Chlamydia Pneumonia in Atypical Pneumonia

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Chlamydia Pneumonia in Atypical Pneumonia

• Ri ???
• Date 02/25/2008

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Atypical Pneumonia

• Lower respiratory tract infections due to
  specific respiratory pathogens
• Chlamydia psittaci (psittacosis),
• Francisella tularensis (tularemia),
• Coxiella burnetii (Q fever),
• Chlamydia pneumoniae,
• Mycoplasma pneumoniae
• Legionella species
• Newly recognized causes of CAP
• Severe acute respiratory syndrome (SARS),
• Hantavirus
• Avian influenza,
• ? Viral CAPs

Zoonotic
Nonzoonotic
Clin Microbiol Infect 2006 12 (Suppl. 3) 1224
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Atypical Pneumonia

• 15 of all CAPs, mostly sporadic, more common
  than typical bacterial pathogens in mild or
  ambulatory CAP in adults.
• As a cause of Nursing home-acquired pneumonia
  (NHAP) or Nosocomial pneumonia (NP)
• ? Rare
• Main feature differentiating atypical from
  typical CAP pathogens
• Presence of extrapulmonary findings

Clin Microbiol Infect 2006 12 (Suppl. 3) 1224
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Prevalence of atypical respiratory pathogens in
patients with community-acquired pneumonia (CAP)
Eur Respir J 2004 24 171181
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Clin Microbiol Infect 2006 12 (Suppl. 3) 1224
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Clin Microbiol Infect 2006 12 (Suppl. 3) 1224
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-- URI involvement -- Ear signs, laryngitis,
non-exudative pharyngitis
HRlt120 w/ BT39.4?
Clin Microbiol Infect 2006 12 (Suppl. 3) 1224
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M. pneumoniae and C. pneumoniae
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Features of C. pneumoniae

• G(-) Obligate intracellular bacteria? Require a
  different therapeutic approach
• Constitute the majority of CAPs in young adults
  in the ambulatory or outpatient settings
• Potential role in coronary artery disease and
  multiple sclerosis, also associated with acute
  airway hypersensitivity (AE of asthma and COPD)

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Diagnosis of Chlamydia Pneumonia

• Clinical laboratory methods for identification of
  C. pneumoniae are suboptimal
• Poor correlation between serology and culture
  and/or PCR
• It is rare to definitively establish a diagnosis
  of C. pneumoniae in the clinical setting?
  Treatment is most often on an empirical basis

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Diagnostic Modalities

• Culture requires nasopharyngeal swabs
• Antibody tests (complement fixation and
  microimmunofluorescence)
• Direct antigen detection (direct
  immunofluorescence DFA and enzyme immunoassay
  EIA)
• Polymerase chain reaction (PCR)

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Lab Diagnosis of C. pneumoniae

• MIF? detect IgG, IgM, and IgA
• Acute infection? fourfold rise in IgG titer, a
  single IgM titer gt16,or a single IgG titer gt512.
  
• Past or preexisting infection 16ltIgG titerlt512
• PCR
• Rapid identification, sensitive
• Limited to test antimicrobial susceptibility, not
  provide an isolate

• Pediatric Pulmonology 36384390 (2003) UpTodate

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Thank you for the attention!