Colonisation with filamentous fungi and acute asthma exacerbations in children

Abstract

Introduction: Aspergillus fumigatus airway colonisation in adults with asthma is associated with reduced lung function. There is a paucity of data on fungal colonisation in children with asthma although fungal sensitisation has been associated with more severe disease. In vitro studies have shown that stimulation of epithelial cells with fungal antigen promotes secretion of the mucin MUC5AC, which has been implicated in airway hyperactivity. Our study aim was to evaluate the association between fungal airway colonisation and exacerbation prone asthma in children. Methods: Children with acute exacerbation of asthma who were seen on an admissions unit and children with stable asthma or no history of asthma (controls) from outpatient clinics were recruited. Sputum was obtained either via nebulisation with hypertonic saline in children with stable asthma and controls or nebulisation with 0.9% saline in children with acute asthma. Sputum culture was focused to detect filamentous fungi, in particular Aspergillus fumigatus . Results: Adequate sputum was obtained from 130 children, 34 acute asthma, 80 stable asthma and 16 control. Filamentous fungi was isolated from 41% of children with acute asthma and 18% of children with stable asthma, p=0.010. Aspergillus fumigatus was the predominant fungi isolated. No filamentous fungi were isolated in sputum from healthy controls. Conclusions: Aspergillus fumigatus is the commonest filamentous fungus isolated from children with asthma and was found in a significantly higher number of children with an acute exacerbation compared to stable asthma. Fungal airway colonisation appears to be uncommon in children without respiratory disease.