The Chlamydiae are a group of bacteria, all of which are intracellular parasites of eukaryotic cells. Most described species infect mammals and birds, but some have been found in other hosts, such as amoebae. Originally they were treated as the single genus Chlamydia, but now several different genera are recognized. They are related to certain other bacterial groups, notably the Thermomicrobia, but are generally given their own phylum. Phyla/Divisions Actinobacteria Aquificae Bacteroidetes/Chlorobi Chlamydiae/Verrucomicrobia Chloroflexi Chrysiogenetes Cyanobacteria Deferribacteres Deinococcus-Thermus Dictyoglomi Fibrobacteres/Acidobacteria Firmicutes Fusobacteria Gemmatimonadetes Nitrospirae Planctomycetes Proteobacteria Spirochaetes Thermodesulfobacteria Thermomicrobia Thermotogae Bacteria (singular, bacterium) are a major group of living organisms. ... In cell biology, molecular biology and related fields, the word intracellular means inside the cell. It is used in contrast to extracellular (outside the cell). ... Kingdoms Animalia - Animals Fungi Plantae - Plants Protista Eukaryotes (also spelled eucaryotes) are organisms with complex cells, in which the genetic material is organized into membrane-bound nuclei. ... Classes Thermomicrobia phylum is a phenotype of the green non-sulfur bacteria. ...

Chlamydiae have a life-cycle involving two distinct forms. Infection takes place by means of elementary bodies (EB), which are metabolically inactive. These are taken up within a cellular vacuole, where they grow into larger reticulate bodies (RB), which reproduce. Ultimately new elementary bodies are produced and expelled from the cell. Vacuoles are large membrane-bound compartments within some eukaryotic cells where they serve a variety of different functions: capturing food materials or unwanted structural debris surrounding the cell, sequestering materials that might be toxic to the cell, maintaining fluid balance (called turgor) within the cell, exporting unwanted substances from the...

There are three main species of chlamydiae that infect humans:

• Chlamydia trachomatis, which causes the eye-disease trachoma and the sexually transmitted infection chlamydia;
• Chlamydophila pneumoniae, which causes a form of pneumonia;
• Chlamydophila psittaci, which causes psittacosis.