Microbiota in the respiratory tract of infants born with cystic fibrosis are different to healthy infants even in the first year of life, the largest study to date reveals.

Members of the Swiss Cystic Fibrosis Infant Lung Development (SCLID) study group took over 400 nasal samples from 30 infants with cystic fibrosis and over 800 samples from 48 healthy controls.

They identified an increase in both Staphylococcus aureus and coagulase- negative Staphylococci in the children with cystic fibrosis.

Potentially beneficial bacteria such as Corynebacteriaceae  was also absent— a finding the authors said was often overlooked in culture-based studies that are mostly focused on potential pathogens.

The research team also found an “unexpected trend” of increased coagulase- negative Staphylococci during antibiotic treatment.

“These findings are clinically important in view of the crucial role that bacterial pathogens have in the disease progression of cystic fibrosis in early life,” the study authors wrote in the Lancet Respiratory Medicine.

The findings could assist in the prevention of early disease progression in infants with cystic fibrosis, they said.

The researchers used oligotyping which enabled them to differentiate Staphylococcus aureus from coagulase-negative Staphylococci.

“The method allowed for accurate species designation… and, therefore, provides very important information about bacterial species” they added.