Exposure to (1?→?3)-β-D-glucans in swine farms

The aim of this study was to assess the exposure to organic dust and (1 → 3)-β-D-glucans in the buildings where an intensive breeding of swine is going on and evaluation of the impact of the breeding technical conditions on the observed levels of bioaerosols. The study was carried out in 30 swine farms differentiated by the size of the herd and technical conditions of breeding. In 35 randomly selected buildings, air samples were collected by stationary measurements to determine the concentrations of organic dust and (1 → 3)-β-D-glucans in inhalable and respirable fractions. Furthermore, each of the investigated buildings was precisely characterized by means of a questionnaire for technical conditions and type of breeding. In each of the points, the microclimate parameters were measured, i.e., temperature, relative humidity, CO₂ concentration and air velocity. The analyzed levels of organic dust and (1 → 3)-β-D-glucans were characterized by a wide range of concentrations. For inhalable fraction, they reached respectively: organic dust (0.43–11.8 mg/m³), (1 → 3)-β-D-glucans (14–3,594 ng/m³). For respirable fraction, the results were as follows: organic dust (0.01–4.69 mg/m³), (1 → 3)-β-D-glucans (1–703 ng/m³). The concentrations of (1 → 3)-β-D-glucans were positively correlated with organic dust (r = 0.68; p < 0.001). The most significant factor increasing the concentrations of organic dust and (1 → 3)-β-D-glucans was the use of bedding in the form of cut straw. Additionally, the levels of (1 → 3)-β-D-glucans were affected by manual forage feeding, mechanical manure disposal and the lack of the liquid manure container in breeding buildings. In view of the hazardous effects of biological agents on the health of swine-breeding workers, the swine management systems without beddings should be used, along with automated dosing techniques.     

β(1 → 3)-glucan aerosols in different occupational environments

The aim of this preliminary study was to assess exposure to β(1 → 3)-glucan as well as inhalable dust and viable fungi in different occupational environments. The study was conducted in three different industrial plants: metal plant where metalworking fluids were applied, wastewater treatment plant, and waste composting plant. In selected points simultaneously the stationary air sampling was performed to evaluate the levels of inhalable dust, β(1 → 3)-glucan, and to make a quantitative analysis of airborne fungi. All variables describing the exposure were characterized by a wide range of concentrations. The results were as follows: β(1 → 3)-glucan (1.38–65.1 ng/m³), inhalable dust (0.03–2.93 mg/m³), and fungi (0.16–285 × 10² CFU/m³). The highest concentrations for all parameters were found in the composting plant. In the composting plant, a statistically significant correlation was found between β(1 → 3)-glucan and fungal levels (r = 0.89; p < 0.05). In the metal industry and composting plant, the participation of alkali-soluble fraction was stable, exceeding 90% of all β(1 → 3)-glucan. However, in the wastewater treatment plant, its average amount was much lower—73.6%. The study showed that β(1 → 3)-glucan was present in different occupational environments and it should be taken into consideration as an important part of bioaerosols. However, more studies are required to assess the concentration levels as well as all determinants of exposure.     

Bioaerosol emissions arising during application of municipal solid-waste compost

Although application of composted municipal waste has its benefits, there are also concerns about a range of adverse effects. Bioaerosol emissions are one cause of concern because of related health problems. To assess the concentration of bioaerosols emitted during application of compost, fungi and bacteria were collected using an Andersen biosampler. Temperature and relative humidity were also recorded at each location. Total bacterial concentrations averaged 2,887 cfu/m³ for background samples and 6,727 cfu/m³ for compost-application samples, which constitutes a significant difference. The mean concentration of fungi during application of compost was three times greater than the background, but the difference was not significant. Concentrations of total bacteria in compost-application samples decreased significantly with increasing humidity. These results indicated that bioaerosol emissions as a result of application of compost could increase levels of exposure to bacteria and pose a potential health risk for exposed individuals.     

Air biocontamination in a variety of agricultural industry environments in Egypt: a pilot study

Inhalation of airborne microorganisms and organic dust is an occupational concern among workers in agricultural industries. Airborne microorganisms and particulate matter samples were collected from poultry house, flourmill, textile, and food industry sites by use of liquid impinger and gravimetric samplers. Particulate matter concentrations were recorded at median concentrations of 1.56, 1.92, 4.39, and 0.7 mg/m³ in the occupied poultry house, textile, flourmill, and food indoor working environments, respectively. The highest median particulate matter concentration (27.9 mg/m³) was detected at the flourmill’s stack site. The highest median indoor concentration of culturable airborne bacteria (6.23 × 10⁵ CFU/m³) was found at the occupied poultry-house site and the lowest concentration (4.6 × 10³ CFU/m³) was found at the food industry site. The highest median indoor concentration of culturable airborne fungi (3.15 × 10⁴ CFU/m³) was found at the flourmill site whereas the lowest (1.24 × 10³ CFU/m³) was found at the textile industry site. Bacillus and Staphylococcus were the predominant Gram-positive bacteria whereas Acinetobacter and Klebsiella were the predominant Gram-negative bacteria. Escherichia coli and Salmonella were only detected in the indoor air at the poultry house site. Aspergillus flavus, Aspergillus niger, Penicillium, and yeast were the predominant fungal types at flourmill, textile, food industry, and poultry house, respectively. Workers were continuously exposed to airborne microorganisms at a median value of 10⁴ CFU/m³ in all the industries studied.     

Evaluation of bio-aerosols at an animal feed manufacturing industry: A case study

Both total and biological particles (totalculturable bacteria, Gram negative bacteria,mold and actinomycetes) were measured at ananimal feed manufacturing industry. Suspendedparticle concentration ranged from 1.72 to2.3 mg m^–3 with a mean value of1.97 mg m^–3. Airborne microorganisms weredetected in lower concentrations than thoseassociated with suspended dust andfeed-materials. Bacterial concentrations weretwo to three times higher than concentrationsof mold and actinomycetes. Bacterialconcentrations averaged4.86 × 10³ cfu m^–3; 2.6 × 10⁴cfu m^–3 and 3.96 × 10⁷ cfu g^–1 inair, associated with suspended dust andfeed-materials, respectively, whereas moldconcentrations averaged 7.33 × 10²cfu m^–3; 1.97 × 10³ cfu m^–3 and7 × 10⁵ cfu g^–1 of the correspondingenvironments, respectively. Enterobacterspp and Klebsiella spp were the mostabundant Gram negative bacteria, whereas Bacillus species. were the most dominant Grampositive bacteria. Aspergllius niger,other Aspergillus species and Penicillium were the dominant mold isolates.Acremonium was only detected in feedmaterials, whereas Aspergillus fumigatuswas only detected in air. The animal feedindustry environment has a significantbio-contamination and many of microorganismsimplicated in respiratory problems weredetected in this environment.     

Bioaerosol emissions in a poultry litter burning plant

This study investigates the exposure of workers to biological particles in a poultry litter burning plant in operation. The microorganism concentrations were examined at different workplaces during procedures leading to increased emissions. The concentrations of culturable airborne mesophilic, xerophilic and thermophilic microorganisms in the ambient air were tested inside and outside of the burning plant using two different methods of measuring. The focus of this study was on the quantitative evaluation of culturable bacteria as well as the quantitative and qualitative evaluation of gram-negative bacteria, fungi and thermophilic actinomycetes. The maximum airborne concentrations were found in the delivery hall. Mesophilic bacteria concentrations reached up to 1.7 × 10⁶ CFU/m³; gram-negative bacteria up to 9.1 × 10² CFU/m³. Fungal propagule concentrations for xerophilic fungi were between 1.2 × 10³ and 2.9 × 10⁴ CFU/m³ and for mesophilic fungi between 4.4 × 10² and 2.9 × 10⁴ CFU/m³. Among fungi, Aspergillus niger, Eurotium herbariorum and Scopulariopsis brevicaulis species were dominant. Thermophilic actinomycetes reached airborne concentrations of 8.7 × 10⁴ CFU/m³, with increased concentrations of the pathogens causing extrinsic allergic alveolitis. The high concentrations of airborne microorganisms in poultry litter burning plants and the potential hazard of the intake of microorganisms including potential pathogens require the introduction of consistent measures in both technical areas and personnel management.     

Measurements of total and culturable bacteria in the alfresco atmosphere using a wet-cyclone sampler

Alfresco (def. clean, outdoor) airborne bacteria were collected with a commercially available wet-cyclone bioaerosol sampler to demonstrate its use, sample processing and resultant observations of total and culturable bacteria in mid-summer in the mid-Willamette River Valley, OR. Some critiques of the system are given. The maximum and minimum total and culturable airborne bacterial concentrations in the samples were 5.9 × 10⁵ and 8.8 × 10² cells m⁻³, and 1.3 × 10⁴ and 3.1 CFU m⁻³, respectively. What is thought to be a diurnal cycle was also observed for both fractions with highest concentrations during the day and lowest at dawn and dusk. The culturable bacteria as a percentage of the total, was maximal at mid-day (≈ 3%) and minimal at early morning and late evening (≈ 0.5–2%). Contrarily, the total bacteria in the downwind dust plume of a grass seed combine was 2.9 × 10⁶ cells m⁻³ and of these approximately 73% were culturable, a much greater culturable percentage than found in the alfresco outdoor atmosphere.     

Seasonal Variations of Indoor Microbial Exposures and Their Relation to Temperature,Relative Humidity,and Air Exchange Rate

Indoor microbial exposure has been related to adverse pulmonary health effects. Exposure assessment is not standardized, and various factors may affect the measured exposure. The aim of this study was to investigate the seasonal variation of selected microbial exposures and their associations with temperature, relative humidity, and air exchange rates in Danish homes. Airborne inhalable dust was sampled in five Danish homes throughout the four seasons of 1 year (indoors, n = 127; outdoors, n = 37). Measurements included culturable fungi and bacteria, endotoxin, N-acetyl-beta-d-glucosaminidase, total inflammatory potential, particles (0.75 to 15 μm), temperature, relative humidity, and air exchange rates. Significant seasonal variation was found for all indoor microbial exposures, excluding endotoxin. Indoor fungi peaked in summer (median, 235 CFU/m³) and were lowest in winter (median, 26 CFU/m³). Indoor bacteria peaked in spring (median, 2,165 CFU/m³) and were lowest in summer (median, 240 CFU/m³). Concentrations of fungi were predominately higher outdoors than indoors, whereas bacteria, endotoxin, and inhalable dust concentrations were highest indoors. Bacteria and endotoxin correlated with the mass of inhalable dust and number of particles. Temperature and air exchange rates were positively associated with fungi and N-acetyl-beta-d-glucosaminidase and negatively with bacteria and the total inflammatory potential. Although temperature, relative humidity, and air exchange rates were significantly associated with several indoor microbial exposures, they could not fully explain the observed seasonal variations when tested in a mixed statistical model. In conclusion, the season significantly affects indoor microbial exposures, which are influenced by temperature, relative humidity, and air exchange rates.     

Assessment of Bioaerosols in Swine Barns by Filtration and Impaction

Bioaerosol concentrations inside one naturally ventilated and one mechanically ventilated swine finishing barn were assessed by sampling air using membrane filtration and impaction (six-stage Andersen sampler), and assayed by culture method. The barns, located on the same commercial farm in northeast Kansas, did not show any significant difference (p > 0.05) in concentrations of total and respirable airborne microorganisms. The overall mean total concentrations inside the two barns were 6.6 × 10⁴ colony forming units (CFU)/m³ (SD = 3.8 × 10⁴ CFU/m³) as measured by filtration and 8.6 × 10⁴ CFU/m³ (SD = 5.1 × 10⁴ CFU/m³) by impaction. The overall mean respirable concentrations were 9.0 × 10³ CFU/m³ (SD = 4.1 × 10³ CFU/m³) measured by filtration and 2.8 × 10⁴ CFU/m³ (SD = 2.2 × 10⁴ CFU/m³) by impaction. Total and respirable CFU concentrations measured by impaction were significantly (p < 0.05) higher than that by filtration. The persistent strains of microorganisms were various species of the following genera: Staphylococcus, Pseudomonas, Bacillus, Listeria, Enterococcus, Nocardia, Lactobacillus, and Penicillium. It appears that filtration sampling can be used for a qualitative survey of bioaerosols in swine barns while the Andersen sampler is suitable for both quantitative and qualitative assessments. Received: 2 April 2001 / Accepted: 13 June 2001     

Exposure to airborne microorganisms,hyphal fragments,and pollen in a field of organically grown strawberries

Many working environments are predisposed for larger than average amounts of fungi and other microorganisms often due to organic material being handled. From 2003 to 2007, the area used for strawberry production in Denmark increased by 62%. The purpose of this study was to determine the levels of exposure to microorganisms, endotoxin, (1→3)-β-d-glucan (β-glucan), and pollen in a field of strawberries. The study was carried out in eastern Denmark from the middle of June to the beginning of August 2008. The strawberries were grown organically, and microbiological pest control agents (MPCAs) were applied during this and former growth seasons. In order to measure exposure to inhalable bioaerosol components, we used stationary filter samplers. Bioaerosol sampling was performed during 4 working days, and a total of 57 samplings were performed. The filters were analysed for contents of fungi, MPCAs, endotoxin, β-glucan, and pollen. The mean exposure was 6,154 CFU Cladosporium sp. m⁻³, 1.0 × 10⁵ fungal spores m⁻³, 4.1 × 10⁴ hyphal fragments m⁻³, 5.8 × 10³ pollen m⁻³, 57.3 ng β-glucan m⁻³, and 8.9 endotoxin units (EU) m⁻³. A significant and positive correlation was found between β-glucan and fungal spores and between CFU of Cladosporium sp. and CFU of fungi. We selected specifically for Metarhizium anisopliae, Beauveria bassiana, and the applied MPCAs Trichoderma harzianum, T. polysporum, and Bacillus thuringiensis but found none of these species. In conclusion, our study shows that berry pickers in this organic strawberry field were potentially subjected to higher levels of fungal spores, Cladosporium sp., hyphal fragments, pollen, and thus also β-glucan than is usually seen in outdoor air. Exposure to MPCAs was not seen. The exposure to endotoxin was only slightly higher than e.g. in a town.     

A Study of Air Microbe Levels in Different Areas of a Hospital

Airborne transmission is an important route for many microbial pathogens in outdoor and indoor environments, including hospitals. A 2-year-long survey of bioaerosol quality in operating theatres (OT), hospital rooms (HR) and maternity wards (MW) at a hospital in Murcia, Spain, was performed. Total aerobic counts (TAC) and fungal load (FL) were assessed using a microbiological air sampler (MAS-100 single-stage impactor). While fungal levels were below 1 cfu/m³ (0–7.33 cfu/m³) in OT, they were higher in MW (mean, 6.9 cfu/m³; range 0.44–44.67 cfu/m³) and in HR (mean, 10.6 cfu/m³; range, 0–266 cfu/m³). In OT the aerobic counts were considerably higher, with a mean of 25.6 cfu/m³ (range, 1.67–157 cfu/m³). MW and HR also showed higher means for total aerobic counts compared to OT. Seasonal changes were not detected in mould and bacteria levels in OT. Hospital renovation occurred during this study and OT adjacent to renovated areas were closed. A survey of TAC and FL in OT resumed when renovation was completed. We observed an outstanding increase in FL (more than 100 cfu/m³), particularly Aspergillus spp., during this period, but no significant changes in TAC were observed after renovation.     

Indoor and outdoor airborne fungal propagule concentrations in Mexico City

Thirty homes of asthmatic adults located in Mexico City were examined to determine the predominant culturable fungi and the changes in their airborne concentrations. Fungi were cultured and identified microscopically from air samples collected in naturally ventilated homes, during both wet (July–August) and cool dry (November–December) seasons, and from settled dust from the same homes. Airborne dust from indoor yielded 99–4950 cfu m⁻³, and settled dust 10²–10⁶ cfu g⁻¹ on DG18 agar. The indoor geometric mean concentration of airborne fungi during the cool dry season was 460 cfu m⁻³ while in the wet season it was 141 cfu m⁻³. Similarly, numbers of airborne fungal propagules out of doors decreased 60% between the dry and wet season. In general, the total fungal concentrations in indoor air were less than 10³ cfu m⁻³ and a large proportion of them was collected in Stage-2 of the Andersen sampler. Moreover, the ratio between indoor and outdoor concentrations was <3:1. Five of the 30 sampled homes yielded >500 cfu m⁻³ of one genus, with up to 1493Cladosporium cfu m⁻³ or 2549Penicillium cfu m⁻³. Also, these two genera were predominant in both airborne and settled dust, and their concentrations were greater indoors than out, indicating a possible indoor source of fungal propagules. The predominant species wereCladosporium herbarum, Penicillium aurantiogriseum andP. chrysogenum. These results suggest that exposure to large concentrations of fungi occurs indoors and is associated with both seasons of the year and with particular home characteristics.     

in living rooms occupied by cigarette smokers and non-smokers in Sosnowiec, Upper Silesia, Poland

In 12 selected flats in Sosnowiec, Upper Silesia, the concentrations of particulate aerosol, bioaerosol and bacterial endotoxin were examined. Concentrations of particulate aerosol, bacteria, fungi and endotoxin were in the order of 10¹–10² μg/m³, 10¹–10³ cfu/m³, 10⁰–10² cfu/m³ and 10⁻²–10⁻¹ ng/m³, respectively. The most numerous group of microorganisms in indoor air during the winter season were Gram positive mesophilic bacteria. They were more common in flats polluted with tobacco smoke. The concentrations of airborne endotoxins were higher in flats polluted with tobacco smoke in all size ranges. The highest level of endotoxins was found in the fraction of fine particles below 5μm.     

Inhalable dust,endotoxins and (1–3)-β-<Emphasis Type="SmallCaps">d</Emphasis>-glucans as indicators of exposure in waste sorting plant environment

The aim of the study was to assess the levels of inhalable dust, endotoxins and (1–3)-β-d-glucans as agents harmful to the respiratory tract of workers of municipal waste sorting plants and interaction between these agents based on the measurements taken in two plants with different processing capacities. The study was conducted in summer season in two waste sorting plants (WSPs) differing in processing capacity. Samples of bioaerosol for inhalable dust (gravimetric method), endotoxins (LAL test in kinetic, chromogenic version) and (1–3)-β-d-glucans (Glucatell test in kinetic version) were collected from 42 sorting workers using individual aspirators with glass fiber filters during the work shift. Average geometric concentrations (geometric standard deviation; min–max) of inhalable dust, endotoxins and (1–3)-β-d-glucans were: WSP1: 1.7 mg m^?3 (2.2; 0.6–6.9 mg m^?3); 15.9 ng m^?3 (2.1; 5.4–78.9 ng m^?3), 55.1 ng m^?3 (1.8; 20.7–188.6 ng m^?3) and WSP2: 0.8 mg m^?3 (2.2; 0.2–3.8 mg m^?3), 9.8 ng m^?3 (2.4; 1.6–29.7 ng m^?3), 45.0 ng m^?3 (3.2, 5.7–212.9 ng m^?3), respectively. A significantly higher concentration of inhalable dust was recorded in WSP1 with bigger processing capacity compared to WSP2 (less processing capacity). Significant (p < 0.05) and very high correlations (Spearman rank R > 0.7) were found between the concentrations of all analyzed harmful agents. Processing capacity of waste sorting plants differentially affects the concentrations of inhalable dust, whereas concentrations of endotoxins and glucans are less clearly affected. This suggests that relative concentrations of endotoxin and glucan are depending on the waste sorting capacity.     

Occupational exposure to airborne Bacillus thuringiensis kurstaki HD1 and other bacteria in greenhouses and vegetable fields

When microorganisms are used for pest control in vegetable production, the active organisms become part of the microbiota growers are exposed to. The aim of this study was to quantify vegetable growers' exposure to the bacterial strain Bacillus thuringiensis kurstaki strain HD1 (termed HD1) from the biocontrol agent Dipel®, and other airborne mesophilic bacteria. Personal (n=102) and stationary (n=43) measurements of exposure were performed in greenhouses and open fields. Air samples were analysed by plate counts, and total counts with a microscope. Isolates resembling HD1 were identified by PCR analysis. HD1-like bacteria were only detected in environments where Dipel® was used. In a greenhouse with Dipel® treated tomato plants, the growers' exposure to airborne HD1-like bacteria reached 5300 cfu/m³ and 1400 cfu/m³ during harvest and clearing of old plants, respectively. In untreated greenhouses, the highest concentration of total mesophilic bacteria, 1,100,000 cfu/m³, was detected in a cucumber greenhouse. The median concentrations of mesophilic bacteria in tomato greenhouses were significantly lower than the median concentrations in cucumber greenhouses. There was no significant difference in exposure to mesophilic bacteria in tomato greenhouses and in vegetable fields. We found that greenhouse workers, especially in cucumber production, were exposed to high concentrations of total bacteria. Thus, the already present airborne bacteria in greenhouses might have a greater influence on growers' health than applied biocontrol strains. However, further studies are needed to establish an occupational threshold limit for airborne bacteria and to secure a healthy working environment for vegetable growers.     

A case study of airborne culturable microorganisms in a poultry slaughterhouse in Styria, Austria

According to Council Directive 90/679/EEC on the protection of workers from risks related to exposure to biological agents at work, nature, degree and duration of workers’ exposure to microorganisms must be determined. This directive has already been implemented in waste and wastewater management. The present case study investigates concentration and composition of microorganisms in a poultry slaughterhouse in the State of Styria, Austria. From June to November 2002, measurements were conducted at the sampling sites ‘moving rail’ and ‘gall bladder separation’ using the Andersen six stage viable cascade impactor and the SKC BioSampler. The results of this study were compared with other previous studies which were carried out using the same device (ACFM) and the same measurement methods. At the processing area of the ‘moving rail’, the median concentration of airborne mesophilic bacteria was 1.7×10⁶ CFU/m³ which is 8000 times higher than the background concentration of residential areas (approx. 210 CFU/m³). The airborne microorganisms concentration was 1.7×10⁴ CFU/m³ at composting plants which is 100 times lower than at a workplace of a poultry slaughterhouse. The study shows that poultry slaughterhouse employees are exposed to high concentrations of airborne microorganisms throughout the entire work time without using a respiratory protective device. For the protection of employees against airborne biological agents, relevant measures should be introduced to this field of work.     

Airborne concentrations of bacteria and fungi in Thailand border market

Thailand border market is where the local Thais, Cambodians, Laotians, and Burmeses exchange their goods and culture at the border checkpoints. It is considered to be the source of aerial disease transmission especially for foreigners because it is always very crowded with people from all walks of life. Unhealthy air quality makes this area high risk of spread of airborne diseases. This study assessed airborne concentrations of bacteria and fungi in a border market to improve exposure estimates and develop efficient control strategies to reduce health risk. The density and distribution of airborne bacteria and fungi were investigated in the Chong Chom border market in Surin Province, Thailand. Eighteen air sampling sites were taken from outdoors and various work environments including indoor footpaths, wooden handicraft shops, electronic shops, the secondhand clothing shops, and fruit market areas. Exposed Petri plate method and liquid impinger sampler were used for sampling at the breathing zone, 1.5 m above the floor level, during weekend and holiday. Meteorological factors such as relative humidity, temperature, and light intensity were collected by portable data logger. The relative humidity was 67–73%, and temperature 29–33°C, and light varied between 18 and 270 Lux m⁻². Gram-positive and Gram-negative bacteria were found at a mean value of 10⁴ CFU m⁻³, and airborne fungi of 10³ CFU m⁻³ were recorded. The highest concentration of culturable airborne microorganisms was found along the indoor footpath (9.62 × 10⁴ CFU m⁻³ and 750.00 CFU/plate/h for impingement and sedimentation methods, respectively), the fruit market area (7.86 × 10⁴ CFU m⁻³ and 592.42 CFU/plate/h for impingement and sedimentation methods, respectively), and the secondhand clothing shop (4.59 × 10³ CFU m⁻³ and 335.42 CFU/plate/h for impingement and sedimentation methods, respectively) for Gram-positive bacteria, Gram-negative bacteria, and fungi, respectively. The lowest concentration of Gram-positive bacteria, Gram-negative bacteria, and fungi was found only at the outdoor area at 1.53 × 10⁴ CFU m⁻³, 0.93 × 10⁴ CFU m⁻³ and 0.80 × 10³ CFU m⁻³ by means of impingement method and 136.67 CFU/plate/h, 69.25 CFU/plate/h, and 62.00 CFU/plate/h by means of sedimentation methods for Gram-positive bacteria, Gram-negative bacteria, and fungi, respectively. The most frequently present airborne bacteria were identified as Bacillus, Corynebacteria, Diplococcus, Micrococcus, Acinetobacter, Alcaligenes, Enterobacter, and spore former rods. Acremonium, Aspergillus, Cladosporium, Penicillium, and Sporotrichum were the most frequently found aerosol fungi genera. The distribution of airborne microorganisms correlated with relative humidity and light factors based on principal component analysis. In conclusion, the border market is a potential source of aerial disease transmission and a various hazards of bioaerosols for workers, consumers, sellers, and tourists. The bioaerosol concentration exceeded the standard of occupational exposure limit. Many major indicators of allergenic and toxigenic airborne bacteria and fungi, Acinetobacter, Enterobacter, Pseudomonas, Cladosporium, Alternaria, Aspergillus, and Penicillium, were found in the various market environments.     

Assessment of bioaerosols at a concentrated dairy operation

Increased bioaerosol loadings in downwind plumes from concentrated animal feeding operations (CAFOs) may increase the risk for allergy and infection in humans. In this study, we monitored airborne concentrations of culturable bacteria and fungi at upwind (background) and downwind sites at a 10,000 milking cow dairy over the course of a year. The average bacterial concentrations at the upwind site were 8.4 × 10³ colony forming units (CFU) m⁻³ and increased to 9.9 × 10⁵ CFU m⁻³ at the downwind edge of the cattle lots, decreasing to 6.3 × 10⁴ CFU m⁻³ 200 m farther downwind. At the same sites, the average fungal concentrations were 515, 945, and 1,010 CFU m⁻³, respectively. Significant correlations between the ambient weather conditions and airborne fungal and bacterial concentrations were identified. Sequence analysis of PCR-amplified DNA from bacterial clones and fungal isolates revealed genus and species level differences between upwind and downwind sites. Although we could not cultivate gram-negative bacteria, bacterial clones at downwind sites identified as being gram-negative matched with the following genera: Acinetobacter, Bradyrhizobium, Escherichia, Idiomarina, Methylobacterium, Ralstonia, and Novosphingobium. Fungal isolates from downwind matched with the following genera: Acremonium, Alternaria, Ascomycte, Aspergillus, Basidiomycete, Cladosporium, Davidiella, Doratomyces, Emericella, Lewia, Onygenales, Penicillium, Rhizopus, and Ulocladium. None of the bacterial and fungal sequence matches were affiliated with genera and species known to be pathogenic to humans. Overall, the data suggest that exposure to bioaerosols in the downwind environment decreases with increasing distance from the open-lot dairy.     

Atrazine degradation by aerobic microorganisms isolated from the rhizosphere of sweet flag (Acorus calamus L.)

In presented study the capability of microorganisms isolated from the rhizosphere of sweet flag (Acorus calamus) to the atrazine degradation was assessed. Following isolation of the microorganisms counts of psychrophilic bacteria, mesophilic bacteria and fungi were determined. Isolated microorganisms were screened in terms of their ability to decompose a triazine herbicide, atrazine. Our results demonstrate that within the rhizosphere of sweet flag there were 3.8 × 10⁷ cfu of psychrophilic bacteria, 1.8 × 10⁷ cfu of mesophilic bacteria, and 6 × 10⁵ cfu of fungi per 1 g of dry root mass. These microorganisms were represented by more than 20 different strains, and at the first step these strains were grown for 5 days in the presence of atrazine at a concentration of 5 mg/l. In terms of the effect of this trial culture, the bacteria reduced the level of atrazine by an average of about 2–20%, but the average level of reduction by fungi was in the range 18–60%. The most active strains involved in atrazine reduction were then selected and identified. These strains were classified as Stenotrophomonas maltophilia, Bacillus licheniformis, Bacillus megaterium, Rahnella aquatilis (three strains), Umbelopsis isabellina, Volutella ciliata and Botrytis cinerea. Culturing of the microorganisms for a longer time resulted in high atrazine degradation level. The highest degradation level was observed at atrazine concentrations of 5 mg/l for S. maltophilia (83.5% after 15 days of culture) and for Botrytis sp. (82% after 21 days of culture). Our results indicate that microorganisms of the sweet flag rhizosphere can play an important role in the bioremediation of atrazine-contaminated sites.     

Microbial Aerosols: Estimated Contribution of Combine Harvesting to an Airshed

From plate counts of the airborne microorganisms in the downwind dust plume of operating grass-seed combines, the mean source concentrations were calculated to be 6.4 × 10⁸ and 4.7 × 10⁸/m³, respectively, potentially accounting for at least 41.9% of the bacteria and 35.1% of the fungi in the airshed in the Willamette Valley, Oregon.