the deeper connective tissues of the oysters, and evading destruction by the oysters' phagocytic hemocytes. To further investigate the mechanism of these infections, genes vital to the function of Salmonella's two main type III secretion systems were disrupted and the survivability of these knockout mutants within oysters was assayed. When the Salmonella pathogenicity island 1 and 2 mutant strains were exposed to oysters, there were no detectable deficiencies in their abilities to survive, suggesting that Salmonella's long-term infection of oysters does not rely upon these two important pathogenicity islands and must be due to some other, currently unknown, mechanism.
生食牡蛎是食源性疾病的一个重要危险因素，沙门氏菌是在市场牡蛎中发现的多种病原体之一。我们实验室之前的工作发现，沙门氏菌在实验室条件下能够在牡蛎中存活超过 2 个月，本研究旨在进一步研究沙门氏菌在牡蛎中的组织亲和力和持续存在机制。免疫组织化学用于显示沙门氏菌能够突破上皮屏障，感染牡蛎更深层的结缔组织，并逃避牡蛎吞噬性血球的破坏。为了进一步研究这些感染的机制，我们破坏了对沙门氏菌两种主要 III 型分泌系统功能至关重要的基因，并检测了这些敲除突变体在牡蛎中的存活能力。当沙门氏菌致病性岛 1 和 2 突变株暴露于牡蛎时，它们在生存能力方面没有明显的缺陷，这表明沙门氏菌对牡蛎的长期感染并不依赖于这两个重要的致病性岛，而必须依赖于一些其他目前未知的机制。
