Children's noses 'hold clues to lung infection risk'
Researchers from the University of Edinburgh led the medical study.
Examining the bacterial makeup of a child's nose could help doctors improve the diagnosis and treatment of serious lung infections, scientists say.
Researchers from the University of Edinburgh found that bacteria and viruses at the back of the nose and throat of children with respiratory infections is different to that of healthy youngsters.
These differences indicate the severity of the condition and could help doctors predict how long the affected child needs to spend in hospital.
In less serious cases they could be helped to recover naturally, reducing the need for antibiotics.
Lower respiratory tract infections (LRTIs), including pneumonia and bronchiolitis, are a leading cause of death in under-fives around the world. Symptoms include shortness of breath, weakness and fever.
Professor Debby Bogaert of Edinburgh University's Medical Research Council Centre for Inflammation Research, who led the study, said: "Lung infections can be extremely serious in children and babies and are very distressing for parents.
"Our findings show for the first time that the total microbial community in the respiratory tract - rather than a single virus or a bacteria - is a vital indicator of respiratory health.
"This could really impact on how doctors diagnose LRTIs and use precious antibiotics to fight infections."
Researchers worked with teams in the Netherlands to take samples from more than 150 children under the age of six hospitalised with an LRTI and compared them with samples from healthy children.
They found the 'microbiome' - the population of bacteria and viruses - at the back of the nose and throat was related to that seen in the lungs, making it easier to understand and diagnose infections.
The microbiome profiles allowed them to identify 92% of children as being healthy or ill when combined with factors such as the child's age. It also provided a marker of the infection's severity.
The study, funded by the Netherlands Organisation for Scientific Research, is published in the journal The Lancet Respiratory Medicine.