Transfer of environmental microbes to the skin and respiratory tract of humans after urban green space exposure

How the Built Environment Shapes Children's Microbiome: A Systematic Review

This systematic review aims to synthesize key empirical findings to understand how various elements of the built environment influence the microbiome concerning children's health and well-being. A comprehensive literature search was conducted across multiple databases, focusing on studies that examined the relationship between built environment factors and the microbiome aspects of childhood. A total of 42 studies were included in the final systematic review. We analyzed these studies from a range of different lenses, starting with basic research questions and variables to types of built environments, age groups of children, sampling strategy, bioinformatics, and the biological methods utilized. This review highlights a growing emphasis on children's exposure to nature within built environments and its potential to beneficially alter the microbiome, with 38% of studies addressing this link. It also identifies a significant research gap in connecting built environment design features (landscape and/or architectural) to microbiome outcomes and associated health, behavioral, and mental health impacts on children. The findings indicate that interventions aimed at improving the built environment quality via design could foster healthier microbiomes in children's environments. This review underscores the need for interdisciplinary research and policy initiatives that integrate microbiome science with built environment design to promote children's health and well-being.

Skin bacterial community dynamics of hands and forearms before and after military field exercise

The human skin microbiome is crucial for health and immunity, especially under the extreme conditions military personnel face. Soldiers often encounter unique stressors and hygienic challenges that can alter their skin's microbial composition, particularly in field environments. In this study, we aimed to investigate the impact of military field exercises on the diversity and composition of the skin bacterial microbiota using 16S rRNA sequencing. We conducted a longitudinal study of Norwegian soldiers (n = 19) participating in outdoor training operations during the NATO winter exercise Cold Response 2022. Skin swabs were taken from soldiers' hands and forearms before and after the 10-day military exercise, and following a 3-week post-exercise leave. Our results reveal hand- and forearm-specific shifts in bacterial populations associated with the exercise, likely influenced by environmental exposure, reduced hygiene, and heightened social contact. Alpha diversity increased on forearms while remaining stable on hands, which appeared more resilient to perturbations. Both sites exhibited temporal changes in composition, with soil- and water-associated bacteria enriched post-exercise; most being transient on hands but more sustained on forearms. The soldiers' microbiomes converged during the exercise, then diverged in the post-exercise leave period, and neither skin site returned to baseline composition at follow-up. Our findings highlight the impact of collaborative outdoor activities on microbial communities and suggest that resilience and stability differ between skin sites.IMPORTANCEOptimizing soldier health and resilience is critical for maintaining military readiness and operational effectiveness. The skin, as the body's first line of defense, is subjected to numerous challenges in military environments. Unique environmental and hygiene challenges can disrupt the skin microbiome and increase susceptibility to skin and soft tissue infections. This longitudinal research provides valuable insights into the effects of military service on the bacterial dynamics of the skin microbiome but can also inform hygiene management and disease prevention in comparable situations.

Microbial communities on dry natural rocks are richer and less stressed than those on man-made playgrounds

In modern urbanized societies, the incidence of major immune-mediated diseases is several times higher than before World War II. A potential explanation is that these diseases are triggered by limited possibilities to be exposed to rich environmental microbiota. This requires that the urban environment hosts less and poorer microbiota than the natural environment. The current study was designed to test the assumption that urban man-made environments host less and poorer environmental microbiota, compared to natural habitats. We selected two types of dry environments, natural rocks and playground rubber mats, both of which were used daily and extensively by children. In quantitative PCR and next-generation sequencing, bacterial abundance and richness were higher on the natural rocks than the rubber mats. Altogether, 67 amplicon sequence variants (ASVs) belonging mostly to Actinobacteria and Proteobacteria were indicative of rock microbiota, while three ASVs were indicative of rubber mats. Interestingly, bacteria formed more complex networks on rubber mats than natural rocks. Based on the literature, this indicates that the studied artificial dry environment is more challenging and stressful for bacterial communities than dry natural rocks. The results support the hypothesis that urban man-made environments host poor microbial communities, which is in accordance with the biodiversity hypothesis of immune-mediated diseases.IMPORTANCEThe current study provides new evidence that artificial urban play environments host poor microbial communities and provide a stressful environment for microbes, as compared to dry natural rocks. Through this, the current study underlines the need to enhance microbial diversity in urban areas, especially in outdoor play environments, which have a crucial role in providing essential microbial exposure for the development of children's immune system. This research can potentially offer guidance for urban planning and public health strategies that support planetary health.

Environmental impacts on childhood rhinitis: The role of green spaces, air pollutants, and indoor microbial communities in Taiyuan, a city in Northern China

Rhinitis is one of the most common respiratory diseases, influenced by various environmental factors such as green space, air pollution and indoor microbiomes. However, their interactions and combined effects have not been reported. We recruited 1121 preschool children from day care centers in a northern city of China. Health and demographic data were collected through questionnaires answered by the children's parents. Surrounding green space was assessed by Normalized Difference Vegetation Index (NDVI), Enhanced Vegetation Index (EVI) and land cover data of grassland proportion within 1500/3000 m. Ambient air pollution was estimated using the inverse distance weighted (IDW), and the indoor microbiome in classroom vacuum dust was profiled by bacterial 16S rRNA and fungal ITS amplicon sequencing. Mixed-effect logistic regression revealed the proportion of natural grassland, grassland leaf-off and total grassland was negatively associated with current rhinitis. Stratified analysis indicated that greater green space exposure was associated with a reduced current rhinitis in children at high levels of air pollution. Additionally, grassland also protects children against environmental tobacco smoke at home. Indoor microbiome analysis showed Haemophilus and Dolosigranulum were enriched in low-rhinitis day care centers, while Amaricoccus, Blautia and Mycosphaerella were enriched in high-rhinitis day care centers. Mediation analysis indicated that the indoor microbiome did not have significant mediating effects on the relationship between green space and children's current rhinitis. This is the first study to reveal interactions of green space, air pollution and indoor microbiome on rhinitis, providing new insights into how environmental factors collectively influence respiratory health in children.

Occurrence and human exposure risk of antibiotic resistance genes in tillage soils of dryland regions: A case study of northern Ningxia Plain, China

Agricultural soils are important source and sink of antibiotic resistance genes (ARGs). However, little is known about the fate of ARGs in dryland soils, while its human exposure risks were seriously overlooked. Taking the northern Ningxia Plain as a case, this study explored the occurrence of ARGs and its relationship with mobile genetic elements (MGEs), pathogens, and environmental factors. Furthermore, the concentrations of airborne ARGs by soil wind erosion and the human exposure doses of soil ARGs were evaluated. The results showed the abundances of different regions ranged from 4.0 × 105 to 1.6 × 106 copies/g. Soil ARGs are driven by MGEs, but multiply impacted by soil properties, nutrition, and bacterial community. Vibrio metschnikovii, Acinetobacter schindleri, and Serratia marcescens are potential pathogenic hosts for ARGs. Further exploration revealed the concentration of ARGs loaded in dust by soil wind erosion reached more than 105 copies/m3, which were even higher than those found in sewage treatment plants and hospitals. Skin contact is the primary route of ARGs exposure, with a maximum dose of 24071.33 copies/kg/d, which is largely attributed to ARGs loaded in dust. This study bridged the gap on ARGs in dryland soils, and provided reference for human exposure risk assessment of soil ARGs.

Green space quantity and exposure in relation to the risk of immune-mediated diseases: a scoping review

The growing global incidence of immune-mediated and inflammatory diseases (IMIDs) is worrisome, with evidence suggesting that environmental factors, notably urbanization and the reduction of green spaces, may act as potential instigators. However, conflicting findings in studies necessitate a closer examination of recent research (January 2020 - February 2024) to elucidate the factors contributing to these inconsistencies. This review explores study protocols to avoid erroneously endorsing the null hypothesis of no association between green space coverage and IMID risks. A literature search adhering to PRISMA-ScR guidelines yielded 46 relevant papers from Google Scolar and Pub Meb. The studies varied in design, with 17 being longitudinal, 24 cross-sectional, and five focusing on longitudinal parent-offspring connections. Geographic scope differed, with 21 multi-location and 25 single-location studies. Participant numbers ranged from 144 to 982,131 across diverse demographics. Additionally, some studies examined disease frequencies in large groups (several million people) residing in specific regions. Green space metrics encompassed NDVI, land cover data, plant biodiversity, and novel indexes, measured within 7.5-5000 m diameter buffers around residences or schools. The review advises against making definitive statements regarding the relationship between urban green spaces and the prevalence of IMIDs. It suggests that inconsistencies in study results may stem from variations in study designs and methodologies, as well as the complex, interacting mechanisms through which green spaces affect immune health. Future research recommendations include larger cohorts, early-life exposure data, and testing specific hypotheses related to vegetation types and participants' genetic predispositions.

A Breath of Fresh Air: Perspectives on Inhaled Nutrients and Bacteria to Improve Human Health

We propose that the human respiratory system and olfactory pathways sequester airborne nutrients (vitamins, fatty acids, and trace minerals) that are beneficial for health, which we term "aeronutrients." In addition, airborne bacteria, termed "aeromicrobes," have the potential for positive health effects by improving species diversity in the microbiotas of the respiratory and gastrointestinal tracts. These concepts have implications for people living in urban areas or those who have limited access to nature, such as astronauts exposed for long periods to highly filtered air that may be depleted of aeronutrients and aeromicrobes. The possibility that fresh air contributes to human nutrition and health may stimulate a re-evaluation of guidelines pertaining to nutrition and access to natural environments, and will open new avenues of scientific enquiry.

Effects of urban green space habitats and tree species on ectomycorrhizal fungal diversity

Ectomycorrhizal fungi (EMF) are key symbiotic microbial components for the growth and health of trees in urban greenspace habitats (UGSHs). However, the current understanding of EMF diversity in UGSHs remains poor. Therefore, in this study, using morphological classification and molecular identification, we aimed to investigate EMF diversity in three EMF host plants: Cedrus deodara in the roadside green belt, and C. deodara, Pinus massoniana, and Salix babylonica in the park roadside green belt, in Guiyang, China. A total of 62 EMF Operational Taxonomic Units (OTUs) were identified, including 13 EMF OTUs in the C. deodara roadside green belt, and 23, 31, and 9 EMF OTUs in the park green belts. C. deodara, P. massoniana, and S. babylonica were respectively identified in park green belts. Ascomycota and Basidiomycota were the dominant phylum in the EMF communities in roadside and park green habitat, respectively. The Shannon and Simpson indexes of the C. deodara EMF community in the park green belt were higher than those in the roadside green belt. EMF diversity of the tree species in the park green belt was P. massoniana > C. deodara > S. babylonica. Differences in EMF community diversity was observed among the different greening tree species in the UGSHs. UGSHs with different disturbance gradients had a significant impact on the EMF diversity of the same greening tree species. These results can be used as a scientific reference for optimizing the design and scientific management of UGSHs.

How mobility pattern shapes the association between static green space and dynamic green space exposure

Greenspaces are crucial for enhancing mental and physical health. Recent research has shifted from static methods of assessing exposure to greenspaces, based on fixed locations, to dynamic approaches that account for individual mobility. These dynamic evaluations utilize advanced technologies like GPS tracking and remote sensing to provide more precise exposure estimates. However, little work has been conducted to compare dynamic and static exposure assessments and the effect of individual mobility on these evaluations. This study delves into how greenspaces around homes and workplaces, along with mobility patterns, affect dynamic greenspace exposure in Hong Kong. Data was collected from 787 participants in four communities in Hong Kong using GPS, portable sensors, and surveys. Using multiple statistical tests, our study revealed significant variations in participants' daily mobility patterns across socio-demographic and temporal factors. Further, using linear mixed-effects models, we identified complex and statistically significant interactions between participants' static greenspace exposure and their mobility patterns. Our findings suggest that individual mobility patterns significantly modify the relationship between static and dynamic greenspace exposure and play a critical role in explaining socio-demographic and temporal context differences in the relationship between static and dynamic greenspace exposure.

Skin exposure to soil microbiota elicits changes in cell-mediated immunity to pneumococcal vaccine

A resilient immune system is characterized by its capacity to respond appropriately to challenges, such as infections, and it is crucial in vaccine response. Here we report a paired randomized intervention-control trial in which we evaluated the effect of microbially rich soil on immune resilience and pneumococcal vaccine response. Twenty-five age and sex matched pairs of volunteers were randomized to intervention and control groups. The intervention group rubbed hands three times a day in microbially rich soil until participants received a pneumococcal vaccine on day 14. Vaccine response, skin and gut bacteriome and blood cytokine levels were analyzed on days 0, 14 and 35. Peripheral blood mononuclear cells (PBMCs) were stimulated with vaccine components and autoclaved soil for cytokine production. Commensal bacterial community shifted only in the intervention group during the 14-day intervention period. When PBMCs collected on day 14 before the vaccination were stimulated with the vaccine components, IFN-y production increased in the intervention but not in the control group. On day 35, vaccination induced a robust antibody response in both groups. In parallel, gut bacterial community was associated with TGF-β plasma levels and TGF-β decrease in plasma was lower in the intervention group. The results indicate that exposure to microbially rich soil can modulate the cell-mediated immunity to components in pneumococcal vaccine.

Spatial distribution of residential environment, genetic susceptibility, and psoriasis: A prospective cohort study

Background

Genetic and environmental factors contribute to psoriasis, but the impact of residential environments on this condition remains uncertain. We aimed to investigate the association of residential environments with psoriasis risk and explore its interaction with genes.

Methods

We retrieved data on the spatial distribution of residential environments at 300 and 1000 m buffer zones from the UK Biobank, including the proportions of natural environments, domestic gardens, green spaces, and blue spaces within these zones. We then used Cox hazard models to estimate the hazard ratios (HRs) and 95% confidence intervals (CIs) for the associations between residential environments and psoriasis risk. Lastly, we constructed polygenic risk scores to determine genetic susceptibility and further analyse the interaction with residential environments.

Results

Overall, 3755 incident cases of psoriasis were documented during a median follow-up of 12.45 years. Compared with the lowest exposure quantile (Q1), Q4 exposure to natural environments (1000 m buffer: HR = 1.16, 95% CI = 1.05-1.29; 300 m buffer: HR = 1.12, 95% CI = 1.02-1.24) and green spaces (1000 m buffer: HR = 1.16, 95% CI = 1.04-1.28; 300m buffer: HR = 1.10, 95% CI = 1.00-1.21) increased the risk of psoriasis, while Q4 exposure to domestic gardens (1000 m buffer: HR = 0.85, 95% CI = 0.77-0.93; 300m buffer: HR = 0.91, 95% CI = 0.83-1.00) and Q3 exposure to blue spaces (1000 m buffer: HR = 0.89, 95% CI = 0.81-0.98) were negatively associated with psoriasis risk. Among participants with a high genetic risk, those exposed to high levels of natural environments (1000 m buffer: HR = 1.49, 95% CI = 1.15-1.93; 300 m buffer: HR = 1.39, 95% CI = 1.10-1.77) and green spaces (300 m buffer: HR = 1.30, 95% CI = 1.04-1.64) had a higher risk of psoriasis, while those exposed to blue spaces (1000 m buffer: HR = 0.78, 95% CI = 0.63-0.98) had a lower risk of psoriasis. We also observed joint effects of genetic risk and residential environments and an antagonistic additive interaction between blue spaces and genetic risk (P = 0.011).

Conclusions

We observed that residing in natural environments and green areas increased the risk of psoriasis in our sample, while proximity to blue spaces and domestic gardens was associated to reduced risks. The association of residential environments with psoriasis risk was modified by genetic susceptibility.

The oral microbiome is associated with HPA axis response to a psychosocial stressor

Intense psychosocial stress during early life has a detrimental effect on health-disease balance in later life. Simultaneously, despite its sensitivity to stress, the developing microbiome contributes to long-term health. Following stress exposure, HPA-axis activation regulates the "fight or flight" response with the release of glucose and cortisol. Here, we investigated the interaction between the oral microbiome and the stress response. We used a cohort of 115 adults, mean age 24, who either experienced institutionalisation and adoption (n = 40) or were non-adopted controls (n = 75). Glucose and cortisol measurements were taken from participants following an extended socially evaluated cold pressor test (seCPT) at multiple time points. The cohort´s oral microbiome was profiled via 16S-V4 sequencing on microbial DNA from saliva and buccal samples. Using mixed-effect linear regressions, we identified 12 genera that exhibited an interaction with host's cortisol-glucose response to stress, strongly influencing intensity and clearance of cortisol and glucose following stress exposure. Particularly, the identified taxa influenced the glucose and cortisol release profiles and kinetics following seCPT exposure. In conclusion, our study provided evidence for the oral microbiome modifying the effect of stress on the HPA-axis and human metabolism, as shown in glucose-cortisol time series data.

Urban sports fields support higher levels of soil butyrate and butyrate-producing bacteria than urban nature parks

Butyrate-producing bacteria colonise the gut of humans and non-human animals, where they produce butyrate, a short-chain fatty acid with known health benefits. Butyrate-producing bacteria also reside in soils and soil bacteria can drive the assembly of airborne bacterial communities (the aerobiome). Aerobiomes in urban greenspaces are important reservoirs of butyrate-producing bacteria as they supplement the human microbiome, but soil butyrate producer communities have rarely been examined in detail. Here, we studied soil metagenome taxonomic and functional profiles and soil physicochemical data from two urban greenspace types: sports fields (n = 11) and nature parks (n = 22). We also developed a novel method to quantify soil butyrate and characterised the in situ activity of butyrate-producing bacteria. We show that soil butyrate was higher in sports fields than nature parks and that sports fields also had significantly higher relative abundances of the terminal butyrate production genes buk and butCoAT than nature parks. Soil butyrate positively correlated with buk gene abundance (but not butCoAT). Soil moisture (r = .50), calcium (r = -.62), iron (ρ = .54), ammonium nitrogen (ρ = .58) and organic carbon (r = .45) had the strongest soil abiotic effects on soil butyrate concentrations and iron (ρ = .56) and calcium (ρ = -.57) had the strongest soil abiotic effects on buk read abundances. Overall, our findings contribute important new insights into the role of sports fields as key exposure reservoirs of butyrate producing bacteria, with important implications for the provision of microbiome-mediated human health benefits via butyrate.

Short-term passive greenspace exposures have little effect on nasal microbiomes: A cross-over exposure study of a Māori cohort

Indigenous health interventions have emerged in New Zealand aimed at increasing people's interactions with and exposure to macro and microbial diversity. Urban greenspaces provide opportunities for people to gain such exposures. However, the dynamics and pathways of microbial transfer from natural environments onto a person remain poorly understood. Here, we analysed bacterial 16S rRNA amplicons in air samples (n = 7) and pre- and post-exposure nasal samples (n = 238) from 35 participants who had 30-min exposures in an outdoor park. The participants were organised into two groups: over eight days each group had two outdoor park exposures and two indoor office exposures, with a cross-over study design and washout days between exposure days. We investigated the effects of participant group, location (outdoor park vs. indoor office), and exposures (pre vs. post) on the nasal bacterial community composition and three key suspected health-associated bacterial indicators (alpha diversity, generic diversity of Gammaproteobacteria, and read abundances of butyrate-producing bacteria). The participants had distinct nasal bacterial communities, but these communities did not display notable shifts in composition following exposures. The community composition and key health bacterial indicators were stable throughout the trial period, with no clear or consistent effects of group, location, or exposure. We conclude that 30-min exposure periods to urban greenspaces are unlikely to create notable changes in the nasal microbiome of visitors, which contrasts with previous research. Our results suggest that longer exposures or activities that involves closer interaction with microbial rich ecological components (e.g., soil) are required for greenspace exposures to result in noteworthy changes in the nasal microbiome.

Impact of Plant-Microbe Interactions with a Focus on Poorly Investigated Urban Ecosystems-A Review

The urbanization process, which began with the Industrial Revolution, has undergone a considerable increase over the past few decades. Urbanization strongly affects ecological processes, often deleteriously, because it is associated with a decrease in green spaces (areas of land covered by vegetation), loss of natural habitats, increased rates of species extinction, a greater prevalence of invasive and exotic species, and anthropogenic pollutant accumulation. In urban environments, green spaces play a key role by providing many ecological benefits and contributing to human psychophysical well-being. It is known that interactions between plants and microorganisms that occur in the rhizosphere are of paramount importance for plant health, soil fertility, and the correct functioning of plant ecosystems. The growing diffusion of DNA sequencing technologies and "omics" analyses has provided increasing information about the composition, structure, and function of the rhizomicrobiota. However, despite the considerable amount of data on rhizosphere communities and their interactions with plants in natural/rural contexts, current knowledge on microbial communities associated with plant roots in urban soils is still very scarce. The present review discusses both plant-microbe dynamics and factors that drive the composition of the rhizomicrobiota in poorly investigated urban settings and the potential use of beneficial microbes as an innovative biological tool to face the challenges that anthropized environments and climate change impose. Unravelling urban biodiversity will contribute to green space management, preservation, and development and, ultimately, to public health and safety.

Greenness and its composition and configuration in association with allergic rhinitis in preschool children

BACKGROUND

Few studies focus on the associations of green space composition and configuration with children's allergic rhinitis (AR).

METHODS

A multi-center population-based cross-sectional study was performed in 7 cities in mainland of China between 2019 and 2020, recruiting 36,867 preschool children. Information on the current AR symptoms and demographics were collected by questionnaire. Exposure to residential greenness was estimated by Normalized Difference Vegetation Index (NDVI, 1000 m buffer) around the residences. Greenness composition was estimated in 3 main categories: forest, grassland, shrubland. Configuration of each category and total greenness (a spatial resolution of 10 m × 10 m) was estimated by 6 landscape pattern metrics to quantify their area, shape complexity, aggregation, connectivity, and patch density. Exposure to daily ambient particulate matter (PM1, PM2.5 and PM10, a spatial resolution of 1 km × 1 km) was estimated. Multilevel logistic regression models were applied to analyze the associations of greenness and its composition and configuration with AR, and mediation effects by PMs were examined by mediation analysis models.

RESULTS

The prevalence of self-reported current AR in preschool children was 33.1%. Two indicators of forest, Aggregation Index of forest patches (AIforest) (odds ratio (OR):0.92, 95% Confidential Interval (CI): 0.88-0.97), and Patch Cohesion of forest (COHESIONforest) (OR: 0.93, 95% CI:0.89-0.98) showed significantly negative associations with AR symptoms. Mediation analyses found the associations were partially mediated by PMs. Age, exclusive breastfeed duration and season were the potential effect modifiers. The associations varied across seven cities.

CONCLUSION

Our findings suggest the inverse associations of the aggregation and connectivity of forest patches surrounding residence addresses with AR symptoms. Since the cross-sectional study only provides associations rather than causation, further studies are needed to confirm our results as well as the underlying mechanisms.

Childcare centre soil microbiomes are influenced by substrate type and surrounding vegetation condition

Urban development has profoundly reduced human exposure to biodiverse environments, which is linked to a rise in human disease. The 'biodiversity hypothesis' proposes that contact with diverse microbial communities (microbiota) benefits human health, as exposure to microbial diversity promotes immune training and regulates immune function. Soils and sandpits in urban childcare centres may provide exposure to diverse microbiota that support immunoregulation at a critical developmental stage in a child's life. However, the influence of outdoor substrate (i.e., sand vs. soil) and surrounding vegetation on these environmental microbiota in urban childcare centres remains poorly understood. Here, we used 16S rRNA amplicon sequencing to examine the variation in bacterial communities in sandpits and soils across 22 childcare centres in Adelaide, Australia, plus the impact of plant species richness and habitat condition on these bacterial communities. We show that sandpits had distinct bacterial communities and lower alpha diversity than soils. In addition, we found that plant species richness in the centres' yards and habitat condition surrounding the centres influenced the bacterial communities in soils but not sandpits. These results demonstrate that the diversity and composition of childcare centre sandpit and soil bacterial communities are shaped by substrate type, and that the soils are also shaped by the vegetation within and surrounding the centres. Accordingly, there is potential to modulate the exposure of children to health-associated bacterial communities by managing substrates and vegetation in and around childcare centres.

Association of Residential Greenness Exposure with Depression Incidence in Adults 50 Years of Age and Older: Findings from the Cohort Study on Global AGEing and Adult Health (SAGE) in China

BACKGROUND

Depression is a social and public health problem of great concern globally. Identifying and managing the factors influencing depression are crucial for preventing and decreasing the burden of depression.

OBJECTIVES

Our objectives are to explore the association between residential greenness and the incidence of depression in an older Chinese population and to calculate the disease burden of depression prevented by greenness exposure.

METHODS

This study was the Chinese part of the World Health Organization Study on Global AGEing and Adult Health (WHO SAGE). We collected the data of 8,481 residents ≥ 50 years of age in China for the period 2007-2018. Average follow-up duration was 7.00 (± 2.51 ) years. Each participant was matched to the yearly maximum normalized difference vegetation index (NDVI) at their residential address. Incidence of depression was assessed using the Composite International Diagnostic Interview (CIDI), self-reports of depression, and/or taking depression medication. Association between greenness and depression was examined using the time-dependent Cox regression model with stratified analysis by sex, age, urbanicity, annual family income, region, smoking, drinking, and household cooking fuels. Furthermore, the prevented fraction (PF) and attributable number (AN) of depression prevented by exposure to greenness were estimated.

RESULTS

Residential greenness was negatively associated with depression. Each interquartile range (IQR) increase in NDVI 500 -m buffer was associated with a 40% decrease [hazard ratio  ( HR ) = 0.60 ; 95% confidence interval (CI): 0.37, 0.97] in the risk of depression incidence among the total participants. Subgroup analyses showed negative associations in urban residents (HR = 0.32 ; 95% CI: 0.12, 0.86) vs. rural residents, in high-income residents (HR = 0.28 ; 95% CI: 0.11, 0.71) vs. low-income residents, and in southern China (HR = 0.50 ; 95% CI: 0.26, 0.95) vs. northern China. Over 8.0% (PF = 8.69 % ; 95% CI: 1.38%, 15.40%) and 1,955,199 (95% CI: 310,492; 3,464,909) new cases of depression may be avoided by increasing greenness exposures annually across China.

DISCUSSION

The findings suggest protective effects of residential greenness exposure on depression incidence in the older population, particularly among urban residents, high-income residents, and participants living in southern China. The construction of residential greenness should be included in community planning. https://doi.org/10.1289/EHP13947.

Urban indoor gardening enhances immune regulation and diversifies skin microbiota - A placebo-controlled double-blinded intervention study

According to the hygiene and biodiversity hypotheses, frequent exposure to environmental microbiota, especially through soil contact, diversifies commensal microbiota, enhances immune modulation, and ultimately lowers the risk of immune-mediated diseases. Here we test the underlying assumption of the hygiene and biodiversity hypotheses by instructing volunteers to grow edible plants indoors during the winter season when natural exposure to environmental microbiota is low. The one-month randomized, placebo-controlled double-blind trial consisted of two treatments: participants received either microbially diverse growing medium or visually similar but microbially poor growing medium. Skin microbiota and a panel of seven immune markers were analyzed in the beginning of the trial and after one month. The diversity of five bacterial phyla (Bacteroidetes, Planctomycetes, Proteobacteria, Cyanobacteria, and Verrucomicrobia) and one class (Bacteroidia) increased on the skin of participants in the intervention group while no changes were observed in the placebo group. The number of nodes and edges in the co-occurrence networks of the skin bacteria increased on average three times more in the intervention group than in the placebo group. The plasma levels of the immunomodulatory cytokine interleukin 10 (IL-10) increased in the intervention group when compared with the placebo group. A similar trend was observed in the interleukin 17A (IL-17A) levels and in the IL-10:IL-17A ratios. Participants in both groups reported high satisfaction and adherence to the trial. The current study provides evidence in support of the core assumption of the hygiene and biodiversity hypotheses of immune-mediated diseases. Indoor urban gardening offers a meaningful and convenient approach for increasing year-round exposure to environmental microbiota, paving the way for other prophylactic practices that might help prevent immune-mediated diseases.

Greenspace and human microbiota: A systematic review

BACKGROUND

Potential effect of greenspace exposure on human microbiota have been explored by a number of observational and interventional studies, but the results remained mixed. We comprehensively synthesized these studies by performing a systematic review following Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines.

METHODS

Comprehensive literature searches in three international databases (PubMed, Embase, and Web of Science) and three Chinese databases (China National Knowledge Infrastructure, Wanfang, and China Biology Medicine disc) were conducted from inception to November 1, 2023. Observational and interventional studies that evaluated associations between greenspace exposure and human microbiota at different anatomical sites were included. Studies were assessed using the National Toxicology Program's office of Health Assessment and Translation risk of bias tool and certainty of evidence was assessed using the Grading of Recommendations, Assessment, Development and Evaluation framework. Two authors independently performed study selection, data extraction, and risk of bias assessment, and evidence grading. Study results were synthesized descriptively.

RESULTS

Twenty studies, including 11 observational studies and 9 interventional studies, were finally included into the systematic review. The microbiota of the included studies was from gut (n = 13), skin (n = 10), oral cavity (n = 5), nasal cavity (n = 5) and eyes (n = 1). The majority of studies reported the associations of greenspace exposure with increased diversity (e.g., richness and Shannon index) and/or altered overall composition of human gut (n = 12) and skin microbiota (n = 8), with increases in the relative abundance of probiotics (e.g., Ruminococcaceae) and decreases in the relative abundance of pathogens (e.g., Streptococcus and Escherichia/Shigella). Due to limited number of studies, evidence concerning greenspace and oral, nasal, and ocular microbiota were still inconclusive.

CONCLUSION

The current evidence suggests that greenspace exposure may diversify gut and skin microbiota and alter their composition to healthier profiles. These findings would be helpful in uncovering the potential mechanisms underlying greenspace and human health and in promoting a healthier profile of human microbiota.

Integrating microbiome science and evolutionary medicine into animal health and conservation

Microbiome science has provided groundbreaking insights into human and animal health. Similarly, evolutionary medicine - the incorporation of eco-evolutionary concepts into primarily human medical theory and practice - is increasingly recognised for its novel perspectives on modern diseases. Studies of host-microbe relationships have been expanded beyond humans to include a wide range of animal taxa, adding new facets to our understanding of animal ecology, evolution, behaviour, and health. In this review, we propose that a broader application of evolutionary medicine, combined with microbiome science, can provide valuable and innovative perspectives on animal care and conservation. First, we draw on classic ecological principles, such as alternative stable states, to propose an eco-evolutionary framework for understanding variation in animal microbiomes and their role in animal health and wellbeing. With a focus on mammalian gut microbiomes, we apply this framework to populations of animals under human care, with particular relevance to the many animal species that suffer diseases linked to gut microbial dysfunction (e.g. gut distress and infection, autoimmune disorders, obesity). We discuss diet and microbial landscapes (i.e. the microbes in the animal's external environment), as two factors that are (i) proposed to represent evolutionary mismatches for captive animals, (ii) linked to gut microbiome structure and function, and (iii) potentially best understood from an evolutionary medicine perspective. Keeping within our evolutionary framework, we highlight the potential benefits - and pitfalls - of modern microbial therapies, such as pre- and probiotics, faecal microbiota transplants, and microbial rewilding. We discuss the limited, yet growing, empirical evidence for the use of microbial therapies to modulate animal gut microbiomes beneficially. Interspersed throughout, we propose 12 actionable steps, grounded in evolutionary medicine, that can be applied to practical animal care and management. We encourage that these actionable steps be paired with integration of eco-evolutionary perspectives into our definitions of appropriate animal care standards. The evolutionary perspectives proposed herein may be best appreciated when applied to the broad diversity of species under human care, rather than when solely focused on humans. We urge animal care professionals, veterinarians, nutritionists, scientists, and others to collaborate on these efforts, allowing for simultaneous care of animal patients and the generation of valuable empirical data.

Biodiversity and human health: A scoping review and examples of underrepresented linkages

Mounting evidence supports the connections between exposure to environmental typologies(such as green and blue spaces)and human health. However, the mechanistic links that connect biodiversity (the variety of life) and human health, and the extent of supporting evidence remain less clear. Here, we undertook a scoping review to map the links between biodiversity and human health and summarise the levels of associated evidence using an established weight of evidence framework. Distinct from other reviews, we provide additional context regarding the environment-microbiome-health axis, evaluate the environmental buffering pathway (e.g., biodiversity impacts on air pollution), and provide examples of three under- or minimally-represented linkages. The examples are (1) biodiversity and Indigenous Peoples' health, (2) biodiversity and urban social equity, and (3) biodiversity and COVID-19. We observed a moderate level of evidence to support the environmental microbiota-human health pathway and a moderate-high level of evidence to support broader nature pathways (e.g., greenspace) to various health outcomes, from stress reduction to enhanced wellbeing and improved social cohesion. However, studies of broader nature pathways did not typically include specific biodiversity metrics, indicating clear research gaps. Further research is required to understand the connections and causative pathways between biodiversity (e.g., using metrics such as taxonomy, diversity/richness, structure, and function) and health outcomes. There are well-established frameworks to assess the effects of broad classifications of nature on human health. These can assist future research in linking biodiversity metrics to human health outcomes. Our examples of underrepresented linkages highlight the roles of biodiversity and its loss on urban lived experiences, infectious diseases, and Indigenous Peoples' sovereignty and livelihoods. More research and awareness of these socioecological interconnections are needed.

Green Space and Internalizing or Externalizing Symptoms Among Children

Importance

Evidence suggests that living near green space supports mental health, but studies examining the association of green space with early mental health symptoms among children are rare.

Objective

To evaluate the association between residential green space and early internalizing (eg, anxiety and depression) and externalizing (eg, aggression and rule-breaking) symptoms.

Design, Setting, and Participants

Data for this cohort study were drawn from the Environmental Influences on Child Health Outcomes cohort; analysis was conducted from July to October 2023. Children born between 2007 and 2013 with outcome data in early (aged 2-5 years) and/or middle (aged 6-11 years) childhood who resided in 41 states across the US, drawing from clinic, hospital, and community-based cohorts, were included. Cohort sites were eligible if they recruited general population participants and if at least 30 children had outcome and residential address data to measure green space exposure. Nine cohorts with 13 sites met these criteria. Children diagnosed with autism or developmental delay were excluded, and 1 child per family was included.

Exposures

Green space exposure was measured using a biannual (ie, summer and winter) Normalized Difference Vegetation Index, a satellite image-based indicator of vegetation density assigned to monthly residential history from birth to outcome assessment.

Main Outcome and Measures

Child internalizing and externalizing symptoms were assessed using the Child Behavior Checklist for Ages 1½ to 5 or 6 to 18. The association between green space and internalizing and externalizing symptoms was modeled with multivariable linear regression using generalized estimating equations, adjusting for birthing parent educational level, age at delivery, child sex, prematurity, and neighborhood socioeconomic vulnerability. Models were estimated separately for early and middle childhood samples.

Results

Among 2103 children included, 1061 (50.5%) were male; 606 (29.1%) identified as Black, 1094 (52.5%) as White, 248 (11.9%) as multiple races, and 137 (6.6%) as other races. Outcomes were assessed at mean (SD) ages of 4.2 (0.6) years in 1469 children aged 2 to 5 years and 7.8 (1.6) years in 1173 children aged 6 to 11 years. Greater green space exposure was associated with fewer early childhood internalizing symptoms in fully adjusted models (b = -1.29; 95% CI, -1.62 to -0.97). No associations were observed between residential green space and internalizing or externalizing symptoms in middle childhood.

Conclusions and Relevance

In this study of residential green space and children's mental health, the association of green space with fewer internalizing symptoms was observed only in early childhood, suggesting a sensitive period for nature exposure. Policies protecting and promoting access to green space may help alleviate early mental health risk.

Green and blue space exposure and non-communicable disease related hospitalizations: A systematic review

The global increase in non-communicable diseases (NCDs) presents a critical public health concern. Emerging evidence suggests that exposure to natural environments may reduce the risk of developing NCDs through multiple pathways. The present systematic review aims to synthesize and evaluate the observational evidence regarding associations between exposure to green and blue spaces and hospital admissions related to NCDs. A comprehensive literature search strategy was conducted in Embase (Ovid), PubMed, and Web of Science. The risk of bias and quality of the evidence were assessed using The Navigation Guide methodology, an approach specifically designed for environmental health research. Of 3060 search results, 17 articles were included. Notably, the majority of the studies (n = 14; 82.4%) were published from 2020 onwards. Most studies were conducted in the United States (n = 6; 35.3%) and China (n = 4; 23.5%). Exposure to green spaces was assessed through all studies, while only three included blue spaces. In terms of study design, cohort design was employed in nearly half of the studies (n = 8; 47.1%), followed by case-crossover design (n = 3, 17.6%). Over 75% of the included studies (n = 13) had a high or probably high rating in the risk of bias assessment. The studies encompassed diverse NCD outcome domains; cardiovascular diseases (CVDs) (n = 10), respiratory diseases (RSDs) (n = 2), heat-related diseases (n = 1), metabolic diseases (n = 2), cancer (n = 1), neurodegenerative diseases (NDDs) (n = 2), and mental health disorders (n = 2). The present review suggests that a clear link between blue space exposure and NCD hospital admissions is not evident. However, exposure to green spaces appears to predominantly have a protective effect, although the direction of the association varies across different outcome domains. The heterogeneity among the outcome domains together with the limited number of studies, emphasizes the need for more robust evidence.

Evaluation of urinary limonene metabolites as biomarkers of exposure to greenness

Exposure to plants is known to improve physical and mental health and living in areas of high vegetation is associated with better health. The addition of quantitative measures of greenness exposure at individual-level to other objective and subjective study measures will help establish cause-and-effect relationships between greenspaces and human health. Because limonene is one of the most abundant biogenic volatile organic compounds emitted by plants, we hypothesized that urinary metabolites of inhaled limonene can serve as biomarkers of exposure to greenness. To test our hypothesis, we analyzed urine samples collected from eight human volunteers after limonene inhalation or after greenness exposure using liquid chromatography-high resolution mass spectrometry-based profiling. Eighteen isomers of nine metabolites were detected in urine after limonene inhalation, and their kinetic parameters were estimated using nonlinear mixed effect models. Urinary levels of most abundant limonene metabolites were elevated after brief exposure to a forested area, and the ratio of urinary limonene metabolites provided evidence of recent exposure. The identities and structures of these metabolites were validated using stable isotope tracing and tandem mass spectral comparison. Together, these data suggest that urinary metabolites of limonene, especially uroterpenol glucuronide and dihydroperillic acid glucuronide, could be used as individualized biomarkers of greenness exposure.

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.

Environmental microbiome in the home and daycare settings during the COVID-19 pandemic, and potential risk of non-communicable disease in children

An exposure to diverse microbial population early in life is important for the development of immunity against various non-communicable diseases including asthma, childhood leukaemia and other cancers. Social mixing in daycare settings helps with exposure to a variety of microbes. However, social isolation and a high emphasis on workplace hygiene during the COVID pandemic may have affected children's exposure to diverse microbiota. The structure of microbial communities and their role in developing immunity to various diseases are not well understood. In this study, we investigated the structure of microbial communities in daycare and home settings during the pandemic. Interestingly, microbial diversity was relatively higher in dust samples collected from homes, with human-associated taxa being more prevalent compared to those from daycare settings. Environmental microbes were more abundant in dust samples from daycare providers. These results potentially suggest that cleaning practices during the pandemic may have influenced the diversity and microbial abundance of the daycare samples. Several bacterial taxa detected in both the environments are known to induce anti-inflammatory and immunomodulatory responses, conferring protection from various diseases. Therefore, exposure to diverse microbial population in early childhood may play an important role in developing immunity against various non-communicable and infectious diseases.

Daily occupational exposure in swine farm alters human skin microbiota and antibiotic resistome

Antimicrobial resistance (AMR) is a major threat to global public health, and antibiotic resistance genes (ARGs) are widely distributed across humans, animals, and environment. Farming environments are emerging as a key research area for ARGs and antibiotic resistant bacteria (ARB). While the skin is an important reservoir of ARGs and ARB, transmission mechanisms between farming environments and human skin remain unclear. Previous studies confirmed that swine farm environmental exposures alter skin microbiome, but the timeline of these changes is ill defined. To improve understanding of these changes and to determine the specific time, we designed a cohort study of swine farm workers and students through collected skin and environmental samples to explore the impact of daily occupational exposure in swine farm on human skin microbiome. Results indicated that exposure to livestock-associated environments where microorganisms are richer than school environment can reshape the human skin microbiome and antibiotic resistome. Exposure of 5 h was sufficient to modify the microbiome and ARG structure in workers' skin by enriching microorganisms and ARGs. These changes were preserved once formed. Further analysis indicated that ARGs carried by host microorganisms may transfer between the environment with workers' skin and have the potential to expand to the general population using farm workers as an ARG vector. These results raised concerns about potential transmission of ARGs to the broader community. Therefore, it is necessary to take corresponding intervention measures in the production process to reduce the possibility of ARGs and ARB transmission.

Alterations in nasal microbiota of patients with amyotrophic lateral sclerosis

BACKGROUND

Links between alterations in gut microbiota composition and amyotrophic lateral sclerosis (ALS) have previously been reported. This study aimed to examine the microbiota in the nasal cavity of ALS.

METHODS

Sixty-six ALS patients and 40 healthy caregivers who live in close proximity with patients were enrolled. High throughput metagenomic sequencing of the 16S ribosomal deoxyribonucleic acid (rDNA) gene V3-V4 region of nasal microbiota was used to characterize the alpha and beta diversity and relative abundance of bacterial taxa, predict function, and conduct correlation analysis between specific taxa and clinical features.

RESULTS

The nasal microbiome of ALS patients showed lower alpha diversity than that of corresponding healthy family members. Genera Gaiella , Sphingomonas , Polaribacter _1, Lachnospiraceae _NK4A136_group, Klebsiella , and Alistipes were differentially enriched in ALS patients compared to controls. Nasal microbiota composition in ALS patients significantly differed from that in healthy subjects (unweighted UniFrac P = 0.001), while Linear discriminant analysis Effect Size (LEfSe) analysis indicated that Bacteroidetes and Firmicutes dominated healthy nasal communities at the phylum level, whereas Actinobacteria was the predominant phylum and Thermoleophilia was the predominant class in ALS patients. Genus Faecalibacterium and Alistipes were positively correlated with ALS functional rating scale revised (ALSFRS-R; rs = 0.349, P = 0.020 and rs = 0.393, P = 0.008), while Prevotella -9 and Bacteroides operational taxonomic units (OTUs) were positively associated with lung function (FVC) in ALS patients ( rs = 0.304, P = 0.045, and rs = 0.300, P = 0.048, respectively). Prevotella -1 was positively correlated with white blood cell counts (WBC, rs = 0.347, P = 0.021), neutrophil percentage (Neu%, rs = 0.428, P = 0.004), and neutrophil-to-lymphocyte ratio (NLR, rs = 0.411, P = 0.006), but negatively correlated with lymphocyte percentage (Lym%, rs = -0.408, P = 0.006). In contrast, Streptococcus was negatively associated with Neu% ( rs = -0.445, P = 0.003) and NLR ( rs = -0.436, P = 0.003), while positively associated with Lym% ( rs = 0.437, P = 0.003). No significant differences in nasal microbiota richness and evenness were detected among the severe and mild ALS patients.

CONCLUSIONS

ALS is accompanied by altered nasal microbial community composition and diversity. The findings presented here highlight the need to understand how dysbiosis of nasal microbiota may contribute to the development of ALS.

Quality criteria of nature-based interventions in healthcare facilities: a scoping review

Introduction

Implementing integrated nature-based interventions that simultaneously serve human health and the restoration of biodiversity in healthcare facilities is considered a promising strategy. As an emerging field of research and practice in healthcare, identification of quality criteria is necessary to support desired outcomes related to biodiversity, human health and intervention processes. This study is part of a larger research project in collaboration with the Flemish Agency of Nature and Forest in Belgium.

Methods

A scoping review was conducted in accordance with the Joanna Briggs Institute methodology for scoping reviews, in PubMed, Medline, Web of Science and Scopus. A step-by-step tabular screening process was conducted to identify relevant studies and reviews of nature-based interventions, published in English between January 2005 and April 2023. A qualitative content analysis was conducted and the results were then presented to the project steering group and a panel of stakeholders for refinement.

Results

After filtering on the eligibility criteria, and with focus on healthcare facilities, 14 articles were included in this study. A preliminary nature-based interventions quality framework with a set of quality indicators has been developed.

Discussion

When designing integrated nature-based interventions, a needs analysis of users and the outdoor environment should be conducted. Next, the integration of a One Health and biodiversity perspective and the application of a complex intervention framework, could support the quality of the design and implementation of nature-based interventions in healthcare facilities and facilitate their assessment. In future work, more rigorous research into the design and implementation of integrated nature-based interventions is needed to test and refine the quality criteria in practice.

A review of factors influencing sensitive skin: an emphasis on built environment characteristics

Background

Sensitive skin (SS) is a condition characterized by hyperreactivity. Impacting around 37 percent of the worldwide population and exerting an influence on the quality of life for affected individuals. Its prevalence rate has increased due to factors such as elevating stress levels and deteriorating environmental conditions. The exposome factors influencing SS have extended from demographic, biological attributes, and lifestyle to external environments. Built environments (BEs) have demonstrated as root drivers for changes in behaviors and environmental exposure which have the potential to trigger SS, but the review of the associations between BEs and SS is currently lacking.

Objective

This review aims to achieve two primary objectives: (1) Examine exposome factors that exert influence on SS at the individual and environmental levels. (2) Develop a theoretical framework that establishes a connection between BEs and SS, thereby offering valuable insights into the impact of the built environment on this condition.

Methods

An extensive literature search was carried out across multiple fields, including sociology, epidemiology, basic medicine, clinical medicine, and environmental research, with a focus on SS. To identify pertinent references, renowned databases such as PubMed, Web of Science, and CNKI were utilized.

Results

SS is the outcome of interactions between individual attributes and environmental factors. These influencing factors can be categorized into five distinct classes: (1) demographic and socioeconomic characteristics including age, gender, and race; (2) physiological and biological attributes such as emotional changes, skin types, sleep disorders, and menstrual cycles in women; (3) behavioral factors, such as spicy diet, cosmetic use, alcohol consumption, and physical exercise; (4) natural environmental features, including climate conditions and air pollution; (5) built environmental features such as population density, green space availability, road network density, and access to public transportation, also have the potential to affect the condition.

Conclusion

The importance of interdisciplinary integration lies in its ability to ascertain whether and how BEs are impacting SS. By elucidating the role of BEs in conjunction with other factors in the onset of SS, we can provide guidance for future research endeavors and the formulation of interventions aimed at mitigating the prevalence of SS.

Current methods for evaluating people's exposure to green space: A scoping review

People's exposure to green space is a critical link between urban green space and urban residents' health. Since green space may affect human health through multiple pathways regarding diverse human health outcomes, the measurement of people's exposure to green space must be tailored to concrete study contexts and research questions. In this scoping review, we systematically categorized the available green space representations and metrics in the last two decades that can be used to derive people's exposure to green space regarding different research topics. A three-phase systematic review was conducted after a generalized search of relevant research articles from the three most-used publication databases, namely Scopus, the Web of Science, and PubMed. We identified 260 research articles that particularly discuss green space representations and metrics. We further developed a multi-pathway framework to articulate the complicated context issues in green space studies. We categorized the most relevant green space representations and metrics into five groups, including green space indices, the delineation, inventory, and usage of green space, the spatiotemporal evolution of green space, the attributes and components of green space, and the green space landscape and fragmentation. Finally, we discussed the inter-conversion between different green space representations and metrics, the "mobility-turn" in green space studies and how it may affect the derivation of people's exposure to green space, and other potential methodological issues in measuring people's exposure to green space. Our scoping review provides the most comprehensive framework and categories for deriving people's exposure to green space to date, which may strongly support a broad range of studies that concern green space's health effects.

The association between greenery type and gut microbiome in schizophrenia: did all greenspaces play the equivalent role?

In recent years, attention has been focused on the benefit of greenspace on mental health, and it is suggested this link may vary with the type of greenspace. More and more studies have emphasized the influence of the gut microbiome on schizophrenia (SCZ). However, the effects of greenspaces on the gut microbiota in SCZ and the effect of different types of greenspaces on the gut microbiota remain unclear. We aim to examine if there were variations in the effects of various greenspace types on the gut microbiome in SCZ. Besides, we sink to explore important taxonomic compositions associated with different greenspace types. We recruited 243 objects with schizophrenia from Anhui Mental Health Center and collected fecal samples for 16Sr RNA gene sequencing. Three types of greenery coverage were calculated with different circular buffers (800, 1500, and 3000 m) corresponding to individual addresses. The association between greenspace and microbiome composition was analyzed with permutational analysis of variance (PERMANOVA). We conducted the linear regression to capture specific gut microbiome taxa associated with greenery coverage. Tree coverage was consistently associated with microbial composition in both 1500 m (R2 = 0.007, P = 0.030) and 3000 m (R2 = 0.007, P = 0.039). In contrast, there was no association with grass cover in any of the buffer zones. In the regression analysis, higher tree coverage was significantly correlated with the relative abundance of several taxa. Among them, tree coverage was positively associated with increased Bifidobacterium longum (β = 1.069, P = 0.004), which was the dominant composition in the gut microbiota. The relationship between greenspace and gut microbiome in SCZ differed by the type of greenspace. Besides, "tree coverage" may present a dominant effect on the important taxonomic composition. Our findings might provide instructive evidence for the design of urban greenspace to optimize health and well-being in SCZ as well as the whole people.

Association between Residential Greenness and Human Microbiota: Evidence from Multiple Countries

BACKGROUND

Greenness, referring to a measurement of the density of vegetated land (e.g., gardens, parks, grasslands), has been linked with many human health outcomes. However, the evidence on greenness exposure and human microbiota remains limited, inconclusive, drawn from specific regions, and based on only modest sample size.

OBJECTIVES

We aimed to study the association between greenness exposure and human microbial diversity and composition in a large sample across 34 countries and regions.

METHODS

We explored associations between residential greenness and human microbial alpha-diversity, composition, and genus abundance using data from 34 countries. Greenness exposure was assessed using the normalized difference vegetation index and the enhanced vegetation index mean values in the month before sampling. We used linear regression models to estimate the association between greenness and microbial alpha-diversity and tested the effect modification of age, sex, climate zone, and pet ownership of participants. Differences in microbial composition were tested by permutational multivariate analysis of variance based on Bray-Curtis distance and differential taxa were detected using the DESeq2 R package between two greenness exposure groups split by median values of greenness.

RESULTS

We found that higher greenness was significantly associated with greater richness levels in the palm and gut microbiota but decreased evenness in the gut microbiota. Pet ownership and climate zone modified some associations between greenness and alpha-diversity. Palm and gut microbial composition at the genus level also varied by greenness. Higher abundances of the genera Lactobacillus and Bifidobacterium, and lower abundances of the genera Anaerotruncus and Streptococcus, were observed in people with higher greenness levels.

DISCUSSION

These findings suggest that residential greenness was associated with microbial richness and composition in the human skin and gut samples, collected across different geographic contexts. Future studies may validate the observed associations and determine whether they correspond to improvements in human health. https://doi.org/10.1289/EHP12186.

Mechanism and implications of pro-nature physical activity in antagonizing psychological stress: the key role of microbial-gut-brain axis

Appropriate physical activities and a biodiversity-rich environment are conducive to the relief of psychological stress, and pro-nature physical activities are a combination of the two, which has good application potential in antagonizing psychological stress, but the intervention mechanism is still unclear. The microbiota-gut-brain axis is cyclically associated with psychological stress, and psychological stress can affect the microbiota through the gut-brain pathway, and conversely, the microbiota can also affect the psychological stress-induced symptoms. It is suggested that the microbe-gut-brain axis may provide a new perspective and target for the treatment of psychological stress-related diseases. Pro-nature physical activity can improve the number of Firmicutes, short-chain fatty acids, Akkermansia bacteria, and the gut-brain barrier and further affect the HPA axis, BDNF, and serotonin pathways of gut-brain two-way communication, thereby maintaining the body's homeostasis and reducing antagonistic psychological stress. According to the comprehensive influence of physical activities on the microbiota-gut-brain axis, a "green + exercise prescription hypothesis" in line with the holistic medical concept is revealed, which is expected to be effective in the prevention, alleviation, and treatment of irritable bowel syndrome and neurodegenerative diseases. It provides new means for treating psychological stress-related diseases such as mental disorders and mood disorders. In addition, it enlightens the construction of green infrastructure that is conducive to the diversified contact of microorganisms in outdoor physical activities venues and induces healthy interaction between the human body and the microbial population in the natural ecology. However, the current research is still in its early stages, and the intervention effect and mechanism of pro-nature physical activities need further demonstration in the future.

The Gut Microbiome and Residential Surrounding Greenness: a Systematic Review of Epidemiological Evidence

PURPOSE OF REVIEW

A healthy indigenous intestinal microbiome is essential for human health. Well-established gut microbiome determinants only explain 16% of the inter-individual variation in gut microbiome composition. Recent studies have focused on green space as a potential determinant of the intestinal microbiome. We systematically summarize all evidence concerning the association between green space and intestinal bacterial diversity, evenness, and richness indices, specific bacterial taxa, and potential underlying mechanisms.

RECENT FINDINGS

Seven epidemiological studies were included in this review. The majority of the included studies (n = 4) reported a positive association between green space and intestinal bacterial diversity, evenness, and richness, while two reported the opposite. There was little overlap between the publications regarding the association between green space and the relative abundance of specific bacterial taxa. Only a decrease in the relative abundance of Bacteroidetes, Bacteroides, and Anaerostipes and an increase in Lachnospiraceae and Ruminococcaceae were reported in multiple studies, predominantly suggesting that green space is positively associated with the intestinal microbiome composition, and subsequently with human health. Lastly, the only examined mechanism was a reduction in perceived psychosocial stress. Mechanisms indicated in blue and white represent tested or hypothesized mechanisms, respectively. The graphical abstract was created with illustrations from BioRender, Noun Project, and Pngtree.

Air pollution-associated shifts in the human airway microbiome and exposure-associated molecular events

Publications addressing air pollution-induced human respiratory microbiome shifts are reviewed in this article. The healthy respiratory microbiota is characterized by a low density of bacteria, fungi and viruses with high diversity, and usually consists of Bacteroidetes, Firmicutes, Proteobacteria, Actinobacteria, Fusobacteria, viruses and fungi. The air's microbiome is highly dependent on air pollution levels and is directly reflected within the human respiratory microbiome. In addition, pollutants indirectly modify the local environment in human respiratory organs by reducing antioxidant capacity, misbalancing proteolysis and modulating inflammation, all of which regulate local microbiomes. Improving air quality leads to more diverse and healthy microbiomes of the local air and, subsequently, residents' airways.

Diversity and compositional differences of the airborne microbiome in a biophilic indoor environment

Biophilic design based on indoor planting plays an important role in human physical and mental well-being. To investigate and assess the effects of indoor planting on air quality, we sequenced 16S rRNA gene amplicons to compare the airborne bacterial microbiomes of three planting rooms before and after installing natural materials (plants, soil, water, etc.) with distinct biophilic attributes. Incorporation of indoor plantings significantly increased the taxonomic diversity of the airborne microbiome in each room, and we observed different microbiome compositions in each room. The proportional contribution of each bacterial source to the airborne microbiome in the indoor planting rooms was estimated by SourceTracker2. This analysis revealed that the proportion of airborne microbial sources (e.g., plants and soil) varied depending on the natural materials installed. Our results have important implications for indoor planting with biophilic design to control the indoor airborne microbiome.

Birch pollen-The unpleasant herald of spring

Type I respiratory allergies to birch pollen and pollen from related trees of the order Fagales are increasing in industrialized countries, especially in the temperate zone of the Northern hemisphere, but the reasons for this increase are still debated and seem to be multifaceted. While the most important allergenic molecules of birch pollen have been identified and characterized, the contribution of other pollen components, such as lipids, non-allergenic immunomodulatory proteins, or the pollen microbiome, to the development of allergic reactions are sparsely known. Furthermore, what also needs to be considered is that pollen is exposed to external influences which can alter its allergenicity. These external influences include environmental factors such as gaseous pollutants like ozone or nitrogen oxides or particulate air pollutants, but also meteorological events like changes in temperature, humidity, or precipitation. In this review, we look at the birch pollen from different angles and summarize current knowledge on internal and external influences that have an impact on the allergenicity of birch pollen and its interactions with the epithelial barrier. We focus on epithelial cells since these cells are the first line of defense in respiratory disease and are increasingly considered to be a regulatory tissue for the protection against the development of respiratory allergies.

Residential green space improves cognitive performances in primary schoolchildren independent of traffic-related air pollution exposure

BACKGROUND

Cognitive performances of schoolchildren have been adversely associated with both recent and chronic exposure to ambient air pollution at the residence. In addition, growing evidence indicates that exposure to green space is associated with a wide range of health benefits. Therefore, we aimed to investigate if surrounding green space at the residence improves cognitive performance of primary schoolchildren while taking into account air pollution exposure.

METHODS

Cognitive performance tests were administered repeatedly to a total of 307 primary schoolchildren aged 9-12y, living in Flanders, Belgium (2012-2014). These tests covered three cognitive domains: attention (Stroop and Continuous Performance Tests), short-term memory (Digit Span Forward and Backward Tests), and visual information processing speed (Digit-Symbol and Pattern Comparison Tests). Green space exposure was estimated within several radii around their current residence (50 m to 2000 m), using a aerial photo-derived high-resolution (1 m²) land cover map. Furthermore, air pollution exposure to PM_2.5 and NO₂ during the year before examination was modelled for the child's residence using a spatial-temporal interpolation method.

RESULTS

An improvement of the children's attention was found with more residential green space exposure independent of traffic-related air pollution. For an interquartile range increment (21%) of green space within 100 m of the residence, a significantly lower mean reaction time was observed independent of NO₂ for both the sustained-selective (-9.74 ms, 95% CI: -16.6 to -2.9 ms, p = 0.006) and the selective attention outcomes (-65.90 ms, 95% CI: -117.0 to -14.8 ms, p = 0.01). Moreover, green space exposure within a large radius (2000 m) around the residence was significantly associated with a better performance in short-term memory (Digit-Span Forward Test) and a higher visual information processing speed (Pattern Comparison Test), taking into account traffic-related exposure. However, all associations were attenuated after taking into account long-term residential PM_2.5 exposure.

CONCLUSIONS

Our panel study showed that exposure to residential surrounding green space was associated with better cognitive performances at 9-12 years of age, taking into account traffic-related air pollution exposure. These findings support the necessity to build attractive green spaces in the residential environment to promote healthy cognitive development in children.

Which soil microbiome? Bacteria, fungi, and protozoa communities show different relationships with urban green space type and use-intensity

Exposure to diverse microbial communities early in life can help support healthy human immune function. Soil microbiomes in public and private urban green spaces are potentially important sources of contact with diverse microbiomes for much of the global population. However, we lack understanding of how soil microbial communities vary across and within urban green spaces, and whether these patterns vary across microbial kingdoms; closing this knowledge gap may help us optimise green spaces' capacities to provide this ecosystem service. Here we explore the diversity and community compositions of soil microbiomes across urban green space types in Tasmania, Australia. Specifically, we analysed soil bacterial, fungal, and protozoan diversity and composition across private backyards and public parks. Within parks, we conducted separate sampling for areas of high and low intensity use. We found that: (i) bacteria, fungi, and protozoa showed different patterns of variation, (ii) bacterial alpha-diversity was lowest in low-intensity use areas of parks, (iii) there was relatively little variation in the community composition across backyards, and high and low intensity-use park areas and (iv) neither human-associated bacteria, nor potential microbial community function of bacteria and fungi differed significantly across green space types. To our knowledge, this is the first urban soil microbiome analysis which analyses these three soil microbial kingdoms simultaneously across public and private green space types and within public spaces according to intensity of use. These findings demonstrate how green space type and use intensity may impact on soil microbial diversity and composition, and thus may influence our opportunity to gain healthy exposure to diverse environmental microbiomes.

Variable preterm oral microbiome stabilizes and reflects a full-term infant profile within three months

BACKGROUND

Preterm infants suffer higher morbidity and mortality rates compared to full-term infants, but little is known about how changes to oral and respiratory tract microbiota may impact disease development.

METHODS

Here, very preterm neonates (n = 50) were selected to study oral and respiratory microbiota development during the first few months post-birth, where 26 individuals were diagnosed with BPD and/or sepsis. These infants were compared to 14 healthy full-term infants and 16 adults. Microbiota diversity, composition, and species abundances were calculated from 16S ribosomal RNA gene sequences in buccal swabs and tracheal aspirates at two time points (within a week and 1-3 months post-birth).

RESULTS

Collection time point was the biggest factor to significantly influence the preterm oral microbial diversity and composition. In addition, BPD and sepsis were linked to distinct preterm oral microbiota diversity and composition, and opportunistic pathogens previously associated with these diseases were identified in the initial sample for both healthy preterm neonates and those with the disease. Compared to the full-term infant and adult dataset, preterm infant diversity and composition was initially significantly different, but resembled full-term infant diversity and composition over time.

CONCLUSION

Overall, consequences of microbiota development need further examination in preterm infant infections and later development.

IMPACT

Non-gut microbiota research on preterm infants is limited. At one week post-birth, preterm infants harbor distinct oral microbiota that are not shared with full-term children or adults, eventually becoming similar to full-term infants at 36 weeks postmenstrual age. DNA from potential opportunistic pathogens was observed in the mouth and lungs of preterm infants within a week of birth, and microbes associated with BPD were identified in the lungs. Oral microbiota in preterm infants over the first 2-3 months is unique and may be connected to short- and long-term health outcomes in these children.

Environmental justice and allergic disease: A Work Group Report of the AAAAI Environmental Exposure and Respiratory Health Committee and the Diversity, Equity and Inclusion Committee

Environmental justice is the concept that all people have the right to live in a healthy environment, to be protected against environmental hazards, and to participate in decisions affecting their communities. Communities of color and low-income populations live, work, and play in environments with disproportionate exposure to hazards associated with allergic disease. This unequal distribution of hazards has contributed to health disparities and is largely the result of systemic racism that promotes segregation of neighborhoods, disinvestment in predominantly racial/ethnic minority neighborhoods, and discriminatory housing, employment, and lending practices. The AAAAI Environmental Exposure and Respiratory Health Committee and Diversity, Equity and Inclusion Committee jointly developed this report to improve allergy/immunology specialists' awareness of environmental injustice, its roots in systemic racism, and its impact on health disparities in allergic disease. We present evidence supporting the relationship between exposure to environmental hazards, particularly at the neighborhood level, and the disproportionately high incidence and poor outcomes from allergic diseases in marginalized populations. Achieving environmental justice requires investment in at-risk communities to increase access to safe housing, clean air and water, employment opportunities, education, nutrition, and health care. Through policies that promote environmental justice, we can achieve greater health equity in allergic disease.

Indigenous Knowledge and the Microbiome-Bridging the Disconnect between Colonized Places, Peoples, and the Unseen Influences That Shape Our Health and Well-Being

Indigenous Peoples have a rich and long-standing connection with the environments that they descend from-a connection that has informed a deep and multifaceted understanding of the relationship between human well-being and the environment. Through cultural narratives and practices, much of this knowledge has endured despite the ongoing effects that colonization has had on many Indigenous peoples across the world. These narratives and practices, based on observation, experimentation, and practical application over many generations, have the potential to make compelling contributions to our understanding of the environmental microbiome and its relationship to health. Furthermore, the inclusion of Indigenous perspectives regarding the microbiome opens pathways to those who rarely engage with the field and its learnings. Within the scientific community, Indigenous perspectives have not always been acknowledged as valid contributions and are often seen as myth or lacking rigor. Thus, this paper aims to explore an Indigenous perspective of the microbiome as an unseen influence on health and well-being by framing the importance of the natural environment, Indigenous knowledge and leadership, and future research directions that can contribute to this domain. Although the Indigenous perspective in this article reflects the experiences, worldviews, and knowledge of two New Zealand Māori authors, it is hoped that the concepts discussed can relate to Indigenous peoples, and non-Indigenous advocates, globally.

Composition of Culturable Microorganisms in Dusts Collected from Sport Facilities in Finland during the COVID-19 Pandemic

Sport facilities represent extreme indoor environments due to intense cleaning and disinfection. The aim of this study was to describe the composition of the cultivated microbiota in dust samples collected in sport facilities during the COVID-19 pandemic. A dust sample is defined as the airborne dust sedimented on 0.02 m² within 28 d. The results show that the microbial viable counts in samples of airborne dust (n = 9) collected from seven Finnish sport facilities during the pandemic contained a high proportion of pathogenic filamentous fungi and a low proportion of bacteria. The microbial viable counts were between 14 CFU and 189 CFU per dust sample. In seven samples from sport facilities, 20-85% of the microbial viable counts were fungi. Out of 123 fungal colonies, 47 colonies belonged to the potentially pathogenic sections of Aspergillus (Sections Fumigati, Nigri, and Flavi). Representatives of each section were identified as Aspergillus fumigatus, A. flavus, A. niger and A. tubingensis. Six colonies belonged to the genus Paecilomyces. In six samples of dust, a high proportion (50-100%) of the total fungal viable counts consisted of these potentially pathogenic fungi. A total of 70 isolates were considered less likely to be pathogenic, and were identified as Aspergillus section Nidulantes, Chaetomium cochliodes and Penicillium sp. In the rural (n = 2) and urban (n = 7) control dust samples, the microbial viable counts were >2000 CFU and between 44 CFU and 215 CFU, respectively, and consisted mainly of bacteria. The low proportion of bacteria and the high proportion of stress tolerant, potentially pathogenic fungi in the dust samples from sport facilities may reflect the influence of disinfection on microbial communities.

Residential greenness and air pollution's association with nasal microbiota among asthmatic children

Both greenness and air pollution have widely been linked with asthma. However, the potential mechanism has rarely been investigated. This study aimed to identify the association between residential greenness and air pollution (fine particulate matter [PM_2.5]; nitrogen dioxide [NO₂]; ozone [O₃]) with nasal microbiota among asthmatic children during the recovery phase. The normalized difference vegetation index was used to assess the extent of residential greenness. Spatiotemporal air pollution variation was estimated using an integrated hybrid kriging-LUR with the XG-Boost algorithm. These exposures were measured in 250-m intervals for four incremental buffer ranges. Nasal microbiota was collected from 47 children during the recovery phase. A generalized additive model controlled for various covariates was applied to evaluate the exposure-outcome association. The lag-time effect of greenness and air pollution related to the nasal microbiota also was examined. A significant negative association was observed between short-term exposure to air pollution and nasal bacterial diversity, as a one-unit increment in PM_2.5 or O₃ significantly decreased the observed species (PM_2.5: -0.59, 95%CI -1.13, -0.05 and O₃: -0.93, 95%CI -1.54, -0.32) and species richness (PM_2.5: -0.64, 95%CI -1.25, -0.02 and O₃: -0.68, 95%CI -1.43, -0.07). Considering the lag-time effect, we found a significant positive association between greenness and both the observed species and species richness. In addition, we identified a significant negative association for all pollutants with the observed species richness. These findings add to the evidence base of the links between nasal microbiota and air pollution and greenness. This study establishes a foundation for future studies of how environmental exposure plays a role in nasal microbiota, which in turn may affect the development of asthma.

Presence of Gram-negative bacteria and Staphylococcus aureus on the skin of blood donors in the Democratic Republic of the Congo

BACKGROUND

Skin bacteria may contaminate blood products but few data are available on sub-Saharan Africa (sSA). We assessed the presence of Gram-negative bacteria and Staphylococcus aureus on blood donor skin and evaluated skin antisepsis in the Democratic Republic of the Congo (DRC).

STUDY DESIGN AND METHODS

Among blood donors at the National Blood Transfusion Center (NBTC) and at a rural hospital, the antecubital fossa skin of the non-disinfected arm (not used for blood collection) was swabbed (25cm² surface) and cultured for total and Gram-negative bacterial counts. Bacteria were identified with MALDI-TOF and tested for antibiotic susceptibility by disk diffusion. For evaluation of the NBTC antisepsis procedure (i.e., ethanol 70%), the culture results of the disinfected arm (used for blood collection) were compared with those of the non-disinfected arm.

RESULTS

Median total bacterial counts on 161 studied non-disinfected arms were 1065 Colony-Forming Units (CFU) per 25 cm² , with 43.8% (70/160) of blood donors growing Gram-negative bacteria and 3.8% (6/159) Staphylococcus aureus (2/6 methicillin-resistant). Non-fermentative Gram-negative rods predominated (74/93 isolates, majority Pseudomonas spp., Acinetobacter spp.). Enterobacterales comprised 19/93 isolates (mostly Pantoea spp. and Enterobacter spp.), 5/19 were multidrug-resistant. In only two cases (1.9%, 2/108) the NBTC antisepsis procedure met the acceptance criterion of ≤2 CFU/25 cm² .

CONCLUSION

Skin bacterial counts and species among blood donors in DRC were similar to previously studied Caucasian populations, including cold-tolerating species and bacteria previously described in transfusion reactions. Prevention of contamination (e.g., antisepsis) needs further evaluation and customization to sSA.

COVID-19: Reducing the risk via diet and lifestyle

This review shows that relatively simple changes to diet and lifestyle can significantly, and rapidly, reduce the risks associated with coronavirus disease 2019 (COVID-19) in terms of infection risk, severity of disease, and even disease-related mortality. A wide range of interventions including regular exercise, adequate sleep, plant-based diets, maintenance of healthy weight, dietary supplementation, and time in nature have each been shown to have beneficial effects for supporting more positive health outcomes with COVID-19, in addition to promoting better overall health. This paper brings together literature from these areas and presents the argument that non-pharmaceutical approaches should not be overlooked in our response to COVID-19. It is noted that, in several cases, interventions discussed result in risk reductions equivalent to, or even greater than, those associated with currently available vaccines. Where the balance of evidence suggests benefits, and the risk is minimal to none, it is suggested that communicating the power of individual actions to the public becomes morally imperative. Further, many lives could be saved, and many harms from the vaccine mandates avoided, if we were willing to embrace this lifestyle-centred approach in our efforts to deal with COVID-19.

Temporary establishment of bacteria from indoor plant leaves and soil on human skin

BACKGROUND

Plants are found in a large percentage of indoor environments, yet the potential for bacteria associated with indoor plant leaves and soil to colonize human skin remains unclear. We report results of experiments in a controlled climate chamber to characterize bacterial communities inhabiting the substrates and leaves of five indoor plant species, and quantify microbial transfer dynamics and residence times on human skin following simulated touch contact events. Controlled bacterial propagule transfer events with soil and leaf donors were applied to the arms of human occupants and repeatedly measured over a 24-h period using 16S rRNA gene amplicon sequencing.

RESULTS

Substrate samples had greater biomass and alpha diversity compared to leaves and baseline skin bacterial communities, as well as dissimilar taxonomic compositions. Despite these differences in donor community diversity and biomass, we observed repeatable patterns in the dynamics of transfer events. Recipient human skin bacterial communities increased in alpha diversity and became more similar to donor communities, an effect which, for soil contact only, persisted for at least 24 h. Washing with soap and water effectively returned communities to their pre-perturbed state, although some abundant soil taxa resisted removal through washing.

CONCLUSIONS

This study represents an initial characterization of bacterial relationships between humans and indoor plants, which represent a potentially valuable element of biodiversity in the built environment. Although environmental microbiota are unlikely to permanently colonize skin following a single contact event, repeated or continuous exposures to indoor biodiversity may be increasingly relevant for the functioning and diversity of the human microbiome as urbanization continues.

Gut and lung microbiome profiles in pregnant mice

In recent years, microbiome research has expanded from the gastrointestinal tract to other host sites previously thought to be abacterial such as the lungs. Yet, the effects of pregnancy in the lung and gut microbiome remains unclear. Here we examined the changes in the gut and lung microbiome in mice at 14 days of gestation. Lung tissue and stool samples were collected from pregnant and non-pregnant female BALB/c mice, DNA was isolated, amplified, and bacterial specific V4 16S rRNA gene was sequenced. Using an in-house bioinformatic pipeline we assessed the microbial composition of each organ using stool and lung tissue samples. The stool data showed that Lachnospiraceae and Lactobacillaceae were more abundant in the pregnant mice. Likewise, Lactobacillaceae were dominant in the lungs of pregnant mice. However, Streptococcaceae were dominant in the lungs of non-pregnant mice with a low microbial abundance in the pregnant mice. A permutation test showed that pregnancy significantly contributes to the variance in both the lung and stool microbiome. At the same time, we estimate that 49% of the total detected operational taxonomic units were shared between the stool and lung data. After removing common stool-associated bacteria from the lung dataset, no microbial differential abundance was detected between the pregnant and non-pregnant lung microbial community. Thus, pregnancy contributes to variance to the lung and stool microbiome but not in the unique lung microbiota.