Yeasts prefer daycares and molds prefer private homes

Indoor fungi can cause negative health effects due to the production of toxins or volatiles that trigger the immune system of the occupants. To what degree indoor fungi (mycobiomes) differ between buildings with different usage is poorly known. Here, we compare the indoor mycobiomes in 123 children’s daycare centers and 214 private homes throughout Norway, as revealed by metabarcoding of DNA extracted from dust samples collected by community scientists. Although the fungal richness per se was similar in dust samples from daycares and homes, the fungal community composition differed. Yeast fungi, distributed mainly across the orders Saccharomycetales, Filobasidiales and Tremellales, were proportionally more abundant in the daycares, while filamentous fungi, including spore-producing molds such as Aspergillus, Penicillum and Cladosporium, were relatively more abundant in homes. Number of occupants, which is considerably higher in daycares, correlated significantly with the fungal community shift. We hypothesize that the density of occupants and their age distribution drive the systematic difference of yeasts and filamentous fungi in the two building types.

室内真菌可通过产生毒素或挥发性物质触发居住者免疫系统，进而对健康造成负面影响。目前学界对不同用途建筑内的室内真菌群落（mycobiome）间的差异程度仍知之甚少。本研究通过社区科学家采集的粉尘样本提取DNA，并运用元条形码（metabarcoding）技术分析，对比了挪威全境123所儿童日托中心与214户私人住宅内的室内真菌群落。尽管日托中心与住宅的粉尘样本中真菌丰富度本身并无显著差异，但二者的真菌群落组成却存在明显区别。主要分布于酵母菌目（Saccharomycetales）、锁掷酵母目（Filobasidiales）与银耳目（Tremellales）的酵母菌，在日托中心内的相对丰度更高；而包括曲霉属（Aspergillus）、青霉属（Penicillum）、枝孢属（Cladosporium）在内的产孢丝状霉菌，则在住宅中相对更为富集。日托中心的居住者数量远高于住宅，且该因素与真菌群落结构的转变存在显著相关性。我们推测，居住者密度及其年龄分布，是驱动两类建筑内酵母菌与丝状真菌群落产生系统性差异的核心因素。