Fungal DNA in dust in Swedish day care centres: associations with respiratory symptoms, fractional exhaled nitrogen oxide (FeNO) and C-reactive protein (CRP) in serum among day care centre staff.

Abstract

To study associations between fungal DNA in day care centres, fractional exhaled nitric oxide (FeNO) and inflammatory markers in day care centre staff. Totally, 62 staff (90 %) from five day care centres in Sweden participated. All were females. Settled dust was collected and analysed for five sequences of fungal DNA by quantitative PCR. Levels of FeNO (NIOX MINO 50 ml/min) and serum levels of eosinophilic cationic protein, myeloperoxidase (MPO) and high-sensitivity C-reactive protein in blood (HsCRP) were measured. Dynamic spirometry was performed, and dyspnoea was measured. Biomarkers and dyspnoea ratings were log-transformed, and associations were analysed by linear mixed models, adjusting for age, atopy, smoking, body mass index (BMI), ETS and dampness/mould at home. Geometric mean (GM) for FeNO was 15.3 ppb, 6% were smokers, 14% were obese, 31% were overweight and 18% had atopy. GM concentration was 2.16 × 10(5) cell equivalents (CE)/g for total fungal DNA, 2310 CE/g for Aspergillus/penicillium (Asp/Pen) DNA, 17 CE/g for Aspergillus versicolor DNA and 14 CE/g dust for Streptomyces DNA. FeNO was associated with total fungal DNA (p = 0.004), Asp/Pen DNA (p = 0.005) and Streptomyces DNA (p = 0.03). HsCRP was associated with total fungal DNA (p = 0.03) and BMI (p = 0.001). Dyspnoea was associated with Asp/Pen DNA (p = 0.04). Subjects with ETS at home had lower lung function (FEV1) (p = 0.03), and those with dampness/mould at home had lower MPO (p = 0.03). Fungal contamination in day care centres, measured as fungal DNA, can be a risk factor for airway inflammation, and CRP is associated with BMI.