Showing papers on "Bioaerosol published in 2013"

Seasonal variability in bacterial and fungal diversity of the near-surface atmosphere.

Abstract: Bacteria and fungi are ubiquitous throughout the Earth's lower atmosphere where they often represent an important component of atmospheric aerosols with the potential to impact human health and atmospheric dynamics. However, the diversity, composition, and spatiotemporal dynamics of these airborne microbes remain poorly understood. We performed a comprehensive analysis of airborne microbes across two aerosol size fractions at urban and rural sites in the Colorado Front Range over a 14-month period. Coarse (PM10-2.5) and fine (PM2.5) particulate matter samples were collected at weekly intervals with both bacterial and fungal diversity assessed via high-throughput sequencing. The diversity and composition of the airborne communities varied across the sites, between the two size fractions, and over time. Bacteria were the dominant type of bioaerosol in the collected air samples, while fungi and plants (pollen) made up the remainder, with the relative abundances of fungi peaking during the spring and summer months. As bacteria made up the majority of bioaerosol particles, we analyzed the bacterial communities in greater detail using a bacterial-specific 16S rRNA gene sequencing approach. Overall, bacterial taxonomic richness and the relative abundances of specific bacterial taxa exhibited significant patterns of seasonality. Likewise, airborne bacterial communities varied significantly between sites and across aerosol size fractions. Source-tracking analyses indicate that soils and leaves represented important sources of bacteria to the near-surface atmosphere across all locations with cow fecal bacteria also representing an important source of bioaerosols at the more rural sites during early fall and early spring. Together, these data suggest that a complex set of environmental factors, including changes in atmospheric conditions and shifts in the relative importance of available microbial sources, act to control the composition of microbial bioaerosols in rural and urban environments.

Fluorescent biological aerosol particles measured with the Waveband Integrated Bioaerosol Sensor WIBS-4: laboratory tests combined with a one year field study

Abstract: . In this paper bioaerosol measurements conducted with the Waveband Integrated Bioaerosol Sensor mark 4 (WIBS-4) are presented. The measurements comprise aerosol chamber characterization experiments and a one-year ambient measurement period at a semi-rural site in South Western Germany. This study aims to investigate the sensitivity of WIBS-4 to biological and non-biological aerosols and detection of biological particles in the ambient aerosol. Several types of biological and non-biological aerosol samples, including fungal spores, bacteria, mineral dust, ammonium sulphate, combustion soot, and fluorescent polystyrene spheres, were analyzed by WIBS-4 in the laboratory. The results confirm the sensitivity of the ultraviolet light-induced fluorescence (UV-LIF) method to biological fluorophores and show the good discrimination capabilities of the two excitation wavelengths/detection wavebands method applied in WIBS-4. However, a weak cross-sensitivity to non-biological fluorescent interferers remains and is discussed in this paper. All the laboratory studies have been undertaken in order to prepare WIBS-4 for ambient aerosol measurements. According to the one-year ambient aerosol study, number concentration of fluorescent biological aerosol particles (FBAP) show strong seasonal and diurnal variability. The highest number concentration of FBAP was measured during the summer term and decreased towards the winter period when colder and drier conditions prevail. Diurnal FBAP concentrations start to increase after sunset and reach maximum values during the late night and early morning hours. On the other hand, the total aerosol number concentration was almost always higher during daytime than during nighttime and a sharp decrease after sunset was observed. There was no correlation observed between the FBAP concentration and the meteorological parameters temperature, precipitation, wind direction and wind speed. However, a clear correlation was identified between the FBAP number concentration and the relative humidity. Humidity-controlled release mechanisms of some fungal spore species are discussed as a possible explanation.

Development and Performance Evaluation of an Exhaled-Breath Bioaerosol Collector for Influenza Virus

Abstract: The importance of the aerosol mode for transmission of influenza is unknown. Understanding the role of aerosols is essential to developing public health interventions such as the use of surgical masks as a source control to prevent the release of infectious aerosols. Little information is available on the number and size of particles generated by infected persons, which is partly due to the limitations of conventional air samplers, which do not efficiently capture fine particles or maintain microorganism viability. We designed and built a new sampler, called the G-II, that collects exhaled-breath particles that can be used in infectivity analyses. The G-II allows test subjects to perform various respiratory maneuvers (i.e., tidal breathing, coughing, and talking) and allows subjects to wear a mask or respirator during testing. A conventional slit impactor collects particles greater than 5.0 μm. Condensation of water vapor is used to grow remaining particles, including fine particles, to a size large enoug...

Release of Free DNA by Membrane-Impaired Bacterial Aerosols Due to Aerosolization and Air Sampling

Abstract: We report here that stress experienced by bacteria due to aerosolization and air sampling can result in severe membrane impairment, leading to the release of DNA as free molecules. Escherichia coli and Bacillus atrophaeus bacteria were aerosolized and then either collected directly into liquid or collected using other collection media and then transferred into liquid. The amount of DNA released was quantified as the cell membrane damage index (ID), i.e., the number of 16S rRNA gene copies in the supernatant liquid relative to the total number in the bioaerosol sample. During aerosolization by a Collison nebulizer, the ID of E. coli and B. atrophaeus in the nebulizer suspension gradually increased during 60 min of continuous aerosolization. We found that the ID of bacteria during aerosolization was statistically significantly affected by the material of the Collison jar (glass > polycarbonate; P B. atrophaeus; P < 0.001). When E. coli was collected for 5 min by filtration, impaction, and impingement, its ID values were within the following ranges: 0.051 to 0.085, 0.16 to 0.37, and 0.068 to 0.23, respectively; when it was collected by electrostatic precipitation, the ID values (0.011 to 0.034) were significantly lower (P < 0.05) than those with other sampling methods. Air samples collected inside an equine facility for 2 h by filtration and impingement exhibited ID values in the range of 0.30 to 0.54. The data indicate that the amount of cell damage during bioaerosol sampling and the resulting release of DNA can be substantial and that this should be taken into account when analyzing bioaerosol samples.

Occupational exposure to airborne microorganisms, endotoxins and β-glucans in poultry houses at different stages of the production cycle

Abstract: The aim of the presented study was to assess the exposure of poultry workers to airborne microorganisms, endotoxins and β-glucans during different stages of the chicken production cycle in 3 commercially-operated poultry houses Personal and stationary sampling was carried out to assess exposure to both viable and total microbial aerosols The stationary measurements of PM10 were performed to establish the level of endotoxins and β-glucans The concentrations of bacterial and fungal aerosols ranged from 25×10(2) CFU/m(3)-29×10(6) CFU/m(3), and from 18×10(2) CFU/m(3)-18×10(5) CFU/m(3), respectively The number of culturable microorganisms was significantly lower than their total counts, constituting from 00004%-64% of the total microbial flora The level of PM10 in poultry facilities did not exceed 45 mg/m(3) After the flock entered the clean house, the level of endotoxins and β-glucans increased from below detection limit to 8,364 ng/m(3) and from 08 ng/m(3) to 6,886 ng/m(3), respectively The presented study shows that professional activities in poultry farms are associated with constant exposure to bioaerosol, which may pose a health hazard to workers It was found that workers' exposure to airborne microorganisms increased with consecutive stages of the chicken production cycle

Characterization of biological aerosol exposure risks from automobile air conditioning system

Abstract: Although use of automobile air conditioning (AC) was shown to reduce in-vehicle particle levels, the characterization of its microbial aerosol exposure risks is lacking. Here, both AC and engine filter dust samples were collected from 30 automobiles in four different geographical locations in China. Biological contents (bacteria, fungi, and endotoxin) were studied using culturing, high-throughput gene sequence, and Limulus amebocyte lysate (LAL) methods. In-vehicle viable bioaerosol concentrations were directly monitored using an ultraviolet aerodynamic particle sizer (UVAPS) before and after use of AC for 5, 10, and 15 min. Regardless of locations, the vehicle AC filter dusts were found to be laden with high levels of bacteria (up to 26,150 CFU/mg), fungi (up to 1287 CFU/mg), and endotoxin (up to 5527 EU/mg). More than 400 unique bacterial species, including human opportunistic pathogens, were detected in the filter dusts. In addition, allergenic fungal species were also found abundant. Surprisingly, unexpected fluorescent peaks around 2.5 μm were observed during the first 5 min use of AC, which was attributed to the reaerosolization of those filter-borne microbial agents. The information obtained here can assist in minimizing or preventing the respiratory allergy or infection risk from the use of automobile AC system.

Airborne microorganisms emitted from wastewater treatment plant treating domestic wastewater and meat processing industry wastes

Abstract: Experiments were conducted to study the airborne microbial contamination generated by a wastewater treatment plant (WWTP). Aerosol samples were collected simultaneously, by sedimentation and impact methods, from the area and the surroundings of the WWTP. Total colony forming units (CFUs) of heterotrophic bacteria (HPC), as well as members of the Enterobacteriaceae, staphylococci, enterococci, actinomycetes, and microscopic fungi were determined. Bacterial (HPC) concentrations ranged between 101 and 104 CFU/m3, fungi 0 and 104 CFU/m3. Higher numbers of HPC bacteria in air samples were observed in summer, fungi in autumn. The main emission of microorganisms to atmospheric air was from the mechanical sewage treatment devices of the WWTP. The facilities of the biological sewage treatment of the plant did not generate large amounts of bioaerosols. In the air obtained from the premises of the WWTP, 25 species of the Enterobacteriaceae were isolated (Salmonella spp., Klebsiella pneumoniae, Escherichia coli). At the fence and in the surroundings only Pantoea spp. were identified. This suggests that the sewage bacteria were mainly discharged in the area of the WWTP. The presence of enteric bacteria, especially Enterobacteriaceae reflects the level of air pollution with bioaerosols from sewage and is an important factor during monitoring the quality of the air around WWTPs.

Observations of fluorescent and biological aerosol at a high-altitude site in central France

Abstract: . Total bacteria, fungal spore and yeast counts were compared with ultraviolet-light-induced fluorescence (UV-LIF) measurements of ambient aerosol at the summit of the Puy de Dome (PdD) mountain in central France (1465 m a.s.l), which represents a background elevated site. Bacteria, fungal spores and yeast were enumerated by epifluorescence microscopy (EFM) and found to number 2.2 to 23 L−1 and 0.8 to 2 L−1, respectively. Bacteria counts on two successive nights were an order of magnitude larger than in the intervening day. A wide issue bioaerosol spectrometer, version 3 (WIBS-3) was used to perform UV-LIF measurements on ambient aerosol sized 0.8 to 20 μm. Mean total number concentration was 270 L−1 (σ = 66 L−1), found predominantly in a size mode at 2 μm for most of the campaign. Total concentration (fluorescent + non-fluorescent aerosol) peaked at 500 L−1 with a size mode at 1 μm because of a change in air mass origin lasting around 48 h. The WIBS-3 features two excitation and fluorescence detection wavelengths corresponding to different biological molecules, although non-biological interferents also contribute. The mean fluorescent particle concentration after short-wave (280 nm; associated with tryptophan) excitation was 12 L−1 (σ = 6 L−1), and did not vary much throughout the campaign. In contrast, the mean concentration of particles fluorescent after long-wave (370 nm; associated with NADH) excitation was 95 L−1 (σ = 25 L−1), and a nightly rise and subsequent fall of up to 100 L−1 formed a strong diurnal cycle in the latter. The two fluorescent populations exhibited size modes at 3 μm and 2 to 3 μm, respectively. A hierarchical agglomerative cluster analysis algorithm was applied to the data and used to extract different particle factors. A cluster concentration time series representative of bacteria was identified. This was found to exhibit a diurnal cycle with a maximum peak appearing during the day. Analysis of organic mass spectra recorded using an aerosol mass spectrometer (AMS; Aerodyne Inc.) suggests that aerosol reaching the site at night was more aged than that during the day, indicative of sampling the residual layer at night. Supplementary meteorological data and previous work also show that PdD lies in the residual layer/free troposphere at night, and this is thought to cause the observed diurnal cycles in organic-type and fluorescent aerosol particles. Based on the observed disparity between bacteria and fluorescent particle concentrations, fluorescent non-PBA is likely to be important in the WIBS-3 data and the surprisingly high fluorescent concentration in the residual layer/free troposphere raises questions about a ubiquitous background in continental air during the summer.

Evaluation of Bioaerosols in Five Educational Hospitals Wards Air in Hamedan, During 2011-2012

Abstract: Materials and Methods: In this cross sectional research, 30 wards in five educational hospitals of Hamadan city were studied. More than 180 air samples were collected from the hospitals. The samples were transferred to blood agar and Sabouraud medium and cultivated immediately. Type and number of colonies were determined in the laboratory. Bioaerosol concentrations were calculated in terms of cfu/ m 3 . After bioaerosols isolation, the isolates were identified by morphology of colony, Gram staining and by standard biochemical tests as required for bacterial or fungal bioaerosols. The SPSS software was used for data management. ANOVA and t-test statistical analyses were also used. Results: As the results demonstrated, highest and lowest averages of bioaerosol density were obtained from Shahid Beheshti and Fatemieh Hospitals (36.18 cfu/m 3 Vs. 24.03 cfu/m 3 ), respectively. Highest and lowest concentrations of bioaerosols were found in Women1 and operating room wards of Fatemiyeh Hospital, respectively (54.4cfu/m 3 VS. 13.3cfu/m 3 ). It appears that there had been no significant correlation between concentration of bioaerosols in the hospitals and available guideline values (P = 0.3). The highest fungal populations were Penicelium spp. (32.06%), Cladosporium spp. (20.5%), Aspergillus fumigatus (14.61%) and A. niger (7.43%), respectively. The highest bacterial population was coagulase-negative staphylococci (32.49%), Bacillus spp. (14.74%), Micrococcus spp. (13.68%) and Staphylococcus aureus (11.34%), respectively. Conclusions: Quantitative bioaerosols concentration in the air of some hospitals was more than the available guideline i.e. 30 cfu/m 3 . Bioaerosol density of all surveyed hospitals can relate to patients presence in wards and their visitors, incorrect ventilation, and probably inefficient disinfection. Most surveyed hospitals have no air treatment systems thus to reduce bioaerosol concentration, standard ventilation systems should designed and utilized.

Monitoring of bioaerosol inhalation risks in different environments using a six-stage Andersen sampler and the PCR-DGGE method

Abstract: Increasing evidences show that inhalation of indoor bioaerosols has caused numerous adverse health effects and diseases. However, the bioaerosol size distribution, composition, and concentration level, representing different inhalation risks, could vary with different living environments. The six-stage Andersen sampler is designed to simulate the sampling of different human lung regions. Here, the sampler was used in investigating the bioaerosol exposure in six different environments (student dorm, hospital, laboratory, hotel room, dining hall, and outdoor environment) in Beijing. During the sampling, the Andersen sampler was operated for 30 min for each sample, and three independent experiments were performed for each of the environments. The air samples collected onto each of the six stages of the sampler were incubated on agar plates directly at 26 °C, and the colony forming units (CFU) were manually counted and statistically corrected. In addition, the developed CFUs were washed off the agar plates and subjected to polymerase chain reaction (PCR)-denaturing gradient gel electrophoresis (DGGE) for diversity analysis. Results revealed that for most environments investigated, the culturable bacterial aerosol concentrations were higher than those of culturable fungal aerosols. The culturable bacterial and fungal aerosol fractions, concentration, size distribution, and diversity were shown to vary significantly with the sampling environments. PCR-DGGE analysis indicated that different environments had different culturable bacterial aerosol compositions as revealed by distinct gel band patterns. For most environments tested, larger (>3 μm) culturable bacterial aerosols with a skewed size distribution were shown to prevail, accounting for more than 60 %, while for culturable fungal aerosols with a normal size distribution, those 2.1-4.7 μm dominated, accounting for 20-40 %. Alternaria, Cladosporium, Chaetomium, and Aspergillus were found abundant in most environments studied here. Viable microbial load per unit of particulate matter was also shown to vary significantly with the sampling environments. The results from this study suggested that different environments even with similar levels of total microbial culturable aerosol concentrations could present different inhalation risks due to different bioaerosol particle size distribution and composition. This work fills literature gaps regarding bioaerosol size and composition-based exposure risks in different human dwellings in contrast to a vast body of total bioaerosol levels.

Virus occupational exposure in solid waste processing facilities.

Abstract: It is well known that workers involved in the management of solid waste are at risk of exposure to bioaerosol, which is generally studied in relation to bacteria, fungi, and endotoxins. However, to date, there have been no reports on the incidence of work-related infectious diseases. To determine if occupational exposure to viruses occurs upon exposure to waste-related activities, monitoring was carried out in a landfill, a waste recycling plant, an incineration plant, and a waste collection vehicles. Air and surfaces were sampled and analyzed for torque teno virus (TTV), human adenovirus (HAdV), norovirus, rotavirus, and enterovirus using polymerase chain reaction (PCR)-based techniques. Positivity was confirmed by sequencing and quantification with real-time PCR; infectivity was also tested for culturable viruses. Samples were analyzed in parallel for mean total bacterial and fungi counts in both the summer and winter. In total, 30% (12/40) of air and 13.5% (5/37) of surface samples collected in plants were positive for HAdV and TTV. Among the eight HAdV-positive samples, six (75%), revealed in landfill and recycling plant air and in incinerator and waste vehicles surfaces, were able to replicate in cell culture and were subsequently confirmed as infective. The frequency of detection of virus-positive samples was similar in both seasons, but with evident differences in the type of virus detected: TTV and HAdV were more frequently detected in the summer and winter, respectively. The area of highest viral contamination was the paper selection landfill. Fungi and bacterial contamination did not correlate with viral presence or concentration. In conclusion, we evidence that working with solid and liquid waste can lead to infectious viruses, included in Group 2 of the European Directive 90/679/CEE pathogens list; thus, further investigation on the sources and routes of contamination is needed in order to assess the occupational risk.

Enhancing Bioaerosol Sampling by Andersen Impactors Using Mineral-Oil-Spread Agar Plate

Abstract: As a bioaerosol sampling standard, Andersen type impactor is widely used since its invention in 1950s, including the investigation of the anthrax attacks in the United States in 2001. However, its related problems such as impaction and desiccation stress as well as particle bounce have not been solved. Here, we improved its biological collection efficiencies by plating a mineral oil layer (100 µL) onto the agar plate. An Andersen six-stage sampler and a BioStage impactor were tested with mineral-oil-spread agar plates in collecting indoor and outdoor bacterial and fungal aerosols. The effects of sampling times (5, 10 and 20 min) were also studied using the BioStage impactor when sampling environmental bioaerosols as well as aerosolized Bacillus subtilis (G+) and Escherichia coli (G-). In addition, particle bounce reduction by mineral-oil-plate was also investigated using an optical particle counter (OPC). Experimental results revealed that use of mineral-oil-spread agar plate can substantially enhance culturable bioaerosol recoveries by Andersen type impactors (p-values<0.05). The recovery enhancement was shown to depend on bioaerosol size, type, sampling time and environment. In general, more enhancements (extra 20%) were observed for last stage of the Andersen six-stage samplers compared to the BioStage impactor for 10 min sampling. When sampling aerosolized B. subtilis, E. coli and environmental aerosols, the enhancement was shown to increase with increasing sampling time, ranging from 50% increase at 5 min to ∼100% at 20 min. OPC results indicated that use of mineral oil can effectively reduce the particle bounce with an average of 66% for 10 min sampling. Our work suggests that enhancements for fungal aerosols were primarily attributed to the reduced impaction stress, while for bacterial aerosols reduced impaction, desiccation and particle bounce played major roles. The developed technology can readily enhance the agar-based techniques including those high volume portable samplers for bioaerosol monitoring.

Microbial Contents of Vacuum Cleaner Bag Dust and Emitted Bioaerosols and Their Implications for Human Exposure Indoors

Abstract: Vacuum cleaners can release large concentrations of particles, both in their exhaust air and from resuspension of settled dust. However, the size, variability, and microbial diversity of these emissions are unknown, despite evidence to suggest they may contribute to allergic responses and infection transmission indoors. This study aimed to evaluate bioaerosol emission from various vacuum cleaners. We sampled the air in an experimental flow tunnel where vacuum cleaners were run, and their airborne emissions were sampled with closed-face cassettes. Dust samples were also collected from the dust bag. Total bacteria, total archaea, Penicillium/Aspergillus, and total Clostridium cluster 1 were quantified with specific quantitative PCR protocols, and emission rates were calculated. Clostridium botulinum and antibiotic resistance genes were detected in each sample using endpoint PCR. Bacterial diversity was also analyzed using denaturing gradient gel electrophoresis (DGGE), image analysis, and band sequencing. We demonstrated that emission of bacteria and molds (Penicillium/Aspergillus) can reach values as high as 1E5 cell equivalents/min and that those emissions are not related to each other. The bag dust bacterial and mold content was also consistent across the vacuums we assessed, reaching up to 1E7 bacterial or mold cell equivalents/g. Antibiotic resistance genes were detected in several samples. No archaea or C. botulinum was detected in any air samples. Diversity analyses showed that most bacteria are from human sources, in keeping with other recent results. These results highlight the potential capability of vacuum cleaners to disseminate appreciable quantities of molds and human-associated bacteria indoors and their role as a source of exposure to bioaerosols.

Effects of ultraviolet germicidal irradiation and swirling motion on airborne Staphylococcus aureus, Pseudomonas aeruginosa and Legionella pneumophila under various relative humidities

Abstract: UNLABELLED Staphylococcus aureus, Pseudomonas aeruginosa, and Legionella pneumophila have been detected in indoor air and linked to human infection. It is essential to adopt control methods to inactivate airborne pathogens. By passing bioaerosols horizontally into a UV device at two flow rates (Qs) and moving cells around a central UVC lamp at relative humidity (RH) of 12.7-16.7%, 58.7-59.6%, and 87.3-90%, the effects of swirling motion and 254-nm ultraviolet germicidal irradiation (UVGI) against bioaerosols were assessed under UV-off and UV-on settings, respectively. An inverse relationship between RH and UVGI effectiveness was observed for every test bioaerosol (r = -0.74 ∼ -0.81, P < 0.0001). Increased UV resistance with RH is likely associated with the hygroscopicity of bioaerosols, evident by increased aerodynamic diameters at high RH (P < 0.05). UVGI effectiveness was significantly increased with decreasing Q (P < 0.0001). Moreover, P. aeruginosa was the most susceptible to UVGI, while the greatest UV resistance occurred in L. pneumophila at low RH and S. aureus at medium and high RH (P < 0.05). Results of UV off show P. aeruginosa and L. pneumophila were more sensitive to air-swirling motion than S. aureus (P < 0.05). Overall, test bioaerosols were reduced by 1.7-4.9 and 0.2-1.7 log units because of the UVGI and swirling movement, respectively. PRACTICAL IMPLICATIONS The studied UV device, with a combination of swirling motion and UVGI, is effective to inactivate airborne S. aureus, P. aeruginosa, and L. pneumophila. This study also explores the factors governing the UVGI and swirling motion against infectious bioaerosols. With understanding the environmental and operational parameters, the studied UV device has the potential to be installed indoors where people are simultaneously present, for example, hospital wards and nursing homes, to prevent the humans from acquiring infectious diseases.

Municipal landfill sites as sources of microorganisms potentially pathogenic to humans

Abstract: The present research was aimed at assessing the quality of air and soil on the premises and in the vicinity of the municipal landfill sites in Torun with regard to the presence of pathogenic bacteria, potentially dangerous to humans. Air samples (the impaction method using a MAS-100 impactor) and soil samples were collected from seven sampling sites including the operating and closed landfill cells, sampling sites located near leachate ponds, and sampling sites located outside the above premises. The research also involved assessing microbial air contamination in three indoor spaces on the premises of the landfill sites. Microbial tests involved the determination of the number of culturable mesophilic, mannitol-positive, and α- and β-hemolytic bacteria in the air, determination of the number of coliform bacteria, spore-forming Clostridium perfringens in soil, and the presence of Salmonella in soil. The results indicate that bioaerosol emitted by this municipal facility is the source of hemolytic bacteria (≤300 CFU m−3 of air), as well as of pathogenic bacteria (Pseudomonas aeruginosa and Bacillus subtilis). The highest risk of exposure to biological agents was determined in the sorting facility. Over sixty percent of air samples in this sampling site presented high pollution degree with mesophilic bacteria (500–2000 CFU m−3 of air) and over one fourth of air samples presented very high pollution degree (>2000 CFU m−3 of air). Indoor air in other rooms was considered highly/moderately contaminated (100–2000 CFU m−3 of air). The highest risk related to the presence of Salmonella, Clostridium perfringens, and coliform bacteria in soil was determined at the operating landfill cell and near the leachate pond of the closed landfill cell. At the operating landfill cell the total coli ranged from 4–1226 MPN g−1 of dry mass of soil and Clostridium perfringens ranged from

Culturable airborne bacteria in outdoor poultry-slaughtering facility

Abstract: Airborne bacteria are important biological components of the aerosols and have a close relationship with human health as they can have adverse effects through infection and toxicity; higher concentrations can result in various microbial diseases. Moreover, they have a great influence on air quality in Beijing. In this study, a systematic survey on culturable airborne bacteria was carried out for 1 year at a slaughtering plant in Beijing. Bacterial samples were collected with FA-1 sampler for 3 min, three times each day, for three consecutive days of each month from three sampling sites using BIOLOG identification technology. Results showed that Gram-positive bacteria contributed 80%-85% and were much more prevalent than Gram-negative bacteria. Amongst 47 genera of bacteria, including 31 Gram-positive bacteria and 16 Gram-negative bacteria, Micrococcus, Staphylococcus, Bacillus, Corynebacterium, and Pseudomonas were dominant, and Micrococcus, which contributed 20%-30%, was the most dominant genus. The concentration of airborne bacteria was significantly higher in shed used to stay chicken waiting for slaughtering (SSC) and entrances to personnel and transport vehicles with products (EPV) than in green belt (GB). During the year, bacterial concentrations in summer and autumn were much higher than in winter and spring in SSC and EPV, and there were no significant variations in bacterial concentrations in GB. In different periods, a lower concentration of airborne bacteria was found at 13:00.

Bioaerosol analysis based on a label-free microarray readout method using surface-enhanced Raman scattering.

Abstract: Bacterial contamination of indoor air is a serious threat to human health. Pathogenic germs can be transferred from the liquid to the aerosol phase, for instance, when water is sprayed in the air, such as in shower rooms, air conditioners, or fountains. Existing analytical methods for biological indoor air-quality assessment and contamination monitoring are mostly time consuming as they generally require a cultivation step. The need for a rapid, sensitive, and selective detection method for bioaerosols is evident. Our approach is based on the combination of a commercial wet particle sampler (Coriolis μ, Bertin Technologies, France) and a label-free microarray readout based on surface-enhanced Raman scattering (SERS) for detection, which was established in our laboratories. Heat-inactivated Escherichia coli bacteria were used as test microorganisms. An E. coli suspension was sprayed into the chamber by a jet air nebulizer. The resulting bioaerosol was dried, neutralized, and then collected by a Coriolis μ sampler. The bacteria collected were detected by a recently developed microarray readout system, based on label-free SERS detection. A special data evaluation procedure was applied in order to fully exploit the selectivity of the detection scheme, resulting in a detection limit of 144 particles per cubic centimeter.

Estimation of bioaerosol in indoor environment in the university

Abstract: min for 1 min. This study reveals interesting relationship between the concentration of fungal spores and bacteria in relation to both environmental and human factor. Most observed fungal species detected in the samples were Rhizopus oryzae, Aspergillus nidulans and Aspergillus flavus. Specific bacterial identification was not possible but Gram staining followed by microscopic analysis helped in deriving the different shapes of bacteria collected. Bacillus and Coccus were found maximally. Indoor/Outdoor ratio above 1 for fungal spores signified higher source in the indoor environment at different sections. In indoor environment highest fungal concentration was found in Basement (3140 -3 -3 colony-forming units (CFU) m ) while lowest in 3rd floor (2560 CFU m ). In case of bacterial concentration both Gram negative and positive bacteria were found maximum in the Reading Hall -3 -3 (792 and 696 CFU m , respectively) while lowest in 3rd floor (475 and 437 CFU m , respectively). Higher bacterial counts were primarily attributed to the number of library occupants. High concentration may be due to larger rate of shedding of human skin cells, microbes released from respiratory tract and transport of microbes from floor surfaces on suspended particles.

Bioaerosols from a food waste composting plant affect human airway epithelial cell remodeling genes.

Abstract: The composting procedure in food waste plants generates airborne bioaerosols that have the potential to damage human airway epithelial cells. Persistent inflammation and repair responses induce airway remodeling and damage to the respiratory system. This study elucidated the expression changes of airway remodeling genes in human lung mucoepidermoid NCI-H292 cells exposed to bioaerosols from a composting plant. Different types of microorganisms were detectable in the composting plant, using the agar culture method. Real-time polymerase chain reaction was used to quantify the level of Aspergillus fumigatus and the profile of remodeling genes. The real-time PCR results indicated that the amount of A. fumigatus in the composting hall was less than 102 conidia. The endotoxins in the field bioaerosols were determined using a limulus amebocyte lysate test. The endotoxin levels depended on the type of particulate matter (PM), with coarse particles (2.5–10 μm) having higher endotoxin levels than did fine particles (0.5–2.5 μm). After exposure to the conditioned medium of field bioaerosol samples, NCI-H292 cells showed increased pro-inflammatory interleukin (IL)-6 release and activated epidermal growth factor receptor (EGFR), transforming growth factor (TGF)-β1 and cyclin-dependent kinase inhibitor 1 (p21WAF1/CIP1) gene expression, but not of matrix metallopeptidase (MMP)-9. Airborne endotoxin levels were higher inside the composting hall than they were in other areas, and they were associated with PM. This suggested that airborne bioaerosols in the composting plant contained endotoxins and microorganisms besides A. fumigatus that cause the inflammatory cytokine secretion and augment the expression of remodeling genes in NCI-H292 cells. It is thus necessary to monitor potentially hazardous materials from bioaerosols in food composting plants, which could affect the health of workers.

Relationship Between Biologically Fluorescent Aerosol and Local Meteorological Conditions

Abstract: Time-resolved characterization of biological aerosol is important both for understanding environmental processes that affect biological aerosols and for determining realistic test conditions for the evaluation of bioaerosol detection systems. Very little work has been done to develop an understanding of the temporal fluctuations in bioaerosol concentration. During an experiment from 1–10 November 2008 ambient biological aerosol and meteorological data were collected. A FLIR/ICx/S3I Instantaneous Bioaerosol Analysis and Collection sensor was used to count both the biological and nonbiological aerosol in two size bins. The data indicate that the ambient relative humidity affects the optically observable concentration of biological aerosol with higher relative humidity generally associated with higher biological aerosol concentrations. The short timescale over which these correlations exist implies an aerosol process, rather than a change in aerosol source. © 2013 American Association for Aerosol Research

Surface plasmon resonance-based real-time bioaerosol detection.

Abstract: Aims: Rapid and precise bioaerosol detection in different environments has become an important research and technological issue over last decades. Previously, we employed a real-time PCR protocol in conjunction with personal bioaerosol sampler for rapid detection of airborne viruses. The approach has been proved to be specific and sensitive. However, a period of time required for entire procedure was in manner of hours. Some new developments are required to decrease the detection time down to real-time protocols. Methods and Results: Presently, a surface plasmon resonance (SPR)-based immunosensor that coupled with a specific antigen-antibody reaction could offer sensitive, specific, rapid and label-free detection. This study describes the possibility of combining the personal sampler with SPR technology for qualitative and extremely rapid detection of airborne micro-organisms. Common viral surrogate MS2 bacteriophage, frequently used in bioaerosol studies, was employed as a model organism. The results of the sensor functionalizing procedure with monoclonal anti-MS2 antibody and optimization of the chip performance are presented. The SPR-based detection of the airborne virus was found to be very fast; the viral presence was detected in less than 2 min, and the entire procedure (sampling and analysis) was undertaken in 6 min, which could be considered as real-time detection for this type of measurements. Conclusions: The combination of SPR with the personal sampler targeted towards bioaerosol detection was proven to be feasible. The SPR sensor was found to be highly stable and suitable for multiple utilizations without significant decrease in response. The suggested approach opens new possibilities for the development of portable and rapid (almost real time) bioaerosol monitors. Significance and Impact of the Study: This technology is the first in the world real-time bioaerosol monitor. This outcome would be of strong interest to individuals representing public health, biosecurity, defence forces, environmental sciences and many others.

Particle counting and microbiological air sampling: Results of the simultaneous use of both procedures in different types of hospital rooms

Abstract: Introduction In order to assess the relationship between the concentrations of airborne fungi and particles, particle counting was combined with fungal air sampling in several rooms of a hospital. Methods Concentrations of ≥0.5 μm particles (P05) and ≥1 μm particles (P1) were measured using a particle counter; fungal air sampling was performed with volumetric air samplers, which impacted air on Rodac plates with Sabouraud chloramphenicol agar. Particle counts were categorised according to ISO 14644-1 standard cut-off points; their association with fungal detection was assessed with Fisher's exact test. Results Forty-two simultaneous samplings were carried out: 24 in operating rooms, 13 in rooms for burns or haematology patients, 3 in pharmacy clean rooms, and two in other procedure rooms. Filamentous fungi were recovered in 5 samples, which also had higher particle counts. No fungi were detected in 12 samplings with both P05 and P1 concentrations below the maximum for class 6 clean rooms; 4 of 7 samplings with both concentrations within the range for class 8 clean rooms were positive for fungi. The association between fungal detection and higher particle counts was statistically significant, both for P05 (p = .004) and P1 (p = .003). There was a partial overlap between the concentrations of particles of samplings which were positive or negative for fungi. Conclusions There is a relationship between the concentrations of P05 and P1 and airborne fungi in hospital rooms. When both P05 and P1 concentrations are below the maximum for class 6 clean rooms, a negative fungal detection can be predicted.

The Efficient Method for Simultaneous Monitoring of the Culturable as Well as Nonculturable Airborne Microorganisms

Abstract: Cultivation-based microbiological methods are a gold standard for monitoring of airborne micro-organisms to determine the occupational exposure levels or transmission paths of a particular infectious agent. Some highly contagious microorganisms are not easily culturable but it is becoming evident that cultivation and molecular methods are complementary and in these cases highly relevant. We report a simple and efficient method for sampling and analyzing airborne bacteria with an impactor-type high-flow-rate portable air sampler, currently used for monitoring culturable bacteria or fungi. A method is reported for extraction of nucleic acids from impacted cells without prior cultivation and using agarose as a sampling matrix. The DNA extraction efficiency was determined in spiked samples and, samples taken from a wastewater treatment plant and an alpine area. The abundance, diversity and quantity of total bacteria were analysed by a quantitative polymerase chain reaction, and by construction and analysis of clone libraries. The method does not interfere with downstream PCR analysis and can cover the gap between traditional culture and molecular techniques of bioaerosol monitoring.

Identification of Bioaerosols Released from an Egg Production Facility in the Southeast United States.

Abstract: This field study investigated biological characteristics of aerosols emitted from a commercial egg production farm (layer operation). Bioaerosol samples were taken on this farm at five sampling locations covering emission source (inside a layer barn) and four ambient surrounding stations at four wind directions. All-glass impingers (AGI) were used for the field sampling. AGI fluid samples were plated in duplicate on Trypticase Soy Agar for growth of bacteria and Sabouraud Dextrose Agar for growth of fungi. The most prominent bacterial colony types were identified using a combination of methods that include recording characteristics of colony morphology; performing a Gram staining method and metabolic analyses using the Biolog system. Results from thirty-five AGI samples taken at the five stations through seven sampling events over four seasons indicate that there were significantly lower total bacterial concentrations in the samples collected from ambient stations as compared with the samples col...

The role of nursing activities on the bioaerosol production in hospital wards

Abstract: Transport of infectious particles through the air has the potential to contaminate the indoor environment creating reservoirs of infectious material on surfaces. There is evidence that typical nursing activities can release large quantities of bacteria including MRSA into the hospital air, which may lead to surface contamination thereby increasing opportunities for further spread. Air sampling studies were conducted over a period of 5 days on a four-bed bay in a respiratory ward. Results showed that sampled bioaerosols are more likely to be carried on large particles >5 µm in diameter, and that the relationship between bioaerosols and particle size varies when respiratory interventions are in use. Increased activity in the hospital bay was shown to correlate to increased concentrations of bioaerosols whereas sedentary visitors did not. In particular, the occurrence of patient washing that occurred behind closed curtains correlated to large values of bioaerosol release. Floor cleaning generated large number of particles, but with no significant increase in sampled bioaerosols. This provides valuable information for understanding when and where bioaerosols are released on a hospital ward which may inform future research into physical segregation of patients and the definition of bioaerosol sources in computer simulations.