Salmonella enterica Serovar Enteritidis Pathogenicity Island 1 Is Not Essential for but Facilitates Rapid Systemic Spread in Chickens
Salmonella enterica Serovar Enteritidis Pathogenicity Island 1 Is Not Essential for but Facilitates Rapid Systemic Spread in Chickens
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DOI：
10.1128/iai.00039-09
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发表时间：
2009-07-01
影响因子：
3.1
通讯作者：
Koester, Wolfgang
中科院分区：
文献类型：
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作者：
Desin, Taseen S.;Lam, Po-King S.;Koester, Wolfgang
肠道沙门氏菌亚种血清型肠炎是人类食源性疾病的主要原因，主要与食用受污染的禽肉和禽蛋有关。为了引起感染，肠炎沙门氏菌已知使用两种III型分泌系统，这两种分泌系统编码在两个沙门氏菌致病性岛（SPI-1和SPI-2）上，其中第一种被认为在入侵和细菌摄取中起主要作用。为了研究SPI-1在鸡定植中的作用，我们构建了影响SPI-1完整区域（40kb）和invG基因的缺失突变体。Delta SPI-1和Delta invG突变株的SPI-1效应蛋白SipD的分泌均受到抑制。利用极化人肠上皮细胞（Caco-2）进行的体外分析显示，两种突变菌株的侵袭性都低于野生型菌株。当鸡盲肠和小肠外植体同时感染野生型和德尔塔SPI-1突变株时，也得到了类似的观察结果。用野生型和三角洲SPI-1型菌株对1周龄鸡进行口腔攻击，结果表明在鸡盲肠的定殖没有差异。然而，在Delta SPI-1毒株攻毒的鸟类中，肝脏和脾脏的全身感染被延迟。这些数据表明，SPI-1促进了鸡的全身性感染，但对细菌的入侵和全身性传播不是必需的。
Salmonella enterica subsp. enterica serovar Enteritidis is a leading cause of human food-borne illness that is mainly associated with the consumption of contaminated poultry meat and eggs. To cause infection, S. Enteritidis is known to use two type III secretion systems, which are encoded on two salmonella pathogenicity islands, SPI-1 and SPI-2, the first of which is thought to play a major role in invasion and bacterial uptake. In order to study the role of SPI-1 in the colonization of chicken, we constructed deletion mutants affecting the complete SPI-1 region (40 kb) and the invG gene. Both Delta SPI-1 and Delta invG mutant strains were impaired in the secretion of SipD, a SPI-1 effector protein. In vitro analysis using polarized human intestinal epithelial cells (Caco-2) revealed that both mutant strains were less invasive than the wild-type strain. A similar observation was made when chicken cecal and small intestinal explants were coinfected with the wild-type and Delta SPI-1 mutant strains. Oral challenge of 1-week-old chicken with the wild-type or Delta SPI-1 strains demonstrated that there was no difference in chicken cecal colonization. However, systemic infection of the liver and spleen was delayed in birds that were challenged with the Delta SPI-1 strain. These data demonstrate that SPI-1 facilitates systemic infection but is not essential for invasion and systemic spread of the organism in chickens.