Liu L J, Krahmer M, Fox A, Feigley C E, Featherstone A, Saraf A, Larsson L
Department of Environmental Health, University of Washington, Seattle, USA.
J Air Waste Manag Assoc. 2000 Nov;50(11):1957-67. doi: 10.1080/10473289.2000.10464225.
Bacterial cell envelope components are widely distributed in airborne dust, where they act as inflammatory agents causing respiratory symptoms. Measurements of these agents and other environmental factors are assessed in two elementary schools in a southeastern city in the United States. Muramic acid (MA) was used as a marker for bacterial peptidoglycan (PG), and 3-hydroxy fatty acids (3-OH FAs) were used as markers for Gram-negative bacterial lipopolysaccharide (LPS). Culturable bacteria were collected using an Andersen sampler with three different culture media. In addition, temperature (T), relative humidity (RH), and CO2 were continuously monitored. Concentrations of airborne MA and 3-OH FAs were correlated with total suspended particulate (TSP) levels. Outdoor MA (mean = 0.78-1.15 ng/m3) and 3-OH FA levels (mean = 2.19-2.18 ng/m3) were similar at the two schools. Indoor concentrations of airborne MA and 3-OH FAs differed significantly between schools (MA: 1.44 vs. 2.84 ng/m3; 3-OH FAs: 2.96 vs. 4.57 ng/m3). Although indoor MA levels were low, they were significantly related to teachers' perception of the severity of indoor air quality (IAQ) problems in their classrooms. Concentrations of CO2 correlated significantly with all bacteria measurements. Because CO2 levels were related to the number of occupants and the ventilation rates, these findings are consistent with the hypothesis that the children and teachers are sources of bacterial contamination. Many culturable bacteria present in indoor air are opportunistic organisms that can be infectious for compromised individuals, while both culturable and nonculturable bacterial remnants act as environmental toxins for both healthy and compromised individuals. Measuring the "total bacteria load" would be most accurate in assessing the biotoxicity of indoor air. Chemical analysis of MA and 3-OH FAs, when coupled with the conventional culture method, provides complementary information for assessing biocontamination of indoor air.
细菌细胞壁成分广泛分布于空气中的灰尘中，在那里它们作为炎症介质引发呼吸道症状。在美国东南部一个城市的两所小学对这些介质和其他环境因素进行了测量。胞壁酸（MA）被用作细菌肽聚糖（PG）的标志物，3-羟基脂肪酸（3-OH FAs）被用作革兰氏阴性菌脂多糖（LPS）的标志物。使用带有三种不同培养基的安德森采样器收集可培养细菌。此外，持续监测温度（T）、相对湿度（RH）和二氧化碳。空气中MA和3-OH FAs的浓度与总悬浮颗粒物（TSP）水平相关。两所学校的室外MA（平均值 = 0.78 - 1.15 ng/m³）和3-OH FA水平（平均值 = 2.19 - 2.18 ng/m³）相似。两所学校空气中MA和3-OH FAs的室内浓度差异显著（MA：1.44对2.84 ng/m³；3-OH FAs：2.96对4.57 ng/m³）。尽管室内MA水平较低，但它们与教师对教室室内空气质量（IAQ）问题严重程度的感知显著相关。二氧化碳浓度与所有细菌测量值显著相关。由于二氧化碳水平与居住人数和通风率有关，这些发现与儿童和教师是细菌污染源的假设一致。室内空气中存在的许多可培养细菌是机会性生物体，对免疫力低下的个体可能具有传染性，而可培养和不可培养的细菌残留物对健康和免疫力低下的个体都作为环境毒素。测量“总细菌负荷”在评估室内空气的生物毒性方面最为准确。MA和3-OH FAs的化学分析与传统培养方法相结合，为评估室内空气的生物污染提供了补充信息。
