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Introduction: Pathogen introduction and transmission at the farm, regional, or national level are associated with reduced animal welfare and negative impacts on herd economics. Ongoing infectious disease surveillance, active or passive, is therefore of high importance. For optimal resolution, each pig is sampled individually, for example by collecting blood or nasal swabs. In recent years, oral fluids have become very useful for population surveillance at the pen level. Another alternative is sampling the air to capture pathogens circulating across the entire barn via bioaerosols. Objective: This study aimed to examine the potential utility of bioaerosol metagenomics for pathogen detection on pig farms. Methods: Bioaerosols via automated air sampler, and oral fluid via pen-based ropes, were collected from each of two Scottish indoor pig farms. All samples were subjected to conventional routine bacterial isolation. Total genomic nucleic acids were extracted for PCR screening for three pig DNA viruses, three bacterial Mycoplasma species and an RNA virus. Illumina shotgun metagenomic sequencing was also conducted. Results: Oral fluids contained more DNA compared to bioaerosol samples. DNA integrity exhibited limited impact on PCR or sequence yield. While Streptococcus suis could be cultured from a single oral fluid sample, reads mapped to S. suis were detectable in all metagenomic samples. Other bacterial pig pathogens, including Mycoplasma hyorhinis, M. hyopneumoniae and M. hyosynoviae, were detected in oral fluid and aerosols by PCR and metagenomics. One of the two farms was PRRSV positive, and the virus was detectable via PCR in oral fluids but not in bioaerosols. Antimicrobial resistance (AMR) gene profiles had less variation between bioaerosols and oral fluids. Some identified AMR genes had strikingly similar abundance overall. Conclusion: Overall, these findings indicate that there is potential utility of bioaerosol metagenomics for pathogen surveillance on pig farms; however, more research is needed for technical and cost optimization to allow for routine pathogen detection on livestock farms. [ABSTRACT FROM AUTHOR]

This study investigates airborne bacterial and fungal communities in south-eastern Italy and Albania using advanced DNA-based techniques and compositional data analysis (CoDa). We assess the significance of airborne microbial communities, detailing our methodologies for site selection, sample collection, DNA extraction, and data analysis. Our results reveal distinct differences in microbial composition between the two regions, driven by local environmental factors. Specifically, Albanian samples showed higher abundances of bacterial species such as Rubellimicrobium roseum and Sphingomonas cynarae, while Italian samples were characterized by a prevalence of Truepera radiovictrix and Rubrobacter radiotolerans. In terms of fungi, Albanian sites exhibited greater abundance of Mycosphaerella tassiana, Aureobasidium pullulans, and Ascochyta herbicola. Aitchison distance-based dendrograms and principal component analysis (PCA) biplots, utilizing singular value decomposition, clearly delineated a geographical separation of microbial communities, underscoring the impact of regional atmospheric conditions on microbial composition. In the discussion, we interpret these findings in the context of regional environmental factors, highlighting their implications for understanding regional differences in airborne microbial communities. The conclusion emphasizes the effectiveness of advanced DNA techniques and CoDa in environmental microbiology, offering insights into how local environmental conditions shape microbial communities and suggesting directions for future research and public health considerations. [ABSTRACT FROM AUTHOR]

• In Beijing's super sandstorm 2021, 5700 amplicon sequence variants were detected. • Airborne bacteria in sandstorms were compared with the after-storm and haze days. • The sandstorm newly brought 10 pathogenic bacterial genera to the atmosphere. • Small bioaerosols (0.65–1.1 µm) were still suspended after the sandstorm subsided. Sandstorm, which injects generous newly emerging microbes into the atmosphere covering cities, adversely affects the air quality in built environments. However, few studies have examined the change of airborne bacteria during severe sandstorm events. In this work, we analyzed the airborne bacteria during one of the strongest sandstorms in East Asia on March 15th, 2021, which affected large areas of China and Mongolia. The characteristics of the sandstorm were compared with those of the subsequent clean and haze days. The composition of the bacterial community of air samples was investigated using quantitative polymerase chain reaction (qPCR) and high-throughput sequencing technology. During the sandstorm, the particulate matter (PM) concentration and bacterial richness were extremely high (PM 2.5 : 207 µg/m3; PM 10 : 1630 µg/m3; 5700 amplicon sequence variants/m3). In addition, the sandstorm brought 10 pathogenic bacterial genera to the atmosphere, posing a grave hazard to human health. As the sandstorm subsided, small bioaerosols (0.65–1.1 µm) with a similar bacterial community remained suspended in the atmosphere, bringing possible long-lasting health risks. [Display omitted] [ABSTRACT FROM AUTHOR]

[Display omitted] • A fully bio-based filtration membrane (SGFM) is fabricated based on the gel-confined phase separation. • SGFM can provide lower pressure drop, higher filtration efficiency, and superior microbial survivability for bioaerosol sampling. • By simplifying the elution and extraction process, maximum sample transfer and vigorous recovery was achieved by SGFM. • Green capture was first proposed in air filtration for accurate and sensitive detection of airborne microbes. Air filtration has become a desirable route for collecting airborne microbes. However, the potential biotoxicity and sterilization of current air filtration membranes often lead to undesired inactivation of captured microbes, which greatly limits microbial non-traumatic transfer and recovery. Herein, we report a gel-confined phase separation strategy to rationally fabricate a fully bio-based filtration membrane (SGFM) using soluble soybean polysaccharide and gelatin. The versatile SGFM features fascinating honeycomb micro-nano architecture and hierarchical interconnected porous structures for microbial capture, and achieves a lower pressure drop, higher interception efficiency (99.3%), and superior microbial survivability than commercial gelatin filtration membranes. Particularly, the water-dissolvable SGFM can greatly simplify the elution and extraction process after bioaerosol sampling, thereby bringing about maximum sample transfer and vigorous recovery of collected microbes. Meanwhile, green capture coupled with ATP bioluminescence endows the SGFM with rapid and quantitative detection capability for airborne microbes. This work may pave the way for designing green protocols for the detection of bioaerosols. [ABSTRACT FROM AUTHOR]

Bioaerosols, including airborne bacteria, are significant pollutants affecting both indoor and outdoor air quality, with implications for human health. Despite extensive research on indoor air quality, there is a notable lack of comprehensive data on ambient bacterial concentrations and their interactions with pollutants and meteorological factors. This review focuses on bacterial aerosols in the atmosphere, measured using the culture-based method, considered the "gold standard" for microorganism detection and identification. Studies reveal significant variability in bacterial concentrations across different environments and seasons, influenced by factors such as temperature, humidity, wind speed, solar radiation, and precipitation, underscoring the need for further research and monitoring to enhance health risk assessments and mitigation strategies. The presence of air pollutants such as particulate matter (PM) and ozone (O3) further complicates these dynamics. The authors emphasize the need for more extensive research on outdoor bacterial aerosols and recommend that future studies prioritize detailed bioaerosol characterization to establish comprehensive exposure standards in ambient air, thereby improving public health protection and environmental management practices. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Microorganism pollutants can be bacteria, fungi and spores in the room. Microorganisms that are distributed in space are known as bioaerosols. The spread of bioaerosol in hospitals can result in danger to human health, especially for patients with weakened immune systems. Risk assessment is very important for an organization or institution to overcome current and future risks related to contamination. The QMRA approach has been applied to inform standards for the microbiological quality of food, water, air, and touched surfaces. The method uses descriptive analytics with a literature review design. Data was obtained through searches on the electronic databases Pubmed, Elsevier, and Google Scholar. Keyword terms such as: (Bioaerosol * and Airborne * and Infections * and Hospital *), ( Bioaerosol * and Microorganisms * and Inhalation ), ( Airborne * and Microbial and * Hospital * or Intensive Room *), ( Bioaerosol * Quantitative Microbial Risk Assessment (QMRA)* and Hospital-Acquired Infection* and Intensive Care unit ) . health risks AND sensitivity AND aerosol pollution AND microorganisms OR fungi OR bacteria AND montercarlo AND intensive care OR hospital rooms: (Bioaerosol * and Airborne * and Infections * and Hospital *), ( Bioaerosol * and Microorganisms * and Inhalation ), ( Airborne * and Microbial and * Hospital * or Intensive Room *), (Bioaerosol * Quantitative Microbial Risk Assessment (QMRA) * and Hospital-Acquired Infection * and Intensive Care unit ) . health risks AND sensitivity AND aerosol pollution AND microorganisms OR fungi OR bacteria AND monter carlo AND intensive care OR hospital rooms are used. The search covered research conducted over the past ten years, from 2012 to 2022. Of the 27 articles found using the search terms, seventeen articles were selected for examination. The four categories of analysis are population, type of study, aims, and findings. According to research, one of the parameters for evaluating indoor environmental quality is bioaerosol. Microbial bioaerosol media in the air are ambient air and indoor air. The routes of exposure can be through ingestion/swallowing, direct contact and inhalation/inhalation. The cause of hospital infections is because hospital environmental conditions do not meet the requirements, causing high levels of room air germs. Poor hospital indoor air quality can cause HAIs. Therefore increasing levels of mechanical or natural ventilation as well as regular cleaning and maintenance activities can play an important role in improving indoor air quality. [ABSTRACT FROM AUTHOR]

Bioaerosols can be spread through coughing, sneezing, respiratory droplets and aerosol particles, and public awareness of the health risks of bioaerosols has increased. Based on bioaerosol culturable microbe concentration data collected from March–December in 2015, 2018 and 2019, the health risks of bioaerosols were assessed by air quality level, month, population, and particle size using an average daily dose rate model. The concentration of culturable microorganisms is related to the air quality index (AQI). Under AQI values ranging from 51–100, the concentration of culturable microorganisms was the highest, while the concentration of culturable microorganisms was the lowest for AQI values ranging from 101–150. The health risk in June and July 2015 was the highest, the change trends in 2018 and 2019 were similar, the health risk was the highest in October, and the health risk of bioaerosols along the inhalation route was 103–104 times that along the exposure route. The health risk of bioaerosols was generally higher in summer and autumn than in spring and winter over the three-year period. The health risk for different categories of individuals indicated the same trend over the 3-year period, with the health risk for adults exceeding that for children and the health risk for men exceeding that for women. The health risk of bioaerosols was high under particle sizes ranging from 1.10–4.70 μm. The study results could provide data support for the analysis of bioaerosol-related health risks and offer a reference for the prevention and control of urban microbial diseases. [ABSTRACT FROM AUTHOR]

Airborne pathogens pose a great threat to public health, and their appearance in bioaerosol also increases the contiguousness due to the long survival time and transmitting range. Real-time monitoring and rapid detection methods provide more effective prevention and control of airborne pathogens. The whole procedure could be divided into bioaerosol collection and detection processes. This review presents the basic principles and recent advances in commonly used methods for each of these two steps. We categorized four different kinds of collection methods based on their principles and discussed possible enrichment methods against a small amount of targets. Four different detection methods were compared regarding their ability to perform rapid testing. In the final section, we analyzed the latest trend in combining all these steps to set up a single device or platform for rapid, automated, and continuous on-site bioaerosol monitoring to overcome time and space constraints and increase the speed of the entire monitoring process. We conclude that an integrated all-in-one system using a microfluidic platform is the most promising solution for real-time monitoring of airborne pathogens, since they are capable of simplifying operational steps, efficient collection, and high-throughput detection, demonstrating the strong potential of field-deployable platforms. [ABSTRACT FROM AUTHOR]

Concerns regarding air pollution and the risk of infectious diseases caused by bioaerosols have led to growing demand for effective filtration solutions. The effective capture of bioaerosols is essential; however, addressing the potential multiplication of captured aerosols on the air filter over time is also crucial. Therefore, the development of air filters with enhanced antimicrobial protection is imperative for preventing the proliferation of bioaerosols and ensuring safer and healthier air filtration systems. In this study, antimicrobial peptides conjugated nanostructures were used to enhance the capture and killing of bioaerosols with synergistic chemo-mechano-antimicrobial actions. We designed a puncturable nanostructure on an air filter and functionalized it with the antimicrobial LL-37 peptide. Bioaerosol filtration and antimicrobial performance tests were conducted to evaluate the synergistic effects of the antimicrobial puncturable nanostructures on bioaerosol removal. The peptide-conjugated puncturable nanostructured air filter outperformed bare air filters in bioaerosol capture and exhibited significantly better contact-killing properties against bioaerosols. These attributes indicate the ability of the filter to significant capture and kill airborne pathogens. The synergetic chemo-mechano-antimicrobial nanostructured filter is promising for combating airborne threats and serves as a safe filtration solution that is free from biotoxicity concerns and is suitable for widespread implementation in the market. [ABSTRACT FROM AUTHOR]

Smoke from wildland fires contains more diverse, viable microbes than typical ambient air, yet little is known about the sources and sinks of smoke‐borne microorganisms. Data from molecular‐based surveys suggest that smoke‐borne microorganisms originate from material associated with the vegetation and underlying soils that becomes aerosolized during combustion, however, the sources of microbes in smoke have not yet been experimentally assessed. To elucidate this link, we studied high‐intensity forest fires in the Fishlake National Forest, Utah, USA and applied source‐sink modeling to assemblages of 16S ribosomal RNA (rRNA) gene sequences recovered from samples of smoke, vegetation, and soil. Our results suggest that 70% of the bacterial taxa in smoke originated from the local aspen (Populus tremuloides) (33%) and soil (37%) communities. In comparison, 42% of bacteria in air sampled prior to the fires could be attributed to these terrestrial sources. When the bacterial assemblages in smoke were modeled as sources to the local communities, they contributed an average of 25% to the terrestrial sinks versus an estimated contribution of <4% from ambient air. Our results provide support for the role of wildland fire in bacterial dispersal and the working hypothesis that smoke is an environmental reservoir of microbes for receiving ecosystems. Plain Language Summary: Microbes (bacteria and fungi) have been detected in wildland fire smoke using DNA technology and have been successfully cultured. Many of these organisms are associated with vegetation and soil, so it has been assumed that the microbes originate in the materials that are combusted during a fire, including vegetation and litter. This study uses DNA collected from vegetation, soil, air collected on a clear day, and wildland fire smoke at the same location to measure the connection between bacteria encountered on the surface and in the air. In addition to an inventory of the bacteria that are common to the surface and the atmosphere, we also used modeling to estimate the source communities that contributed to the suite of bacteria that were detected in each place. We found close relationships between surface sources and smoke and a much weaker exchange between clear air and the surface. These results provide more evidence for wildland fire smoke as a mechanism for transporting bacteria between ecosystems. Key Points: Most bacterial taxa in wildland fire smoke can be traced to local surface vegetation and soil communitiesThe bacterial assemblage in ambient air was mostly derived from unknown sourcesLocal terrestrial communities are more closely linked to smoke‐borne bacteria than those in ambient air, implicating smoke as a biological dispersal agent [ABSTRACT FROM AUTHOR]

On-site bioaerosol monitoring is essential for estimating microbial biomass and mitigating the risk of infection induced by aerosol transmission. This study introduces a novel electrostatic bioaerosol sampler, which is fabricated by the use of 3D printing, for rapid bioaerosol collection. Aerosol particles were charged and enriched in the sampler. Relationships between particle sizes and collection efficiencies under varying charging voltages were established using a charging model. The design of the sampler was optimized using commercial software, incorporating electrostatic field analysis, computational fluid dynamics (CFD), and particle trajectory simulations. To validate the sampler's collection efficiency, polystyrene (PS) spheres in an aerosol dispenser were atomized into an aerosol. The sampler collection efficiency exceeded 90% for particles larger than 1.2 μm under an applied voltage of 4.7 kV and an airflow rate of 2 L/min. The enrichment capacity was greater than 153,000 for particles larger than 1.2 μm under an applied voltage of 4.7 kV and an airflow rate of 8 L/min. With the merits of low cost, miniaturization, and high collection efficiency, the sampler can be used to collect samples on-site and in remote areas to verify the pathogens and reduce the risk of infection through aerosol transmission. [ABSTRACT FROM AUTHOR]

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.

Abstract This study explores potential of LiDAR technology to rapidly detect aerosolized biological terror agents in the atmosphere. It assesses the application by simulating extinction coefficients and the Ångström exponent at various wavelengths (266, 1064, 1571, and 2000 nm), focusing on differentiating bioaerosols from typical atmospheric particles. The simulation analysis evaluates changes in aerosol distributions and related extinction coefficient and Ångström exponent shifts under clean, normal, and bad atmospheric conditions. The findings indicate that the 1064 nm wavelength effectively detects bioaerosol presence, with a combination of 1064 nm and 1571 nm providing optimal Ångström exponent use for particle size differentiation. This dual-wavelength approach is highlighted as a practical method for bioaerosol detection, showcasing a significant sensitivity to variations in particle quantity and size, which are critical in biological threat scenarios. In conclusion, the study offers guidance for selecting LiDAR wavelengths for biological agent detection systems. While providing a theoretical framework for practical applications, it also underlines the need for further experimental work to confirm findings and fine-tune technology for real-world monitoring and threat management. This research contributes to the development of effective monitoring strategies against the backdrop of biological terror threats. Graphical Abstract

Introduction: Protection of the respiratory system has been a vital, and for this purpose, various solutions have been proposed, including the use of masks. One of the most important parameters to measure the effectiveness of the mask against the penetration of microbial agents. The present study was conducted with the aim of evaluating the bacterial and particle filtration of medical masks. Material and Methods: To assess bacterial performance, the national standard 6138, compliant with EN14683, and Type I medical masks were utilized. Staphylococcus aureus bacterial suspension was prepared and passed through the mask using a nebulizer and through an impactor with a flow rate of 28.3 l/min. Plates containing soy agar were placed in the impactor. Subsequently, all plates were incubated, and the bacterial filtration efficiency (BFE) of the masks was determined by counting the bacterial colonies that passed through the mask’s media as a percentage of the total bacteria. It is worth noting that the pressure drop and particle filtration efficiency were also determined for all masks Results: Based on the results of the particle removal performance for the particle size of 3 µ, the masks were categorized into three groups with efficiency above 99%, above 95% and 90%. According to the standard, all masks had an acceptable pressure drop below 40 Pa. The acceptable bacterial filtration rate for type I masks should be above 95%. The results showed that type A and B masks have an acceptable bacterial filtration rate and there is a significant correlation between the types of masks examined in terms of bacterial and particle efficiency. Conclusion: The results showed that different types of masks under investigation have significant differences in terms of particle capture efficiency and bacterial filtration performance. In addition, there is a significant correlation between bacterial and particle filtration efficiency.

AbstractThe human living environment serves as a habitat for microorganisms and the presence of ubiquitous airborne microbes significantly impacts the natural material cycle. Through ongoing experimentation with beneficial microorganisms, humans have greatly benefited from airborne microbes. However, airborne pathogens endanger human health and have the potential to induce fatal diseases. Tracking airborne microbes is a critical prerequisite for a better understanding of bioaerosols, harnessing their potential advantages, and mitigating associated risks. Although technological breakthroughs have enabled significant advancements in accurately monitoring airborne pathogens, many puzzles about these microbes remain unanswered due to their high variability and environmental diffusibility. Consequently, advanced techniques and strategies for special identification, early warning, and efficient eradication of microbial contamination are continuously being sought. This review presents a comprehensive overview of the research status of airborne microbes, concentrating on the recent advances and challenges in sampling, detection, and inactivation. Particularly, the fundamental design principles for the collection and timely detection of airborne pathogens are described in detail, as well as critical factors for eliminating microbial contamination and enhancing indoor air quality. In addition, future research directions and perspectives for controlling airborne microbes are also suggested to promote the translation of basic research into real products. [ABSTRACT FROM AUTHOR]

Low-flow showerheads offer consumers economic and water-saving benefits, yet their use may inadvertently affect the microbial content of produced water and water-associated aerosols. This study aimed to compare the abundance and microbial composition of bacteria in shower water and associated respirable aerosols produced by various low flow rate (1, 1.5, and 1.8 gpm) showerheads. Our findings indicate that the lowest-flow showerhead produces water with lower total microbial and opportunistic bacterial pathogen densities compared to higher low flow rate counterparts. However, microbiome analysis revealed that 1.8 gpm flow rate showerheads exhibit reduced abundance of Gramnegative organisms and common biofilm-forming organisms, suggesting potentially lower pathogenicity compared to 1 and 1.5 gpm low-flow showerheads. Additionally, the number of respirable aerosols produced by showerheads as well as the partitioning of certain microorganisms from the water to aerosol phases was negatively correlated with flow rate, suggesting that there may be increasing exposure potential to pathogenic bioaerosols when using a 1gpm showerhead compared to a 1.8 gpm showerhead. However, the 1.5 gpm showerhead seemed to balance microbial partitioning, aerosol generation, and water conservation. Moreover, the microbial composition of aerosols produced from shower water was more influenced by the age of the showerhead than the flow rate, highlighting the significance of biofilm formation on the microbial community. Overall, our findings underscore the importance of evaluating the microbial risk associated with low-flow showerheads using multiple metrics in both water and aerosols, and dynamically assessing this over time, to ensure accurate future risk assessment. [ABSTRACT FROM AUTHOR]

Horses stay in different types of stables; especially during the cold season, they stay inside for most of the day. A stable is also a place where many people spend quite a lot of time either as employees who care for and train horses or as equine enthusiasts. Keeping horses in stables causes their constant exposure to high concentrations of particulate matter (PM) and molds in the air inside these facilities. The study was conducted in Udórz Stud Farm located in the southern region of Poland. It was carried out in two different types of stables: three runners and two box stables. The study continued for 2 years; samples were collected in each season of the year. The following devices were used: a six-stage Andersen-Graseby cascade impactor, the DustTrak™ II Aerosol Monitor 8530. The obtained results allowed for the conclusion that horses kept in box stables are exposed to lower concentrations of molds and yeasts than those kept in runners. Molds dominated in the stable air during humid periods—spring and autumn—while yeasts were more prominent during summer and winter. It was observed that cleaning stables reduces the morphotic elements of fungi in the air, even though it results in a higher level of particulate matter in the stable air. It should be noted that microclimate conditions were optimal for horses practically throughout the whole year. Key points: • In stables, there is a high level of air intoxication, both by yeast and by mold fungi • The concentrations of fungi in the air depend on the season and the stable cleaning procedure • The PM concentrations depend on the type of stable [ABSTRACT FROM AUTHOR]

The aims of this study encompass the characterization of process parameters and the antimicrobial potential during operation of a novel non-thermal plasma (NTP) source in a duct system containing a particulate matter (PM) filter thus mimicking the interior of an air purifier. Simulating conditions of a long-term operation scenario, in which bacterial aerosols in indoor environments accumulate on PM filters, the filter surfaces were artificially inoculated with Escherichia coli (E. coli) and exposed to an air stream enriched with reactive species. Electrical power consumption, key plasma parameters, volume flow and air flow velocity, reactive gas species concentrations as well as inactivation rates of E. coli were assessed. The NTP operated at a gas temperature close to ambient air temperature and featured a mean electron energy of 9.4 eV and an electron density of 1∙1019 m−3. Ozone was found to be the dominating reactive gas species with concentrations of approx. 10 ppm in close vicinity to the PM filters. An inactivation rate of 99.96 % could be observed after exposure of the PM filters to the gas stream for 15 min. This inactivation efficiency appears very competitive in combating realistic bacterial aerosol concentrations in indoor environments. [ABSTRACT FROM AUTHOR]

This study explores potential of LiDAR technology to rapidly detect aerosolized biological terror agents in the atmosphere. It assesses the application by simulating extinction coefficients and the Ångström exponent at various wavelengths (266, 1064, 1571, and 2000 nm), focusing on differentiating bioaerosols from typical atmospheric particles. The simulation analysis evaluates changes in aerosol distributions and related extinction coefficient and Ångström exponent shifts under clean, normal, and bad atmospheric conditions. The findings indicate that the 1064 nm wavelength effectively detects bioaerosol presence, with a combination of 1064 nm and 1571 nm providing optimal Ångström exponent use for particle size differentiation. This dual-wavelength approach is highlighted as a practical method for bioaerosol detection, showcasing a significant sensitivity to variations in particle quantity and size, which are critical in biological threat scenarios. In conclusion, the study offers guidance for selecting LiDAR wavelengths for biological agent detection systems. While providing a theoretical framework for practical applications, it also underlines the need for further experimental work to confirm findings and fine-tune technology for real-world monitoring and threat management. This research contributes to the development of effective monitoring strategies against the backdrop of biological terror threats. [ABSTRACT FROM AUTHOR]

Aerosol microbiome studies have received increased attention as technological advancements have made it possible to dive deeper into the microbial diversity. To enhance biomass collection for metagenomic sequencing, long-term sampling is a common strategy. While the impact of prolonged sampling times on microorganisms' culturability and viability is well-established, its effect on nucleic acid stability remains less understood but is essential to ensure representative sample collection. This study evaluated four air samplers (SKC BioSampler, SASS3100, Coriolis μ, BioSpot-VIVAS 300-P) against a reference sampler (isopore membrane filters) to identify nucleic acid stability during long-term sampling. Physical sampling efficiencies determined with a fluorescent tracer for three particle sizes (0.8, 1, and 3 μm), revealed high efficiencies (> 80% relative to reference) for BioSampler, SASS3100, and BioSpot-VIVAS for all particle sizes, and for Coriolis with 3 μm particles. Coriolis exhibited lower efficiency for 0.8 μm (7%) and 1 μm (50%) particles. During 2-h sampling with MS2 and Pantoea agglomerans, liquid-based collection with Coriolis and BioSampler showed a decrease in nucleic acid yields for all test conditions. BioSpot-VIVAS displayed reduced sampling efficiency for P. agglomerans compared to MS2 and the other air samplers, while filter-based collection with SASS3100 and isopore membrane filters, showed indications of DNA degradation for 1 μm particles of P. agglomerans after long-term sampling. These findings show that long-term air sampling affects nucleic acid stability in both liquid- and filter-based collection methods. These results highlight bias produced by bioaerosol collection and should be considered when selecting an air sampler and interpreting aerosol microbiome data. [ABSTRACT FROM AUTHOR]

During the month of February in 2019, the Western USA experienced elevated precipitation levels, corresponding to atmospheric river events, ending a drought period. Rainwater samples were collected at four time points across two weeks and analyzed by microscopy, analytical chemistry, and long-read sequencing methods. Quantification of whole cells showed concentrations of > 106 cells/L. Imaged cells from fluorescent and scanning electron microscopy included microeukaryotes. Analytic chemistry detected Na+ and Cl− ions, which were in agreement with back trajectories of an oceanic origin and atmospheric river occurrence. Taxonomic investigation of long-read sequences generated from the Nanopore MinION resulted in a high proportion of read assignments to fungal groups. For bacterial taxonomies, common rainwater-associated bacterial genera were present at higher proportions than other bacterial groups: Erwinia, Hymenobacter, Pseudomonas, and Pantoea. The microscopy data support the potential of intact and viable cell wet deposition into local environments and the taxonomic identification of common atmospheric-associated bacterial genera from long-read sequencing highlights the potential usefulness of this platform for atmospheric samples and field campaigns. [ABSTRACT FROM AUTHOR]

Suspended particles of biological origin comprising of virus, fragments of plants and animals dander, pollen grains, fungal spores and bacteria known as bioaerosols have become a major concern in the past decades. In the present study reports, the concentration and size distribution of fungal bioaerosol in and around a sugar mill situated in the Muzaffarnagar region of Uttar Pradesh, India, are presented. The sampling was performed in the winter when the mill used to be in the operational mode. The highest mean fungal concentration was observed at the cutter site (4022 ± 321 cfu/m3) and lowest at storage site (832 ± 85 cfu/m3). The maximum and minimum concentration of fungal bioaerosol was observed during January (3090 ± 174 cfu/m3) and March (629 ± 69 cfu/m3) respectively. During the entire sampling period, the fine fraction of fungal bioaerosol was observed to be significantly higher at all the sites, whereas coarse fraction was lower. The association between fine and coarse fractions of bioaerosols showed a very strong positive relationship. The levels of fungal bioaerosol and their association with the meteorological parameters in sugar mill were also conducted. A positive association with the relative humidity and wind speed was observed at significance level of p < 0.05, whereas a negative relation was observed with temperature at p < 0.05. The lifetime average daily dose was calculated for both inhalation and dermal; among them LADDinhalation is ~ 5 times over LADDdermal. The health risk index was observed as < 1 for both inhalation and dermal routes, whereas HIinhalation value was 105 times higher than the HIdermal value. The dominant fungi genera found in the air of examined dwellings were Penicillium spp., Aspergillus spp., Cladosporium spp., and Alternaria spp., which occurred predominantly at all of the studied sites during the sampling period. [ABSTRACT FROM AUTHOR]

The potential health risks posed by bioaerosols containing pathogens originating from wastewater treatment plants (WWTPs) have gaining intensive attention. This study designated sampling locations within a WWTP situated in Xi'an, a major city in northwest China. The airborne bacterial concentration, taxonomic composition, and the associated health risks were analyzed in the aeration tanks with bottom microporous aeration system. The Anaerobic-Anoxic-Oxic (AAO) tank emitted significantly higher culturable bacteria (1.58×104 CFU m−3 in spring, 6.69×103 CFU m−3 in winter) compared to Double-ditch (DE) oxidation ditch and aerated grit chamber (AGC) chamber, aligning with 16S rDNA quantification results. The bacterial concentrations are higher in spring than that in winter, with the AAO tank posing the highest exposure risk during the spring season. The dominant genera in the air samples include Cutibacterium, Lawsonella, Acinetobacter, Pseudomonas, and Aeromonas. Among the identified genus, 139 bacterial genera were identified as potential human pathogens like Neisseria, Moraxella, Haemophilus, Escherichia-Shigella and Streptococcus. These pathogens further elevate exposure risks from WWTP bioaerosols. This study provides relevant information on the seasonal health risk variations tied to bioaerosol emissions from diverse aeration tanks with bottom microporous aeration system in the mega city of northwest China, emphasizing the imperative to enhance the management and control measures for bioaerosols originating from the AAO tank.

The importance of aerosols (particles suspended in air) produced during dental procedures became more apparent than ever during the COVID-19 pandemic. Concerns over transmission of infection in these aerosols led to unprecedented disruption to dental services across the world, adversely impacting patients’ oral health. This article discusses the evidence related to airborne transmission of infectious diseases and the relevance to dentistry. The production of bioaerosols (aerosols carrying biological material) during dental procedures is explored, as well as how the potential risks posed by these bioaerosols can be controlled. A better understanding of dental bioaerosols is needed to prevent similar disruption to dental services in future outbreaks, and to reduce the risk of infection of dental professionals when treating patients with active infections who require urgent or emergency dental care.

ABSTRACT: Conventional cages for laying hens will be banned in Canada as of 2036, and the egg industry is transitioning toward enriched colony housing and aviaries. While higher concentrations of particulate matter have been previously reported in aviaries and other cage-free housing systems, concentrations of total bacteria and archaea suspended in the air are still uncharacterized in Canadian enriched colonies and aviaries. The aim of the present study was to conduct a longitudinal survey of airborne total bacteria and of airborne total archaea in twelve enriched colonies and twelve aviaries in Eastern Canada during a whole laying period. High-throughput sequencing of 16S rRNA gene amplicons was used to reveal and compare bacterial diversity at the start and the end of the production cycle, and during the cold and the warm seasons. Total bacterial and archaeal concentrations were significantly higher in aviaries (p < 0.05) versus enriched colonies, and in the cold season for both housing types (p < 0.05). While flock age did not have a significant effect on total bacterial and archaeal concentrations, it did on bacterial diversity in both enriched colony houses and aviaries (p < 0.05). The 2 housing systems were significantly different in their diversity of bacteria.

IntroductionPathogen introduction and transmission at the farm, regional, or national level are associated with reduced animal welfare and negative impacts on herd economics. Ongoing infectious disease surveillance, active or passive, is therefore of high importance. For optimal resolution, each pig is sampled individually, for example by collecting blood or nasal swabs. In recent years, oral fluids have become very useful for population surveillance at the pen level. Another alternative is sampling the air to capture pathogens circulating across the entire barn via bioaerosols.ObjectiveThis study aimed to examine the potential utility of bioaerosol metagenomics for pathogen detection on pig farms.MethodsBioaerosols via automated air sampler, and oral fluid via pen-based ropes, were collected from each of two Scottish indoor pig farms. All samples were subjected to conventional routine bacterial isolation. Total genomic nucleic acids were extracted for PCR screening for three pig DNA viruses, three bacterial Mycoplasma species and an RNA virus. Illumina shotgun metagenomic sequencing was also conducted.ResultsOral fluids contained more DNA compared to bioaerosol samples. DNA integrity exhibited limited impact on PCR or sequence yield. While Streptococcus suis could be cultured from a single oral fluid sample, reads mapped to S. suis were detectable in all metagenomic samples. Other bacterial pig pathogens, including Mycoplasma hyorhinis, M. hyopneumoniae and M. hyosynoviae, were detected in oral fluid and aerosols by PCR and metagenomics. One of the two farms was PRRSV positive, and the virus was detectable via PCR in oral fluids but not in bioaerosols. Antimicrobial resistance (AMR) gene profiles had less variation between bioaerosols and oral fluids. Some identified AMR genes had strikingly similar abundance overall.ConclusionOverall, these findings indicate that there is potential utility of bioaerosol metagenomics for pathogen surveillance on pig farms; however, more research is needed for technical and cost optimization to allow for routine pathogen detection on livestock farms.

BackgroundSeveral studies suggest that far-field transmission (>6 ft) explains a significant number of COVID-19 superspreading outbreaks.ObjectiveTherefore, quantifying the ratio of near- and far-field exposure to emissions from a source is key to better understanding human-to-human airborne infectious disease transmission and associated risks.MethodsIn this study, we used an environmentally-controlled chamber to measure volatile organic compounds (VOCs) released from a healthy participant who consumed breath mints, which contained unique tracer compounds. Tracer measurements were made at 0.76 m (2.5 ft), 1.52 m (5 ft), 2.28 m (7.5 ft) from the participant, as well as in the exhaust plenum of the chamber.ResultsWe observed that 0.76 m (2.5 ft) trials had ~36-44% higher concentrations than other distances during the first 20 minutes of experiments, highlighting the importance of the near-field exposure relative to the far-field before virus-laden respiratory aerosol plumes are continuously mixed into the far-field. However, for the conditions studied, the concentrations of human-sourced tracers after 20 minutes and approaching the end of the 60-minute trials at 0.76 m, 1.52 m, and 2.28 m were only ~18%, ~11%, and ~7.5% higher than volume-averaged concentrations, respectively.SignificanceThis study suggests that for rooms with similar airflow parameters disease transmission risk is dominated by near-field exposures for shorter event durations (e.g., initial 20-25-minutes of event) whereas far-field exposures are critical throughout the entire event and are increasingly more important for longer event durations.Impact statementWe offer a novel methodology for studying the fate and transport of airborne bioaerosols in indoor spaces using VOCs as unique proxies for bioaerosols. We provide evidence that real-time measurement of VOCs can be applied in settings with human subjects to estimate the concentration of bioaerosol at different distances from the emitter. We also improve upon the conventional assumption that a well-mixed room exhibits instantaneous and perfect mixing by addressing spatial distances and mixing over time. We quantitatively assessed the exposure levels to breath tracers at alternate distances and provided more insights into the changes on "near-field to far-field" ratios over time. This method can be used in future to estimate the benefits of alternate environmental conditions and occupant behaviors.

Abstract Background Many instruments used in dentistry are rotary, such as handpieces, water syringes, and ultrasonic scalers that produce aerosols. The spray created by these instruments can carry, in addition to water, droplets of saliva, blood, and microorganisms, which can pose a risk of infections for healthcare professionals and patients. Due to the COVID-19 pandemic, this gained attention. Objective The aim was to carry out a systematic review of the evidence of the scope of the aerosol produced by ultrasonic scaler in environmental contamination and the influence of the use of intraoral suction reduction devices. Design Scientific literature was searched until June 19, 2021 in 6 databases: Pubmed, EMBASE, Web of science, Scopus, Virtual Health Library and Cochrane Library, without restrictions on language or publication date. Studies that evaluated the range of the aerosol produced by ultrasonic scaler during scaling/prophylaxis and the control of environmental contamination generated by it with the use of low (LVE) and high (HVE) volume evacuation systems were included. Results Of the 1893 potentially relevant articles, 5 of which were randomized controlled trials (RCTs). The meta-analysis of 3 RCTs showed that, even at different distances from the patient’s oral cavity, there was a significant increase in airborne bacteria in the dental environment with the use of ultrasonic scaler. In contrast, when meta-analysis compared the use of HVE with LVE, there was no significant difference (P = 0.40/CI -0.71[-2.37, 0.95]) for aerosol produced in the environment. Conclusions There is an increase in the concentration of bioaerosol in the dental environment during the use of ultrasonic scaler in scaling/prophylaxis, reaching up to 2 m away from the patient’s mouth and the use of LVE, HVE or a combination of different devices, can be effective in reducing air contamination in the dental environment, with no important difference between different types of suction devices.

Speleotherapy is one of the non-pharmacological methods for the treatment and rehabilitation of patients with chronic respiratory diseases, especially those with chronic obstructive pulmonary disease (COPD) and asthma. On the one hand, one of the alleged main advantages of speleotherapeutic caves is the low microbial load in the air and the absence of other aeroallergens, but on the other hand, due to the lack of comprehensive air monitoring, there is little information on the pristine and human-influenced aerobiota in such environments. The aim of this study was to assess the anthropogenic effects of speleotherapy on the air microbiota and to investigate its potential impact on human health in Sežana Hospital Cave (Slovenia). From May 2020 to January 2023, air samples were collected in the cave before and after speleotherapeutic activities using two different volumetric air sampling methods—impaction and impingement—to isolate airborne microbiota. Along with sampling, environmental data were measured (CO2, humidity, wind, and temperature) to explore the anthropogenic effects on the aerobiota. While the presence of patients increased microbial concentrations by at least 83.3%, other parameters exhibited a lower impact or were attributed to seasonal changes. The structure and dynamics of the airborne microbiota are similar to those in show caves, indicating anthropization of the cave. Locally, concentrations of culturable microorganisms above 1000 CFU/m3 were detected, which could have negative or unpredictable effects on the autochthonous microbiota and possibly on human health. A mixture of bacteria and fungi typically associated with human microbiota was found in the air and identified by MALDI-TOF MS with a 90.9% identification success rate. Micrococcus luteus, Kocuria rosea, Staphylococcus hominis, and Staphylococcus capitis were identified as reliable indicators of cave anthropization. [ABSTRACT FROM AUTHOR]

Studies on bioaerosol bacterial biodiversity have relevance in both ecological and health contexts, and molecular methods, such as 16S rRNA gene-based barcoded sequencing, provide efficient tools for the analysis of airborne bacterial communities. Standardized methods for sampling and analysis of bioaerosol DNA are lacking, thus hampering the comparison of results from studies implementing different devices and procedures. Three samplers that use gelatin filtration, swirling aerosol collection, and condensation growth tubes for collecting bioaerosol at an aeration tank of a wastewater treatment plant in Trieste (Italy) were used to determine the bacterial biodiversity. Wastewater samples were collected directly from the untreated sewage to obtain a true representation of the microbiological community present in the plant. Different samplers and collection media provide an indication of the different grades of biodiversity, with condensation growth tubes and DNA/RNA shieldTM capturing the richer bacterial genera. Overall, in terms of relative abundance, the air samples have a lower number of bacterial genera (64 OTUs) than the wastewater ones (75 OTUs). Using the metabarcoding approach to aerosol samples, we provide the first preliminary step toward the understanding of a significant diversity between different air sampling systems, enabling the scientific community to orient research towards the most informative sampling strategy. [ABSTRACT FROM AUTHOR]

Fungi are ubiquitous and metabolically versatile. Their dispersion has important scientific, environmental, health, and economic implications. They can be dispersed through the air by the aerosolization of near surfaces or transported from distant sources. Here, we tested the contribution of local (scale of meters) versus regional (kilometers) sources by analyzing an airborne fungal community by ITS sequencing around a copper mine in the North of Chile. The mine was the regional source, whereas the soil and vegetal detritus were the local sources at each point. The airborne community was highly homogeneous at ca. 2000 km2, impeding the detection of regional or local contributions. Ascomycota was the dominant phylum in the three communities. Soil and vegetal detritus communities had lower alpha diversity, but some taxa had abundance patterns related to the distance from the mine and altitude. On the contrary, the air was compositionally even and unrelated to environmental or spatial factors, except for altitude. The presence of plant pathogens in the air suggests that other distant sources contribute to this region's airborne fungal community and reinforces the complexity of tracking the sources of air microbial communities in a real world where several natural and human activities coexist. [ABSTRACT FROM AUTHOR]

Isolation of extracellular vesicles (EV) has been developing rapidly in parallel with the interest in EVs. However, commonly utilized protocols may not suit more challenging samplematrixes and could potentially yield suboptimal results. Knowing and assessing the pitfalls of isolation procedure to be used, should be involved to some extent for EV analytics. EVs in cow milk are of great interest due to their abundancy and large-scale availability as well as their cross-species bioavailability and possible use as drug carriers. However, the characteristics of milk EVs overlap with those of other milk components. This makes it difficult to isolate and study EVs individually. There exists also a lack of consensus for isolation methods. In this study, we demonstrated the differences between various differential centrifugation-based approaches for isolation of large quantities of EVs from cow milk. Samples were further purified with gradient centrifugation and size exclusion chromatography (SEC) and differenceswere analyzed. Quality measurements were conducted onmultiple independent platforms. Particle analysis, electron microscopy and RNA analysis were used, to comprehensively characterize the isolated samples and to identify the limitations and possible sources of contamination in the EV isolation protocols. Vesicle concentration to protein ratio and RNA to protein ratios were observed to increase as samples were purified, suggesting co-isolation with major milk proteins in direct differential centrifugation protocols. We demonstrated a novel size assessment of vesicles using a particle mobility analyzer that matched the sizing using electron microscopy in contrast to commonly utilized nanoparticle tracking analysis. Based on the standards of the International Society for Extracellular Vesicles and the quick checklist of EVTrack. org for EV isolation, we emphasize the need for complete characterization and validation of the isolation protocol with all EV-related work to ensure the accuracy of results and allow further analytics and experiments. [ABSTRACT FROM AUTHOR]

The airborne transmission of disease relies on the ability of microbes to survive aerosol transport and, subsequently, cause infection when interacting with a host. The length of time airborne microorganisms remain infectious in aerosol droplets is a function of numerous variables. We present measurements of mass and heat transfer from liquid aerosol droplets combined with airborne survival data for Escherichia coli MRE162, an ACDP category 1 microorganism used as a model system, under a wide range of environmental conditions, droplet compositions and microbiological conditions. In tandem, these companion measurements demonstrate the importance of understanding the complex relationship between aerosol microphysics and microbe survival. Specifically, our data consist of the correlation of a wide range of physicochemical properties (e.g., evaporation rates, equilibrium water content, droplet morphology, compositional changes in droplet solute and gas phase, etc.), with airborne viability decay to infer the impact of aerosol microphysics on airborne bacterial survival. Thus, a mechanistic approach to support prediction of the survival of microorganisms in the aerosol phase as a function of biological, microphysical, environmental, and experimental (aerosol-generation and sampling) processes is presented. Specific findings include the following: surfactants do not increase bacteria stability in aerosol, while both the bacteria growth phase and bacteria concentration may affect the rate at which bacteria decay in aerosol. [ABSTRACT FROM AUTHOR]

A study was carried out in a waste sorting plant (WSP) located in France, treating dry recyclable household waste (DRHW) as well as dry recyclable commercial and industrial waste (DRCIW). Stationary and personal inhalable samples were collected in the WSP in order to investigate bioaerosols (sampling on a filter; 2 L/min and 10 L/min) and airborne dust (CIP; 10 L/min). The aim of the study was to assess the extent to which the measurement of concentration, species composition, and particle size distribution contributes to a better assessment of the biological risks associated with exposure. The results confirmed that waste and waste sorting activities are sources of airborne fungi. Indeed, ambient concentrations ranged from 7.3 × 103 to 8.5 × 105 colony-forming units (CFU)/m3 for culturable fungi and up to 4 mg/m3 for dust. Personal exposure to inhalable dust was found up to 3 mg/m3 for dust and ranged from 8.6 × 103 to 1.5 × 106 CFU/m3 for fungi. Airborne fungal communities were found to be dominated by the Penicillium genera in both bioaerosols and settled dust samples, followed by the Aspergillus, Cladosporium, Wallemia, Mucor, and Rhizopus genera. Fungi were carried by particles of aerodynamic diameters, mainly between around 2.0 and 10.0 µm. The findings dealing with size distribution and biodiversity of bioaerosols suggest that employees are exposed to complex bioaerosols during their work and help to make a finer diagnosis of the risks involved, which is often difficult in the absence of any occupational exposure limit (OEL) value for bioaerosols in general. [ABSTRACT FROM AUTHOR]

In the wake of the COVID-19 pandemic, the scientific community has been galvanized to unravel the enigmatic role of bioaerosols in the transmission of infectious agents. This literature review, anchored in the extensive Web of Science Core Collection database covering the period from 1990 to 2023, utilizes a bibliometric approach to chart the dynamic landscape of bioaerosol research. It meticulously documents the paradigm shifts and burgeoning areas of inquiry that have emerged in the aftermath of the pandemic. This review meticulously maps out the sources and detection strategies of pathogens in a variety of ecosystems. It clearly shows that impaction and filtration sampling methods, followed by colony counting and PCR-based detection techniques, were predominantly used in the scientific works within the previous three decades. It synthesizes the progress and limitations inherent in a range of models for predicting aerosol-mediated pathogen spread and provides a comparative analysis of eDNA technology and traditional analytical techniques for bioaerosols. The accuracy of these detection methods and forecasting models is paramount for the early recognition of transmission risks, which, in turn, paves the way for prompt and effective disease mitigation strategies. By providing a thorough analysis of the historical progression and current state of bioaerosol research, this review illuminates the path ahead, identifying the critical research needs that will drive the field's advancement in the years to come. [ABSTRACT FROM AUTHOR]

The design of ventilation and air conditioning systems in university classrooms is paramount to ensure students' correct number of air changes per hour and an optimal thermal profile for their comfort. With the spread of the COVID-19 virus, these systems will inevitably need to evolve to cope with the current virus and any new airborne pathogens. The aim of this study is to analyze the quality of the ventilation system and the importance of the use of PPE in Lecture Hall C of the University of Naples Federico II compared to the premises in Piazzale Tecchio. After dimensioning the lecture theatre with the Autodesk software AutoCAD 2021, CFD simulations were carried out with the Computational Fluid Dynamics program Ansys 2021 R2. To study the trajectory of virus droplets released by a potentially infected student in the center of the classroom, the multispecies model was used, with carbon dioxide serving as the tracer gas for the virus cloud. After determining the CO2 contour zones at fifteen-minute intervals for a total duration of two hours, the probability of infection was calculated using the Wells–Riley equation. [ABSTRACT FROM AUTHOR]

Optimising ventilation strategy for an indoor environment necessitates systematically evaluating the influence of a diverse combination of physical and operational parameters in the design space. This study proposes a methodology that couples an evolutionary algorithm (genetic algorithm) with an evaluation mechanism (computational fluid dynamics) to determine the optimal ventilation strategy for an inpatient ward. The traditional approach would exhaustively simulate numerous scenarios to identify the optimal combination of parameters meeting the design objective. The proposed methodology would iteratively evaluate diverse design solutions with fewer CFD simulations than the traditional approach. The results of design space exploration suggest that design parameters, namely, location of the infected patient; air change rate; flow rate through local exhaust grille; and number, location and size of supply air diffuser and local air exhaust grille, are critical in minimising the risk of cross-infection caused through contact transmission in a ward. [ABSTRACT FROM AUTHOR]

Healthcare personnels (HCPs) are at risk of respiratory infectious diseases during patient care activities. HCPs rely primarily on personal protective equipment to prevent pathogen exposures, but there is a need to develop alternative, or complementary control strategies, including engineering controls. The objective of this study was to evaluate the ability of the 3 designs (denoted D 1A, D 1B, and D 2) of the University of Utah Containment Ventilation for Exposure Reduction (U-COVER), a protective barrier enclosure device to contain respirable aerosols when placed over a simulated patient. The 2 primary performance metrics were the percent reduction in: (i) the concentration of respirable aerosols in the simulated breathing zone of an HCP, and (ii) surface contamination outside the device, which were tested using salt aerosols and fluorescein aerosols, respectively. Briefly, salt or fluorescein aerosols were generated as though expelled by a prone patient under 3 conditions: (i) no device (control), (ii) with the device but without exhaust ventilation, and (iii) with the device with exhaust ventilation. Device D 2 was also tested under simulated use conditions, in which cardboard "arms" were placed inside the device ports. All 3 device designs showed the ability to reduce particle concentrations in the simulated HCP breathing zone and on surfaces by >99% with exhaust ventilation compared to the control condition. Without exhaust ventilation, device performance was lower and highly variable. Under simulated use conditions, device D 2 reduced particle concentrations in the simulated HCP breathing zone by ≥91% and on surfaces by >99% relative to control for all combinations of "arms" tested. The U-COVER device demonstrates excellent aerosol containment and warrants further testing with dynamic simulated or actual use conditions. [ABSTRACT FROM AUTHOR]

Bioaerosols are airborne suspensions of fine solid or liquid particles containing biological substances such as viruses, bacteria, cellular debris, fungal spores, mycelium, and byproducts of microbial metabolism. The global Coronavirus disease 2019 (COVID-19) pandemic and the previous emergence of severe acute respiratory syndrome (SARS), Middle East respiratory syndrome (MERS), and influenza have increased the need for reliable and effective monitoring tools for bioaerosols. Bioaerosol collection and detection have aroused considerable attention. Current bioaerosol sampling and detection techniques suffer from long response time, low sensitivity, and high costs, and these drawbacks have forced the development of novel monitoring strategies. Microfluidic technique is considered a breakthrough for high performance analysis of bioaerosols. In recent years, several emerging methods based on microfluidics have been developed and reported for collection and detection of bioaerosols. The unique advantages of microfluidic technique have enabled the integration of bioaerosol collection and detection, which has a higher efficiency over conventional methods. This review focused on the research progress of bioaerosol collection and detection methods based on microfluidic techniques, with special attention on virus aerosols and bacterial aerosols. Different from the existing reviews, this work took a unique perspective of the targets to be collected and detected in bioaerosols, which would provide a direct index of bioaerosol categories readers may be interested in. We also discussed integrated microfluidic monitoring system for bioaerosols. Additionally, the application of bioaerosol detection in biomedicine was presented. Finally, the current challenges in the field of bioaerosol monitoring are presented and an outlook given of future developments. [ABSTRACT FROM AUTHOR]

Bioaerosols are small airborne particles composed of microbiological fragments, including bacteria, viruses, fungi, pollens, and/or by-products of cells, which may be viable or non-viable wherever applicable. Exposure to these agents can cause a variety of health issues, such as allergic and infectious diseases, neurological disorders, and cancer. Therefore, detecting and identifying bioaerosols is crucial, and bioaerosol sampling is a key step in any bioaerosol investigation. This review provides an overview of the current bioaerosol sampling methods, both passive and active, as well as their applications and limitations for rapid on-site monitoring. The challenges and trends for detecting airborne microorganisms using molecular and immunological methods are also discussed, along with a summary and outlook for the development of prompt monitoring technologies. [ABSTRACT FROM AUTHOR]

Low-flow showerheads offer consumers economic and water-saving benefits, yet their use may inadvertently affect the microbial content of produced water and water-associated aerosols. This study aimed to compare the abundance and microbial composition of bacteria in shower water and associated respirable aerosols produced by various low flow rate (1, 1.5, and 1.8 gpm) showerheads. Our findings indicate that the lowest-flow showerhead produces water with lower total microbial and opportunistic bacterial pathogen densities compared to higher low flow rate counterparts. However, microbiome analysis revealed that 1.8 gpm flow rate showerheads exhibit reduced abundance of Gram-negative organisms and common biofilm-forming organisms, suggesting potentially lower pathogenicity compared to 1 and 1.5 gpm low-flow showerheads. Additionally, the number of respirable aerosols produced by showerheads as well as the partitioning of certain microorganisms from the water to aerosol phases was negatively correlated with flow rate, suggesting that there may be increasing exposure potential to pathogenic bioaerosols when using a 1gpm showerhead compared to a 1.8 gpm showerhead. However, the 1.5 gpm showerhead seemed to balance microbial partitioning, aerosol generation, and water conservation. Moreover, the microbial composition of aerosols produced from shower water was more influenced by the age of the showerhead than the flow rate, highlighting the significance of biofilm formation on the microbial community. Overall, our findings underscore the importance of evaluating the microbial risk associated with low-flow showerheads using multiple metrics in both water and aerosols, and dynamically assessing this over time, to ensure accurate future risk assessment.

Bioaerosols produced during animal production have potential adverse effects on the health of workers and animals. Our objective was to investigate characteristics, antibiotic-resistance genes (ARGs), and health risks of bioaerosols in various animal barns. Poultry and swine barns had high concentrations of airborne bacteria (11156 and 10917 CFU/m3, respectively). Acinetobacter, Clostridium sensu stricto, Corynebacterium, Pseudomonas, Psychrobacter, Streptococcus, and Staphylococcus were dominant pathogenic bacteria in animal barns, with Firmicutes being the most abundant bacterial phylum. Based on linear discriminant analysis effect size (LEfSe), there were more discriminative biomarkers in cattle barns than in poultry or swine barns, although the latter had the highest abundance of bacterial pathogens and high abundances of ARGs (including tetM, tetO, tetQ, tetW sul1, sul2, ermA, ermB) and intI1). Based on network analyses, there were higher co-occurrence patterns between bacteria and ARGs in bioaerosol from swine barns. Furthermore, in these barns, relative abundance of bacteria in bioaerosol samples was greatly affected by environmental factors, mainly temperature, relative humidity, and concentrations of CO2, NH3, and PM2.5. This study provided novel data regarding airborne bio-contaminants in animal enclosures and an impetus to improve management to reduce potential health impacts on humans and animals.

The paper presents an assessment of the mycological air quality in classrooms of school buildings located in Lesser Poland. In 10 schools, 5 sampling points were designated: 4 indoors and 1 as an "outdoor background". A 6-stage Andersen impactor was used to collect fungal aerosol samples. During sampling, dust measurements were made (using the DustTrak II dust meter) as well as temperature and relative humidity. The predominant genera of fungi were determined by the MALDI-TOF MS method. The results indicated no statistically significant differences in indoor air fungal concentrations among the tested locations (p>0.05). The highest concentrations were observed in large classrooms (max. 2,678 CFU∙m-3), however, these differences were not statistically significant across different types of school rooms (Kruskal-Wallis test: p>0.05). All rooms exhibited similar levels of fungal aerosol contamination. Relative air humidity had a significant influence on the number of microorganisms. The most frequently isolated fungi belonged to Cladosporium, Penicillium, and Aspergillus genera. Fungal aerosol concentrations in the tested classrooms did not exceed proposed limit values for this type of indoor environment. The results suggest that natural ventilation in classrooms is insufficient to ensure adequate microbiological quality of indoor air.