Vibrio cholerae residing in food vacuoles expelled by protozoa are more infectious in vivo
Vibrio cholerae residing in food vacuoles expelled by protozoa are more infectious in vivo
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DOI：
10.1038/s41564-019-0563-x
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发表时间：
2019-12-01
影响因子：
28.3
通讯作者：
McDougald, Diane
中科院分区：
文献类型：
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作者：
Espinoza-Vergara, Gustavo;Noorian, Parisa;McDougald, Diane
霍乱弧菌与环境中的许多生物相互作用，包括异养原生生物（原生动物）。据报道，几种原生动物在以某些病原体为食时，会在排出的食物液泡（efv）中释放未消化的细菌。虽然已经报道了efv的生产，但它们作为病原体传播媒介的生物学作用仍然未知。在这里，我们报道纤毛原虫释放含有霍乱弧菌的efv。efv是稳定的，其中的细胞不受多种压力的保护，当在37摄氏度或有营养物质存在的情况下孵育时，大量细胞逃逸。我们发现，受ToxR正调控的主要外膜蛋白OmpU在efv的产生中起作用。值得注意的是，efv释放的细胞在体外和体内都比浮游细胞具有生长和定植优势。研究结果表明，efv促进了霍乱弧菌在环境中的生存，增强了其传染潜力，并可能促进了霍乱弧菌流行菌株的传播。这些结果提高了我们对霍乱弧菌的持久性机制和传播方式的理解，并可能进一步应用于其他已被证明由efv中的原生生物释放的机会性病原体。
Vibrio cholerae interacts with many organisms in the environment, including heterotrophic protists (protozoa). Several species of protozoa have been reported to release undigested bacteria in expelled food vacuoles (EFVs) when feeding on some pathogens. While the production of EFVs has been reported, their biological role as a vector for the transmission of pathogens remains unknown. Here we report that ciliated protozoa release EFVs containing V. cholerae. The EFVs are stable, the cells inside them are protected from multiple stresses, and large numbers of cells escape when incubated at 37 degrees C or in the presence of nutrients. We show that OmpU, a major outer membrane protein positively regulated by ToxR, has a role in the production of EFVs. Notably, cells released from EFVs have growth and colonization advantages over planktonic cells both in vitro and in vivo. Our results suggest that EFVs facilitate V. cholerae survival in the environment, enhancing their infectious potential and may contribute to the dissemination of epidemic V. cholerae strains. These results improve our understanding of the mechanisms of persistence and the modes of transmission of V. cholerae and may further apply to other opportunistic pathogens that have been shown to be released by protists in EFVs.