Kids' 'Microbiome' May Play Key Role in Asthma

TUESDAY, Dec. 24, 2019 (HealthDay News) -- Microbes that live in a child's upper airway could be linked to severe asthma attacks, new research suggests.

For parents, it's an all-too familiar scene: A child's seemingly harmless cough quickly escalates to wheezing, gasping and an urgent need for emergency treatment. Asthma is the leading chronic disease in kids and third-most common cause of hospitalization among those under 15, according to the Asthma and Allergy Foundation of America.

Now, a new study found an association between asthma flare-ups in children and the makeup of the upper-airway microbiome, communities of microscopic organisms that include bacteria.

"In the future, we wish to understand whether the upper-airway bacteria can play a causal role in the severity of asthma symptoms," said study author Dr. Yanjiao Zhou, who conducted the research at Washington University School of Medicine in St. Louis. She is now an assistant professor of medicine at UConn Health in Farmington, Conn.

Zhou and her colleagues collected data on 214 school-aged children who were part of a clinical trial. Participants had mild to moderate asthma that was being treated with daily inhaled corticosteroids.

Nasal samples were collected twice -- once when asthma was under control, and again when kids had the signs of an emerging flare-up, what the investigators called the "yellow zone."

The researchers said kids who had early warning signs of a flare-up were more likely to have bacteria associated with the disease colonizing their upper airways -- specifically, Staphylococcus, Streptococcus and Moraxella.

Conversely, at times when their asthma was well-controlled, their airways contained good bacteria, primarily Corynebacterium and Dolosigranulum, the researchers reported.

Their findings were published Dec. 16 in the journal Nature Communications.

This relatively new focus of respiratory research follows extensive studies of gut bacteria populations.

"We know certain [environmental] factors can affect the gut microbiome, including diet and overuse of antibiotics," Zhou said. Other factors -- including vaginal delivery and breastfeeding -- are believed to affect a child's microbiome from birth. Both expose infants to their mothers' immune-stimulating gut bacteria.

"We know less about what controls the upper-airway microbiome," Zhou said.

While the recent study did link some upper airway bacteria to good asthma outcomes and other bacteria to acute flare-ups, it couldn't prove cause-and-effect. Researchers said they were unable to determine whether changes in the microbiome drove asthma activity, or if viral infection triggered changes in the microbiome.

They hope future studies will be able to answer this question, and perhaps lead to improved treatment options.

"The airway microbiome may be a relevant compartment that determines asthma control in children," said senior author Dr. Avraham Beigelman, director of the Kipper Institute of Allergy and Immunology in Tel Aviv. "If proven in additional mechanistic studies, we may be able to develop innovative asthma treatments that target the airway microbiome."

More information

The U.S. National Heart, Lung, and Blood Institute has more on asthma.