肠致病菌,比如沙门氏菌,与许多新鲜农产品爆发有关,构成重大公共卫生威胁。沙门氏菌在新鲜农产品上持续较长时间的能力部分归因于其形成生物膜的能力,这对食品去污构成了挑战,并可能增加食物链中的致病菌负荷。防止沙门氏菌在食品和食品加工环境中定植对于减少食源性暴发的发生率至关重要。了解新鲜农产品的建立机制将为净化方法的发展提供信息。我们使用转座子导向的插入位点测序(TraDIS-Xpress)来研究肠道沙门氏菌鼠伤寒沙门氏菌随时间定植和建立在新鲜农产品上的机制。我们建立了苜蓿定植模型,并将发现与从玻璃表面获得的结果进行了比较。随着时间的推移,与玻璃表面相比,我们的研究确定了苜蓿上沙门氏菌建立所需的不同机制。这些包括III型分泌系统(sirC),Fe-S团簇组装(iscA),姜黄素降解(curA),和铜公差(cueR)。跨表面的共享途径包括NADH氢化酶合成(nuoA和nuoB),菌毛调节(FIMA和FIMZ),应激反应(rpoS),LPSO-抗原合成(rfbJ),铁收购(ybaN),和乙醇胺利用(eutT和eutQ)。值得注意的是,随着时间的推移,鞭毛生物合成对生物和非生物环境的定植产生了不同的影响。随着时间的推移,了解沙门氏菌在生物和非生物表面上建立的遗传基础提供了有价值的见解,可以为靶向抗菌疗法的开发提供信息。最终提高整个食品加工链的食品安全。
目的:沙门氏菌是英国第二大最昂贵的食源性疾病,每年占2亿英镑,与新鲜农产品有关的许多疫情爆发,如绿叶蔬菜,黄瓜,西红柿,和苜蓿芽。沙门氏菌在新鲜农产品中定殖和建立自己的能力构成了重大挑战,阻碍净化工作,增加患病风险。了解沙门氏菌随时间定殖植物的关键机制是找到预防和控制新鲜农产品污染的新方法的关键。这项研究确定了紫花苜蓿沙门氏菌定植的重要基因和途径,并使用全基因组筛选将其与玻璃定植进行了比较。在鞭毛生物合成中起作用的基因,脂多糖生产,严格的反应调节在植物和玻璃之间的重要性不同。这项工作加深了我们对沙门氏菌对植物定植的要求的理解,揭示了基因本质是如何随着时间和不同环境而变化的。这些知识是制定有效策略以降低食源性疾病风险的关键。
Enteropathogenic bacteria, such as Salmonella, have been linked to numerous fresh produce outbreaks, posing a significant public health threat. The ability of Salmonella to persist on fresh produce for extended periods is partly attributed to its capacity to form biofilms, which pose a challenge to food decontamination and can increase pathogenic bacterial load in the food chain. Preventing Salmonella colonization of food products and food processing environments is crucial for reducing the incidence of foodborne outbreaks. Understanding the mechanisms of establishment on fresh produce will inform the development of decontamination approaches. We used Transposon-Directed Insertion site Sequencing (TraDIS-Xpress) to investigate the mechanisms used by Salmonella enterica serovar Typhimurium to colonize and establish on fresh produce over time. We established an alfalfa colonization model and compared the findings to those obtained from glass surfaces. Our research identified distinct mechanisms required for Salmonella establishment on alfalfa compared with glass surfaces over time. These include the type III secretion system (sirC), Fe-S cluster assembly (iscA), curcumin degradation (curA), and copper tolerance (cueR). Shared pathways across surfaces included NADH hydrogenase synthesis (nuoA and nuoB), fimbrial regulation (fimA and fimZ), stress response (rpoS), LPS O-antigen synthesis (rfbJ), iron acquisition (ybaN), and ethanolamine utilization (eutT and eutQ). Notably, flagellum biosynthesis differentially impacted the colonization of biotic and abiotic environments over time. Understanding the genetic underpinnings of Salmonella establishment on both biotic and abiotic surfaces over time offers valuable insights that can inform the development of targeted antibacterial therapeutics, ultimately enhancing food safety throughout the food processing chain.
OBJECTIVE: Salmonella is the second most costly foodborne illness in the United Kingdom, accounting for £0.2 billion annually, with numerous outbreaks linked to fresh produce, such as leafy greens, cucumbers, tomatoes, and alfalfa sprouts. The ability of Salmonella to colonize and establish itself in fresh produce poses a significant challenge, hindering decontamination efforts and increasing the risk of illness. Understanding the key mechanisms of Salmonella to colonize plants over time is key to finding new ways to prevent and control contamination of fresh produce. This study identified genes and pathways important for Salmonella colonization of alfalfa and compared those with colonization of glass using a genome-wide screen. Genes with roles in flagellum biosynthesis, lipopolysaccharide production, and stringent response regulation varied in their significance between plants and glass. This work deepens our understanding of the requirements for plant colonization by Salmonella, revealing how gene essentiality changes over time and in different environments. This knowledge is key to developing effective strategies to reduce the risk of foodborne disease.