Asthma linked to bacterial colonization in the airway

Kathleen Blanchard's picture
Asthma and bacteria colonization linked

Researchers suggest asthma may be caused by a diversity of bacteria in the airways that colonize.

Scientists from University of California-San Francisco found high numbers of specific bacteria in patients with asthma that were not found in airway samples from healthy patients.

Study co-author Homer Boushey, MD, a UCSF professor of medicine in the division of Pulmonary and Critical Care Medicine says, "People thought that asthma was caused by inhalation of allergens but this study shows that it may be more complicated than that – asthma may involve colonization of the airways by multiple bacteria."

In the study, the scientists collected samples of bacteria from the airway lining of 65 asthmatic adults, over a period of three years, comparing to 10 healthy subjects.


Yvonne J. Huang, MD, the paper's first author explains, "We know fairly little about the diversity, complexity and collective function of bacteria living in the respiratory tract, and how they might contribute to diseases like asthma." The research showed the airways in the asthma patients contain an abundance of microorganisms that were tied to greater sensitivity in the respiratory tract.

"People have viewed asthma as a misdirected immune reaction to environmental exposures, but few have thought of it in the context of airway microbiota composition,'' said senior author Susan Lynch, PhD, an assistant professor of medicine and director of the UCSF Colitis and Crohn's Disease Microbiome Research Core in the division of gastroenterology.

In each analysis, patients with asthma were found to have far more bacteria in the airway than healthy study participants. Patients with the worse asthma symptoms had the most bacterial colonization.

The researchers say the findings might lead to new treatments for asthma or possibly a cure. Further studies are needed to understand how specific colonies of bacteria in the airways lead to the development of asthma.

JACI: doi:10.1016/j.jaci.2010.10.048
"Airway microbiota and bronchial hyperresponsiveness in patients with suboptimally controlled asthma"