Chlamydial Pneumonia

Chlamydial pneumonia

Chlamydial pneumonia is a pneumonia cause by one of several forms of Chlamydial bacteria . The three major forms of Chlamydia responsible for pneumonia are Chlamydia pneumoniae, Chlamydia psittaci, and Chlamydia trachomatis.

In reaction to infection, infected lung tissue may become obstructed with secretions. As part of a generalized swelling or inflammation of the lungs, the fluid or pus secretions block the normal vascular exchanges that take place in the alveolar air sacs. Blockage of the alveoli results in a decreased oxygenation of the blood and deprivation of oxygen to tissues.

Chlamydia pneumoniae (in older literature known as "Taiwan acute respiratory agent") usually produces a condition known as "walking pneumonia," a milder form of pneumonia that may only result in a fever and persistent cough. Although the symptoms are usually mild, they can be debilitating and dangerous to at risk groups that include the elderly, young children, or to individuals already weakened by another illness. Chlamydia pneumoniae spreads easily and the high transmission rate means that many individuals within a population—including at risk individuals can be rapidly exposed.

Species of chlamydiae can be directly detected following cultivation in embryonated egg cultures and immunofluorescence staining or via polymerase chain reaction (PCR ). Chlamydiae can also be detected via specific serologic tests.

Chlamydia psittaci is an avian bacteria that is transmitted by human contact with infected birds, feathers from infected birds, or droppings from infected birds. The specific pneumonia (psittacosis) may be severe and last for several weeks. The pneumonia is generally more dangerous than the form caused by Chlamydia pneumoniae.

Chlamydia trachomatis is the underlying bacterium responsible for one of several types of sexually transmitted diseases (STD). Most frequently Chlamydia trachomatis results in an inflammation of the urethra (nongonococcal urethritis) and pelvic inflammatory disease. Active Chlamydia trachomatis infections are especially dangerous during pregnancy because the newborn may come in contact with the bacteria in the vaginal canal and aspirate the bacteria into its lung tissue from coating left on the mouth and nose. Although many newborns develop only mild pneumonia, because the lungs of a newborn are fragile, especially in pre-term babies, any infection of lung tissue is serious and can be life-threatening.

Specific antibiotics are used to fight chlamydial pneumonias. Erythromycin and erythromycin derivatives are used to combat Chlamydia pneumoniae and Chlamydia trachomatis. Tetracycline is usually effective against Chlamydia psittaci.

See also Bacteria and bacterial infection; Transmission of pathogens