From rxpgnews.com
Key to Potential Vaccine to COPD Bacteria
By American Thoracic Society
Jul 16, 2005, 00:13
Researchers believe that the acquisition and reasonably quick clearance of a bacterial strain called Moraxella catarrhalis from the lungs of chronic obstructive pulmonary disease (COPD) patients results in long-lasting, strain-specific protection from reacquisition and has important implications for vaccine development. The investigators assessed 104 adults with COPD for 81 months. They said that bacteria cause many of the exacerbations which characterize the disease and that such organisms, through chronic colonization, contribute to the airway inflammation that is the hallmark of the disease.
COPD is a term for lung diseases characterized by airflow obstruction that interferes with normal breathing. The two most frequent disease conditions that underlie COPD are severe emphysema and chronic bronchitis. Years of smoking are the primary cause for the diseases that underlie COPD, which, in 2002, claimed the lives of 120,000 Americans and cost the nation $37.2 billion.
In the study, the authors pointed out that 10.2 percent of the 560 exacerbations were likely caused by M. catarrhalis bacteria.
According to the authors, for the 20 million adults in the U.S. who have COPD, exacerbations occur at a rate of 1 to 2 annually. Based on their estimates, M. catarrhalis bacteria causes 2 to 4 million exacerbations annually in the U.S. Most individuals carried the organism M. catarrhalis for only a single monthly clinic visit. This relatively short duration of infection is in striking contrast to that observed for H. influenzae bacteria which colonized subsets of patients for a much longer time.
According to the researchers, the long-lasting, strain-specific protection offered by the acquisition and clearance of M. catarrhalis supports the concept that humans make protective responses that are capable of clearing the bacteria from the respiratory tract and preventing reacquisition. They said that their future work will focus on developing similar protective responses.
The study appears in the second issue for July 2005 of the American Thoracic Society's peer-reviewed American Journal of Respiratory and Critical Care Medicine.
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