Members of the phylum Chlamydiae are obligate intracellular bacteria that were discovered about a century ago. Although Chlamydiae are major pathogens of humans and animals, they were long recognized only as a phylogenetically well-separated, small group of closely related microorganisms. The diversity of chlamydiae, their host range, and their occurrence in the environment had been largely underestimated. Today, several chlamydia-like bacteria have been described as symbionts of free-living amoebae and other eukaryotic hosts. Some of these environmental chlamydiae might also be of medical relevance for humans. Their analysis has contributed to a broader understanding of chlamydial biology and to novel insights into the evolution of these unique microorganisms.

中文翻译：

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衣原体在真核生物中作为共生体。

衣原体门的成员是大约一个世纪前发现的专性细胞内细菌。尽管衣原体是人类和动物的主要病原体，但长久以来它们只被认为是系统发育上分离良好的一小群密切相关的微生物。衣原体的多样性，寄主范围以及它们在环境中的发生都被大大低估了。如今，几种衣原体样细菌已被描述为自由活动的变形虫和其他真核宿主的共生体。这些环境衣原体中的某些也可能对人类具有医学意义。他们的分析有助于更广泛地了解衣原体生物学，并为了解这些独特微生物的进化提供了新颖见解。