Effect of Zinc in Attaching and Effacing E. coli Infection

描述（由申请人提供）：在几个大陆的贫困儿童研究中，锌已被证明可以减少牙周病的持续时间和严重程度。虽然锌的这些有益作用首先归因于纠正营养不良儿童的锌缺乏，但研究表明，即使在研究前血清锌水平正常的儿童中，锌也有有益的作用。在健康实验动物和培养细胞试验中对肠道病原体的研究也显示了锌在非缺锌动物或条件下的保护作用。在我们的实验室中，我们发现锌强烈地抑制了几种重要的致病因子的产生。coli菌株的体外培养。然后，我们将这些观察结果扩展到兔EPEC菌株，并发现了类似的结果。家兔是EPEC感染的天然宿主，为锌的体内药效研究提供了良好的动物模型。现在，我们也有体外数据表明，锌也抑制志贺菌的毒力。 大肠杆菌（STEC，也称为肠出血性E.大肠杆菌或EHEC）。在人源性EPEC、兔EPEC和STEC中，锌降低细菌产生的毒力因子，包括粘附素、分泌的效应蛋白和滋贺毒素（Stx）。我们建议在体外和体内进一步研究锌对A/E.coli感染的影响。具体目标有3个：具体目标1：确定锌对E.大肠杆菌（包括EPEC、REPEC和STEC）在不同生长条件下（以及在存在抗生素的情况下）的体外培养。 具体目标2：确认并进一步确定锌对结扎兔回肠袢中体内A/E.coli感染的影响，并检查其对这些袢中STEC感染的影响。 具体目标3：确定体内锌给药是否可以保护家兔免受REPEC和STEC的口胃感染。除了检查锌对临床病程和肠道病理学的影响外，我们还将检查锌是否可以防止STEC诱导的肠外病理学（特别是肾损伤）。对于这些研究，我们将使用一种新的出血性结肠炎（HC）和溶血性尿毒综合征（HUS）模型，该模型在用表达Stx 1或Stx 2的REPEC菌株攻击的荷兰皮带兔中发展。 公共卫生相关性：“附着和去除E。大肠杆菌”包括2组产大肠杆菌。大肠杆菌、肠致病性E.大肠埃希菌（EPEC）和肠出血性大肠杆菌（E.大肠杆菌（EHEC，又称滋贺致突变E. coli或STEC）。肠出血性大肠杆菌，如菌株O 157：H7，由于食源性暴发而受到广泛宣传。锌抑制这两组E.我们希望进一步研究锌，看看它是否可以用作治疗这些感染。

DESCRIPTION (provided by applicant): Zinc has been shown to reduce the duration and severity of diarrheal diseases in studies of poor children on several continents. Although these beneficial effects of zinc were first attributed to correction of a zinc deficiency in malnourished children, studies have shown beneficial zinc effects even in children with normal serum zinc levels before study. Studies of enteric pathogens in healthy experimental animals and cultured cell assays have also shown protective effects of zinc in non-zinc deficient animals or conditions. In our laboratories we discovered that zinc strongly inhibits the production of several important virulence factors human enteropathogenic E. coli strains in vitro. We then extended those observations to rabbit EPEC strains and found similar results. Rabbits are natural hosts for EPEC infection, so they constitute a good animal model for us to test zinc efficacy in vivo. Now we also have in vitro data showing that zinc also inhibits virulence in Shiga-toxigenic E. coli (STEC, also known as enterohemorrhagic E. coli, or EHEC). In human-derived EPEC, rabbit EPEC, and STEC, zinc decreases the bacterial production of virulence factors, including adhesins, secreted effector proteins and Shiga toxin (Stx). We propose to further examine the effect of zinc on A/E E.coli infections both in vitro and in vivo. There are 3 specific aims: Specific Aim 1: Determine the direct effects of zinc on attaching and effacing E. coli (including EPEC, REPEC and STEC) in vitro under different growth conditions (and in the presence of antibiotics). Specific Aim 2.: To confirm and further define the effects of zinc on A/E E.coli infection in vivo in ligated rabbit ileal loops, and to examine its effect on STEC infections in these loops. Specific Aim 3: Determine if zinc administration in vivo can protect rabbits against orogastric infections with REPEC and STEC. In addition to examining the effects of zinc on clinical disease course and intestinal pathology, we will also examine if zinc can protect against extra-intestinal pathology induced by STEC (especially kidney damage). For these studies we will use a new model of hemorrhagic colitis (HC) and hemolytic uremic syndrome (HUS) which develops in Dutch Belted rabbits challenged with REPEC strains expressing Stx1 or Stx2. PUBLIC HEALTH RELEVANCE: "Attaching and Effacing E. coli" includes 2 groups of diarrhea-producing E. coli, enteropathogenic E. coli (EPEC) and enterohemorrhagic E. coli (EHEC, also called Shiga toxigenic E. coli, or STEC). EHEC, such as strain O157:H7, has received wide publicity due to foodborne outbreaks. Zinc inhibits the virulence of both of these groups of E. coli, and we wish to study zinc further to see if it could be used as a treatment for these infections.