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Study Reveals New Strain of Bacteria
Potential Source of COPD Flare-ups

Flare-ups of emphysema and chronic bronchitis, which can be life-threatening, are often triggered by infections from newly encountered strains of common germs, a study found.

Chronic Obstructive Pulmonary Disease (COPD) is the fourth leading cause of death in the United states. It caused 119,000 deaths and hospitalized 729,000 people in 2000, according to the U.S. Centers for Disease Control and Prevention (CDC).

In the study, doctors at the Veterans Administration hospital in Buffalo, N.Y., had 81 patients check in once a month over 56 months to give a sputum sample. There were 1,975 visits total.

Flare-ups were diagnosed in 33 percent of the visits when the phlegm carried a new strain of bacteria, senior author Timothy F. Murphy reported recently in New England Journal of Medicine.

That compared to 15.4 percent of the visits at which the lab did not find any new strains, said Murphy, chief of infectious diseases at the VA Western New York Health Care System.

Previous studies have found that people can get infected over and over by the same bacteria, but DNA analysis now allows scientists to determine one strain from another.

Dr. Norman Edelman, the American Lung Association's consultant for scientific affairs, said the study suggests COPD flare-ups are more likely to be caused by bacteria than had been thought. But he said it doesn't indicate that antibiotic treatment should be increased.

Current standards already call for doctors to use antibiotics for patients who have particular difficulty breathing, more phlegm than usual or green phlegm, a sign of infection.

"At the moment it doesn't change medical practice. But it opens a number of doors in terms of potential research approaches," said Dr. Alan Fein, chief of pulmonary and critical care medicine at Northshore-Long Island Jewish Health System.

The study found the bacteria with new strains most often found during COPD flare-ups were Haemophilus influenzae, Moraxella catarrhalis and Streptococcus pneumoniae. Researchers said all three may hit the same inflammation trigger in humans. That could allow treatment which targets a particular molecule on the bacteria, the way some newer painkillers target the enzyme which causes arthritis.

H. influenzae is found in the throat of 75 percent of healthy adults and children. "H. influenzae as a species is incredibly genetically diverse," Murphy said.

The immune system "recognizes" a protein which makes up about half of the bacterium's surface. The protein varies from strain to strain, so a person immune to one strain can get sick from another, Murphy added. Other, smaller molecules are the same on all or most of the strains, and Murphy and other researchers are trying to use them to create a vaccine.

H. influenzae once was thought to cause the flu and one form caused childhood meningitis before vaccinations became common.

Although there is a vaccine against the strain which causes meningitis in children under 2, there is a huge number and wide variety of strains, Murphy said.

Source: U.S. Centers for Disease Control and Prevention and various U.S. news sources.

 

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