The effect of long-term propionate adaptation on the stress resistance of Salmonella Enteritidis
The effect of long-term propionate adaptation on the stress resistance of Salmonella Enteritidis
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DOI：
10.1111/j.1365-2672.2010.04750.x
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发表时间：
2010-10-01
影响因子：
4
通讯作者：
Kwon, Y. M.
中科院分区：
文献类型：
--
作者：
Calhoun, L. N.;Kwon, Y. M.
目的：肠道细菌病原体在体内模拟应激条件下的适应性表型是重要的，因为它们有可能增强抗逆性和改善旨在控制传播和传染性的措施。肠炎沙门氏菌血清型肠炎（S. Enteritidis）在其整个感染周期中会遇到各种这样的环境，包括在食品加工过程中和受感染宿主肠道内高浓度的短链脂肪酸丙酸（PA）。通过这项研究，我们旨在阐明PA适应在肠炎沙门氏菌抗逆性中的意义。方法和结果：我们已经证明（利用体外应激试验），与未适应的沙门氏菌相比，在PA存在下生长到固定阶段的肠炎沙门氏菌对体内常见应激源的抵抗力显著增强，包括极端酸性和氧化/亚硝化应激。然而，在小鼠模型中，PA适应细胞和未适应细胞之间的竞争性感染表明，适应细胞在体内处于明显的劣势，导致感染小鼠的盲肠定植减少。结论：我们的研究结果表明，长期PA适应在体外诱导对特定胁迫的强抗性的同时，也通过抑制生物体的定植能力降低了适应细胞的整体感染性。研究的意义和影响：在肠炎沙门氏菌中，PA的适应与体外诱导抗逆性表型密切相关。体外抗逆性的增强可能会增加这种病原体的环境持久性和/或总体传播性，而总体而言，由于pa适应肠炎沙门氏菌的定植能力下降，病原体的毒力可能会受到阻碍。
Aims:Adaptive phenotypes of enteric bacterial pathogens in response to in vivo-mimicking stress conditions are important because of their potentiality to enhance stress resistance and ameliorate measures intended to control transmission and infectivity. Salmonella enterica serotype Enteritidis (S. Enteritidis) encounters a variety of such environments throughout its infection cycle, including high concentrations of the short-chain fatty acid, Propionate (PA), during food processing and within the gut of infected hosts. With this study, we aimed to elucidate the significance of PA adaptation on stress resistance in S. Enteritidis.Methods and Results:We have shown (utilizing in vitro stress assays) that S. Enteritidis grown to stationary phase in the presence of PA has a dramatically enhanced resistance to commonly encountered in vivo stressors, including extreme acidity and oxidative/nitrosative stresses when compared to unadapted salmonellae. However, competitive infection between PA adapted and unadapted cells within a murine model showed that adapted cells were at a distinct disadvantage in vivo, resulting in decreased caecal colonization in infected mice.Conclusions:Our results suggest that, while long-term PA adaptation induces strong resistance to specific stresses in vitro, it also reduces the overall infectivity of the adapted cells by inhibiting the organism's colonization ability.Significance and Impact of the Study:In S. Enteritidis, PA adaptation is strongly associated with the induction of stress-resistant phenotypes in vitro. Enhanced stress resistance ex vivo may increase environmental persistence and/or the overall transmissibility of this pathogen, while overall the virulence of the pathogen is likely to be hindered as a result of the decreased colonization ability of PA-adapted S. Enteritidis.