Chlamydia pneumoniae was discovered only after several years and many misconceptions. It was first isolated in 1961 during a study of eye disease. Researchers thought that it was a new strain of Chlamydia trachomatis, which was a known cause of eye disease. At that time, C. pneumoniae was called TW-183. Several years later, advances in cell culture allowed researchers to distinguish TW-183 as a separate species from C. trachomatis. They were still unsure of TW-183’s role; because although it was found in the eye, they determined it did not cause disease in the eye. Later, TW-183 was used as a control in a study to determine whether C. trachomatis caused respiratory infection. The study took a drastic turn when several of the control patients developed pneumonia. So, partially by accident and after several more studies, it was determined that TW-183 caused the respiratory illness and was thus named after it (Kuo).
C. pneumoniae is an obligate intracellular parasite that exists in two forms. The extracellular form is called the elementary body (EB). The pear-shaped EB attaches to a possible host cell and is phagocytized by the cell. Once in the cell, the EB transforms to the reticulate body (RB), which is capable of undergoing replication by using host cell energy (Kuo).
C. pneumoniae is a gram-negative bacterium. It grows poorly in culture. It requires all amino acids except lysine to grow in, and it grows best in a cell culture. Specimens used in culture are usually taken from throat swabs (Kuo).
Humans are the only known host for C. pneumoniae. Infections of C. pneumoniae occur mostly in children, and are found throughout the world. Infections cause respiratory diseases such as pneumonia, bronchitis, and sinusitis. The disease is transmitted by respiratory secretions that can stay viable in aerosols for short time periods and on surfaces for up to thirty hours (Kuo).
Despite the interesting characteristics described above, I choose this microbe for a completely different reason. I am very interested in cardiology, so I wanted to find out about microbes that are found in the cardiovascular system. One of the most interesting things about C. pneumoniae is that it is suspected to be associated with coronary artery disease. In recent research, many of the artery-blocking plaques contain evidence of C. pneumoniae infection. Much more research is needed to determine whether C. pneumoniae is a cause of the plaques and consequentially, whether patients with a history of C. pneumoniae infections may be at higher risk for heart disease (Campbell).
ReferencesCampbell, Kuo, and Grayston. “Chlamydia pneumoniae” and Cardiovascular Disease. Emerging Infectious Diseases. Vol. 4. 8 March 2004. <http://www.cdc.gov/ncidod/EID/vol4no4/campbell.htm>
Kuo, Jackson, Campbell, and Grayston. “Chlamydia pneumoniae” (TWAR). Clinical Microbiology Reviews, October 1995. Vol. 8. 8 March 2004. <http://cmr.asm.org/cgi/reprint/8/4/451.pdf>
*Disclaimer - This report was written by a student participaring in a microbiology course at the Missouri University of Science and Technology. The accuracy of the contents of this report is not guaranteed and it is recommended that you seek additional sources of information to verify the contents.
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