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
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
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
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
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
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.