Chlamydia trachomatis, an obligate intracellular human pathogen, is one of four bacterial species in the genus Chlamydia. C. trachomatis is a gram-negative bacterium, therefore its cell wall components retain the counter-stain safranin and appear pink under a light microscope. It is ovoid in shape.
The inclusion bodies of Chlamydia trachomatis were first described in 1942; the Chlamydia trachomatis agent was first cultured in the yolk sacs of eggs by Professor Feifan Tang et al in 1957.
C. trachomatis includes three human biovars:
serovars Ab, B, Ba, or C — cause trachoma: infection of the eyes, which can lead to blindness
serovars D-K — cause urethritis, pelvic inflammatory disease, ectopic pregnancy, neonatal pneumonia, and neonatal conjunctivitis
serovars L1, L2 and L3 — lymphogranuloma venereum (LGV).
Many, but not all, C. trachomatis strains have an extrachromosomal plasmid.
Chlamydia can exchange DNA between its different strains, thus the evolution of new strains is common.
Chlamydophila trachomatis
Chlamydia trachomatis
Klebsiella rhinoscleromatis
Treponema pallidum
Haemophilus ducreyi
Neisseria gonorrhoeae
Ureaplasma urealyticum
Trichomonas vaginalis