Afanou Komlavi Anani, Straumfors Anne, Skogstad Asbjørn, Nilsen Terje, Synnes Ole, Skaar Ida, Hjeljord Linda, Tronsmo Arne, Green Brett James, Eduard Wijnand
National Institute of Occupational Health, Oslo, Norway.
Norwegian Veterinary Institute, Oslo, Norway.
Appl Environ Microbiol. 2014 Nov;80(22):7122-30. doi: 10.1128/AEM.01740-14. Epub 2014 Sep 12.
Submicronic particles released from fungal cultures have been suggested to be additional sources of personal exposure in mold-contaminated buildings. In vitro generation of these particles has been studied with particle counters, eventually supplemented by autofluorescence, that recognize fragments by size and discriminate biotic from abiotic particles. However, the fungal origin of submicronic particles remains unclear. In this study, submicronic fungal particles derived from Aspergillus fumigatus, A. versicolor, and Penicillium chrysogenum cultures grown on agar and gypsum board were aerosolized and enumerated using field emission scanning electron microscopy (FESEM). A novel bioaerosol generator and a fungal spores source strength tester were compared at 12 and 20 liters min(-1) airflow. The overall median numbers of aerosolized submicronic particles were 2 × 10(5) cm(-2), 2.6 × 10(3) cm(-2), and 0.9 × 10(3) cm(-2) for A. fumigatus, A. versicolor, and P. chrysogenum, respectively. A. fumigatus released significantly (P < 0.001) more particles than A. versicolor and P. chrysogenum. The ratios of submicronic fragments to larger particles, regardless of media type, were 1:3, 5:1, and 1:2 for A. fumigatus, A. versicolor, and P. chrysogenum, respectively. Spore fragments identified by the presence of rodlets amounted to 13%, 2%, and 0% of the submicronic particles released from A. fumigatus, A. versicolor, and P. chrysogenum, respectively. Submicronic particles with and without rodlets were also aerosolized from cultures grown on cellophane-covered media, indirectly confirming their fungal origin. Both hyphae and conidia could fragment into submicronic particles and aerosolize in vitro. These findings further highlight the potential contribution of fungal fragments to personal fungal exposure.
真菌培养物释放的亚微米级颗粒被认为是受霉菌污染建筑物中个人暴露的额外来源。已经使用颗粒计数器研究了这些颗粒的体外生成，最终通过自发荧光进行补充，颗粒计数器通过大小识别碎片并区分生物颗粒和非生物颗粒。然而，亚微米级颗粒的真菌来源仍不清楚。在本研究中，使用场发射扫描电子显微镜（FESEM）对在琼脂和石膏板上生长的烟曲霉、杂色曲霉和产黄青霉培养物产生的亚微米级真菌颗粒进行雾化并计数。在12和20升/分钟（-1）的气流下比较了一种新型生物气溶胶发生器和一种真菌孢子源强度测试仪。烟曲霉、杂色曲霉和产黄青霉雾化后的亚微米级颗粒总数中位数分别为2×10（5）个/平方厘米、2.6×10（3）个/平方厘米和0.9×10（3）个/平方厘米。烟曲霉释放的颗粒明显（P<0.001）多于杂色曲霉和产黄青霉。无论培养基类型如何，烟曲霉、杂色曲霉和产黄青霉的亚微米级碎片与较大颗粒的比例分别为1:3、5:1和1:2。通过小梗的存在鉴定的孢子碎片分别占烟曲霉、杂色曲霉和产黄青霉释放的亚微米级颗粒的13%、2%和0%。有小梗和无小梗的亚微米级颗粒也从覆盖有玻璃纸的培养基上生长的培养物中雾化出来，间接证实了它们的真菌来源。菌丝和分生孢子都可以破碎成亚微米级颗粒并在体外雾化。这些发现进一步突出了真菌碎片对个人真菌暴露的潜在贡献。
