Chlamydia pneumoniae infection
Summary
Definition
History and exam
Other diagnostic factors
- overcrowding (risk factor)
- illness in other family members
- cough
- fever
- headache
- crackles on chest auscultation
- wheezes on chest auscultation
- tachypnea
- pleuritic chest pain
- dullness to percussion/reduced air entry/decreased tactile fremitus
Risk factors
- overcrowding
Diagnostic tests
1st tests to order
- chest x-ray
- WBC count with differential
- nucleic acid amplification tests for Chlamydia pneumoniae
Treatment algorithm
adults
children
Contributors
Authors
Margaret R. Hammerschlag, MD
Professor of Pediatrics and Medicine
Director
Division of Pediatric Infectious Diseases
SUNY Downstate Medical Center
Brooklyn, NY
Disclosures
MRH is an author of a number of references cited in this topic.
Peer reviewers
Florian Tagini, MD, PhD
Infectious disease physician
Lausanne University Hospital
Lausanne
Switzerland
Disclosures
FT declares that he has no competing interests.
David L Hahn, MD, MS
Clinical Advisory Board
Intracell Research Group
Wake Forest, NC
Disclosures
DLH declares that he has no competing interests.
Yuji Oba, MD, FCCP
Associate Professor of Clinical Medicine
Division of Pulmonary/Critical Care Medicine
School of Medicine
University of Missouri-Columbia
Columbia, MO
Disclosures
YO declares that he has no competing interests.
Sebastian Johnston, MB, BS, PhD, FRCP
Professor of Respiratory Medicine
Honorary Consultant Physician in Allergy and Respiratory Medicine
Department of Respiratory Medicine
Imperial College School of Medicine
London
UK
Disclosures
SJ has received fees for speaking, and research and consultant fees from Sanofi Pasteur, Aventis, GlaxoSmithKline, AstroZeneca, Merck, Pfizer, Centocor, and Synergen.
Peer reviewer acknowledgements
BMJ Best Practice topics are updated on a rolling basis in line with developments in evidence and guidance. The peer reviewers listed here have reviewed the content at least once during the history of the topic.
Disclosures
Peer reviewer affiliations and disclosures pertain to the time of the review.
References
Key articles
Kumar S, Hammerschlag MR. Acute respiratory infection due to Chlamydia pneumoniae: current status of diagnostic methods. Clin Infect Dis. 2007 Feb 15;44(4):568-76. Abstract
Hammerschlag MR, Kohlhoff SA, Dean D. Chlamydia pneumoniae. In: Blaser MJ, Cohen JI, Holland SM, eds. Mandell, Douglas, and Bennett’s principles and practice of infectious diseases. 10th ed. Philadelphia, PA: Elsevier; 2025:188, 2296-304.
Rockey DD, Lenart J, Stephens RS. Genome sequencing and our understanding of Chlamydiae. Infect Immun. 2000 Oct;68(10):5473-9.Full text Abstract
Tagini F, Puolakkainen M, Greub G, et al. From coughs to complications: the story of Chlamydia pneumoniae. J Med Microbiol. 2025 Apr;74(4):002006.Full text Abstract
Reference articles
A full list of sources referenced in this topic is available to users with access to all of BMJ Best Practice.
Differentials
- Coronavirus disease 2019 (COVID-19)
- Mycoplasma pneumoniae pneumonia
- Pneumonia, bacterial
More DifferentialsGuidelines
- Diagnosis and treatment of adults with community-acquired pneumonia
More GuidelinesPatient information
Pneumonia
More Patient information
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