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Chlamydia pneumoniae and chronic bronchitis: association with severity and bacterial clearance following treatment
  1. F Blasi1,
  2. S Damato3,
  3. R Cosentini2,
  4. P Tarsia2,
  5. R Raccanelli3,
  6. S Centanni4,
  7. L Allegra1,
  8. The Chlamydia InterAction with COPD (CIAC) Study Group*
  1. 1Institute of Respiratory Diseases, University of Milan, IRCCS Ospedale Maggiore di Milano, Milan, Italy
  2. 2Department of Emergency Medicine, University of Milan, IRCCS Ospedale Maggiore Milano
  3. 3Division of Pneumology, University of Milan Bicocca, Ospedale di Seregno, Milan, Italy
  4. 4Respiratory Unit, Institute of Lung Disease, Ospedale San Paolo, University of Milan, Italy
  1. Correspondence to:
    Dr F Blasi, Istituto di Tisiologia e Malattie dell’Apparato Respiratorio, Università degli Studi di Milano, Pad. Litta, IRCCS Ospedale Maggiore di Milano, Via F Sforza 35, I-20122 Milan, Italy;


Background: A study was undertaken to evaluate Chlamydia pneumoniae chronic infection, other respiratory infections, and functional impairment in patients with chronic bronchitis (stage 1) and to examine chronic C pneumoniae infection, rate of acute exacerbations of chronic bronchitis, and rate of C pneumoniae eradication following antibiotic treatment (stage 2).

Methods: In the stage 1 study respiratory specimens from 42 patients with steady state chronic bronchitis were analysed for Gram staining, sputum culture, and C pneumoniae DNA detection by nested touchdown polymerase chain reaction (PCR). On the basis of the results of stage 1, a second population of 141 consecutive patients with steady state mild to moderate chronic bronchitis (FEV1 ≥50% predicted) was studied. On admission, at regular intervals, and at exacerbation all patients underwent serological testing for C pneumoniae (microimmunofluorescence) and a nested touchdown PCR to detect C pneumoniae DNA was performed on peripheral blood mononuclear cells (PBMCs). Patients were assessed over a 12 month period. Information regarding the previous 12 months was taken from medical records.

Results: Chronic colonisation of the sputum with C pneumoniae was significantly associated with lower FEV1 and greater airway bacterial colonisation. On admission to the stage 2 study, 80 patients were PCR negative and 61 were PCR positive. Over the 2 years a mean (SD) of 1.43 (1.32) acute exacerbations occurred in PCR negative patients and 2.03 (1.21) in PCR positive patients (p<0.01). During the 12 month follow up period 34 PCR positive patients had acute exacerbations and were treated with azithromycin for 6 weeks. Serological evidence of acute C pneumoniae reinfection/reactivation was found in two of the 34 patients. The rate of C pneumoniae DNA clearance from blood following treatment was 29% at follow up.

Conclusion: Chronic colonisation with C pneumoniae is associated with a higher rate of exacerbations of chronic bronchitis. Long term treatment is required to obtain clearance of the organism from the blood.

  • Chlamydia pneumoniae
  • chronic obstructive pulmonary disease
  • azithromycin
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  • * The following members of the CIAC Study Group participated in this study: C Arosio, C Dotti, L Fagetti, M Forloni, A Grugnetti, D Lattuada, N Morelli, C Papetti, C Pravettoni, Institute of Respiratory Diseases, University of Milan, IRCCS Ospedale Maggiore Milano, Italy; G Graziadei, G G Torgano, C Canetta, Department of Emergency Medicine, IRCCS Ospedale Maggiore Milano, Italy; P A Santus, Respiratory Unit, Institute of Lung Disease Ospedale San Paolo, University of Milan, Italy.

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