Gardnerella spp. are considered a hallmark of bacterial vaginosis, a dysbiosis of the vaginal microbiome. There are four cpn60 sequence-based subgroups within the genus (A, B, C and D), and thirteen genome species have been defined recently. Gardnerella spp. co-occur in the vaginal microbiome with varying abundance, and these patterns are shaped by a resource-dependent, exploitative competition, which affects the growth rate of subgroups A, B and C negatively. The growth rate of rarely abundant subgroup D, however, increases with the increasing number of competitors, negatively affecting the growth rate of others. We hypothesized that a nutritional generalist lifestyle and minimal niche overlap with the other more abundant Gardnerella spp. facilitate the maintenance of subgroup D in the vaginal microbiome through negative frequency-dependent selection. Using 40 whole-genome sequences from isolates representing all four subgroups, we found that they could be distinguished based on the content of their predicted proteomes. Proteins associated with carbohydrate and amino acid uptake and metabolism were significant contributors to the separation of subgroups. Subgroup D isolates had significantly more of their proteins assigned to amino acid metabolism than the other subgroups. Subgroup D isolates were also significantly different from others in terms of number and type of carbon sources utilized in a phenotypic assay, while the other three could not be distinguished. Overall, the results suggest that a generalist lifestyle and lack of niche overlap with other Gardnerella spp. leads to subgroup D being favoured by negative frequency-dependent selection in the vaginal microbiome.

加德纳菌属 被认为是细菌性阴道病的标志，是阴道微生物群的失调。该属中有四个基于 cpn60 序列的亚组（A、B、C 和 D），最近已定义了 13 个基因组物种。加德纳菌属 在阴道微生物群中以不同的丰度同时出现，这些模式是由资源依赖型、剥削性竞争形成的，这对 A、B 和 C 亚组的生长速度产生负面影响。然而，很少丰富的子组 D 的增长率随着竞争者数量的增加而增加，对其他人的增长率产生负面影响。我们假设营养多面手的生活方式和最小的生态位与其他更丰富的加德纳菌重叠spp. 通过负频率依赖性选择促进阴道微生物组中 D 亚组的维持。使用来自代表所有四个亚组的分离株的 40 个全基因组序列，我们发现可以根据预测的蛋白质组的内容来区分它们。与碳水化合物和氨基酸摄取和代谢相关的蛋白质是亚组分离的重要因素。与其他亚组相比，D 亚组分离物的氨基酸代谢蛋白明显更多。在表型分析中使用的碳源的数量和类型方面，D 亚组分离物也与其他分离物显着不同，而其他三个无法区分。总体而言，结果表明，通才生活方式和缺乏利基与其他生活方式重叠加德纳菌属 导致 D 亚组受到阴道微生物组中负频率依赖性选择的青睐。