Pathogenic mechanisms of chronic Chlamydia infections

Chlamydiae are obligate intracellular bacteria. The genus Chlamydia consists of the species C. trachomatis, C. psittaci, mostly pathogenic for animals, but with some human pathogenic strains, C. pneumoniae, and C. pecorum, pathogenic for cows and pigs. Recently, a bacterium called “Simkania Z” was related to Chlamydia on the 16 S rRNA level. C. trachomatis is divided into the serotypes A, B, and C, responsible for trachoma, the serotypes D–K, which cause common sexually transmitted infections of the genital mucous membranes, and the serotypes L1, L2, and L3, responsible for the lymphogranuloma venereum. C. pneumoniae is not divided into serotypes so far. It causes respiratory infections, chronic juvenile arthritis and is discussed in relation to the pathogenesis of intrinsic asthma and atherosclerosis.