Helicobacter pylori is a fastidious Gram-negative bacterium that infects over half of the world's population, causing chronic gastritis and is a risk factor for stomach cancer. In developing and rural regions where prevalence rate exceeds 60%, persistence and waterborne transmission are often linked to poor sanitation conditions. Here we demonstrate that H. pylori not only survives but also replicates within acidified free-living amoebal phagosomes. Bacterial counts of the clinical isolate H. pylori G27 increased over 50-fold after three days in co-culture with amoebae. In contrast, a H. pylori mutant deficient in a cagPAI gene (cagE) showed little growth within amoebae, demonstrating the likely importance of a type IV secretion system in H. pylori for amoebal infection. We also demonstrate that H. pylori can be packaged by amoebae and released in extracellular vesicles. Furthermore, and for the first time, we successfully demonstrate the ability of two free-living amoebae to revert and recover viable but non-cultivable coccoid (VBNC)-H. pylori to a culturable state. Our studies provide evidence to support the hypothesis that amoebae and perhaps other free-living protozoa contribute to the replication and persistence of human-pathogenic H. pylori by providing a protected intracellular microenvironment for this pathogen to persist in natural aquatic environments and engineered water systems, thereby H. pylori potentially uses amoeba as a carrier and a vector of transmission.

中文翻译：

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变形虫在水生环境中对“不可培养的”幽门螺杆菌细胞存活和恢复的作用。

幽门螺杆菌是一种革兰氏阴性细菌，可感染世界一半以上的人口，引起慢性胃炎，是胃癌的危险因素。在患病率超过60％的发展中和农村地区，持久性和水传播通常与不良的卫生条件有关。在这里，我们证明幽门螺杆菌不仅生存，而且在酸化的自由生活的阿米巴吞噬体中复制。与变形虫共培养三天后，临床分离株幽门螺杆菌G27的细菌计数增加了50倍以上。相反，缺乏cagPAI基因的幽门螺杆菌（cagE）在变形虫内几乎没有生长，表明幽门螺杆菌中IV型分泌系统对变形虫感染的重要性。我们还证明了幽门螺杆菌可以被变形虫包装并在细胞外囊泡中释放。此外，而且这是第一次，我们成功地证明了两个自由活动的变形虫能够将存活但不可培养的球菌（VBNC）-幽门螺杆菌还原并恢复到可培养状态。我们的研究提供证据支持以下假设：变形虫和其他可能存在的原生动物有助于人类致病性幽门螺杆菌的复制和持久性。通过为该病原体提供受保护的细胞内微环境，使其在自然水生环境和工程水系统中持久存在，从而使幽门螺杆菌潜在地利用变形虫作为载体和传播媒介。