Chlamydia trachomatis

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Chlamydia trachomatis
Scientific classification e
Domain: Bacteria
Phylum: Chlamydiae
Class: Chlamydiae
Order: Chlamydiales
Family: Chlamydiaceae
Genus: Chlamydia
Species: C. trachomatis
Binomial name
Chlamydia trachomatis[1]
  • Rickettsia trachomae (sic) Busacca 1935
  • Rickettsia trachomatis (Busacca 1935) Foley and Parrot 1937
  • Chlamydozoon trachomatis (Busacca 1935) Moshkovski 1945

Chlamydia trachomatis, an obligate intracellular human pathogen, is one of four bacterial species in the genus Chlamydia.[2] C. trachomatis is a gram-negative bacterium, therefore its cell wall components retain the counter-stain safranin and appear pink under a light microscope.[3] It can appear as either coccoid or rod shape.[4]

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.[5][6][7]

C. trachomatis includes three human biovars:

Many, but not all, C. trachomatis strains have an extrachromosomal plasmid.[9]

Chlamydia has evolved with exchange of DNA between different strains of Chlamydia to form new strains being common.[10]


Chlamydia species are readily identified and distinguished from other Chlamydia species using DNA-based tests.

Most strains of C. trachomatis are recognized by monoclonal antibodies (mAbs) to epitopes in the VS4 region of MOMP.[11] However, these mAbs may also cross-react with two other Chlamydia species, C. suis and C. muridarum.


Life Cycle

Clinical significance[edit]

C. trachomatis is an obligate intracellular pathogen (i.e., the bacterium lives within human cells) and can cause numerous disease states in both men and women.[2] Both sexes can display urethritis, proctitis (rectal disease and bleeding), trachoma, and infertility. The bacterium can cause prostatitis and epididymitis in men. In women, cervicitis, pelvic inflammatory disease (PID), ectopic pregnancy, and acute or chronic pelvic pain are frequent complications. Neonates born to infected mothers are also susceptible to infections of the eye (conjunctivitis) and lung.[12]

C. trachomatis is the single most important infectious agent associated with blindness (trachoma); approximately 84 million worldwide suffer C. trachomatis eye infections and 8 million are blinded as a result of the infection.[13]


C. trachomatis may be treated with any of several bacteriostatic antibiotics: macrolides (azithromycin, clarithromycin, erythromycin, etc) or tetracyclines (doxycycline, tetracycline, etc).[14]

Laboratory tests[15][edit]

  • Nucleic acid amplification tests (NAAT). These tests find the genetic material (DNA) of Chlamydia bacteria. These tests are the most sensitive tests available, meaning that they are very accurate and that they are very unlikely to have false-negative test results. A polymerase chain reaction (PCR) test is an example of a nucleic acid amplification test. This test can also be done on a urine sample.
  • Enzyme-linked immunosorbent assay (ELISA, EIA). This quick test finds substances (Chlamydia antigens) that trigger the immune system to fight Chlamydia infection.
  • Direct fluorescent antibody test (DFA). This quick test also finds Chlamydia antigens.
  • Chlamydia cell culture. A test in which the suspected chlamydia sample is grown in a vial of cells. The pathogen infects the cells and after a set incubation time (48 hours) the vials are stained and viewed on a fluorescent light microscope. Cell culture is more expensive and takes longer (two days) than the other tests. The culture must be grown in a laboratory.

See also[edit]


  1. ^ J.P. Euzéby. "Chlamydia". List of Prokaryotic names with Standing in Nomenclature. Retrieved 2008-09-11. 
  2. ^ a b Ryan KJ, Ray CG (editors) (2004). Sherris Medical Microbiology (4th ed.). McGraw Hill. pp. 463–70. ISBN 0-8385-8529-9. 
  3. ^ Kenyon College - Dept. of Biology (2006-08-15). "Chlamydia". MicrobeWiki. Retrieved 2008-10-27. 
  4. ^
  5. ^ S Darougar, B R Jones, J R Kimptin, J D Vaughan-Jackson, and E M Dunlop. Chlamydial infection. Advances in the diagnostic isolation of Chlamydia, including TRIC agent, from the eye, genital tract, and rectum. Br J Vener Dis. 1972 December; 48(6): 416–420
  6. ^ TANG FF, HUANG YT, CHANG HL, WONG KC. Further studies on the isolation of the trachoma virus. Acta Virol. 1958 Jul-Sep;2(3):164-70; TANG FF, CHANG HL, HUANG YT, WANG KC. Studies on the etiology of trachoma with special reference to isolation of the virus in chick embryo. Chin Med J. 1957 Jun;75(6):429-47
  7. ^ TANG FF, HUANG YT, CHANG HL, WONG KC. Isolation of trachoma virus in chick embryo. J Hyg Epidemiol Microbiol Immunol. 1957;1(2):109-20
  8. ^ Fredlund H, Falk L, Jurstrand M, Unemo M (2004). "Molecular genetic methods for diagnosis and characterisation of Chlamydia trachomatis and Neisseria gonorrhoeae: impact on epidemiological surveillance and interventions". APMIS : acta pathologica, microbiologica, et immunologica Scandinavica 112 (11–12): 771–84. doi:10.1111/j.1600-0463.2004.apm11211-1205.x. PMID 15638837. 
  9. ^ Carlson JH, Whitmire WM, Crane DD, et al. (June 2008). "The Chlamydia trachomatis Plasmid Is a Transcriptional Regulator of Chromosomal Genes and a Virulence Factor". Infection and immunity 76 (6): 2273–83. doi:10.1128/IAI.00102-08. PMC 2423098. PMID 18347045. 
  10. ^ Nature Genetics (2012-03-12). "Whole genome analysis of Chlamydia trachomatis highlights risks with current method of tracking". Retrieved 2012-03-12. 
  11. ^ Ortiz L, Angevine M, Kim SK, Watkins D, DeMars R (2000). "T-Cell Epitopes in Variable Segments of Chlamydia trachomatis Major Outer Membrane Protein Elicit Serovar-Specific Immune Responses in Infected Humans". Infect. Immun. 68 (3): 1719–23. doi:10.1128/IAI.68.3.1719-1723.2000. PMC 97337. PMID 10678996. 
  12. ^ Pokrzywnicka, M.; Krajewski, P.; Kwiatkowska, M. (2005). "Chlamydia infections in the neonatal period". Medycyna wieku rozwojowego 9 (1): 65–69. PMID 16082067.  edit
  13. ^
  14. ^ Chlamydia Information
  15. ^ "Chlamydia Tests". Sexual Conditions Health Center. WebMD. Retrieved 2012-08-07. 

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