Lentisphaerae is a phylum of bacteria closely related to Chlamydiae and Verrucomicrobia. This section lists the orders of Bacteria within the phylum Chlamydiae. Reports have varied as to whether the Chlamydiae are related to the Planctomycetales or Spirochaetes. Comparison of ribosomal RNA genes has provided a phylogeny of known strains within Chlamydiae. The order Chlamydiales belongs to the class Chlamydiae, phylum Chlamydiae, domain Bacteria. All known Chlamydiae only grow by infecting eukaryotic host cells. At present, Chlamydiae and Chlamydiales are essentially synonymous. Most intracellular Chlamydiae are located in an inclusion body or vacuole. Some believe that persistent chlamydiae are the cause of chronic chlamydial diseases. The phylum Chlamydiae was established in Bergey's Manual of Systematic Bacteriology. The Chlamydiae currently contain eight validly named genera, and 14 genera. Chlamydiae are most successfully isolated while still inside their host cells. In 1966, Chlamydiae were recognized as bacteria and the genus Chlamydia was validated. "Chlamydiae" have the ability to establish long-term associations with host cells. Therefore, Chlamydiae cannot be propagated in bacterial culture media in the clinical laboratory.