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Salem Health: Infectious Diseases & Conditions, 2nd Edition

Chlamydophila pneumoniae infection

by Christine Adamec, , M.B.A.

Category: Diseases and conditions

Anatomy or system affected: Lungs, respiratory system

Definition

Chlamydophila pneumoniae infection is caused by the bacterium Chlamydophila pneumoniae, which leads to pneumonia, bronchitis, sinusitis, and pharyngitis. There are about 100 cases of infection with C. pneumoniae for every 100,000 persons in the United States each year. Infections with C. pneumoniae occur year-round.

Causes

C. pneumoniae infection causes up to 10 percent of the cases of pneumonia that are acquired outside hospitals and nursing homes. Infection is transmitted through droplets of respiratory secretions in the air.

Risk Factors

Persons who are sixty-five to seventy-nine years of age have the greatest risk for infection with C. pneumoniae. In addition, persons of all ages who are immunocompromised also have an elevated risk for infection. These persons include those with human immunodeficiency virus (HIV) infection and those with organ transplants and who consequently must take immunosuppressant drugs to avoid the body’s rejection of the organ.

Symptoms

Headache is a common symptom of C. pneumoniae, as is lethargy. Persons with asthma often experience worsening symptoms, and recurrent infections with this bacterium may lead to the onset of chronic asthma in children and adults. The presence of laryngitis is the most common symptom differentiating persons with infection caused by C. pneumoniae versus infection caused by another bacterium. Fever is another common symptom, as are chills and muscle pain (myalgia). Persistent cough is another frequently occurring symptom. However, some persons have no symptoms because the infection is mild.

Screening and Diagnosis

This infection is diagnosed with nasopharyngeal swabs used to obtain samples; these samples are then cultured. A chest X ray will show if a person has pneumonia, although the X ray does not differentiate the type of pneumonia. A sputum culture test can identify C. pneumoniae. Deoxyribonucleic acid (DNA) tests such as the polymerase chain reaction-enzyme immunoassay are used to identify the bacterium in some outbreaks, but these tests are not practical in diagnosing a person who is not associated with an outbreak of pneumonia. Diagnosis also is based on clinical symptoms.

Treatment and Therapy

Antibiotics such as erythromycin, doxycycline, and tetracycline are used for acute infections. For example, tetracycline may be given at 500 milligram (mg) doses, four times daily for fourteen days; doxycycline at 100 mg twice daily for fourteen days; and erythromycin at 500 mg for fourteen days. If cough or malaise continues after a full course of treatment, the doctor may choose to prescribe a second course of treatment.

Prevention and Outcomes

Stopping a smoking habit decreases the risk for all forms of pneumonia, including infection with C. pneumoniae.

Further Reading

1 

Burllo, Almudena, and Bouza, Emilion. “Chlamydophila pneumoniae.” Infectious Disease Clinics of North America 24 (2010): 61-71.

2 

Krüll, Matthias, and Norbert Suttorp. “Pathogenesis of Chlamydophila pneumoniae Infections: Epidemiology, Immunity, Cell Biology, Virulence Factors.” In Community-Acquired Pneumonia, edited by Norbert Suttorp, Tobias Welte, and Reinhard Marre. Boston: Birkhäuser, 2007.

3 

Lutfiyya, M. Nawal, et al. “Diagnosis and Treatment of Community-Acquired Pneumonia.” American Family Physician 73 (2006): 442-450.

4 

National Heart, Lung, and Blood Institute. “Pneumonia.” Available at http://www.nhlbi.nih.gov/health/dci/diseases/pnu/pnu_whatis.html.

Web Sites of Interest

American Lung Association

http://www.lungusa.org

National Heart, Lung, and Blood Institute

http://www.nhlbi.nih.gov

See also: Airborne illness and disease; Allergic bronchopulmonary aspergillosis; Aspergillosis; Aspergillus; Bacterial infections; Bronchiolitis; Bronchitis; Chlamydophila; Legionnaires’ disease; Pharyngitis and tonsillopharyngitis; Pneumonia; Respiratory route of transmission; Sinusitis; Tuberculosis (TB); Whooping cough.

Citation Types

Type
Format
MLA 9th
Adamec, Christine. "Chlamydophila Pneumoniae Infection." Salem Health: Infectious Diseases & Conditions, 2nd Edition, edited by H. Bradford Hawley, Salem Press, 2020. Salem Online, online.salempress.com/articleDetails.do?articleName=Infect2e_0124.
APA 7th
Adamec, C. (2020). Chlamydophila pneumoniae infection. In H. B. Hawley (Ed.), Salem Health: Infectious Diseases & Conditions, 2nd Edition. Salem Press. online.salempress.com.
CMOS 17th
Adamec, Christine. "Chlamydophila Pneumoniae Infection." Edited by H. Bradford Hawley. Salem Health: Infectious Diseases & Conditions, 2nd Edition. Hackensack: Salem Press, 2020. Accessed September 16, 2025. online.salempress.com.