Impact of Bacteriophages on Virulence and Transmission of Vibrio cholerae

项目总结 噬菌体是专门感染细菌的病毒。噬菌体已经被证明可以发挥作用 在许多细菌病原体的生命周期中发挥重要作用，特别是引起 胃肠道感染。例如，溶原噬菌体将它们的DNA整合到宿主中 基因组可以通过提供毒力因子(如毒素)来发挥积极作用，这些毒力因子可以增强病毒的毒力 它们的宿主细菌。其他被称为裂解噬菌体或剧毒噬菌体的噬菌体可以通过感染和 杀死宿主细菌，从而将病原体的数量减少到所需的阈值以下 疾病。霍乱弧菌是一种通过水传播的病原体，它感染小肠导致严重的 腹泻病霍乱。尽管众所周知，一种称为CTX噬菌体的溶原噬菌体可以增强 通过提供编码霍乱毒素的基因，我们最近发表的初步数据表明 霍乱流行地区常见的几种毒力噬菌体的普遍负面作用 在孟加拉湾附近。这些剧毒噬菌体似乎降低了毒力、传播和潜在的 霍乱弧菌的传播。然而，关于这些噬菌体，我们仍然有很多不知道的地方 它们有能力杀死环境中的霍乱弧菌，抑制霍乱等粪口传播的发生 经常在家庭内，以及它们对出现新的霍乱弧菌菌株的影响。在这个项目中， 我们将对这些地区逐一进行调查。此外，我们还将研究另一种溶原噬菌体的重要性。 在霍乱弧菌的毒力中被称为Kappa。

PROJECT SUMMARY Bacteriophages (phages) are viruses that specifically infect bacteria. Phages have been shown to play important roles in the life cycle of many bacterial pathogens, particularly water-borne pathogens that cause gastrointestinal tract infections. For example, the lysogenic phages, which integrate their DNA into the host genome, can play positive roles by providing virulence factors such as toxins that enhance the virulence of their host bacterium. Other phages known as lytic or virulent phages can play negative roles by infecting and killing their host bacterium, thus reducing the number of the pathogen below the threshold needed to cause disease. Vibrio cholerae is a water-borne pathogen that infects the small intestine to cause the severe diarrheal disease cholera. Although it is well known that a lysogenic phage called the CTX phage enhances virulence by providing the genes encoding cholera toxin, our recently published and preliminary data indicate a pervasive negative role for several virulent phages that are commonly found in cholera endemic areas around the Bay of Bengal. These virulent phages appear to reduce the virulence, transmission, and potentially dissemination of V. cholerae. However, there is much we still do not know about these phages in terms of their ability to kill V. cholerae in the environment, to inhibit fecal-oral transmission of cholera such as occurs frequently within households, and their impact on the emergence of new V. cholerae strains. In this project, we will investigate each of these areas. In addition, we will study the importance of another lysogenic phage called Kappa in the virulence of V. cholerae.