Aboveground plants determine the exchange of pathogens within air-phyllosphere-soil continuum in urban greenspaces.

The microbiome in the air-phyllosphere-soil continuum of urban greenspaces plays a crucial role in re-connecting urban populations with biodiverse environmental microbiomes. However, little is known about whether plant type affects the airborne microbiomes, as well as the extent to which soil and phyllosphere microbiomes contribute to airborne microbiomes. Here we collected soil, phyllosphere and airborne microbes with different plant types (broadleaf tree, conifer tree, and grass) in urban parks. Despite the significant impacts of plant type on soil and phyllosphere microbiomes, plant type had no obvious effects on the diversity of airborne microbes but shaped airborne bacterial composition in urban greenspaces. Soil and phyllosphere microbiomes had a higher contribution to airborne bacteria in broadleaf trees (37.56%) compared to conifer trees (9.51%) and grasses (14.29%). Grass areas in urban greenspaces exhibited a greater proportion of potential pathogens compared to the tree areas. The abundance of bacterial pathogens in phyllosphere was significantly higher in grasses compared to broadleaf and conifer trees. Together, our study provides novel insights into the microbiome patterns in air-phyllosphere-soil continuum, highlighting the potential significance of reducing the proportion of extensively human-intervened grass areas in future urban environment designs to enhance the provision of ecosystem services in urban greenspaces.

Efficacy of 75% alcohol in pretreatment of the Andersen sampler in trapping maximum airborne microbes.

The present study was conducted to evaluate the effects of the pretreatment methods and sampling time on the sampling of airborne bacteria in hospitals. Methods for the pretreatment of Andersen samplers, namely, non-sterilized, 75% ethanol and autoclaving sampled for 5 min, 10 min and 15 min in the general ward and class 1000 clean operating department, respectively, were studied. Statistical analysis was used to compare the differences in sampling results of airborne bacteria under different pretreatment methods, sampling time and environmental conditions. In the first test, the sampling results of the airborne bacteria obtained by pretreatment of the sampler with 75% ethanol and without pre-treatment were not very different, and the sampling results showed a certain declining trend with the extension of the sampling time. In the second test, the pretreatment effect of autoclaving was significantly better than that of 75% ethanol, and the sampling time had no effect on the sampling results. After removing the influencing factors of the environment, the results were consistent with the results of the second test. It was observed that the Andersen samplers should not be pretreated with 75% ethanol before airborne microbes sampling. The pretreatment should be carried out by autoclaving, and the sampling time has little effect on the sampling results.

Spatial and seasonal variation of the airborne microbiome in a rapidly developing city of China.

Exposure to airborne microbes (AM) can affect the human microbiome and has various consequences for human health. Investigating the profiles of AM and the potential bacterial pathogens within, along with the factors influencing their community, is pivotal for understanding the impact of AM on human health. In this study, we collected AM during spring and summer from 11 sites with various levels of urbanization in the city of Xiamen, China. Bacterial community compositions of the AM were determined based on 16S rRNA gene amplicon sequencing. Firmicutes and Proteobacteria were the predominating phyla in the airborne bacterial communities, and a higher (P < 0.05) diversity of AM was found during the summer as compared to the spring. Significant differences in the community structure of the AM and the potential bacterial pathogens within airborne microbes were observed among the seasons and the sites with different levels of urbanization. Increases and/or decreases in the abundance of Bacillus and Acinetobacter could explain a major part of the variations in the AM community compositions. The proportion of potential bacterial pathogens during the summer was significantly higher (P < 0.01) than in the spring, and the relative abundance of several bacterial pathogens (i.e. Burkholderia multivoran, Enterococcus faecium and Streptococcus thermophilus) related to human diseases (39.8% of total pathogens on average) increased with increasing urbanization levels, suggesting that urbanization can increase the AM-associated human health risk.

[Development of a microenvironment test chamber for airborne microbe research].

One of the most important environmental cleanliness indicators is airborne microbe. However, the particularity of clean operating environment and controlled experimental environment often leads to the limitation of the airborne microbe research. This paper designed and implemented a microenvironment test chamber for airborne microbe research in normal test conditions. Numerical simulation by Fluent showed that airborne microbes were evenly dispersed in the upper part of test chamber, and had a bottom-up concentration growth distribution. According to the simulation results, the verification experiment was carried out by selecting 5 sampling points in different space positions in the test chamber. Experimental results showed that average particle concentrations of all sampling points reached 10 7 counts/m 3 after 5 minutes' distributing of Staphylococcus aureus, and all sampling points showed the accordant mapping of concentration distribution. The concentration of airborne microbe in the upper chamber was slightly higher than that in the middle chamber, and that was also slightly higher than that in the bottom chamber. It is consistent with the results of numerical simulation, and it proves that the system can be well used for airborne microbe research.

Monitoring on dust particle and airborne microbe counts in the operating rooms in some municipal hospitals of Xi’an / 中国感染控制杂志

Objective To understand environmental quality status of clean operating rooms in municipal hospitals of Xi’an,and provide reference for ensuring the clean quality of operating rooms.Methods On-site specimen collec-tion and detection were conducted to detect and analyze the cleanlinss of air in clean operating rooms in 15 hospital of Xi’an.Results A total of 51 operating rooms were monitored,secondary and tertiary hospitals had 24 and 27 operating rooms respectively;26 were grade-I and 25 were grade-Ⅲ operating rooms.The qualified rates of dust particle≥0.5μm/particle size in grade-I and grade-Ⅲ clean operating rooms were 76.92% and 80.00% respective-ly,≥5μm/ particle size were 73.08% and 88.00% respectively.The qualified rates of dust particle counts in grade-I and grade-Ⅲ clean operating rooms were 61 .54% and 80.00% respectively,difference was not significant(χ2=2.092,P >0.05 ).The qualified rate of dust particle counts in clean operating rooms in tertiary hospitals was significantly higher than secondary hospitals(85.19% vs 58.33%,χ2 =4.600,P 0.05),in surrounding zone were 95.83% and 92.59% respectively (both P >0.05).Conclusion Dust particle and airborne microbes in some clean operating rooms in municipal hospitals of Xi’an are beyond the standard,supervi-sion and management should be strengthened.

The Concentration and Variation of Airborne Microbe in Guangzhou City / 微生物学通报

One year survey on the concentrations and monthly or seasonal variations of airborne microbe in Guangzhou city were analysed and studied with JWL-IIB airborne microbial sampler. The results showed that the yearly average airborne microbe content of outdoor was 2, 298 cfu/m3, and that of indoor was 1,792 cfu/m3 in Guangzhou city. The monthly variation range of outdoor airborne microbe was from 1,073 to 4,096 cfu/m3, the highest content was 4,096 cfu/m3 in March, and the lowest content was 1,073 cfu/m3 in October. The outdoor airborne bacteria and fungi counts were the highest in spring, next in summer, lower in winter and the lowest in autumn in the four seasons . The yearly average concentrations of outdoor airborne microbe at the Garbage compression station, the business walk street, the key traffic route, the residential area, the industrial district and the garden were 4, 573, 3, 835, 1, 580, 1,413, 1, 197 and 1, 187 cfu/m3respectively; and Ones of indoor at the key traffic route, the tourist three star-route hotel and the subway station were 2,511, 1,699and 1,167 cfu/m3 respectively . The study on airborne microbe can be used for the research of health prevention and environment control measures in Guangzhou .