Gram stain: negative Cell shape: coccoid Arrangement: Oxygen requirements: Other:Chlamydia spp. are among the smallest bacteria -- 0.25 to 1.5 micrometers; obligate intracellular parasites (considered a subgroup or rickettsias); can be cultivated only in living cells or yolk sacks of chicken embryos.
These organisms have a very complex life cycle that includes a number of different forms: "elementary bodies" for transmission from cell to cell; "reticulate bodies" form for division within host cell.
Pathogenicity: causes "trachoma", the greatest single infectious cause of blindness in humans; transmitted by hand contact or by objects such as towels; flies may also carry the bacteria. Also causes "nongonococcal urethritis", one of the most common sexually transmitted diseases in the U.S. Treatment is tetracycline, erythromycin.
*Has been implicated in triggering an immune response that leads to inflammation of the heart!