Center for Microbial Ecology and Technology (CMET), Ghent University, Gent, Belgium.
J Appl Microbiol. 2022 Jan;132(1):167-176. doi: 10.1111/jam.15227. Epub 2021 Aug 8.
Indole is a signaling molecule secreted by over 85 species of bacteria, including several Vibrio species, and it has been reported to affect different bacterial phenotypes such as biofilm formation, motility, and virulence. In this study, we aimed at investigating the inter-strain variability of the effect of indole in 12 different strains belonging to the Harveyi clade of vibrios.
Indole reduced the virulence of all strains towards gnotobiotic brine shrimp larvae. The survival rate of brine shrimp larvae challenged with vibrios pretreated with indole was increased by 1.3-fold to 1.8-fold. Additionally, indole significantly decreased the biofilm formation in all of the strains, decreased the swimming motility in eight of the strains, and decreased swarming motility in five of the strains. When cultured in the presence of exogenous indole, the mRNA level of the pirA and pirB toxin genes were down-regulated to 65% and 46%, and to 62% and 55% in the AHPND-causing strains Vibrio parahaemolyticus M0904 and Vibrio campbellii S01, respectively.
These data indicate that indole has a significant impact on the virulence of different strains belonging to the Harveyi clade of vibrios.
Our results suggest that indole signaling is a valid target for the development of novel therapeutics in order to control infections caused by Harveyi clade vibrios in aquaculture.
吲哚是一种由 85 种以上细菌（包括几种弧菌属物种）分泌的信号分子，已有报道称其影响不同的细菌表型，如生物膜形成、运动性和毒力。在这项研究中，我们旨在研究吲哚对 Harveyi 弧菌属的 12 种不同菌株的影响的菌株间变异性。
吲哚降低了所有菌株对无菌盐水虾幼虫的毒力。用吲哚预处理的弧菌感染盐水虾幼虫后的存活率增加了 1.3 至 1.8 倍。此外，吲哚显著降低了所有菌株的生物膜形成，降低了 8 个菌株的泳动性，降低了 5 个菌株的群集运动性。当在存在外源性吲哚的情况下培养时，pirA 和 pirB 毒素基因的 mRNA 水平下调至 65%和 46%，在引起 AHPND 的菌株副溶血弧菌 M0904 和坎贝尔氏弧菌 S01 中分别下调至 62%和 55%。
这些数据表明吲哚对 Harveyi 弧菌属的不同菌株的毒力有显著影响。
我们的结果表明，吲哚信号是开发新型治疗方法的有效靶点，以控制水产养殖中 Harveyi 弧菌属感染。
