Throughout the golden age of antibiotic discovery, Streptomyces have been unsurpassed for their ability to produce bioactive metabolites. Yet, this success has been hampered by rediscovery. As we enter a new stage of biodiscovery, omics data and existing scientific repositories can enable informed choices on the biodiversity that may yield novel antibiotics. Here, we focus on the chemical potential of rare actinomycetes, defined as bacteria within the order Actinomycetales, but not belonging to the genus Streptomyces. They are named as such due to their less-frequent isolation under standard laboratory practices, yet there is increasing evidence to suggest these biologically diverse genera harbour considerable biosynthetic and chemical diversity. In this review, we focus on examples of successful isolation and genera that have been the focus of more concentrated biodiscovery efforts, we survey the representation of rare actinomycete taxa, compared with Streptomyces, across natural product data repositories in addition to its biosynthetic potential. This is followed by an overview of clinically useful drugs produced by rare actinomycetes and considerations for future biodiscovery efforts. There is much to learn about these underexplored taxa, and mounting evidence suggests that they are a fruitful avenue for the discovery of novel antimicrobials.

在抗生素发现的黄金时代，链霉菌生产生物活性代谢物的能力一直无与伦比。然而，这一成功却因重新发现而受到阻碍。随着我们进入生物发现的新阶段，组学数据和现有的科学知识库可以使我们能够对可能产生新型抗生素的生物多样性做出明智的选择。在这里，我们重点关注稀有放线菌的化学潜力，这些放线菌被定义为放线菌目中的细菌，但不属于链霉菌属。它们之所以如此命名，是因为它们在标准实验室实践中分离的频率较低，但越来越多的证据表明这些生物多样性属具有相当大的生物合成和化学多样性。在这篇综述中，我们重点关注成功分离和属的例子，这些例子一直是更集中的生物发现工作的重点，我们调查了稀有放线菌类群的代表性，与 链霉菌相比，跨天然产品数据存储库以及其生物合成潜力。接下来是对稀有放线菌产生的临床有用药物的概述以及对未来生物发现工作的考虑。关于这些未被充分探索的类群，还有很多值得了解的地方，越来越多的证据表明，它们是发现新型抗菌药物的一条富有成效的途径。