• Biology
    • Chlamydophila pneumoniae is a species of  Chlamydophila, an obligate intracellular bacterium that infects humans and is a major cause of pneumonia.

      C. pneumoniae has a complex life cycle and must infect another cell to reproduce; thus, it is classified as an obligate intracellular pathogen. The full genome sequence for C. pneumoniae was published in 1999. It also infects and causes disease in koalas, frogs, and some reptiles.

      The first known case of infection with C. pneumoniae was a case of conjunctivitis in Taiwan in 1950. This atypical bacterium commonly causes pharyngitis, bronchitis, coronary artery disease and atypical pneumonia in addition to several other possible diseases.

  • Taxonomy
    • Until recently, it was known as Chlamydia pneumoniae, and that name is used as an alternate in some sources. In some cases, to avoid confusion, both names are given.


      Until recently, it was known as Chlamydia pneumoniae, and that name is used as an alternate in some sources. In some cases, to avoid confusion, both names are given.

  • Life cycle and method of infection
    • Chlamydophila pneumoniae is a small gram negative bacterium (0.2 to 1 μm) that undergoes several transformations during its life cycle. It exists as an elementary body (EB) between hosts. The EB is not biologically active, but is resistant to environmental stresses and can survive outside a host for a limited time.

      The EB travels from an infected person to the lungs of an uninfected person in small droplets and is responsible for infection. Once in the lungs, the EB is taken up by cells in a pouch called an endosome by a process called phagocytosis. However, the EB is not destroyed by fusion with lysosomes. It transforms into a reticulate body (RB) and begins to replicate within the endosome. The reticulate bodies must use some of the host’s cellular metabolism to complete its replication. The reticulate bodies then convert back to elementary bodies and are released back into the lung, often after causing the death of the host cell. The EBs are thereafter able to infect new cells, either in the same organism or in a new host.

      Thus, the lifecycle of C. pneumoniae is divided between the elementary body, which is able to infect new hosts but cannot replicate, and the reticulate body, which replicates but is not able to cause new infection.

  • Pathology
    • C. pneumoniae is a common cause of pneumonia around the world; it is typically acquired by otherwise-healthy people and is a form of community-acquired pneumonia. Its treatment and diagnosis are different from historically recognized causes, such as Streptoccocus pneumoniae. Because it does not gram stain well, and because C. pneumoniae bacteria is very different from the many other bacteria causing pneumonia (in the earlier days, it was even thought to be a virus), the pneumonia caused by C. pneumoniae is categorized as an “atypical pneumonia”.
      One meta-analysis of serological data comparing prior C. pneumoniae infection in patients with and without lung cancer found results suggesting prior infection was associated with an increased risk of developing lung cancer.

      In research into the association between C. pneumoniae infection and atherosclerosis and  coronary artery disease, serological testing, direct pathologic analysis of plaques, and in vitro testing suggest infection with C. pneumoniae is a significant risk factor for development of atherosclerotic plaques and Atherosclerosis. C. pneumoniae infection increases adherence of macrophages to endothelial cells in vitro and aortas ex vivo. However, most current research and data are insufficient and do not define how often C. pneumoniae is found in atherosclerotic or normal vascular tissue.

      C. pneumoniae has also been found in the cerebrospinal fluid of patients diagnosed with multiple sclerosis.

  • List of disease
    • Inflammatory and autoimmune diseases of the upper and lower respiratory tract such as rhinitis, sinusitis, pharingitis, bronchitis, pneumonia, asthma bronchiale, chronic obstructive pulmonary disease, etc.

      Inflammatory and degenerative diseases of the brain and spinal cord such as multiple sclerosis, chronic fatigue syndrome, Alzheimer disease, meningoencefalitis, radiculitis, etc.

      Inflammatory diseases of the visual and auditory system such as uveitis, optical neuritis, conjuctivitis, otitis media, etc.

      Nonspecific disorders of the central nervous system such as nervous deafness, myelitis, etc.

      Inflammatory and autoimmune diseases of the heart and blood vessels such as myocarditis, pericarditis, endocarditis, aneurysm, giant-cell arteritis, polyarteritis nodosa, Wegener´s granulomatosis, etc.

      Inflammattory diseases of the urinary system and gastrointestinal tract such as interstitial cystitis, prostatitis, Crohn syndrome, ulcerative colitis, primary sclerosing cholangitis, etc.

      Nonspecific diseases of the urinary system and gastrointestinal tract.

      Chronic inflammatory diseases of the skeleton such as ankylosing spondylitis (Bekhterev syndrome), etc.

      Inflammattory and autoimmune diseases of the skin such as erythema nodosum, pyoderma gangrenosum, Henoch-schonlein purpura, etc.

      Cancer diseases such as lung cancer.

  • Vaccine research
    • There is currently no vaccine to protect against Chlamydophila pneumoniae. Identification of immunogenic antigens is critical for the construction of an efficacious subunit vaccine against C. pneumoniae infections. Additionally, there is a general shortage worldwide of facilities which can identify/diagnose Chlamydia pneumoniae.