The human vaginal microbiome (HVM) plays a fundamental role in women’s reproductive health. For instance, bacterial vaginosis (BV) is characterized by a depletion of lactobacilli and an overgrowth of strict anaerobes. Women with BV may have an increased risk of acquiring sexually transmitted diseases and adverse pregnancy outcomes. Although the HVM is important, the ecological roles of many vaginal species remain unclear and current approaches for investigating them have severe limitations. We previously developed a new high-throughput technology based on the co-cultivation of bacteria in microdroplets to dissect inter-species interactions in microbial communities. Here, we adapted and extended this technology to investigate the HVM and tested it using pairwise model systems. In one case, Lactobacillus jensenii JV-V16, a lactic acid bacterium, and Gardnerella vaginalis ATCC 49145, a bacterium associated with BV, were cultured in microdroplets as pure cultures and co-cultures. Two assays were developed to analyze their growth in microdroplets. First, qPCR was used to quantify the bacteria in pooled microdroplets. Second, cells in individual microdroplets were plated and enumerated on agar media. The results showed that growth of G. vaginalis was severely inhibited by L. jensenii, which recapitulated previous findings of studies conducted in flask batch cultures. Additionally, we validated the general applicability of our technology pipeline with a second co-culture model system by observing that Enterococcus faecalis, another bacterium from the urogenital tract, was also inhibited by L. jensenii. Our results show that co-cultivation and characterization of bacteria in microdroplets provides an effective way to study inter-species interactions in microbial ecosystems.

中文翻译：

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人类阴道细菌的微滴共培养和相互作用表征


人类阴道微生物群（HVM）在女性生殖健康中发挥着重要作用。例如，细菌性阴道病（BV）的特征是乳酸杆菌的消耗和严格厌氧菌的过度生长。患有 BV 的女性感染性传播疾病和不良妊娠结局的风险可能增加。尽管 HVM 很重要，但许多阴道物种的生态作用仍不清楚，并且目前研究它们的方法存在严重局限性。我们之前开发了一种基于微滴中细菌共培养的新高通量技术，以剖析微生物群落中物种间的相互作用。在这里，我们调整并扩展了这项技术来研究 HVM，并使用成对模型系统对其进行测试。在一个案例中，詹氏乳杆菌JV-V16（一种乳酸菌）和阴道加德纳菌ATCC 49145（一种与 BV 相关的细菌）作为纯培养物和共培养物在微滴中进行培养。开发了两种测定法来分析它们在微滴中的生长。首先，使用 qPCR 对合并的微滴中的细菌进行定量。其次，将单个微滴中的细胞铺板在琼脂培养基上并进行计数。结果表明，詹氏乳杆菌严重抑制了阴道G. vaginalis的生长，这概括了之前在烧瓶分批培养中进行的研究结果。此外，我们通过观察另一种来自泌尿生殖道的细菌粪肠球菌也受到詹氏乳杆菌的抑制，验证了我们的技术管道与第二个共培养模型系统的普遍适用性。 我们的结果表明，微滴中细菌的共培养和表征提供了研究微生物生态系统中物种间相互作用的有效方法。