New strains of bacteria complicate the course of lung disease
A recent study found that exacerbations of emphysema and chronic bronchitis are often triggered by infections caused by strains of common microorganisms not previously exposed.
A recent study found that exacerbations of emphysema and chronic bronchitis are often triggered by infections caused by strains of common microorganisms not previously exposed.
It is believed that such exacerbations are responsible for a large number of deaths in chronic obstructive pulmonary disease (COPD), characterized by irreversible disorders, which make it difficult for air to enter the lungs.
COPD is the fourth leading cause of death in the United States. According to the United States Centers for Disease Control and Prevention (CDC), in 2000, 119,000 people died from COPD and 729,000 other patients were hospitalized.
To conduct this study, doctors from the Veteran Administration Hospital in Buffalo, New York, performed a bacteriological analysis of sputum once a month in 81 patients. The sampling continued for 56 months, which represented a total of 1975 visits.
In the August issue of the New England Journal of Medicine, study leader Dr. Timothy F. Murphy reported that exacerbations were seen in 33% of these visits when new strains of bacteria have been detected in sputum. At the same time, of these doctor visits when laboratory tests did not find new strains, only 15.4% were diagnosed with an exacerbation.
As a result of a number of other studies, it has been shown that diseases can be caused by the same microorganisms, but DNA analysis can reveal different strains of these microorganisms.
According to Dr. Norman Edelman, scientific consultant to the American Lung Association, the results of the study suggest that bacteria are much more likely to be responsible for exacerbations of COPD than previously thought. However, this does not mean that antibiotics should be prescribed more often. Existing recommendations urge doctors to use antibiotics in patients with severe breathing difficulties and the release of large volumes or green sputum, which is an indication of an infectious disease.
The head of the pulmonary and emergency medicine department of the Northshore-Long Island Jewish health system, Dr. Alan Fein, believes that the results will not affect medical practice at this time. However, they do offer opportunities for further research.
Most often during exacerbations of COPD, new strains of Haemophilus influenzae, Moraxella catarrhalis and Streptococcus pneumoniae have been found. Researchers believe that all of these microorganisms can use similar mechanisms of action on the human body, causing inflammatory processes. This allows for therapy in which the target is a single molecule on the surface of the bacteria. A similar mechanism is used in new pain relievers when the arthritis-causing enzyme becomes the target of the drug.
H. influenzae can be found on the pharyngeal mucosa in 75% of healthy adults and children. Dr. Murphy notes that despite the existence of a vaccine against the strain that causes meningitis in children under 2 years of age, there is a wide variety of H. influenzae strains with a very great genetic diversity.
When fighting against such microorganisms, the immune system "recognizes" a protein that occupies almost half the surface of the bacteria. This protein is different in different strains, so a person immunized against a strain can develop a disease caused by another variety of this microorganism. Other smaller molecules remain unchanged on all or most strains of the bacteria. These are the little molecules that researchers are trying to use to create a new vaccine.