ABSTRACT

Necrotizing soft tissue infections (NSTI) progress to severe necrosis and result in fatal sepsis within a short time. Vibrio vulnificus is a causative agent and can spread from the initial infection site through soft tissue finally to the systemic circulation of the host. The motility and chemotaxis of this bacterium are essential for proliferation and lethality in a murine model of the infection, but their role in pathogenicity has not been characterized. In this study, we revealed the roles of motility and chemotaxis during the process of V. vulnificus infection. We compared a nonmotile mutant and two nonchemotactic mutants with their parent strain (WT) with regard to bacterial spread using an in vivo imaging system (IVIS) and invasion by detection of bacteria from the muscle and spleen of a murine infection model. WT rapidly spread throughout the infected thigh and invaded deep muscle causing severe tissue damage. The detection rate in the systemic circulation and the lethality were high. On the other hand, the nonmotile mutant stayed at the inoculation site, and the nonchemotactic mutants spread only slowly through the soft tissue of the infected thigh. Detection in the systemic circulation, the degree of tissue damage, and the lethality of nonchemotactic mutants were significantly reduced in mice compared with WT. This study demonstrated that chemotaxis is essential for invasion from the infection site to the deep and distant tissues and the main pathogenic factor for the rapid progression leading to sepsis in V. vulnificus NSTI.

摘要

坏死性软组织感染（NSTI）进展为严重坏死，并在短时间内导致致命性败血症。创伤弧菌是一种病原体，可以从最初的感染部位通过软组织传播到宿主的全身循环。在感染的鼠模型中，这种细菌的运动性和趋化性对于增殖和致死性至关重要，但尚未确定其在致病性中的作用。在这项研究中，我们揭示了运动性和趋化性在V. vulnificus过程中的作用感染。我们比较了一个非运动突变体和两个非趋化突变体及其亲本菌株（WT），利用体内成像系统（IVIS）进行了细菌传播，并通过检测鼠类感染模型的肌肉和脾脏中的细菌入侵进行了比较。野生型迅速扩散到整个受感染的大腿，并侵入深部肌肉，导致严重的组织损伤。体循环中的检出率和致死率很高。另一方面，非运动型突变体停留在接种部位，非趋化性突变体仅缓慢传播通过被感染大腿的软组织。与野生型相比，小鼠的全身循环中的检测，组织损伤的程度和非趋化突变体的致死率显着降低。V. vulnificus NSTI。