中国各气候区冬夏两季住宅室内微生物特征

The characteristics of microorganisms in residence in summer and winter among different climate zones,China

目前微生物对室内空气质量的影响越来越为人们所关注,住宅作为人一生中生活时间最长的建筑,其内部微生物浓度、物种多样性和群落结构的研究还很匮乏.本研究综合采用培养法和高通量测序技术,选取中国5大气候区(严寒气候区、寒冷气候区、夏热冬冷气候区、温和气候区和夏热冬暖气候区)的6座代表城市(哈尔滨、北京、拉萨、南京、昆明和深圳)作为采样点,研究冬夏两季住宅室内细菌(residential airborne bacteria,RIB)与住宅室内真菌(residential airborne fungi,RIF)的浓度水平、物种多样性和群落结构.研究发现,不同气候区、不同季节间的5大气候区住宅室内微生物浓度、物种多样性均存在显著差异;但室内微生物的TOP 3物种相对丰度均值(relative abundance mean,RAM)却相差不大(门水平),且各气候区冬夏两季TOP 3物种RAM近似相等.对结果分析后显示:夏季室内细菌浓度、物种多样性随经度的增加先增加后降低,与真菌变化趋势相反;冬季细菌浓度和经纬度之间不存在相关性;微生物物种多样性随纬度的变化在冬夏两季相反;不论冬夏,降低室内温度和提高室内通风都会降低室内细菌浓度.本研究为分析我国各气候区、不同季节、不同经纬度城市的住宅室内微生物特征提供参考.

Indoor microbes have been listed in the category of indoor air pollutants by World Health Organization(WHO)in 1990.Exposure to a high concentration of airborne bioaerosol potentially causes adverse health effects,such as pneumonia,asthma,and allergies.People spend most of their time in residence in their life,so figuring out the characteristic of residential airborne microbes is very important for occupants’health.However,previous studies mostly focused on indoor microorganisms in public buildings,while very little work has been done on the characteristics of indoor airborne bacteria and fungi in residence.In this study,we investigated the indoor airborne bacterial concentration,fungal concentration,and taxonomic diversity of residences in summer and winter among five different climate zones across China,as well as the community structure,and revealed the correlations between indoor airborne microbial characteristics(concentrations and taxonomic diversity)and geographical location by using polynomial fitting.Culturing and sequencing methods were combined in this study,for which we collected 376 culturable samples and 168 sequencing samples of bacteria and fungi each.We found the bacterial concentrations between summer and winter were significantly different in the hot summer&cold winter climate zone and the hot summer&warm winter climate zone,whereas there was no significant difference between different seasons among different climate zones for fungal concentrations.The bacterial concentrations in the hot summer&cold winter zone(Nanjing,875±553 CFU/m~3)and hot summer&warm winter(Shenzhen,758±473 CFU/m~3)were significantly higher than those in the other climate zones in summer(P<0.05);the lowest bacterial concentrations in winter were found in hot summer&cold winter(Nanjing,191±119 CFU/m~3).For fungi,the highest concentrations were found in the severe cold climate zone(Harbin,743±798 CFU/m~3)and cold climate zone(Lhasa,1369±1380 CFU/m~3)in summer;while the highest was only found in the severe cold climate zone(Harbin,654±493 CFU/m~3)in winter.We also found that the bacterial diversity in the hot summer&cold winter climate zone was significantly different between summer and winter;the fungi diversity in the hot summer&cold winter climate zone and hot summer&warm winter climate zones was significantly different between summer and winter.For bacteria,the lowest taxonomic diversity in summer was found in severe cold climate zone and the highest was found in hot summer&cold winter climate zone;the lowest taxonomic diversity in winter was found in severe cold climate zone and hot summer&cold winter climate zone.For fungi taxonomic diversity,the highest values were found in severe cold climate zone and hot summer&cold winter climate zone in summer;the highest values were found in cold climate zone and hot summer&warm winter climate zone in winter.We analyzed the community structure of bacteria and fungi at the phylum level.The TOP 4 bacterial species and TOP 3 fungal species between different climate zones in summer and winter were similar.The TOP 4 bacteria species in residences were Bacteroidetes,Proteobacteria,Firmicutes,and Actinobacteria.The TOP 3 fungi species were Ascomycota,Basidiomycota,and Zygomycota,except for Beijing,which is located in a cold climate zone.By analyzing the correlations between indoor microbial characteristics and geographical location,we found the variation of indoor microbial diversity with latitude was opposite in summer and winter.In summer,indoor bacterial concentrations and diversity first increased and then decreased with the increase of longitude,which was opposite to the trend of fungi.There was no correlation between winter bacterial concentrations and geographical location.