Airborne fungal communities are more susceptible to anthropogenic activities than bacteria.

Airborne microorganisms (AM) have significant environmental and health implications. Extensive studies have been conducted to investigate the factors influencing the composition and diversity of AM. However, the knowledge of AM with anthropogenic activities has not reach a consensus. In this study, we took advantage of the dramatic decline of outdoor anthropogenic activities resulting from COVID-19 lockdown to reveal their associations. We collected airborne particulate matter before and during the lockdown period in two cities. The results showed that it was fungal diversity and communities but not bacteria obviously different between pre-lockdown and lockdown samples, suggesting that airborne fungi were more susceptible to anthropogenic activities than bacteria. However, after the implementation of lockdown, the co-occurrence networks of both bacterial and fungal community became more complex, which might be due to the variation of microbial sources. Furthermore, Mantel test and correlation analysis showed that air pollutants also partly contributed to microbial alterations. Airborne fungal community was more affected by air pollutants than bacterial community. Notably, some human pathogens like Nigrospora and Arthrinium were negatively correlated with air pollutants. Overall, our study highlighted the more impacts of anthropogenic activities on airborne fungal community than bacterial community and advanced the understanding of associations between anthropogenic activities and AM.

Hunting for a viral proxy in bioaerosols of swine buildings using molecular detection and metagenomics.

There are limited biosecurity measures directed at preventing airborne transmission of viruses in swine. The effectiveness of dust mitigation strategies such as oil sprinkling, to decrease risk of airborne virus transmission are unknown. Metagenomics and qPCR for common fecal viruses were used to hunt for a ubiquitous virus to serve as a proxy when evaluating the efficiency of mitigation strategies against airborne viral infectious agents. Air particles were collected from swine buildings using high-volume air samplers. Extracted DNA and RNA were used to perform specific RT-qPCR and qPCR and analyzed by high-throughput sequencing. Porcine astroviruses group 2 were common (from 102 to 105 genomic copies per cubic meter of air or gc/m3, 93% positivity) while no norovirus genogroup II was recovered from air samples. Porcine torque teno sus virus were detected by qPCR in low concentrations (from 101 to 102 gc/m3, 47% positivity). Among the identified viral families by metagenomics analysis, Herelleviridae, Microviridae, Myoviridae, Podoviridae, and Siphoviridae were dominant. The phage vB_AviM_AVP of Aerococcus was present in all air samples and a newly designed qPCR revealed between 101 and 105 gc/m3 among the samples taken for the present study (97% positivity) and banked samples from 5- and 15-year old studies (89% positivity). According to the present study, both the porcine astrovirus group 2 and the phage vB_AviM_AVP of Aerococcus could be proxy for airborne viruses of swine buildings.

Sampling and analysis methods of air-borne microorganisms in hospital air: a review.

Pathogenic microorganisms can spread in the air as bioaerosols. When the human body is exposed to different bioaerosols, various infectious diseases may occur. As indoor diagnosis and treatment environments, hospitals are relatively closed and have a large flow rate of people. This indoor environment contains complex aerosol components; therefore, effective sampling and detection of microbial elements are essential in airborne pathogen monitoring. This article reviews the sampling and detection of different kinds of microorganisms in bioaerosols from indoor diagnostic and therapeutic settings, with a particular focus on microbial activity. This provides deeper insights into bioaerosols in diagnostic and therapeutic settings.

[Box: see text].

Predicting how varying moisture conditions impact the microbiome of dust collected from the International Space Station.

BACKGROUND: The commercialization of space travel will soon lead to many more people living and working in unique built environments similar to the International Space Station, which is a specialized closed environment that contains its own indoor microbiome. Unintended microbial growth can occur in these environments as in buildings on Earth from elevated moisture, such as from a temporary ventilation system failure. This growth can drive negative health outcomes and degrade building materials. We need a predictive approach for modeling microbial growth in these critical indoor spaces. RESULTS: Here, we demonstrate that even short exposures to varying elevated relative humidity can facilitate rapid microbial growth and microbial community composition changes in dust from spacecraft. We modeled fungal growth in dust from the International Space Station using the time-of-wetness framework with activation and deactivation limited growth occurring at 85% and 100% relative humidity, respectively. Fungal concentrations ranged from an average of 4.4 × 106 spore equivalents per milligram of dust in original dust with no exposure to relative humidity to up to 2.1 × 1010 when exposed to 100% relative humidity for 2 weeks. As relative humidity and time-elevated increased, fungal diversity was significantly reduced for both alpha (Q < 0.05) and beta (R2 = 0.307, P = 0.001) diversity metrics. Bacteria were unable to be modeled using the time-of-wetness framework. However, bacterial communities did change based on constant relative humidity incubations for both beta (R2 = 0.22, P = 0.001) and alpha diversity decreasing with increasing moisture starting at 85% relative humidity (Q < 0.05). CONCLUSION: Our results demonstrate that moisture conditions can be used to develop and predict changes in fungal growth and composition onboard human-occupied spacecraft. This predictive model can be expanded upon to include other spacecraft environmental factors such as microgravity, elevated carbon dioxide conditions, and radiation exposure. Understanding microbial growth in spacecraft can help better protect astronaut health, fortify spacecraft integrity, and promote planetary protection as human activity increases in low-Earth orbit, the moon, Mars, and beyond. Video Abstract.

Improved measurement of airborne viruses using a two-stage highly virus-enriching electrostatic particle concentrator with electric-field-enhancing wire electrodes.

High enrichment of airborne viruses during sampling is critical for their rapid measurement and requires a high sampling flow rate (or velocity), small collection areas, and high collection efficiency; however, high collection efficiency can rarely be achieved at high flow velocities and in small collection areas in electrostatic sampling. Herein, we present improved measurement of airborne viruses using a two-stage highly virus-enriching electrostatic particle concentrator (HEPC) with wire electrodes and high values of the-inlet-velocity-to-collection-electrode-width ratio. This sampler was evaluated using MS2 viruses and 0.05-2.0 µm diameter polystyrene latex particles at 20 liters/min. Computer simulations and experiments agreed well, showing that the wire electrodes increased collection efficiency (by up to 37 % than the without-wire-electrodes case) without high viability losses through local electric field enhancement for high-flow-velocity regions over the collection electrode and minimization of local corona discharge. The relative infectious virus concentrations of the HEPC were 41-70 times higher than those of the BioSampler. Airborne influenza A viruses at field-level concentrations (1.8 × 105 and 2.6 × 104 copies/m3) were also detected at 10-min sampling due to the high enrichment capability of HEPC. The HEPC has strong potential as a rapid airborne virus monitoring system in the field.

Microbial richness and air chemistry in aerosols above the PBL confirm 2,000-km long-distance transport of potential human pathogens.

The existence of viable human pathogens in bioaerosols which can cause infection or affect human health has been the subject of little research. In this study, data provided by 10 tropospheric aircraft surveys over Japan in 2014 confirm the existence of a vast diversity of microbial species up to 3,000 m height, which can be dispersed above the planetary boundary layer over distances of up to 2,000 km, thanks to strong winds from an area covered with massive cereal croplands in Northeast (NE) Asia. Microbes attached to aerosols reveal the presence of diverse bacterial and fungal taxa, including potential human pathogens, originating from sewage, pesticides, or fertilizers. Over 266 different fungal and 305 bacterial genera appeared in the 10 aircraft transects. Actinobacteria, Bacillota, Proteobacteria, and Bacteroidetes phyla dominated the bacteria composition and, for fungi, Ascomycota prevailed over Basidiomycota. Among the pathogenic species identified, human pathogens include bacteria such as Escherichia coli, Serratia marcescens, Prevotella melaninogenica, Staphylococcus epidermidis, Staphylococcus haemolyticus, Staphylococcus saprophyticus, Cutibacterium acnes, Clostridium difficile, Clostridium botulinum, Stenotrophomonas maltophilia, Shigella sonnei, Haemophillus parainfluenzae and Acinetobacter baumannii and health-relevant fungi such as Malassezia restricta, Malassezia globosa, Candida parapsilosis and Candida zeylanoides, Sarocladium kiliense, Cladosporium halotolerans, and Cladosporium herbarum. Diversity estimates were similar at heights and surface when entrainment of air from high altitudes occurred. Natural antimicrobial-resistant bacteria (ARB) cultured from air samples were found indicating long-distance spread of ARB and microbial viability. This would represent a novel way to disperse both viable human pathogens and resistance genes among distant geographical regions.

[Effects of Altitude on Airborne Bacteria and Potential Pathogenic Bacteria： A Case of Shigatse of Xizang].

Airborne microbes are affected by natural environmental factors and have become a global issue due to their potential threat to human health. To explore the effects of altitude on the communities of microbes and potential pathogenic bacteria, we sampled airborne microbes and soils at sites with different altitudes in Shigatse of Xizang. The results showed a significant difference in bacterial communities between air and soil and a decrease in the contribution of soil to airborne bacteria from the sites with a lower altitude to the sites with a higher altitude. The Chao1 indexes of airborne bacteria were significantly higher in the sites with a lower altitude compared to those with a higher altitude, and the bacterial Bray-Curtis distances between sites with a lower altitude were significantly lower than those between sites with a lower altitude and high altitude. These results indicated that altitude would affect the community patterns of airborne bacteria, and the transport of air would decrease the variations in airborne microbial communities between different sites. Proteobacteria, with 84%-91% of average abundance, predominated in the airborne bacterial communities, but different taxa were enriched in sites with different altitudes. For example, the genera of Flavobacterium and Lactobacillus were enriched in sites with a lower altitude and a higher altitude, respectively. A total of 78 potential bacterial pathogens were detected across all samples, and the relative abundance of them in bacterial communities ranged from 2.69% to 38.19%. These findings indicated that altitude would affect the community compositions of airborne bacteria and potential pathogenic bacteria and suggested the potential threat of airborne bacteria to human health. This study provided a scientific basis for better understanding the distributions of airborne microbes and for air quality improvement and disease prevention in China.

Aerosolization ocular surface microorganisms accumulation effect during non-contact tonometer measurements.

PURPOSE: This study aimed to verify that aerosolization ocular surface microorganisms (AOSMs) accumulated during non-contact tonometry (NCT) measurements. METHODS: A total of 508 participants (740 eyes) were enrolled in the study. In Experiment 1, before NCT was performed on each eye, the air was disinfected, and environment air control samples were collected via Air ideal® 3P (Bio Merieux). During NCT measurements, microbial aerosol samples were collected once from each eye. In Experiment 2, we collected initial blank control samples and then repeated Experiment 1. Finally, in Experiment 3, after the background microbial aerosol investigation, we cumulatively sampled AOSMs from each 10 participants then culture once, without any interventions to interrupt the accumulation. The collected samples were incubated and identified using matrix-assisted laser desorption/ ionization time-of-flight mass spectrometry (MALDI-TOF-MS). RESULTS: Pathogenic Aerococcus viridans and other microorganisms from human eyes can spread and accumulate in the air during NCT measurements. The species and quantity of AOSMs produced by NCT measurements can demonstrate an accumulation effect. CONCLUSION: AOSMs generated during NCT measurements are highly likely to spread and accumulate in the air, thereby may increase the risk of exposure to and transmission of bio-aerosols.

Pathogenic Aerococcus viridans and other species of aerosolization ocular surface microorganisms (AOSMs) can spread and accumulate with the increase of NCT measurement person times, demonstrating an accumulation effect.

Optimizing cabin air inlet velocities and personal risk assessment: Introducing the Personal Contamination Ratio (PCR) method for enhanced aircraft cabin infection risk evaluation.

Recurrent epidemics of respiratory infections have drawn attention from the academic community and the general public in recent years. Aircraft plays a pivotal role in facilitating the cross-regional transmission of pathogens. In this study, we initially utilized an Airbus A320 model for computational fluid dynamics (CFD) simulations, subsequently validating the model's efficacy in characterizing cabin airflow patterns through comparison with empirical data. Building upon this validated framework, we investigate the transport dynamics of droplets of varying sizes under three air supply velocities. The Euler-Lagrangian method is employed to meticulously track key parameters associated with droplet transport, enabling a comprehensive analysis of particle behavior within the cabin environment. This study integrates acquired data into a novel PCR (Personal Contamination Rate) equation to assess individual contamination rates. Numerical simulations demonstrate that increasing air supply velocity leads to enhanced stability in the movement of larger particles compared to smaller ones. Results show that the number of potential infections in the cabin decreases by 51.8% at the highest air supply velocity compared to the base air supply velocity, and the total exposure risk rate reduced by 26.4%. Thus, optimizing air supply velocity within a specific range effectively reduces the potential infection area. In contrast to previous research, this study provides a more comprehensive analysis of droplet movement dynamics across various particle sizes. We introduce an improved method for calculating the breathing zone, thereby enhancing droplet counting accuracy. These findings have significant implications for improving non-pharmacological public health interventions and optimizing cabin ventilation system design.

A liquid culture method assisted by ATP analysis for accelerating laboratory experiments on ultraviolet disinfection of airborne bacteria.

The solid culture method for measuring the efficiency of ultraviolet (UV) disinfection of airborne bacteria is time-consuming, typically taking 12-48 h. To expedite such experiments, this study proposed a liquid culture method assisted by adenosine triphosphate (ATP) analysis, as a liquid culture is faster than a solid culture, and measurement of ATP does not require waiting for visible colonies to form. Escherichia coli (E. coli) was used as the experimental bacterium. This study first compared the log reduction of bacteria in liquid as measured by the proposed method and by the traditional solid culture method. The minimum liquid culture time was determined for different bacterial concentration ranges. Finally, the feasibility of the proposed method was validated by UV disinfection experiments on airborne bacteria. The results indicated that the proposed method measured a similar log reduction to that of the solid culture method in liquid experiments. The minimum liquid culture time for E. coli in 105-106 colony forming units (CFU)/mL was 2 h. The validation experiments demonstrated that the proposed method is capable of measuring the UV disinfection efficiency of airborne bacteria. The proposed method can accelerate laboratory experiments on UV disinfection of airborne bacteria, which in turn can support the effective design and utilization of UV disinfection in real life.

Optimal environmental sampling conditions for electrostatic aerosol-to-hydrosol collection of airborne viruses.

Due to adverse effects of viral outbreaks on human health, accurate detection of airborne pathogens is essential. Among many methods available for bioaerosol sampling, electrostatic precipitation (ESP) has been used to directly collect bioaerosols as hydrosols. The performance of an ESP sampler depends on its design, operational and environmental parameters such as air relative humidity (RH), air temperature, sampling liquid type and liquid temperature. Thus, it is essential to identify and maintain optimal conditions throughout sampling process to operate the sampler at its highest capacity. This study provides crucial insights into parameters that affect the collection efficiency of the aerosol-to-hydrosol ESP sampler and its virus recovery. The results indicate that air temperature does not affect collection efficiency, meanwhile, air RH, sampling liquid temperature, and salt concentration are the main parameters that significantly affect collection efficiency. Likewise, when deionized water is used as sampling liquid, hydrogen peroxide concentration increases proportionally with increasing air RH, resulting in significant decrease of virus viability. Consequently, for ESP samplers similar to our study, the following conditions are recommended: air RH of 55-65%, air and sampling liquid temperature of 37 °C, and a mixture of 10-20 mM ascorbic acid in PBS as sampling liquid.

Pathogen shape: Implication on pathogenicity via respiratory deposition.

The shape of environmental aerosols contributes to the discrepancy in their dynamic behavior compared to spherical particles, which have received inadequate consideration. We reported deposition patterns of aerosols and aerosol-transmissible pathogens in real human respiratory systems, taking into account their actual shape, using a validated computational-based model. We found that the shape of the aerosols significantly influenced its deposits and accessibility within the respiratory system, significantly in the tracheobronchial region. As an example, we estimated that over 180 % of differences in deposits in the trachea and bronchi were attributable to pathogens shape, inferring the underlying pathogenicity difference of these regions. These findings, capturing the spatial heterogeneity of pathogens and aerosols deposition in human respiratory system, have major implication for understanding the evolution of aerosol-related disease.

Diffusion behavior and transport risk of bioaerosol particles in a domestic waste landfill site in an arid and cold region of northwestern China.

Bioaerosols have attracted increasing attention as novel contaminants because of their potential role in the spread of disease. In this study, sampling sites were established in a landfill in northwestern China with the aim of investigating the emission and diffusion characteristics of bioaerosols. The results revealed that the counts of airborne bacteria released by landfill cover area (LCA) and waste dumping area (WDA) located in the landfill area reached 18 193 ± 30 CFU/m3 and 10 948 ± 105 CFU/m3, respectively. These two aeras were the main sources of bioaerosol generation. Meanwhile, Corynebacterium spp., Bacteroidetes spp., and Pseudomonas spp. were identified as potential pathogens. A Gaussian model was applied to simulate the diffusion of the bioaerosols; the influence distance was calculated as 12 km from the boundary of the landfill site. The potential health risks of bioaerosol exposure to on-site workers and nearby residents were calculated and evaluated in terms of aerosol concentration, particle size, and pathogenic bacteria. The present study promotes the recognition of the emission behavior of microorganisms in aerosol particles and provides a basis for controlling bioaerosol contamination from landfill sites, particularly those located in cold and arid northwestern regions of China.

Experimental study on the effect of light source arrangements on the disinfection performance of upper-room 222 nm Far-UVC.

The air disinfection efficacy of upper-room 222 nm Far-UVC was experimentally investigated in a real-size chamber under well-mixed air conditions. Two bacteria (Escherichia coli, Staphylococcus epidermidis) and two bacteriophages (MS2, and P22) were selected for the test. The study considered different lamp source arrangements, including single and double sources, stationary and rotating operating modes, and an overlapping mode with a 45° irradiation angle. A numerical view-factor model was developed to analyze the irradiance distributions. Four irradiation angles, 30°, 45°, 60°, and 90°, were chosen. The results show that the lamps operating with an irradiation angle of 45° provide the highest chamber-averaged irradiance. This suggests an optimal irradiance level for a given room dimension, as inferred from the view factor model. Experimental results indicated that the overlapping mode with a 45° irradiation angle consistently outperformed both the stationary mode and rotating mode in disinfection. This can be attributed to the higher chamber-averaged irradiance, which is also supported by the numerical model predictions. The increment ratios ranged from 14.9 % to 42.9 % compared to the stationary mode. The susceptibility constants of Escherichia coli, Staphylococcus epidermidis, MS2, and P22 were measured as 0.572 m2/J, 0.099 m2/J, 0.060 m2/J, and 0.081 m2/J respectively.

Determination of airborne influenza virus and coronavirus infectivity using capsid integrity polymerase chain reaction.

Accurate airborne virus monitoring is important for preventing the spread of infectious diseases. Although standard reverse transcription-quantitative polymerase chain reaction (RT-qPCR) can efficiently detect viral ribonucleic acid (RNA), it cannot determine whether the RNA is associated with active (infectious) or inactive (non-infectious) viruses. Plaque assay is the gold standard for determining viral infectivity but is laborious and time-consuming. This study explored the viral infectivity of H1N1 influenza virus and human coronavirus (HCoV-229E) using capsid integrity RT-qPCR, where virus samples were pretreated with reagents penetrating viruses with damaged capsids, impeding amplification by binding to their RNA. Therefore, the amplified signals corresponded solely to active viruses with undamaged capsids. Propidium monoazide (PMA) and platinum (IV) chloride (PtCl4) were used to investigate the effects of reagent concentration. Feasibility tests revealed that PtCl4 was more efficient than PMA, with optimal concentrations of 125-250 µM and 250-500 µM for H1N1 influenza virus and HCoV-229E, respectively. The results of percentage of active virus showed that capsid integrity RT-qPCR provided a trend similar to that of plaque assay, indicating an accurate measure of viral infectivity. Virus sampling in the laboratory and field highlighted the precision of this methodology for determining viral infectivity. Therefore, this methodology enables rapid and accurate detection of infectious airborne H1N1 influenza virus and HCoV-229E, allowing swift response to outbreaks.

Airborne concentrations of bacteria and mold in Korean public-use facilities: measurement, systematic review, meta-analysis, and probabilistic human inhalation risk assessment.

Bioaerosols adversely affect human health posing risk to users of public facilities in Korea. Between October 2021 and May 2022, airborne bacteria and mold were measured in 1,243 public-use facilities across 23 categories. A systematic review and meta-analysis were performed on these and other studies from June 2004 to May 2021, and the non-carcinogenic risks to humans were assessed using Monte Carlo simulations. For bacteria, the maximum 95th percentile concentration was 584.4 cfu/m3 and 1384.8 cfu/m3 for mold. The heterogeneity statistic I2 was over 50% in all facilities, and for subway station bacteria, there was a significant difference according to the measurement method. The 95th percentile of hazard by population group was 8.83 × 10-2 to 3.42 × 10-1 for bacteria, and 1.31 × 10-1 to 3.55 × 10-1 for mold. The probability of a hazard quotient exceeding 1 for some population groups was derived from exposure to bacteria and mold in the air resulting from the use of all public facilities. The most powerful explanatory factor for risk was exposure time to the facility, both within (up to 0.922 for bacteria and up to 0.960 for mold) and between populations (up to 0.543 for bacteria and 0.483 for mold). This study identified populations at risk of bioaerosol exposure in Korean public-use facilities and estimated the influencing factors, highlighting the need for comprehensive improvement in bioaerosol control in public-use facilities.

Microfluidics-based condensation bioaerosol sampler for multipoint airborne virus monitoring.

To facilitate rapid monitoring of airborne viruses, they must be collected with high efficiency and concentrated in a small volume of a liquid sample. In addition, the development of low-cost miniaturized samplers is essential for multipoint monitoring. Thus, in an attempt to fulfill these requirements, this study developed a microfluidic condensation bioaerosol sampler (MCBS). The developed sampler comprised two parts: a virus growth section and a virus droplet-to-liquid sample conversion section, each of which was fabricated on a chip using microfluidic technology. The condensation nucleus growth technique used in the virus growth section grew nanometer-sized airborne viruses into micro-sized droplets, making it possible to collection of viruses easier and with high efficiency. In addition, the virus droplet-to-liquid sample conversion section controlled the transport of droplets based on electrowetting technology. This enabled the collected airborne viruses to be concentrated in tens of microliters of the liquid sample. To evaluate the performance of both the sections, the virus dropletization, virus collection efficiency, and virus droplet-to-liquid sample conversion efficiency were evaluated through quantitative experiments. H1N1 and HCOV-229E viruses were used to conduct quantitative experiments on MCBS. We could obtain virus liquid samples with at 72.8- and 89.9-times higher concentration through 1:1 evaluation with a commercial sampler. Thus, the developed sampler facilitated efficient collection and concentration of airborne viruses in a compact, cost-effective manner. This is expected to facilitate rapid and accurate multipoint monitoring of viral aerosols.

Air disinfection performance of upper-room ultraviolet germicidal irradiation (UR-UVGI) system in a multi-compartment dental clinic.

Multi-compartment dental clinics present significant airborne cross-infection risks. Upper-room ultraviolet germicidal irradiation (UR-UVGI) system have shown promise in preventing airborne pathogens, but its available application data are insufficient in multi-compartment dental clinics. Therefore, the UR-UVGI system's performance in a multi-compartment dental clinic was comprehensively evaluated in this study. The accuracy of the turbulence and drift flux models was verified by experimental data from ultrasonic scaling. The effects of the ventilation rate, irradiation zone volume, and irradiation flux on UR-UVGI performance were analyzed using computational fluid dynamics coupled with a UV inactivation model. Different patient numbers were considered. The results showed that UR-UVGI significantly reduced virus concentrations and outperformed increased ventilation rates alone. At a ventilation rate of six air changes per hour (ACH), UR-UVGI with an irradiation zone volume of 20% and irradiation flux of 5 µW/cm2 achieved a 70.44% average virus reduction in the whole room (WR), outperforming the impact of doubling the ventilation rate from 6 to 12 ACH without UR-UVGI. The highest disinfection efficiency of UR-UVGI decreased for WRs with more patients. The compartment treating patients exhibited significantly lower disinfection efficiency than others. Moreover, optimal UR-UVGI performance occurs at lower ventilation rates, achieving over 80% virus disinfection in WR. Additionally, exceeding an irradiation zone volume of 20% or an irradiation flux of 5 µW/cm2 notably reduces the improvement rates of UR-UVGI performance. These findings provide a scientific reference for strategically applying UR-UVGI in multi-compartment dental clinics.

[Analysis of Antibiotic Resistance of Bioaerosols from Wastewater Treatment Process].

To explore the prevalence and source of antibiotic resistant genes （ARGs） and pathogenic antibiotic resistant bacteria （PARB） associated with bioaerosols in wastewater treatment plants （WWTPs）, metagenomic sequencing and assembly were applied to elucidate the antibiotic resistome of bioaerosols and wastewater in WWTPs. The results showed that more subtypes of ARGs and a higher abundance of PARB were found in bioaerosols from WWTPs and downwind than those from upwind. Multidrug and macB were respectively the most dominant type and subtype of ARGs in bioaerosols from WWTPs. In total, 37 types of PARB carried at least two or more ARG types and were characterized by multiple drug resistance. At the fine grid, aerated tank, and sludge dewatering room, wastewater was the main source of bioaerosol ARGs and PARB. A total of 32 PARB were easily aerosolized in at least one wastewater treatment unit, such as Pseudomonas aeruginosa and Escherichia coli. This study will provide theoretical support for the risk assessment and health protection of antibiotic resistant pollution associated with bioaerosols from WWTPs.

Quantitative and qualitative assessment of airborne microorganisms during gross anatomical class and the bacterial and fungal load on formalin-embalmed corpses.

Mold growth on body donations remains an underreported yet serious issue in anatomical teaching. Bacterial and fungal growth pose health risks to lecturers and students, alongside with ethical and aesthetic concerns. However, limited information exists on the presence of bacteria and fungi on body donations and their underlying causes. To investigate the potential impact of airborne germs on body donation contamination, we conducted indoor air measurements before, during, and after our anatomical dissection course, with outdoor measurements serving as a control. Tissue samples from the dissected body donations were collected to assess the germ load, with qualitative and quantitative microbiological analyses. Air samples from the dissection hall contained no fungi, but various fungal species were identified in the adjacent stairways and outdoors which implies that fungal occurrence in the dissection hall air was independent of lecturers' and students' presence. Moreover, our results indicate that adequate ventilation filters can effectively reduce indoor fungal germs during courses, while the bacterial load in room air appears to increase, likely due to the presence of lecturers and students. Additionally, the tissue samples revealed no bacterial or fungal germs which implies that our ethanol-formalin-based embalming solution demonstrates an effective long-term antimicrobial preservation of corpses.