Department of Chemical and Biological Work Environment, STAMI National Institute of Occupational Health, Oslo, Norway.
Department of Occupational Medicine and Epidemiology, STAMI National Institute of Occupational Health, Oslo, Norway.
Ann Work Expo Health. 2018 May 28;62(5):559-570. doi: 10.1093/annweh/wxy022.
Assessment of exposure to fungi has commonly been limited to fungal spore measurements that have shown associations between fungi and development or exacerbation of different airway diseases. Because large numbers of submicronic fragments can be aerosolized from fungal cultures under laboratory conditions, it has been suggested that fungal exposure is more complex and higher than that commonly revealed by spore measurements. However, the assessment of fungal fragments in complex environmental matrix remain limited due to methodological challenges. With a recently developed immunolabeling method for field emission scanning electron microscope (FESEM), we could assess the complex composition of fungal aerosols present in personal thoracic samples collected from two Norwegian sawmills. We found that large fungal fragments (length >1 µm) dominated the fungal aerosols indicating that the traditional monitoring approach of spores severely underestimate fungal exposure. The composition of fungal aerosols comprised in average 9% submicronic fragments, 62% large fragments, and 29% spores. The average concentrations of large and submicronic fragments (0.2-1 µm) were 3 × 105 and 0.6 × 105 particles m-3, respectively, and correlated weakly with spores (1.4 × 105 particles m-3). The levels of fragments were 2.6 times higher than the average spore concentration that was close to the proposed hazardous level of 105 spores per m3. The season influenced significantly the fungal aerosol concentrations but not the composition. Furthermore, the ratio of spores in the heterogeneous fungal aerosol composition was significantly higher in saw departments as compared to sorting of green timber departments where the fungal fragments were most prevalent. Being the dominating particles of fungal aerosols in sawmills, fungal fragments should be included in exposure-response studies to elucidate their importance for health impairments. Likewise, the use of fungal aerosol composition in such studies should be considered.
真菌暴露的评估通常仅限于真菌孢子测量，这些测量已经表明真菌与不同气道疾病的发展或恶化之间存在关联。因为在实验室条件下，大量亚微米碎片可以从真菌培养物中气溶胶化，所以有人认为真菌暴露比孢子测量通常所揭示的更为复杂和更高。然而，由于方法学上的挑战，复杂环境基质中真菌碎片的评估仍然有限。我们使用最近开发的用于场发射扫描电子显微镜（FESEM）的免疫标记方法，评估了从挪威两个锯木厂采集的个人胸部样本中存在的真菌气溶胶的复杂组成。我们发现，大的真菌碎片（长度> 1 µm）主导了真菌气溶胶，这表明传统的孢子监测方法严重低估了真菌暴露。真菌气溶胶的组成平均包括 9%的亚微米碎片、62%的大碎片和 29%的孢子。大碎片和亚微米碎片（0.2-1 µm）的平均浓度分别为 3×105 和 0.6×105 个粒子 m-3，与孢子（1.4×105 个粒子 m-3）弱相关。碎片的水平比平均孢子浓度高 2.6 倍，接近每立方米 105 个孢子的危险水平。季节显著影响真菌气溶胶浓度，但不影响其组成。此外，与绿色木材部门的分拣相比，在锯木部门，异质真菌气溶胶组成中的孢子比例明显更高，而真菌碎片在锯木部门最为普遍。真菌碎片作为锯木厂真菌气溶胶的主要颗粒，应该包含在暴露-反应研究中，以阐明其对健康损害的重要性。同样，应该考虑在这些研究中使用真菌气溶胶组成。
