RNA viruses exist in genetically diverse populations due to high levels of mutations, many of which reduce viral fitness. Interestingly, intestinal bacteria can promote infection of several mammalian enteric RNA viruses, but the mechanisms and consequences are unclear. We screened a panel of 41 bacterial strains as a platform to determine how different bacteria impact infection of poliovirus, a model enteric virus. Most bacterial strains, including those extracted from cecal contents of mice, bound poliovirus, with each bacterium binding multiple virions. Certain bacterial strains increased viral co-infection of mammalian cells even at a low virus-to-host cell ratio. Bacteria-mediated viral co-infection correlated with bacterial adherence to cells. Importantly, bacterial strains that induced viral co-infection facilitated genetic recombination between two different viruses, thereby removing deleterious mutations and restoring viral fitness. Thus, bacteria-virus interactions may increase viral fitness through viral recombination at initial sites of infection, potentially limiting abortive infections.

由于高水平的突变，RNA病毒存在于遗传多样性的群体中，其中许多突变降低了病毒的适应性。有趣的是，肠道细菌可以促进几种哺乳动物肠道RNA病毒的感染，但其机制和后果尚不清楚。我们筛选了 41 种细菌菌株作为平台，以确定不同细菌如何影响脊髓灰质炎病毒（一种肠道病毒模型）的感染。大多数细菌菌株，包括从小鼠盲肠内容物中提取的菌株，都与脊髓灰质炎病毒结合，每种细菌与多个病毒体结合。即使病毒与宿主细胞的比例较低，某些细菌菌株也会增加哺乳动物细胞的病毒共感染。细菌介导的病毒共感染与细菌对细胞的粘附相关。重要的是，诱导病毒共感染的细菌菌株促进了两种不同病毒之间的基因重组，从而消除了有害突变并恢复了病毒的适应性。因此，细菌-病毒相互作用可能会通过感染初始位点的病毒重组来提高病毒适应性，从而可能限制流产感染。