Researchers find link between bacteria in infancy and development of childhood asthma

Bacteria colonising the airways of infants can increase their risk of severe respiratory illness and subsequent asthma, a new study led by researchers at the University of Melbourne has revealed.

The findings shed light on the human respiratory microbiome, the community of bacterial and viral cells that live in the human body, and its role in health and disease. The ground breaking microbiome study was published this week in Cell Host and Microbe. Asthma affects around 300 million people worldwide and approximately 10% of Australians, while respiratory illness is one of the most common causes of hospitalisation in children.

Dr Michael Inouye, senior author from the University of Melbourne’s School of Biomedical Sciences, said there is a fast-growing body of evidence showing that the human microbiome plays an integral role in the development of many common and rare diseases. “We know so little about the microbial communities inhabiting us, despite observations that the human body contains more microbial cells than human cells,” he said.

The results of the National Health and Medical Research Council (NHMRC)-funded study will inform strategies to reduce the severity of childhood respiratory illness and risk of asthma, potentially through vaccinating against viruses and bacteria.

“Changes in the microbiome are associated with many metabolic and immune-related diseases, including now asthma, but further research needs to be done to understand the specific roles that the microbes play,” Dr Inouye said. “The nasopharynx of infants is an important reservoir for bacteria and viruses, some of which appear to be associated with a healthy state and some which appear more frequently during acute respiratory illness,” he said. “Our data also show that the presence of Streptococcus in the nasal passages early in life was associated with chronic allergic wheeze at age five, suggesting a potential avenue for asthma prevention.”

Dr Kathryn Holt, senior author of the study from the University of Melbourne’s Department of Biochemistry and Molecular Biology and the Bio21 Institute, said: “One of the most exciting aspects of this study is that it shows that what’s happening in the microbiome of babies impacts not only on their health at the time, but may also have long-lasting impacts in terms of the asthma development several years down the track.”

Dr Holt added: “There has been a lot of interest recently in the impact of genetics on the development of chronic diseases in children. This study adds to the growing evidence that the microbiome also has a key role to play in understanding how diseases develop, and may lead to better management or possibly even prevention of childhood diseases such as asthma.”

(Source: The University of Melbourne, Cell Host and Microbe)