title: Prevalence of positive serology for acute Chlamydia pneumoniae infection in emergency department patients with persistent cough.
abstract: OBJECTIVE
  To determine the prevalence of acute Chlamydia pneumoniae infection in ED patients presenting with a persistent cough.
  
  
  METHODS
  This was a case series consisting of a convenience sample of 65 patients > or = 18 years of age who presented with a chief complaint of a cough lasting > or = 2 weeks. Patients were treated in the ED of an urban university hospital. Patients with immunosuppression, lung disease, pneumonia, or a cough lasting > or = 3 months were excluded. Acute and convalescent sera were assayed for antibody to C. pneumoniae. Subjects with C. pneumoniae antibody titers showing a fourfold rise in either immunoglobin M (IgM) or immunoglobin G (IgG) antibody, an IgM titer of > or = 16, or an IgG titer of > or = 512 were considered to have evidence of acute C. pneumoniae infection.
  
  
  RESULTS
  Thirteen (20%; 95% CI, 11% to 32%) of the 65 subjects had serologic evidence of acute C. pneumoniae infection. Except for an increased rate of fever, clinical signs and symptoms and laboratory studies did not differentiate those who had C. pneumoniae from those who did not have the disease. Patients diagnosed as having Bordetella pertussis or Mycoplasma pneumoniae infection did not have serologic evidence of concurrent C. pneumoniae infection.
  
  
  CONCLUSIONS
  C. pneumoniae infection appears to be associated with a persistent cough in ED patients. Clinicians should consider this organism when evaluating these patients. It is unclear whether antibiotic therapy is indicated for these patients. If antibiotics are used, a tetracycline or macrolide antibiotic would be most appropriate.
authors.affiliation: Department of Emergency Medicine, Vanderbilt University Medical Center, Nashville 37212, USA. seth.wright@mcmail.vanderbilt.edu
authors.forename: S W
authors.initials: SW
authors.lastname: Wright
authors.forename: K M
authors.initials: KM
authors.lastname: Edwards
authors.forename: M D
authors.initials: MD
authors.lastname: Decker
authors.forename: J T
authors.initials: JT
authors.lastname: Grayston
authors.forename: S
authors.initials: S
authors.lastname: Wang
mesh_terms: D000293:Adolescent; D000328:Adult; D000907:Antibodies, Bacterial / Q000302:isolation & purification; D002690:Chlamydia Infections / Q000453:epidemiology*; D016993:Chlamydophila pneumoniae / Q000276:immunology*; D003371:Cough / Q000175:diagnosis / Q000453:epidemiology / Q000382:microbiology*; D003430:Cross-Sectional Studies; D003937:Diagnosis, Differential; D004636:Emergency Service, Hospital; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D015995:Prevalence; D013714:Tennessee
chemical_list: D000907:Antibodies, Bacterial