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Chlamydia pneumoniae, strain TWAR, infection in patients with chronic obstructive pulmonary disease
C D Beaty1, J T Grayston, S P Wang
1Medical Service, Seattle Veterans Administration Medical Center, WA.
Abstract:
TWAR, the only known serovar of Chlamydia pneumoniae, is a newly described bacterium that has been identified as a cause of both epidemics and endemic cases of pneumonia. The role of TWAR infection in patients with chronic obstructive pulmonary disease (COPD) is not known. We conducted a prospective study to establish whether TWAR infection is a common cause of acute exacerbations of COPD. We studied two groups of patients: 44 patients admitted to the hospital with acute exacerbations of COPD, and 65 stable clinic patients with COPD. We found that evidence of acute TWAR infection was infrequent in patients with exacerbations (5%). In contrast, the majority of patients from both groups had serologic evidence of previous TWAR infection (77%). This was not significantly greater than the prevalence found in a small group of patients of similar age and sex without lung disease from the same institution (73%). TWAR was not isolated from the oropharyngeal specimens obtained from 97 subjects, suggesting that it does not colonize the respiratory tract of patients with COPD. This study shows that at the time of low incidence in the community, acute TWAR infection is uncommon in patients with acute exacerbations of COPD. The majority of patients with COPD have, however, been infected with TWAR in the past. The clinical manifestations of these infections are not known and should be the focus of further studies.
Insights
Acute TWAR (Taiwan acute respiratory agent) infection is uncommon in patients experiencing acute exacerbations of chronic obstructive pulmonary disease (COPD). However, most COPD patients show past TWAR infection, warranting further study into its clinical impact.
Area of Science:
- Infectious Diseases
- Respiratory Medicine
- Microbiology
Background:
- Chlamydia pneumoniae, specifically the TWAR serovar, is recognized as a cause of pneumonia.
- The association between TWAR infection and chronic obstructive pulmonary disease (COPD) exacerbations remains unclear.
Purpose of the Study:
- To investigate the prevalence of acute TWAR infections as a cause of acute exacerbations in COPD patients.
- To determine if TWAR colonizes the respiratory tract in COPD patients.
Main Methods:
- Prospective study involving 44 hospitalized COPD patients with acute exacerbations and 65 stable COPD clinic patients.
- Serological testing for acute and previous TWAR infection.
- Oropharyngeal specimen analysis for TWAR isolation.
Main Results:
- Acute TWAR infection was infrequent (5%) in patients with COPD exacerbations during periods of low community incidence.
- A high prevalence of past TWAR infection (77%) was observed in both COPD patient groups.
- Past infection rates in COPD patients were comparable to those in individuals without lung disease (73%).
- TWAR was not isolated from respiratory specimens, indicating no significant colonization.
Conclusions:
- Acute TWAR infection is not a common cause of acute COPD exacerbations when community incidence is low.
- The majority of COPD patients have a history of TWAR infection.
- Further research is needed to understand the clinical significance and manifestations of past TWAR infections in COPD patients.