兰州市春季微生物气溶胶浓度、粒径及细菌群落结构分布特性

Concentration and Particle Size Distribution Characteristics of Microbial Aerosol and Bacterial Community Structure During Spring in Lanzhou City,China

分析了兰州市春季不同时段微生物气溶胶浓度、粒径和细菌群落结构组成的差异,探讨气象条件和空气污染物对微生物气溶胶分布的影响.结果表明,兰州市春季空气环境中总微生物、细菌、真菌和放线菌浓度均值分别为(2730±376)、(2243±354)、(349±38)和(138±22)CFU·m^(-3),其中,细菌占82.16%,明显高于真菌和放线菌(P<0.05).08:00~09:00时段总微生物、细菌和放线菌浓度明显高于18:00~19:00时段,微生物气溶胶浓度变化明显受气象条件和空气污染物的影响.细菌和真菌气溶胶粒子主要分布在前4级(>2.1μm),分别占85.13%和83.26%,而放线菌主要集中在后4级(<4.7μm)上,占73.15%.Illumina MiSeq测序结果表明,08:00~09:00和18:00~19:00时段细菌群落结构组成差异不显著(P>0.05).乳球菌属(Lactococcus)和芽孢杆菌属(Bacillus)为优势菌属,肠球菌属(Enterococcus)、葡萄球菌属(Staphylococcus)、假单胞菌属(Pseudomonas)、不动杆菌属(Acinetobacter)、克雷伯氏菌属(Klebsiella)、欧文氏菌属(Erwinia)、蜡样芽胞杆菌(Bacillus cereus)、无乳链球菌(Streptococcus agalactiae)和产气荚膜梭菌(Clostridium perfringens)等是兰州市春季空气环境的潜在病原菌.本研究结果为揭示兰州市春季微生物气溶胶污染状况以及相关病原菌对人类健康的潜在危害提供基础数据.

The aim of this study was to analyze the differences in the concentration,particle size,and bacterial community structure of microbial aerosols and further investigated the effects of meteorological conditions and air pollutants on microbial aerosol distribution at different periods during spring in Lanzhou.The results showed that the average aerosol concentrations of total microbes,bacteria,fungi,and actinomycetes in the air environment of Lanzhou were(2730±376),(2243±354),(349±38),and(138±22)CFU·m^(-3),respectively.The contribution rate of bacteria was 82.16%,which was significantly higher than that of fungi and actinomycetes(P<0.05).The concentrations of total microorganisms,bacteria,and actinomycetes during 08:00-09:00 were significantly higher than those sampled during 18:00-19:00,indicating that meteorological conditions and air pollutants have a remarkable influence on the concentration of microbial aerosols.Aerosol particles of bacteria and fungi were primarily distributed at the first four levels(>2.1μm),accounting for 85.13%and 83.26%,respectively,while 73.15%of the actinomycetes aerosol particles focused largely on the latter four stages(<4.7μm).Illumina MiSeq sequencing results indicated that there was no significant difference in the composition of the bacterial community(P>0.05)during the periods of 08:00-09:00 and 18:00-19:00.Lactococcus and Bacillus were the dominant bacteria genus.Enterococcus,Staphylococcus,Pseudomonas,Acinetobacter,Klebsiella,Erwinia,Bacillus cereus,Streptococcus agalactiae,and Clostridium perfringens were potential pathogens detected in the air environment of Lanzhou in the spring.The results could provide fundamental data for further revealing the contamination status of microbial aerosols and the potential harm of the related pathogenic bacteria to human health during the spring in Lanzhou.