Early Bacterial Infection May Boost Asthma Risk

Babies exposed to certain germs more likely to develop breathing problems, study finds.

By Serena Gordon
HealthDay Reporter
Wednesday, October 10, 2007; 12:00 AM

Copyright © 2007 ScoutNews, LLC. All rights reserved.

WEDNESDAY, Oct. 10 (HealthDay News) -- Babies who had certain bacterial infections in their first month of life were more likely to develop asthma by the time they were 5 years old, a new study found.

Danish researchers found that infants who tested positive for Streptococcus pneumoniae, Haemophilus influenzae or Moraxella catarrhalis bacteria had more than double the risk of asthma compared to infants who weren't infected. And they had four times the risk of being hospitalized for severe asthma when compared to infants who didn't test positive for these bacteria.

"Colonization of pathogenic bacteria in the newborn child is a strong predictor for the risk of asthma later in childhood," said the study's lead author, Dr. Hans Bisgaard, professor and head of the Danish Pediatric Asthma Center at Copenhagen University Hospital.

Results of the study are published in the Oct. 11 issue of the New England Journal of Medicine.

Despite the increasing prevalence of asthma, scientists still aren't sure exactly what causes the development of this potentially life-threatening airway disease. Genetics appear to be at least partly to blame, and environmental factors also likely play a role. Bacterial infections can trigger asthma symptoms in people who have the disease, but it hasn't been known if bacteria play a role in the initial development of asthma.

To assess the effects of bacteria in the development of asthma, Bisgaard and his colleagues obtained cultures from 321 babies when they were 1 month old. They tested the cultures for S. pneumonia, H. influenzae, M. catarrhalis and Staphylococcus aureus.

The researchers found that 21 percent of the babies were infected with S. pneumoniae, H. influenzae or M. catarrhalis. They also found that infection with these bacteria was associated with a 2.4 times increased risk of a persistent wheeze, a 2.99 times greater risk of acute severe exacerbation of wheeze, and a 3.85 times increased risk of hospitalization for wheeze. No such association was found with S. aureus infection, according to the study.