Analysis of mycotoxins in dust samples from a water damaged building

自2000年以来，NIOSH对潮湿/发霉建筑物居住者的呼吸和非呼吸健康进行了一些流行病学研究，并收集了2000多份储存在-80°C冰柜中的地板/椅子灰尘样本。这些研究的现有数据库包括可培养真菌和细菌、真菌细胞壁成分（麦角甾醇和葡聚糖）、细菌细胞壁成分（内毒素和肽聚糖）以及使用者健康状况的测量。各种不良呼吸和非呼吸健康影响与真菌生物标志物暴露之间的显著关联已得到证实。该项目通过建立在单一样本分析中分析室内环境样本中多种真菌毒素的能力，研究接触真菌毒素与居住者健康之间的关系。作为与奥地利一个研究小组合作的一部分，正在分析大约550个地板灰尘样本，并正在鉴定可能来自真菌的代谢物。这些样本是从多个来源收集的，包括小学和一栋有水损历史的办公楼。样品中存在一些真菌毒素，包括sterigmatocystin、玉米赤霉烯酮、roquefortine C和赭曲霉毒素A，但含量较低。令人惊讶的是，18%的地板灰尘样本含有脱氧雪腐镰刀菌醇（呕吐毒素；范围=4 - 72 pg/mg灰尘），这是一种真菌毒素，可从谷草镰刀菌和其他镰刀菌中释放出来。为了证实他们的发现，NIOSH将把结果与真菌DNA测序数据进行比较。NIOSH利用超高性能LC-MSMS的样品提取和分析方法，能够同时定量室内环境样品中多种真菌次生代谢物。在啮齿动物毒理学研究中，在吸入Stachybotrys chartarum后，在AGS暴露室收集的培养基样品（米粒）和过滤器样品中测量了真菌毒素sterigmatocystin和verrucarol（一种大环毛霉烯的水解产物）。一项评估粉尘样品最佳储存条件的实验正在进行中。

Since 2000, NIOSH has conducted a number of epidemiologic studies on respiratory and non-respiratory health in occupants of damp/moldy buildings, and collected more than 2,000 floor/chair dust samples which have been being stored in -80°C freezers. The existing database from those studies includes measurements on culturable fungi and bacteria, fungal cell wall components (ergosterol and glucan), and bacterial cell wall components (endotoxin and peptidoglycan) as well as occupants’ health. Significant associations between various adverse respiratory and non-respiratory health effects and exposure to fungal biomarkers have been demonstrated. This project examines associations of exposure to mycotoxins with occupants’ health by building the capability of analyzing indoor environmental samples for multiple mycotoxins in a single sample analysis. As part of a collaboration with a research group in Austria, approximately 550 floor dust samples are being analyzed and metabolites that are likely to have originated from fungi are being identified. These samples were collected from multiple sources including elementary schools and an office building with a history of water damage. A number of mycotoxins, including sterigmatocystin, zearalenone, roquefortine C, and ochratoxin A were present in the samples at low levels. Surprisingly, 18% of floor dust samples contained deoxynivalenol (vomitoxin; range=4 – 72 pg/mg of dust), a mycotoxin that can be released from Fusarium graminearum and other Fusarium species. To confirm their findings, NIOSH will compare the results to fungal DNA sequencing data. Using a sample extraction and analysis method for ultra-performance LC-MSMS, NIOSH has been able to simultaneously quantify targeted multiple fungal secondary metabolites in indoor environmental samples. The mycotoxins sterigmatocystin and verrucarol (a hydrolysis product of macrocyclic trichothecene) were measured in culture media samples (rice grains) and filter samples collected in the AGS exposure chamber following inhalation exposures to Stachybotrys chartarum during rodent toxicology studies. An experiment to assess optimal storage conditions for dust samples is ongoing.