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Carrazana E, Ruiz-Gil T, Fujiyoshi S, Tanaka D, Noda J, Maruyama F, Jorquera MA. Potential airborne human pathogens: A relevant inhabitant in built environments but not considered in indoor air quality standards. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 901:165879. [PMID: 37517716 DOI: 10.1016/j.scitotenv.2023.165879] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/29/2023] [Revised: 07/13/2023] [Accepted: 07/27/2023] [Indexed: 08/01/2023]
Abstract
Potential airborne human pathogens (PAHPs) may be a relevant component of the air microbiome in built environments. Despite that PAHPs can cause infections, particularly in immunosuppressed patients at medical centers, they are scarcely considered in standards of indoor air quality (IAQ) worldwide. Here, we reviewed the current information on microbial aerosols (bacteria, fungal and viruses) and PAHPs in different types of built environments (e.g., medical center, industrial and non-industrial), including the main factors involved in their dispersion, the methodologies used in their study and their associated biological risks. Our analysis identified the human occupancy and ventilation systems as the primary sources of dispersal of microbial aerosols indoors. We also observed temperature and relative humidity as relevant physicochemical factors regulating the dispersion and viability of some PAHPs. Our analysis revealed that some PAHPs can survive and coexist in different environments while other PAHPs are limited or specific for an environment. In relation to the methodologies (conventional or molecular) the nature of PAHPs and sampling type are pivotal. In this context, indoors air-borne viruses are the less studies because their small size, environmental lability, and absence of efficient sampling techniques and universal molecular markers for their study. Finally, it is noteworthy that PAHPs are not commonly considered and included in IAQ standards worldwide, and when they are included, the total abundance is the single parameter considered and biological risks is excluded. Therefore, we propose a revision, design and establishment of public health policies, regulations and IAQ standards, considering the interactions of diverse factors, such as nature of PAHPs, human occupancy and type of built environments where they develop.
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Affiliation(s)
- Elizabeth Carrazana
- Programa de Doctorado en Ciencias Mención Biología Celular y Molecular Aplicada, Universidad de La Frontera, Temuco, Chile; Laboratorio de Ecología Microbiana Aplicada, Departamento de Ciencias Químicas y Recursos Naturales, Universidad de La Frontera, Temuco, Chile
| | - Tay Ruiz-Gil
- Laboratorio de Ecología Microbiana Aplicada, Departamento de Ciencias Químicas y Recursos Naturales, Universidad de La Frontera, Temuco, Chile; Programa de Doctorado en Ciencias de Recursos Naturales, Universidad de La Frontera, Temuco, Chile
| | - So Fujiyoshi
- Center for Holobiome and Built Environment (CHOBE), Hiroshima University, Japan; Microbial Genomics and Ecology, PHIS, The IDEC institute, Hiroshima University, Hiroshima, Japan
| | - Daisuke Tanaka
- School of Science Academic Assembly, University of Toyama, Toyama, Japan
| | - Jun Noda
- Graduate School of Veterinary Medicine, Rakuno Gakuen University, Hokkaido, Japan
| | - Fumito Maruyama
- Center for Holobiome and Built Environment (CHOBE), Hiroshima University, Japan; Microbial Genomics and Ecology, PHIS, The IDEC institute, Hiroshima University, Hiroshima, Japan
| | - Milko A Jorquera
- Laboratorio de Ecología Microbiana Aplicada, Departamento de Ciencias Químicas y Recursos Naturales, Universidad de La Frontera, Temuco, Chile; Center for Holobiome and Built Environment (CHOBE), Hiroshima University, Japan; Network for Extreme Environment Research (NEXER), Scientific and Technological Bioresource Nucleus (BIOREN), Universidad de La Frontera, Temuco, Chile.
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2
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Yanagi U, Kaihara N, Simazaki D, Bekki K, Homma Y, Iba C, Asai A, Hayashi M. Bacterial Flora on Mist Outlet Surfaces in 4D Theaters and Suspended Particle Concentration Characteristics during 4D Movie Screenings. Microorganisms 2023; 11:1856. [PMID: 37513027 PMCID: PMC10383669 DOI: 10.3390/microorganisms11071856] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2023] [Revised: 07/17/2023] [Accepted: 07/20/2023] [Indexed: 07/30/2023] Open
Abstract
In this study, we measured suspended particle concentrations during the screening of 4D movies (3 screens and 15 movies) and 2D movies (9 screens and 9 movies) in 3 movie theaters to obtain a more detailed understanding of the situation of suspended particle concentrations and adherent bacterial flora in 4D movie theaters, which have been introduced in increasing numbers in recent years. The adherent bacterial flora on the floor and mist outlet surfaces in the 4D movie theaters were collected and analyzed. During the movie showings, the concentrations of suspended particles in 4D movie theaters were significantly higher than those in 2D movie theaters (p < 0.001). A significant increase in suspended particle concentrations due to 4D movie effects was also observed. The results of the α-diversity and β-diversity analyses indicate that the bacterial flora on the surfaces of mist outlets in 4D movie theaters are similar. Moreover, there are many closely related species, and the bacterial flora are rich and contain rare bacterial species. Many of the bacterial genera that are dominant in 4D theaters are suited to aqueous environments, and bacteria in the water supply system may have an impact on the indoor environment.
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Affiliation(s)
- U Yanagi
- School of Architecture, Kogakuin University, Tokyo 163-8677, Japan
| | - Noriko Kaihara
- Department of Environmental Health, National Institute of Public Health, Wako 351-0197, Japan
| | - Dai Simazaki
- Department of Environmental Health, National Institute of Public Health, Wako 351-0197, Japan
| | - Kanae Bekki
- Department of Environmental Health, National Institute of Public Health, Wako 351-0197, Japan
| | - Yoshinori Homma
- Department of Environmental Health, National Institute of Public Health, Wako 351-0197, Japan
| | - Chiemi Iba
- Graduate School of Engineering, Kyoto University, Kyoto 615-8540, Japan
| | - Atsuto Asai
- Graduate School of Engineering, Kogakuin University, Tokyo 163-8677, Japan
| | - Motoya Hayashi
- Faculty of Engineering, Hokkaido University, Sapporo 060-8628, Japan
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3
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Watanabe K, Yanagi U, Shiraishi Y, Harada K, Ogino F, Asano K. Bacterial Communities in Various Parts of Air-Conditioning Units in 17 Japanese Houses. Microorganisms 2022; 10:microorganisms10112246. [PMID: 36422316 PMCID: PMC9697849 DOI: 10.3390/microorganisms10112246] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2022] [Revised: 11/10/2022] [Accepted: 11/11/2022] [Indexed: 11/16/2022] Open
Abstract
HVAC systems have a significant impact on the indoor environment, and microbial contamination in HVAC systems has a significant effect on the indoor air quality. In this study, to gain a better understanding of the microbial contamination inside ACs, we used NGS to analyze the 16S rRNA gene of bacteria adhering to AC filters, cooling coils, fans, and air outlet surfaces. The five phyla in terms of the highest relative abundance were Proteobacteria, Firmicutes, Actinobacteria, Cyanobacteria, and Bacteroidetes. The surface of an AC filter provides a history of indoor airborne bacterial contamination, and of the 10 bacterial genera we detected with the highest abundance (in the following order: Pseudomonas > Staphylococcus > Paracoccus > Corynebacterium > Acinetobacter > Streptococcus > Methylobacterium > Enhydrobacter > Sphingomonas > Actinotignum) on the filter surface, the top 6 genera were Gram-negative bacteria. Furthermore, the seventh-most abundant genus adhering to the filter surface (Methylobacterium) was the second-most abundant genus on the cooling coil and fan, and the ninth-most abundant genus on the air filter (Sphingomonas) was the third-most abundant genus on the cooling coil. Various factors impact the bacterial flora inside AC units, including the location of the house, AC unit usage, and occupant activity.
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Affiliation(s)
- Kensuke Watanabe
- Graduate School of Engineering, Kogakuin University, Tokyo 163 8677, Japan
| | - U Yanagi
- School of Architecture, Kogakuin University, Tokyo 163 8677, Japan
- Correspondence: ; Tel.: +81-(03)-3340-1468
| | - Yoshiki Shiraishi
- Division of Pulmonary Medicine, Department of Medicine, Tokai University School of Medicine, Isehara 259 1193, Japan
| | - Kazuhiro Harada
- Research & Development, Duskin Co., Ltd., Osaka 564 0043, Japan
| | - Fumitoshi Ogino
- Research & Development, Duskin Co., Ltd., Osaka 564 0043, Japan
| | - Koichiro Asano
- Division of Pulmonary Medicine, Department of Medicine, Tokai University School of Medicine, Isehara 259 1193, Japan
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4
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Jiang X, Wang C, Guo J, Hou J, Guo X, Zhang H, Tan J, Li M, Li X, Zhu H. Global Meta-analysis of Airborne Bacterial Communities and Associations with Anthropogenic Activities. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2022; 56:9891-9902. [PMID: 35785964 PMCID: PMC9301914 DOI: 10.1021/acs.est.1c07923] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
Airborne microbiome alterations, an emerging global health concern, have been linked to anthropogenic activities in numerous studies. However, these studies have not reached a consensus. To reveal general trends, we conducted a meta-analysis using 3226 air samples from 42 studies, including 29 samples of our own. We found that samples in anthropogenic activity-related categories showed increased microbial diversity, increased relative abundance of pathogens, increased co-occurrence network complexity, and decreased positive edge proportions in the network compared with the natural environment category. Most of the above conclusions were confirmed using the samples we collected in a particular period with restricted anthropogenic activities. Additionally, unlike most previous studies, we used 15 human-production process factors to quantitatively describe anthropogenic activities. We found that microbial richness was positively correlated with fine particulate matter concentration, NH3 emissions, and agricultural land proportion and negatively correlated with the gross domestic product per capita. Airborne pathogens showed preferences for different factors, indicating potential health implications. SourceTracker analysis showed that the human body surface was a more likely source of airborne pathogens than other environments. Our results advance the understanding of relationships between anthropogenic activities and airborne bacteria and highlight the role of airborne pathogens in public health.
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Affiliation(s)
- Xiaoqing Jiang
- State
Key Laboratory for Turbulence and Complex Systems, Department of Biomedical
Engineering, College of Future Technology, Peking University, Beijing 100871, China
- Center
for Quantitative Biology, Peking University, Beijing 100871, China
| | - Chunhui Wang
- School
of Life Sciences, Peking University, Beijing 100871, China
| | - Jinyuan Guo
- State
Key Laboratory for Turbulence and Complex Systems, Department of Biomedical
Engineering, College of Future Technology, Peking University, Beijing 100871, China
- Center
for Quantitative Biology, Peking University, Beijing 100871, China
- Department
of Biomedical Engineering, Georgia Institute
of Technology and Emory University, Atlanta, Georgia 30332, United States
| | - Jiaheng Hou
- State
Key Laboratory for Turbulence and Complex Systems, Department of Biomedical
Engineering, College of Future Technology, Peking University, Beijing 100871, China
- Center
for Quantitative Biology, Peking University, Beijing 100871, China
| | - Xiao Guo
- State
Key Laboratory for Turbulence and Complex Systems, Department of Biomedical
Engineering, College of Future Technology, Peking University, Beijing 100871, China
- Center
for Quantitative Biology, Peking University, Beijing 100871, China
| | - Haoyu Zhang
- State
Key Laboratory for Turbulence and Complex Systems, Department of Biomedical
Engineering, College of Future Technology, Peking University, Beijing 100871, China
- Center
for Quantitative Biology, Peking University, Beijing 100871, China
| | - Jie Tan
- State
Key Laboratory for Turbulence and Complex Systems, Department of Biomedical
Engineering, College of Future Technology, Peking University, Beijing 100871, China
- Center
for Quantitative Biology, Peking University, Beijing 100871, China
| | - Mo Li
- School
of Life Sciences, Peking University, Beijing 100871, China
| | - Xin Li
- School
of Life Sciences, Peking University, Beijing 100871, China
- Beijing
National Day School, Beijing 100039, China
| | - Huaiqiu Zhu
- State
Key Laboratory for Turbulence and Complex Systems, Department of Biomedical
Engineering, College of Future Technology, Peking University, Beijing 100871, China
- Center
for Quantitative Biology, Peking University, Beijing 100871, China
- Department
of Biomedical Engineering, Georgia Institute
of Technology and Emory University, Atlanta, Georgia 30332, United States
- . Phone: 8610-6276-7261
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5
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Li X, Liu D, Yao J. Aerosolization of fungal spores in indoor environments. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 820:153003. [PMID: 35031366 DOI: 10.1016/j.scitotenv.2022.153003] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/26/2021] [Revised: 01/05/2022] [Accepted: 01/05/2022] [Indexed: 06/14/2023]
Abstract
Fungi in indoor environments can cause adverse health effects through inhalation and epidermal exposure. The risk of fungal exposure originates from the aerosolization of fungal spores. However, spore aerosolization is still not well understood. This paper provides a review of indoor fungal contamination, especially the aerosolization of fungal spores. We attempted to summarize what is known today and to identify what more information is needed to predict the aerosolization of fungal spores. This paper first reviews fungal contamination in indoor environments and HVAC systems. The detachment of fungal spores from colonies and the spore aerosolization principle are then summarized. Based on the above discussion, prediction methods for spore aerosolization are discussed. This review further clarifies the current situation and future efforts required to accurately predict spore aerosolization. This information is useful for forecasting and controlling the aerosolization of fungal spores.
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Affiliation(s)
- Xian Li
- School of Civil Engineering and Architecture, Linyi University, Linyi 276000, China.
| | - Dan Liu
- School of Civil Engineering and Architecture, Linyi University, Linyi 276000, China
| | - Jian Yao
- School of Civil Engineering and Architecture, Linyi University, Linyi 276000, China
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Sibanda T, Selvarajan R, Ogola HJ, Obieze CC, Tekere M. Distribution and comparison of bacterial communities in HVAC systems of two university buildings: Implications for indoor air quality and public health. ENVIRONMENTAL MONITORING AND ASSESSMENT 2021; 193:47. [PMID: 33415530 PMCID: PMC7790485 DOI: 10.1007/s10661-020-08823-z] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/28/2020] [Accepted: 12/27/2020] [Indexed: 06/12/2023]
Abstract
The installation of HVAC systems in building is meant to enhance indoor air quality as well as increase comfort to occupants. However, HVAC systems have also become a vehicle of contamination of indoor air with potentially pathogenic microorganisms. DNA was extracted from ten HVAC filter dust samples collected from two buildings and subjected to high throughput sequencing analysis to determine the bacterial community structure. Further, the Phylogenetic Investigation of Communities by Reconstruction of Unobserved States (PICRUSt2) software was used to predict the potential functional capabilities of the bacterial communities. Sequencing analysis led to the identification of five major bacterial phyla, including Proteobacteria, Cyanobacteria, Actinobacteria, Firmicutes and Bacteroidetes. At genus level, Mycobacterium, Bacillus, Cupriavidus, Hyphomicrobium and Mesorhizobium were the most dominant. With the exception of the later two bacterial genera, the first three are potential pathogens whose presence in HVAC systems poses a significant public health risk, especially among immunocompromised individuals. Nine pathways associated with antibiotics resistance and bacterial pathogenicity were identified, including polymyxin resistance and peptidoglycan biosynthesis pathways. Further, investigation of the relationship between the detected bacterial meta-communities and predicted potential virulence factors (antibiotic resistance and pathogenic genes) led to the detection of 350 positive associations among 43 core bacteria, 2 pathogenic genes (sitA and uidA) and 14 resistance genes. Overall, the heterogeneous nature of microorganisms found in HVAC systems observed in this study shows that HVAC systems are the origin of airborne infections in indoor environments, and must be periodically cleaned and disinfected to avoid the build-up of pathogens, and the subsequent exposure of human occupants of these pathogens.
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Affiliation(s)
- Timothy Sibanda
- Department of Biological Sciences, University of Namibia, Mandume Ndemufayo Ave, Pionierspark, Windhoek, Namibia.
| | - Ramganesh Selvarajan
- Department of Environmental Sciences, College of Agricultural and Environmental Sciences, UNISA, Johannesburg, South Africa
| | - Henry Jo Ogola
- Department of Environmental Sciences, College of Agricultural and Environmental Sciences, UNISA, Johannesburg, South Africa
- Centre for Research, Innovation and Technology, Jaramogi Oginga Odinga University of Science and Technology, Bondo, Kenya
| | | | - Memory Tekere
- Department of Environmental Sciences, College of Agricultural and Environmental Sciences, UNISA, Johannesburg, South Africa
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7
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Cao L, Yang L, Swanson CS, Li S, He Q. Comparative analysis of impact of human occupancy on indoor microbiomes. FRONTIERS OF ENVIRONMENTAL SCIENCE & ENGINEERING 2020; 15:89. [PMID: 33425458 PMCID: PMC7783699 DOI: 10.1007/s11783-020-1383-1] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/30/2020] [Revised: 10/20/2020] [Accepted: 10/23/2020] [Indexed: 06/12/2023]
Abstract
Educational facilities serve as community hubs and consequently hotspots for exposure to pathogenic microorganisms. Therefore, it is of critical importance to understand processes shaping the indoor microbiomes in educational facilities to protect public health by reducing potential exposure risks of students and the broader community. In this study, the indoor surface bacterial microbiomes were characterized in two multifunctional university buildings with contrasting levels of human occupancy, of which one was recently constructed with minimal human occupancy while the other had been in full operation for six years. Higher levels of human occupancy in the older building were shown to result in greater microbial abundance in the indoor environment and greater proportion of the indoor surface bacterial microbiomes contributed from human-associated microbiota, particularly the skin microbiota. It was further revealed that human-associated microbiota had greater influence on the indoor surface bacterial microbiomes in areas of high occupancy than areas of low occupancy. Consistent with minimal impact from human occupancy in a new construction, the indoor microbiomes in the new building exhibited significantly lower influence from human-associated microbiota than in the older building, with microbial taxa originating from soil and plants representing the dominant constituents of the indoor surface bacterial microbiomes. In contrast, microbial taxa in the older building with extensive human occupancy were represented by constituents of the human microbiota, likely from occupants. These findings provide insights into processes shaping the indoor microbiomes which will aid the development of effective strategies to control microbial exposure risks of occupants in educational facilities.
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Affiliation(s)
- Liu Cao
- Department of Civil and Environmental Engineering, The University of Tennessee, Knoxville, TN 37996 USA
| | - Lu Yang
- Department of Civil and Environmental Engineering, The University of Tennessee, Knoxville, TN 37996 USA
| | - Clifford S. Swanson
- Department of Civil and Environmental Engineering, The University of Tennessee, Knoxville, TN 37996 USA
| | - Shuai Li
- Department of Civil and Environmental Engineering, The University of Tennessee, Knoxville, TN 37996 USA
| | - Qiang He
- Department of Civil and Environmental Engineering, The University of Tennessee, Knoxville, TN 37996 USA
- Institute for a Secure and Sustainable Environment, The University of Tennessee, Knoxville, TN 37996 USA
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Zhou Y, Lai Y, Tong X, Leung MHY, Tong JCK, Ridley IA, Lee PKH. Airborne Bacteria in Outdoor Air and Air of Mechanically Ventilated Buildings at City Scale in Hong Kong across Seasons. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2020; 54:11732-11743. [PMID: 32852192 DOI: 10.1021/acs.est.9b07623] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Studies of the indoor airborne microbiome have mostly been confined to a single location and time point. Here, we characterized, over the course of a year, the geographic variation, building-function dependence, and dispersal characteristics of indoor and outdoor airborne microbiomes (bacterial members only) of eight mechanically ventilated commercial buildings. Based on the Sloan neutral model, airborne microbiomes were randomly dispersed in the respective indoor and outdoor environments and between the two environments during each season. The dominant taxa in the indoor and outdoor environments showed minor variations at each location among seasons. The airborne microbiomes displayed weak seasonality for both indoor and outdoor environments, while a weak geographic variation was found only for the indoor environments. Source tracking results show that outdoor air and occupant skin were major contributors to the indoor airborne microbiomes, but the extent of the contribution from each source varied within and among buildings over the seasons, which suggests variations in local building use. Based on 32 cases of indoor airborne microbiome data, we determined that the indoor/outdoor (I/O) ratio of PM2.5 was not a robust indicator of the sources found indoors. Alternatively, the indoor concentration of carbon dioxide was more closely correlated with the major sources of the indoor airborne microbiome in mechanically ventilated environments.
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Affiliation(s)
- You Zhou
- School of Energy and Environment, City University of Hong Kong, Kowloon, Hong Kong SAR, China
| | - Yonghang Lai
- School of Energy and Environment, City University of Hong Kong, Kowloon, Hong Kong SAR, China
| | - Xinzhao Tong
- School of Energy and Environment, City University of Hong Kong, Kowloon, Hong Kong SAR, China
| | - Marcus H Y Leung
- School of Energy and Environment, City University of Hong Kong, Kowloon, Hong Kong SAR, China
| | - Jimmy C K Tong
- Building Sustainability Group, Arup, Kowloon, Hong Kong SAR, China
| | - Ian A Ridley
- School of Energy and Environment, City University of Hong Kong, Kowloon, Hong Kong SAR, China
| | - Patrick K H Lee
- School of Energy and Environment, City University of Hong Kong, Kowloon, Hong Kong SAR, China
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Microbial Similarity between Students in a Common Dormitory Environment Reveals the Forensic Potential of Individual Microbial Signatures. mBio 2019; 10:mBio.01054-19. [PMID: 31363029 PMCID: PMC6667619 DOI: 10.1128/mbio.01054-19] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
Humans leave behind a microbial trail, regardless of intention. This may allow for the identification of individuals based on the “microbial signatures” they shed in built environments. In a shared living environment, these trails intersect, and through interaction with common surfaces may become homogenized, potentially confounding our ability to link individuals to their associated microbiota. We sought to understand the factors that influence the mixing of individual signatures and how best to process sequencing data to best tease apart these signatures. The microbiota of the built environment is an amalgamation of both human and environmental sources. While human sources have been examined within single-family households or in public environments, it is unclear what effect a large number of cohabitating people have on the microbial communities of their shared environment. We sampled the public and private spaces of a college dormitory, disentangling individual microbial signatures and their impact on the microbiota of common spaces. We compared multiple methods for marker gene sequence clustering and found that minimum entropy decomposition (MED) was best able to distinguish between the microbial signatures of different individuals and was able to uncover more discriminative taxa across all taxonomic groups. Further, weighted UniFrac- and random forest-based graph analyses uncovered two distinct spheres of hand- or shoe-associated samples. Using graph-based clustering, we identified spheres of interaction and found that connection between these clusters was enriched for hands, implicating them as a primary means of transmission. In contrast, shoe-associated samples were found to be freely interacting, with individual shoes more connected to each other than to the floors they interact with. Individual interactions were highly dynamic, with groups of samples originating from individuals clustering freely with samples from other individuals, while all floor and shoe samples consistently clustered together.
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Abstract
Airborne microorganisms are very difficult to assess accurately under field conditions owing to differences in the sample collection efficiency of the selected sampler and variations in DNA extraction efficiencies. Consequently, bioaerosol abundance and biodiversity can be underestimated, making it more difficult to link specific bioaerosol components to diseases and human health risk. Owing to the low biomass in air samples, it remains a challenge to obtain a representative microbiological sample to recover sufficient DNA for downstream analyses. Improved sampling methods are particularly crucial, especially for investigating viral communities, owing to the extremely low biomass of viral particles in the air compared with other environments. Without detailed information about sampling, characterization and enumeration techniques, interpretation of exposure level is very difficult. Despite this, bioaerosol research has been enhanced by molecular tools, especially next-generation sequencing approaches that have allowed faster and more detailed characterization of air samples.
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Sharma A, Richardson M, Cralle L, Stamper CE, Maestre JP, Stearns-Yoder KA, Postolache TT, Bates KL, Kinney KA, Brenner LA, Lowry CA, Gilbert JA, Hoisington AJ. Longitudinal homogenization of the microbiome between both occupants and the built environment in a cohort of United States Air Force Cadets. MICROBIOME 2019; 7:70. [PMID: 31046835 PMCID: PMC6498636 DOI: 10.1186/s40168-019-0686-6] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/18/2018] [Accepted: 04/22/2019] [Indexed: 05/10/2023]
Abstract
BACKGROUND The microbiome of the built environment has important implications for human health and wellbeing; however, bidirectional exchange of microbes between occupants and surfaces can be confounded by lifestyle, architecture, and external environmental exposures. Here, we present a longitudinal study of United States Air Force Academy cadets (n = 34), which have substantial homogeneity in lifestyle, diet, and age, all factors that influence the human microbiome. We characterized bacterial communities associated with (1) skin and gut samples from roommate pairs, (2) four built environment sample locations inside the pairs' dormitory rooms, (3) four built environment sample locations within shared spaces in the dormitory, and (4) room-matched outdoor samples from the window ledge of their rooms. RESULTS We analyzed 2,170 samples, which generated 21,866 unique amplicon sequence variants. Linear convergence of microbial composition and structure was observed between an occupants' skin and the dormitory surfaces that were only used by that occupant (i.e., desk). Conversely, bacterial community beta diversity (weighted Unifrac) convergence between the skin of both roommates and the shared dormitory floor between the two cadet's beds was not seen across the entire study population. The sampling period included two semester breaks in which the occupants vacated their rooms; upon their return, the beta diversity similarity between their skin and the surfaces had significantly decreased compared to before the break (p < 0.05). There was no apparent convergence between the gut and building microbiota, with the exception of communal bathroom door-handles, which suggests that neither co-occupancy, diet, or lifestyle homogenization had a significant impact on gut microbiome similarity between these cadets over the observed time frame. As a result, predictive classifier models were able to identify an individual more accurately based on the gut microbiota (74%) compared to skin (51%). CONCLUSIONS To the best of our knowledge, this is the first study to show an increase in skin microbial similarity of two individuals who start living together for the first time and who are not genetically related or romantically involved. Cohabitation was significantly associated with increased skin microbiota similarity but did not significantly influence the gut microbiota. Following a departure from the occupied space of several weeks, the skin microbiota, but not the gut microbiota, showed a significant reduction in similarity relative to the building. Overall, longitudinal observation of these dynamics enables us to dissect the influence of occupation, diet, and lifestyle factors on occupant and built environment microbial ecology.
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Affiliation(s)
- Anukriti Sharma
- Department of Pediatrics and Scripps Institution of Oceanography, University of California San Diego, La Jolla, CA, 92037, USA
| | - Miles Richardson
- Department of Pediatrics and Scripps Institution of Oceanography, University of California San Diego, La Jolla, CA, 92037, USA
| | - Lauren Cralle
- Department of Pediatrics and Scripps Institution of Oceanography, University of California San Diego, La Jolla, CA, 92037, USA
| | - Christopher E Stamper
- Department of Integrative Physiology, University of Colorado Boulder, Boulder, CO, 80309, USA
| | - Juan P Maestre
- Department of Civil, Architectural and Environmental Engineering, University of Texas Austin, Austin, TX, 78712, USA
| | - Kelly A Stearns-Yoder
- Department of Physical Medicine and Rehabilitation, University of Colorado Anschutz Medical Campus, Aurora, CO, 80045, USA
- Veterans Health Administration, Rocky Mountain Mental Illness Research Education and Clinical Center (MIRECC), Denver Veterans Affairs Medical Center (VAMC), Denver, CO, 80220, USA
- Military and Veteran Microbiome Consortium for Research and Education (MVM-CoRE), Denver, CO, 80220, USA
| | - Teodor T Postolache
- Veterans Health Administration, Rocky Mountain Mental Illness Research Education and Clinical Center (MIRECC), Denver Veterans Affairs Medical Center (VAMC), Denver, CO, 80220, USA
- Military and Veteran Microbiome Consortium for Research and Education (MVM-CoRE), Denver, CO, 80220, USA
- School of Medicine, University of Maryland Baltimore, Baltimore, MD, 21201, USA
- VISN 5 Mental Illness Research Education and Clinical Center (MIRECC), Baltimore, MD, 21201, USA
| | - Katherine L Bates
- Military and Veteran Microbiome Consortium for Research and Education (MVM-CoRE), Denver, CO, 80220, USA
- Department of Biology, United States Air Force Academy, Colorado Springs, CO, 80840, USA
| | - Kerry A Kinney
- Department of Civil, Architectural and Environmental Engineering, University of Texas Austin, Austin, TX, 78712, USA
| | - Lisa A Brenner
- Department of Physical Medicine and Rehabilitation, University of Colorado Anschutz Medical Campus, Aurora, CO, 80045, USA
- Veterans Health Administration, Rocky Mountain Mental Illness Research Education and Clinical Center (MIRECC), Denver Veterans Affairs Medical Center (VAMC), Denver, CO, 80220, USA
- Military and Veteran Microbiome Consortium for Research and Education (MVM-CoRE), Denver, CO, 80220, USA
- Departments of Psychiatry and Neurology, University of Colorado Anschutz Medical Campus, Aurora, CO, 80045, USA
| | - Christopher A Lowry
- Department of Integrative Physiology, University of Colorado Boulder, Boulder, CO, 80309, USA
- Department of Physical Medicine and Rehabilitation, University of Colorado Anschutz Medical Campus, Aurora, CO, 80045, USA
- Veterans Health Administration, Rocky Mountain Mental Illness Research Education and Clinical Center (MIRECC), Denver Veterans Affairs Medical Center (VAMC), Denver, CO, 80220, USA
- Military and Veteran Microbiome Consortium for Research and Education (MVM-CoRE), Denver, CO, 80220, USA
- Center for Neuroscience, University of Colorado Boulder, Boulder, CO, 80309, USA
- Center for Neuroscience, University of Colorado Anschutz Medical Campus, Aurora, CO, 80045, USA
| | - Jack A Gilbert
- Department of Pediatrics and Scripps Institution of Oceanography, University of California San Diego, La Jolla, CA, 92037, USA
| | - Andrew J Hoisington
- Veterans Health Administration, Rocky Mountain Mental Illness Research Education and Clinical Center (MIRECC), Denver Veterans Affairs Medical Center (VAMC), Denver, CO, 80220, USA.
- Military and Veteran Microbiome Consortium for Research and Education (MVM-CoRE), Denver, CO, 80220, USA.
- Department of Systems Engineering and Management, Air Force Institute of Technology, Wright-Patterson AFB, OH, 45433, USA.
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12
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Weiss H, Hertzberg VS, Dupont C, Espinoza JL, Levy S, Nelson K, Norris S. The Airplane Cabin Microbiome. MICROBIAL ECOLOGY 2019; 77:87-95. [PMID: 29876609 PMCID: PMC6318343 DOI: 10.1007/s00248-018-1191-3] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/03/2018] [Accepted: 04/11/2018] [Indexed: 05/07/2023]
Abstract
Serving over three billion passengers annually, air travel serves as a conduit for infectious disease spread, including emerging infections and pandemics. Over two dozen cases of in-flight transmissions have been documented. To understand these risks, a characterization of the airplane cabin microbiome is necessary. Our study team collected 229 environmental samples on ten transcontinental US flights with subsequent 16S rRNA sequencing. We found that bacterial communities were largely derived from human skin and oral commensals, as well as environmental generalist bacteria. We identified clear signatures for air versus touch surface microbiome, but not for individual types of touch surfaces. We also found large flight-to-flight beta diversity variations with no distinguishing signatures of individual flights, rather a high between-flight diversity for all touch surfaces and particularly for air samples. There was no systematic pattern of microbial community change from pre- to post-flight. Our findings are similar to those of other recent studies of the microbiome of built environments. In summary, the airplane cabin microbiome has immense airplane to airplane variability. The vast majority of airplane-associated microbes are human commensals or non-pathogenic, and the results provide a baseline for non-crisis-level airplane microbiome conditions.
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Affiliation(s)
- Howard Weiss
- School of Mathematics, The Georgia Institute of Technology, 686 Cherry St. NW, Atlanta, GA 30313 USA
| | - Vicki Stover Hertzberg
- Nell Hodgson Woodruff School of Nursing, Emory University, 1520 Clifton Rd. NE, Atlanta, GA 30322 USA
| | - Chris Dupont
- J. Craig Venter Institute, 4120 Capricorn Lane, La Jolla, CA 92037 USA
| | - Josh L. Espinoza
- J. Craig Venter Institute, 4120 Capricorn Lane, La Jolla, CA 92037 USA
| | - Shawn Levy
- HudsonAlpha Institute for Biotechnology, 601 Genome Way, Huntsville, AL 35806 USA
| | - Karen Nelson
- J. Craig Venter Institute, 9714 Medical Center Drive, Rockville, MD 20850 USA
| | - Sharon Norris
- Boeing Health Services, The Boeing Company, 3156 160th Ave. NE, Bellevue, WA 98008-2245 USA
| | - The FlyHealthy Research Team
- School of Mathematics, The Georgia Institute of Technology, 686 Cherry St. NW, Atlanta, GA 30313 USA
- Nell Hodgson Woodruff School of Nursing, Emory University, 1520 Clifton Rd. NE, Atlanta, GA 30322 USA
- J. Craig Venter Institute, 4120 Capricorn Lane, La Jolla, CA 92037 USA
- HudsonAlpha Institute for Biotechnology, 601 Genome Way, Huntsville, AL 35806 USA
- J. Craig Venter Institute, 9714 Medical Center Drive, Rockville, MD 20850 USA
- Boeing Health Services, The Boeing Company, 3156 160th Ave. NE, Bellevue, WA 98008-2245 USA
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13
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Nygaard AB, Charnock C. Longitudinal development of the dust microbiome in a newly opened Norwegian kindergarten. MICROBIOME 2018; 6:159. [PMID: 30219104 PMCID: PMC6138906 DOI: 10.1186/s40168-018-0553-x] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/07/2017] [Accepted: 09/05/2018] [Indexed: 05/10/2023]
Abstract
BACKGROUND In Norway, 91% of children aged 1-5 attend kindergarten where they are exposed to indoor microbiomes which can have relevance for development and health. In order to gain a better understanding of the composition of the indoor microbiome and how it is affected by occupancy over time, floor dust samples from a newly opened kindergarten were investigated. Samples were collected during an 11-month period. Samples were analyzed for bacterial composition using 16S rRNA gene sequencing. Samples were also screened for four clinically relevant antibiotic resistance genes. In addition, Petrifilm analyses were used to evaluate surface hygiene. RESULTS Significant changes in the microbial community composition were observed over time (PERMANOVA, P < 0.05). Particularly, changes in the abundance and the proportions of human associated bacteria were found. A decrease in the prevalence of Propionibacterium from over 16% abundance to less than 1% and an increase in Streptococcus from 10 to 16% were the most significant findings. Four classes of clinically relevant antibiotic resistance genes were tested for; three were detected in the dust, indicating the presence of resistant bacteria and a potential for resistance spread. Petrifilm analysis showed that some surfaces in the kindergarten were of consistent poor hygienic quality, and new hygienic routines are required. CONCLUSIONS This study, which is the first of its kind performed at a newly opened kindergarten, reveals changes in the microbiome over time as well as the presence of antibiotic resistance genes and hygiene issues which are of relevance for occupant health.
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Affiliation(s)
- Anders B Nygaard
- Disease and Environmental Exposures Research Group, Department of Life Sciences and Health, OsloMet - Oslo Metropolitan University (OsloMet), Oslo, Norway.
- Department of Civil Engineering and Energy Technology, OsloMet, Oslo, Norway.
| | - Colin Charnock
- Disease and Environmental Exposures Research Group, Department of Life Sciences and Health, OsloMet - Oslo Metropolitan University (OsloMet), Oslo, Norway
- Department of Life Sciences and Health, OsloMet, Oslo, Norway
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14
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Luhung I, Wu Y, Xu S, Yamamoto N, Wei-Chung Chang V, Nazaroff WW. Exploring temporal patterns of bacterial and fungal DNA accumulation on a ventilation system filter for a Singapore university library. PLoS One 2018; 13:e0200820. [PMID: 30020972 PMCID: PMC6051664 DOI: 10.1371/journal.pone.0200820] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2017] [Accepted: 07/03/2018] [Indexed: 11/20/2022] Open
Abstract
Introduction Ventilation system filters process recirculated indoor air along with outdoor air. This function inspires the idea of using the filter as an indoor bioaerosol sampler. While promising, there remains a need to investigate several factors that could limit the accuracy of such a sampling approach. Among the important factors are the dynamics of microbial assemblages on filter surfaces over time and the differential influence of outdoor versus recirculated indoor air. Methods This study collected ventilation system filter samples from an air handling unit on a regular schedule over a 21-week period and analyzed the accumulation patterns of biological particles on the filter both quantitatively (using fluorometry and qPCR) and in terms of microbial diversity (using 16S rDNA and ITS sequencing). Results The quantitative result showed that total and bacterial DNA accumulated monotonically, rising to 41 ng/cm2 for total DNA and to 2.8 ng/cm2 for bacterial DNA over the 21-week period. The accumulation rate of bacterial DNA correlated with indoor occupancy level. Fungal DNA first rose to 4.0 ng/cm2 before showing a dip to 1.4 ng/cm2 between weeks 6 and 10. The dip indicated a possible artifact of this sampling approach for quantitative analysis as DNA may not be conserved on the filter over the months-long service period. The sequencing results indicate major contributions from outdoor air for fungi and from recirculated indoor air for bacteria. Despite the quantitative changes, the community structure of the microbial assemblages was stable throughout the 21-week sampling period, highlighting the robustness of this sampling method for microbial profiling. Conclusion This study supports the use of ventilation system filters as indoor bioaerosol samplers, but with caveats: 1) an outdoor reference is required to properly understand the contribution of outdoor bioaerosols; and 2) there is a need to better understand the persistence and durability of the targeted organisms on ventilation system filters.
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Affiliation(s)
- Irvan Luhung
- SinBerBEST Program, Berkeley Education Alliance for Research in Singapore (BEARS), Singapore, Singapore
- Singapore Centre for Environmental Life Sciences Engineering (SCELSE), Nanyang Technological University, Singapore, Singapore
- * E-mail:
| | - Yan Wu
- SinBerBEST Program, Berkeley Education Alliance for Research in Singapore (BEARS), Singapore, Singapore
- School of Environmental Science and Engineering, Shandong University, Jinan, China
| | - Siyu Xu
- Department of Environmental Health Sciences, Graduate School of Public Health, Seoul National University, Seoul, South Korea
| | - Naomichi Yamamoto
- Department of Environmental Health Sciences, Graduate School of Public Health, Seoul National University, Seoul, South Korea
| | - Victor Wei-Chung Chang
- SinBerBEST Program, Berkeley Education Alliance for Research in Singapore (BEARS), Singapore, Singapore
- Department of Civil Engineering, Monash University, Victoria, Clayton, Australia
| | - William W. Nazaroff
- SinBerBEST Program, Berkeley Education Alliance for Research in Singapore (BEARS), Singapore, Singapore
- Department of Civil and Environmental Engineering, University of California, Berkeley, CA, United States of America
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15
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Li X, Zhang T, Wang S. Measuring detachment of Aspergillus niger spores from colonies with an atomic force microscope. INDOOR AIR 2018; 28:744-753. [PMID: 29943883 DOI: 10.1111/ina.12486] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/29/2018] [Accepted: 06/20/2018] [Indexed: 06/08/2023]
Abstract
Detachment of fungal spores from moldy surfaces and the subsequent aerosolization can lead to adverse health effects. Spore aerosolization occurs when the forces for aerosolization exceed the binding forces of spores with their colonies. The threshold force to detach a spore from a growing colony remains unknown. This investigation measured the detachment of spores of Aspergillus niger from a colony using an atomic force microscope (AFM). The spores were first affixed to the cantilever of the AFM with ultraviolet curing glue, and then, the colony was moved downward until the spores detached. The threshold detachment forces were inferred from the deflection of the cantilever. In addition, the spores were aerosolized in a wind tunnel by a gradual increase of the blowing air speed. The forces measured by the AFM were compared with the hydrodynamic forces for aerosolization. The AFM measurements revealed that a force of 3.27 ± 0.25 nN was required to detach a single spore from the 4-day-old colony, while 1.98 ± 0.13 nN was sufficient for the 10-day-old colony. Slightly smaller detachment forces were observed by the AFM than were determined by the aerosolization tests.
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Affiliation(s)
- Xian Li
- School of Civil Engineering, Dalian University of Technology (DUT), Dalian, China
| | - Tengfei Zhang
- School of Civil Engineering, Dalian University of Technology (DUT), Dalian, China
- School of Environmental Science and Engineering, Tianjin University, Tianjin, China
| | - Shugang Wang
- School of Civil Engineering, Dalian University of Technology (DUT), Dalian, China
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16
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Zhai Y, Li X, Wang T, Wang B, Li C, Zeng G. A review on airborne microorganisms in particulate matters: Composition, characteristics and influence factors. ENVIRONMENT INTERNATIONAL 2018; 113:74-90. [PMID: 29421410 DOI: 10.1016/j.envint.2018.01.007] [Citation(s) in RCA: 113] [Impact Index Per Article: 18.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/24/2017] [Revised: 01/08/2018] [Accepted: 01/12/2018] [Indexed: 05/21/2023]
Abstract
Airborne microorganisms (AM), vital components of particulate matters (PM), are widespread in the atmosphere. Since some AM have pathogenicity, they can lead to a wide range of diseases in human and other organisms, meanwhile, some AM act as cloud condensation nuclei and ice nuclei which let them can affect the climate. The inherent characteristics of AM play critical roles in many aspects which, in turn, can decide microbial traits. The uncertain factors bring various influences on AM, which make it difficult to elaborate effect trends as whole. Because of the potential roles of AM in environment and potent effects of factors on AM, detailed knowledge of them is of primary significance. This review highlights the issues of composition and characteristics of AM with size-distribution, species diversity, variation and so on, and summarizes the main factors which affect airborne microbial features. This general information is a knowledge base for further thorough researches of AM and relevant aspects. Besides, current knowledge gaps and new perspectives are offered to roundly understand the impacts and application of AM in nature and human health.
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Affiliation(s)
- Yunbo Zhai
- College of Environmental Science and Engineering, Hunan University, Changsha 410082, PR China; Key Laboratory of Environmental Biology and Pollution Control, Hunan University, Ministry of Education, Changsha 410082, PR China.
| | - Xue Li
- College of Environmental Science and Engineering, Hunan University, Changsha 410082, PR China; Key Laboratory of Environmental Biology and Pollution Control, Hunan University, Ministry of Education, Changsha 410082, PR China
| | - Tengfei Wang
- College of Environmental Science and Engineering, Hunan University, Changsha 410082, PR China; Key Laboratory of Environmental Biology and Pollution Control, Hunan University, Ministry of Education, Changsha 410082, PR China
| | - Bei Wang
- College of Environmental Science and Engineering, Hunan University, Changsha 410082, PR China; Key Laboratory of Environmental Biology and Pollution Control, Hunan University, Ministry of Education, Changsha 410082, PR China
| | - Caiting Li
- College of Environmental Science and Engineering, Hunan University, Changsha 410082, PR China; Key Laboratory of Environmental Biology and Pollution Control, Hunan University, Ministry of Education, Changsha 410082, PR China
| | - Guangming Zeng
- College of Environmental Science and Engineering, Hunan University, Changsha 410082, PR China; Key Laboratory of Environmental Biology and Pollution Control, Hunan University, Ministry of Education, Changsha 410082, PR China
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17
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Fujiyoshi S, Tanaka D, Maruyama F. Transmission of Airborne Bacteria across Built Environments and Its Measurement Standards: A Review. Front Microbiol 2017; 8:2336. [PMID: 29238327 PMCID: PMC5712571 DOI: 10.3389/fmicb.2017.02336] [Citation(s) in RCA: 54] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2017] [Accepted: 11/13/2017] [Indexed: 11/13/2022] Open
Abstract
Human health is influenced by various factors including microorganisms present in built environments where people spend most of their lives (approximately 90%). It is therefore necessary to monitor and control indoor airborne microbes for occupational safety and public health. Most studies concerning airborne microorganisms have focused on fungi, with scant data available concerning bacteria. The present review considers papers published from 2010 to 2017 approximately and factors affecting properties of indoor airborne bacteria (communities and concentration) with respect to temporal perspective and to multiscale interaction viewpoint. From a temporal perspective, bacterial concentrations in built environments change depending on numbers of human occupancy, while properties of bacterial communities tend to remain stable. Similarly, the bacteria found in social and community spaces such as offices, classrooms and hospitals are mainly associated with human occupancy. Other major sources of indoor airborne bacteria are (i) outdoor environments, and (ii) the building materials themselves. Indoor bacterial communities and concentrations are varied with varying interferences by outdoor environment. Airborne bacteria from the outdoor environment enter an indoor space through open doors and windows, while indoor bacteria are simultaneously released to the outer environment. Outdoor bacterial communities and their concentrations are also affected by geographical factors such as types of land use and their spatial distribution. The bacteria found in built environments therefore originate from any of the natural and man-made surroundings around humans. Therefore, to better understand the factors influencing bacterial concentrations and communities in built environments, we should study all the environments that humans contact as a single ecosystem. In this review, we propose the establishment of a standard procedure for assessing properties of indoor airborne bacteria using four factors: temperature, relative humidity (RH), air exchange rate, and occupant density, as a minimum requirement. We also summarize the relevant legislation by country. Choice of factors to measure remain controversial are discussed.
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Affiliation(s)
- So Fujiyoshi
- Department of Microbiology, Graduate School of Medicine, Kyoto University, Kyoto, Japan
| | - Daisuke Tanaka
- Graduate School of Science and Engineering, University of Toyama, Toyama, Japan
| | - Fumito Maruyama
- Department of Microbiology, Graduate School of Medicine, Kyoto University, Kyoto, Japan
- JST/JICA, Science and Technology Research Partnership for Sustainable Development Program (SATREPS), Tokyo, Japan
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18
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Luhung I, Wu Y, Xu S, Yamamoto N, Chang VWC, Nazaroff WW. DNA accumulation on ventilation system filters in university buildings in Singapore. PLoS One 2017; 12:e0186295. [PMID: 29023520 PMCID: PMC5638523 DOI: 10.1371/journal.pone.0186295] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2016] [Accepted: 09/28/2017] [Indexed: 11/26/2022] Open
Abstract
Introduction Biological particles deposit on air handling system filters as they process air. This study reports and interprets abundance and diversity information regarding biomass accumulation on ordinarily used filters acquired from several locations in a university environment. Methods DNA-based analysis was applied both to quantify (via DNA fluorometry and qPCR) and to characterize (via high-throughput sequencing) the microbial material on filters, which mainly processed recirculated indoor air. Results were interpreted in relation to building occupancy and ventilation system operational parameters. Results Based on accumulated biomass, average DNA concentrations per AHU filter surface area across nine indoor locations after twelve weeks of filter use were in the respective ranges 1.1 to 41 ng per cm2 for total DNA, 0.02 to 3.3 ng per cm2 for bacterial DNA and 0.2 to 2.0 ng DNA per cm2 for fungal DNA. The most abundant genera detected on the AHU filter samples were Clostridium, Streptophyta, Bacillus, Acinetobacter and Ktedonobacter for bacteria and Aspergillus, Cladosporium, Nigrospora, Rigidoporus and Lentinus for fungi. Conditional indoor airborne DNA concentrations (median (range)) were estimated to be 13 (2.6–107) pg/m3 for total DNA, 0.4 (0.05–8.4) pg/m3 for bacterial DNA and 2.3 (1.0–5.1) pg/m3 for fungal DNA. Conclusion Conditional airborne concentrations and the relative abundances of selected groups of genera correlate well with occupancy level. Bacterial DNA was found to be more responsive than fungal DNA to differences in occupancy level and indoor environmental conditions.
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Affiliation(s)
- Irvan Luhung
- Berkeley Education Alliance for Research in Singapore, Singapore, Singapore
- Civil and Environmental Engineering, Nanyang Technological University, Singapore, Singapore
| | - Yan Wu
- Berkeley Education Alliance for Research in Singapore, Singapore, Singapore
- Civil and Environmental Engineering, Nanyang Technological University, Singapore, Singapore
- School of Environmental Science and Engineering, Shandong University, Jinan, China
| | - Siyu Xu
- Graduate School of Public Health, Seoul National University, Seoul, South Korea
| | - Naomichi Yamamoto
- Graduate School of Public Health, Seoul National University, Seoul, South Korea
| | - Victor Wei-Chung Chang
- Berkeley Education Alliance for Research in Singapore, Singapore, Singapore
- Civil and Environmental Engineering, Nanyang Technological University, Singapore, Singapore
- * E-mail:
| | - William W. Nazaroff
- Berkeley Education Alliance for Research in Singapore, Singapore, Singapore
- Civil and Environmental Engineering, University of California, Berkeley, California, United States of America
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19
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Emerson JB, Keady PB, Clements N, Morgan EE, Awerbuch J, Miller SL, Fierer N. High temporal variability in airborne bacterial diversity and abundance inside single-family residences. INDOOR AIR 2017; 27:576-586. [PMID: 27743387 DOI: 10.1111/ina.12347] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/26/2016] [Accepted: 10/10/2016] [Indexed: 05/14/2023]
Abstract
Our homes are microbial habitats, and although the amounts and types of bacteria in indoor air have been shown to vary substantially across residences, temporal variability within homes has rarely been characterized. Here, we sought to quantify the temporal variability in the amounts and types of airborne bacteria in homes, and what factors drive this variability. We collected filter samples of indoor and outdoor air in 15 homes over 1 year (approximately eight time points per home, two per season), and we used culture-independent DNA sequencing approaches to characterize bacterial community composition. Significant differences in indoor air community composition were observed both between homes and within each home over time. Indoor and outdoor air community compositions were not significantly correlated, suggesting that indoor and outdoor air communities are decoupled. Indoor air communities from the same home were often just as different at adjacent time points as they were across larger temporal distances, and temporal variation correlated with changes in environmental conditions, including temperature and relative humidity. Although all homes had highly variable indoor air communities, homes with the most temporally variable communities had more stable, lower average microbial loads than homes with less variable communities.
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Affiliation(s)
- J B Emerson
- Cooperative Institute for Research in Environmental Sciences, University of Colorado at Boulder, Boulder, CO, USA
| | - P B Keady
- Department of Mechanical Engineering, University of Colorado at Boulder, Boulder, CO, USA
| | - N Clements
- Department of Mechanical Engineering, University of Colorado at Boulder, Boulder, CO, USA
| | - E E Morgan
- Department of Molecular, Cellular, and Developmental Biology, University of Colorado at Boulder, Boulder, CO, USA
| | - J Awerbuch
- Department of Mechanical Engineering, University of Colorado at Boulder, Boulder, CO, USA
| | - S L Miller
- Department of Mechanical Engineering, University of Colorado at Boulder, Boulder, CO, USA
| | - N Fierer
- Cooperative Institute for Research in Environmental Sciences, University of Colorado at Boulder, Boulder, CO, USA
- Department of Ecology and Evolutionary Biology, University of Colorado at Boulder, Boulder, CO, USA
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20
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Haaland D, Siegel JA. Quantitative filter forensics for indoor particle sampling. INDOOR AIR 2017; 27:364-376. [PMID: 27385357 DOI: 10.1111/ina.12319] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/04/2016] [Accepted: 07/04/2016] [Indexed: 06/06/2023]
Abstract
Filter forensics is a promising indoor air investigation technique involving the analysis of dust which has collected on filters in central forced-air heating, ventilation, and air conditioning (HVAC) or portable systems to determine the presence of indoor particle-bound contaminants. In this study, we summarize past filter forensics research to explore what it reveals about the sampling technique and the indoor environment. There are 60 investigations in the literature that have used this sampling technique for a variety of biotic and abiotic contaminants. Many studies identified differences between contaminant concentrations in different buildings using this technique. Based on this literature review, we identified a lack of quantification as a gap in the past literature. Accordingly, we propose an approach to quantitatively link contaminants extracted from HVAC filter dust to time-averaged integrated air concentrations. This quantitative filter forensics approach has great potential to measure indoor air concentrations of a wide variety of particle-bound contaminants. Future studies directly comparing quantitative filter forensics to alternative sampling techniques are required to fully assess this approach, but analysis of past research suggests the enormous possibility of this approach.
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Affiliation(s)
- D Haaland
- Department of Civil Engineering, University of Toronto, Toronto, ON, Canada
| | - J A Siegel
- Department of Civil Engineering, University of Toronto, Toronto, ON, Canada
- Dalla Lana School of Public Health, The University of Toronto, Toronto, ON, Canada
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21
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Stamper CE, Hoisington AJ, Gomez OM, Halweg-Edwards AL, Smith DG, Bates KL, Kinney KA, Postolache TT, Brenner LA, Rook GAW, Lowry CA. The Microbiome of the Built Environment and Human Behavior: Implications for Emotional Health and Well-Being in Postmodern Western Societies. INTERNATIONAL REVIEW OF NEUROBIOLOGY 2016; 131:289-323. [PMID: 27793224 DOI: 10.1016/bs.irn.2016.07.006] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
It is increasingly evident that inflammation is an important determinant of cognitive function and emotional behaviors that are dysregulated in stress-related psychiatric disorders, such as anxiety and affective disorders. Inflammatory responses to physical or psychological stressors are dependent on immunoregulation, which is indicated by a balanced expansion of effector T-cell populations and regulatory T cells. This balance is in part driven by microbial signals. The hygiene or "old friends" hypothesis posits that exposure to immunoregulation-inducing microorganisms is reduced in modern urban societies, leading to an epidemic of inflammatory disease and increased vulnerability to stress-related psychiatric disorders. With the global trend toward urbanization, humans are progressively spending more time in built environments, thereby, experiencing limited exposures to these immunoregulatory "old friends." Here, we evaluate the implications of the global trend toward urbanization, and how this transition may affect human microbial exposures and human behavior.
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Affiliation(s)
- C E Stamper
- Center for Neuroscience, University of Colorado Boulder, Boulder, CO, United States
| | - A J Hoisington
- US Air Force Academy, Colorado Springs, CO, United States; Military and Veteran Microbiome Consortium for Research and Education (MVM-CoRE), Denver, CO, United States
| | - O M Gomez
- Center for Neuroscience, University of Colorado Boulder, Boulder, CO, United States
| | | | - D G Smith
- Center for Neuroscience, University of Colorado Boulder, Boulder, CO, United States
| | - K L Bates
- US Air Force Academy, Colorado Springs, CO, United States
| | - K A Kinney
- Military and Veteran Microbiome Consortium for Research and Education (MVM-CoRE), Denver, CO, United States; University of Texas Austin, Austin, TX, United States
| | - T T Postolache
- Military and Veteran Microbiome Consortium for Research and Education (MVM-CoRE), Denver, CO, United States; University of Maryland School of Medicine, Baltimore, MD, United States; VISN 5 Mental Illness Research Education and Clinical Center (MIRECC), Baltimore, MD, United States; Rocky Mountain Mental Illness Research Education and Clinical Center, Denver, CO, United States
| | - L A Brenner
- Military and Veteran Microbiome Consortium for Research and Education (MVM-CoRE), Denver, CO, United States; Rocky Mountain Mental Illness Research Education and Clinical Center, Denver, CO, United States; University of Colorado, Aurora, CO, United States
| | - G A W Rook
- Center for Clinical Microbiology, UCL (University College London), London, United Kingdom
| | - C A Lowry
- Center for Neuroscience, University of Colorado Boulder, Boulder, CO, United States; Military and Veteran Microbiome Consortium for Research and Education (MVM-CoRE), Denver, CO, United States; Rocky Mountain Mental Illness Research Education and Clinical Center, Denver, CO, United States; University of Colorado, Aurora, CO, United States.
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22
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Prussin AJ, Marr LC. Sources of airborne microorganisms in the built environment. MICROBIOME 2015; 3:78. [PMID: 26694197 PMCID: PMC4688924 DOI: 10.1186/s40168-015-0144-z] [Citation(s) in RCA: 173] [Impact Index Per Article: 19.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/27/2015] [Accepted: 12/14/2015] [Indexed: 05/20/2023]
Abstract
Each day people are exposed to millions of bioaerosols, including whole microorganisms, which can have both beneficial and detrimental effects. The next chapter in understanding the airborne microbiome of the built environment is characterizing the various sources of airborne microorganisms and the relative contribution of each. We have identified the following eight major categories of sources of airborne bacteria, viruses, and fungi in the built environment: humans; pets; plants; plumbing systems; heating, ventilation, and air-conditioning systems; mold; dust resuspension; and the outdoor environment. Certain species are associated with certain sources, but the full potential of source characterization and source apportionment has not yet been realized. Ideally, future studies will quantify detailed emission rates of microorganisms from each source and will identify the relative contribution of each source to the indoor air microbiome. This information could then be used to probe fundamental relationships between specific sources and human health, to design interventions to improve building health and human health, or even to provide evidence for forensic investigations.
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Affiliation(s)
- Aaron J Prussin
- Department of Civil and Environmental Engineering, Virginia Polytechnic Institute and State University, Blacksburg, VA, 24061, USA.
| | - Linsey C Marr
- Department of Civil and Environmental Engineering, Virginia Polytechnic Institute and State University, Blacksburg, VA, 24061, USA.
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