Chlamydia trachomatis

Synonyms:

Chlamydia

Classification:

obligate intracellular bacteria

Diseases

Sites and Sources

Diagnostic Factors

Virulence Factors

Treatment and Prevention

Commentary

This rather unusual organism exists as a small dense elementary body or a larger reticulate body with a Gram negative wall structure. It grows only intracellularly. The elementary body is the infectious form of the organism, responsible for attaching to the host cell and promoting its entry. The reticulate body is the intracellular, metabolically active form that divides by binary fission ( as do all bacteria). Chlamydia grows in the phagosome by preventing fusion of the phagosome and lysozome. It causes two different sexually transmitted diseases, NGU and LGV. NGU, or non-gonococcal urethritis, causes a discharge and/or burning on urination and is symptomatic in men more often than women. The discharge is often described as non-purulent but ranges from barely apparent to watery or mucoid to mucopurulent. It is generally agreed that the discharge in a chlamydia infection without a concomitant gonorrheal infection is less purulent than the discharge in gonorrhea. In women, the site of infection is most often the cervix but from there it can ascend to the uterus, fallopian tubes and can even be involved in pelvic inflamatory disease. Babies born to mothers infected with C. trachomatis may become infected and present with conjunctivitis or pneumonia. C. trachomatis can also infect the adult eye, causing trachoma and/or inclusion conjunctivitis. Trachoma, a chronic keratoconjunctivitis, is endemic to Africa and the Middle East where it is spread by flies, while inclusion conjunctivitis can occur anywhere. LGV, or lymphogranuloma venereum, is caused by a different set of serovars than NGU and has very different symptoms. LGV usually presents with swollen inguinal lymph nodes which may have been preceded by one or more painless genital papules or ulcers. The LGV serovar can also cause a conjunctivitis that presents with lymphadenopathy. Other species of Chlamydia include C. psittaci and C. pneumonia.