Airborne Endotoxin Concentrations Research Articles

Influence of different cleaning methods on the concentration of airborne endotoxins and microbial aerosols in the oral clinical environment

AimThis study aims to evaluate the effectiveness of various cleaning methods in reducing airborne endotoxin and microbial aerosols during oral cleaning procedures.MethodForty patients undergoing oral cleaning procedures were randomly assigned to one of four groups (n = 10 per group). Group A received strong suction alone; Group B received strong suction combined with an air disinfection machine; Group C received strong suction combined with a dental electric suction machine; Group D received strong suction in conjunction with both an air disinfection machine and a dental electric suction machine. Airborne aerosol concentrations were assessed at four-time points: before treatment, 30 min into treatment, immediately after treatment, and 60 min after treatment ended. Samples were collected at distances of 20 cm, 60 cm, and 1 m from the patient’s oral cavity using the natural sedimentation method. T-test was used to evaluate the difference among tested groups.ResultsAirborne endotoxins and microbial aerosols levels increased significantly during treatment, with the highest levels observed at 20 cm from the patient’s mouth. During treatment, groups with additional cleaning methods (Groups B, C, and D) exhibited higher levels of airborne endotoxins and microbial aerosols compared to Group A (strong suction alone). However, post-treatment analysis revealed that Group D demonstrated the lowest level of airborne endotoxins and microbial aerosols, while Group A exhibited the highest.ConclusionsImplementing effective aerosol management strategies can significantly reduce aerosol dispersion in the oral clinical environment. Continuous monitoring aerosol concentrations and the application of appropriate control measures are essential for minimizing infection risks for both patients and healthcare providers during oral cleaning procedures.

Respiratory health of broilers following chronic exposure to airborne endotoxin

In and around poultry farms, high concentrations of endotoxins are found that have a negative impact on the health of farmers and local residents. However, little is known about the effects of chronic exposure to endotoxins on the health of poultry. The aim of this study was to identify effects of chronic exposure to airborne endotoxins (E. coli LPS) on the immune system, respiratory tract, disease susceptibility and welfare of broilers. Effects of high (HE) and low endotoxin (LE) concentrations on natural antibody titers (NAb), performance and behavior of broilers were determined. After treatment with a respiratory virus infection, infectious bronchitis virus (IBV), mRNA expression of cytokines and Toll-like receptor (TLR) 4 in the lung, tracheal ciliary activity and lesions in the respiratory tract were determined. Endotoxin affected the immune system and respiratory tract, where HE broilers tended to have lower IgM NAb binding Phosphorylcholine-conjugated to Bovine Serum Albumin, and higher interferon (IFN)-α mRNA expression and more lesions in the nasal tissue compared to LE broilers. Furthermore, HE broilers had higher TLR4 mRNA expression compared to LE broilers. However, endotoxin did not affect NAb levels binding Keyhole Limpet Hemocyanin, IFN-β and interleukin-10 mRNA expression, IBV replication or lesions in the lung and trachea. HE and LE broilers further had similar body weight, but HE broilers showed numerically more passive behavior compared to LE broilers. In conclusion, chronic exposure to high airborne endotoxin concentrations affects components of the immune system and respiratory tract in broilers and could therefore influence disease susceptibility.

A cross sectional study on airborne inhalable microorganisms, endotoxin, and particles in pigeon coops – Risk assessment of exposure

Pigeon breeding is associated with symptoms of the airways. The aim of this study is to illuminate the bacteriological and toxicological characteristics of airborne dust in pigeon coops. Airborne dust was sampled in 31 urban pigeon coops with homing and fancy pigeons, and following the dust was characterized. In total 141 different bacterial species were identified using MALDI-TOF MS, and of these 11 species are classified in risk group 2. Of the cultivable bacteria, Staphylococcus equorum was present in the highest concentration. Microorganisms in the dust were able to form biofilm, and the amount correlated positively with the number of bacteria. Next generation sequencing showed 180 genera with Acinetobacter in highest reads. On average 999 ± 225 ZOTUs were observed per sample with a Shannon-Wiener biodiversity index of 6.17 ± 0.24. Of the identified species the following have previously been suggested as causative agents of extrinsic allergic alveolitis: Alcaligenes faecalis, Bacillus subtilis, Pantoea agglomerans, Sphingobacterium spiritivorum, Thermoactinomyces sp., and Streptomyces albus. Staphylococcus was present on particles with sizes between 1.1 and > 7.0 μm with a geometric mean diameter of particles on 4.7 ± 1.1 μm. Concentrations of airborne endotoxin and dust were elevated compared to references, and the geometric mean concentrations were 102 EU/m3 and 1.07 mg dust/m3, respectively. Upon exposure to the airborne dust human granulocytes produced Reactive Oxidative Species during the first 5 min, and then no further reaction was observed. The concentrations of bacteria in general, Staphylococcus spp., and endotoxin and biodiversity were associated significantly with season, temperature and/or relative humidity, but not with type or density of pigeons. The bacterial composition and biodiversity indices were not affected by type of pigeon. In conclusion, the exposure to bacteria and endotoxin in pigeon houses should not be neglected in the evaluation of causative agents of airways symptoms among pigeon breeders.

Reduction in Indoor Airborne Endotoxin Concentration by the Use of Air Purifier and Its Relationship with Respiratory Health: A Randomized Crossover Intervention Study

Endotoxins are biological components of particulate matter that cause adverse respiratory system effects. Recently, air purifiers have been widely used; however, their effects on endotoxins are not fully understood. We conducted a randomized crossover intervention study to evaluate the effects of air purifiers on indoor endotoxins and occupants’ respiratory health. Thirty-two healthy subjects were randomly assigned to two groups; each group spent four weeks using either a true or sham (filter removed) air purifier. Subsequently, the subjects spent an additional four weeks using the alternative air purifier. The indoor endotoxins in fine (PM2.5) and coarse (PM10–2.5) particulate matter were continuously collected, and pulmonary function was tested repeatedly during the study period. Household characteristics were assessed using a questionnaire. The geometric mean of the PM2.5 endotoxin concentrations was 0.13 EU/m3, which was significantly lower with true purifiers compared with sham purifiers, after adjusting for household characteristics (0.17 EU/m3). In addition, the PM2.5 endotoxin concentrations were significantly greater in reinforced concrete houses than in wooden houses. The PM10–2.5 endotoxin concentrations were significantly greater in homes with two or more household members, and in those with pets. No association was found between endotoxin concentration and respiratory health among the subjects.

Particulate matter and airborne endotoxin concentration in calf barns and their association with lung consolidation, inflammation, and infection

Agricultural operations are important sources of organic dust containing particulate matter (PM) and endotoxins, which have possible negative health consequences for both humans and animals. Dust concentrations and composition in calf barns, as well as the potential health effects for these animals, are scarcely documented. The objective of this study was to measure PM fractions and endotoxin concentrations in calf barns and study their associations with lung consolidation, respiratory tract inflammation, and infection in group-housed calves. In this cross-sectional study, samples from 24 dairy farms and 23 beef farms were collected in Belgium from January to April 2017. PM1.0, PM2.5 and PM10 (defined as particulate matter passing through a size-selective inlet with a 50% efficiency cut-off at a 1.0-μm, 2.5-μm, and 10-μm aerodynamic diameter, respectively) were sampled during a 24-h period using a Grimm aerosol spectrometer (Grimm Aerosol Technik Ainring GmbH & Co. KG). Endotoxin concentration was measured in the PM10 fraction. Thoracic ultrasonography was performed and broncho-alveolar lavage fluid was collected for cytology and bacteriology. Average PM concentrations were 16.3 µg/m3 (standard deviation, SD: 17.1; range: 0.20-771), 25.0 µg/m3 (SD: 25.3; range: 0.50-144.9), and 70.3 µg/m3 (SD: 54.5; range: 1.6-251.2) for PM1.0, PM2.5, and PM10, respectively. Mean endotoxin in the PM10 fraction was 4.2 endotoxin units (EU)/µg (SD: 5.50; range: 0.03-30.3). Concentrations in air were 205.7 EU/m3 (SD: 197.5; range: 2.32-901.0). Lung consolidations with a depth of ≥1, ≥3, and ≥6 cm were present in 43.1% (146/339), 27.4% (93/339), and 15.3% (52/339) of the calves, respectively. Exposure to fine (PM1.0) PM fractions was associated with increased odds of lung consolidations of ≥1 cm (odds ratio, OR: 3.3; confidence interval (CI): 1.5-7.1), ≥3 cm (OR: 2.8; CI: 1.2-7.1), and ≥6 cm (OR: 12.3; CI: 1.2-125.0). The odds of having lung consolidations of ≥1 cm (OR: 13.9; CI: 3.4-58.8) and ≥3 cm (OR: 6.7; 1.7-27.0) were higher when endotoxin concentrations in the dust mass exceeded 8.5 EU/µg. Broncho-alveolar lavage fluid neutrophil percentage was positively associated with PM10 concentration, and epithelial cell percentage was negatively associated with this fraction. Concentration of PM2.5 was positively associated with epithelial cell percentage and isolation of Pasteurella multocida. Although concentrations of fine dust are lower in calf barns than in poultry and pig housings, in this study they were associated with pneumonia in calves. Dust control strategies for reducing fine dust fractions in calf barns may benefit human and animal respiratory health.

Production of composted recycled manure solids from a Canadian dairy farm: Impact on microbial air quality in experimental conditions

ABSTRACT Recycled manure solids (RMS) produced in dairy farms from fresh manure need to be sanitized before using them as bedding material. However, the impact on air quality of composting RMS remains unknown. Four RMS composting methods were tested during a 10-day aging of piles in experimental chambers: static windrow (SW), turned windrow (TW), SW following drum composting for 24 h (DC24) or SW following drum composting for 72 h (DC72). Air samples were collected using a SASS®3100 Dry Air Sampler on days 0 (pilling of the RMS), 5, and 10. Bacteria (16S rRNA genes), Penicillium/Aspergillus, A fumigatus, and 11 human pathogenic bacteria (e.g. Klebsiella pneumonia) were quantified by qPCR while endotoxins and dust particles were, respectively, measured by LAL assays and with a DustTrakTM DRX Aerosol Monitor. On day 0, RMS produced by SW and TW yielded the lowest concentrations of airborne bacteria, while DC24 resulted in the lowest levels of Penicillium/Aspergillus and dust particles. SW method led on day 5 to the lowest concentration of bacteria and Penicillium/Aspergillus, and DC24 and DC72 to the lowest concentration of airborne dust. On day 10, SW and TW piles were associated with the lowest levels of Penicillium/Aspergillus and dust particles. A significant difference was observed between concentration of airborne bacteria, Penicillium/Aspergillus and endotoxins before and during the turnover of TW piles. None of the studied human pathogens was detected in the air samples. Results of the present study suggest that SW and TW are the most promising methods for the production of composted RMS with respect to microbial air quality. However, the experimental chambers do not accurately represent commercial dairy barns and further research on these composting methods is necessary. Finally, the study highlights that bedding material and its management may be determinant factors for air quality in dairy barns. Implications: The research evaluated the impact on microbial air quality of composting recycled manure solids (RMS) produced from fresh cow manure. RMS need to be composted or sanitized before using them as bedding material for animals. The impact on animal health of RMS still needs to be confirmed, while the effect on air quality and the health of dairy farmers is unknown. In the present study, microbial air quality associated with four RMS composting methods was investigated. Data revealed that two methods resulted in lower aerosolization of dust particles, endotoxins, molds, and bacteria.

Ambient concentration of airborne microbes and endotoxins in rural households of southern India

Investigation of microbial communities in the indoor environment is critically important as majority of human life is spent indoors. Airborne microbial flora and their pyrogenic substances can impact human health. They have so far been insufficiently characterized. Here, we quantify bioaerosol concentration and diversity in both indoor and outdoor air of rural households in South India and statistically determine the significant predictor variables influencing them. The median concentration of bacterial and fungal aerosols in indoor air (n = 36 households) was 1031 colony forming units (CFU) m−3 and 580 CFU m−3, respectively, and in outdoor air was 742 CFU m−3 and 680 CFU m−3, respectively. Bacterial species were comprised of the four major phyla Actinobacteria, Firmicutes, Proteobacteria, and Bacteroidetes, and fungal species of Ascomycota, Basidiomycota, and Zygomycota, in both indoor and outdoor air. Multivariable linear regression revealed that outdoor bacterial concentration, the number of house inhabitants, indoor temperature, age of the homes and use of biomass (cow dung or firewood) as cooking fuel were significant predictor variables influencing concentrations of bacteria in the indoor air. The significant predictor variables influencing indoor endotoxin concentrations were indoor bacterial concentration, indoor meteorology (temperature and relative humidity), and use of biomass as cooking fuel. Outdoor fungal concentration was the significant predictor variable influencing fungal concentration in indoor air. Endotoxin concentrations in indoor air ranged from 1.23 to 20.7 EU m−3. Quantitative microbial risk assessment (QMRA) model revealed a probability of infection of resident women from B. anthracis to be 0.0009 to 0.010.

Association of airborne endotoxin concentrations with pulmonary function and airway inflammation among students

TPS 752: Respiratory effects and allergies, Exhibition Hall, Ground floor, August 27, 2019, 3:00 PM - 4:30 PM Background: Few studies have evaluated the short-term effects of airborne endotoxin on respiratory health. We evaluated the relationship between exposure to airborne endotoxin and pulmonary function and airway inflammation among healthy students. Methods: A panel study was conducted in 41 healthy students aged 16 years, for about 1 month in May 2015, in a school on an isolated island in the Seto Inland Sea, Japan. Daily measurements of peak expiratory flow (PEF) and forced expiratory volume in 1 s (FEV1) were performed. Fractional exhaled nitric oxide (FeNO) was also measured once a week during the study period. Coarse (PM10-2.5) and fine (PM2.5) particulate matter samples were collected every 24 h from inside and outside the classroom, and endotoxin concentrations in both fractions were measured using the kinetic Limulus Amebocyte Lysate assay. The associations of pulmonary function and FeNO with 24-h endotoxin concentrations before each measurement were analyzed using mixed-effects models. Results: A decrease in FEV1 was significantly associated with endotoxin concentrations in outdoor PM2.5 (-0.03 L [95% confidence interval (CI): -0.05, -0.01] for an interquartile range (IQR) increase of 0.07 EU/m3). Neither PEF nor FeNO was associated with endotoxin concentrations in any fractions. Among subjects with wheezing during or after exercise, the increase in FeNO was significantly associated with endotoxin concentrations in indoor and outdoor PM10-2.5 (4.4 ppb [95% CI: 0.2, 8.5] and 7.4 ppb [95% CI: 0.3, 14.4] for each IQR increase of 0.12 and 0.19 EU/m3, respectively). Indoor and outdoor mass concentrations of each fraction were associated with neither pulmonary function nor FeNO. Conclusions: These results suggest that endotoxin in outdoor PM2.5 may affect pulmonary function among healthy students. Additionally, endotoxin concentration in PM10-2.5 was significantly associated with FeNO in students with wheezing during or after exercise, indicating the potential of endotoxin to cause airway inflammation.

Jumping on the bed and associated increases of PM10, PM2.5, PM1, airborne endotoxin, bacteria, and fungi concentrations

Jumping on the bed is a favorite behavior of children; however, no study has investigated the increased air pollutants resulting from jumping on the bed. Therefore, we aimed to investigate the elevated concentrations of particulate matter (PM) and bioaerosols from jumping on the bed and making the bed. Simulation of jumping on the bed and making the bed was performed at sixty schoolchildren's houses in Taiwan. PM10, PM2.5, PM1 (PM with aerodynamic diameter less than 10, 2.5, and 1 μm, respectively) and airborne bacteria, fungi and endotoxin concentrations were simultaneously measured over simulation and background periods. Our results show the increase of PM10, PM2.5, PM1, airborne bacteria and fungi through the behavior of jumping on the bed (by 414 μg m-3, 353 μg m-3, 349 μg m-3, 6569 CFU m-3 and 978 CFU m-3, respectively). When making the bed, the PM10, PM2.5, PM1, airborne bacteria and fungi also significantly increased by 4.69 μg m-3, 4.09 μg m-3, 4.15 μg m-3, 8569 CFU m-3, and 779 CFU m-3, respectively. Airborne endotoxin concentrations significantly increased by 21.76 EU m-3 following jumping on the bed and making the bed. Moreover, when jumping on the bed, higher PM2.5 and PM1 concentrations in houses with furry pets rather than no furry pets, and less airborne fungi in apartments than in townhouses were found. For making the bed, lower airborne fungi was found in houses using essential oils rather than no essential oils using. The airborne endotoxin concentrations were positively associated with furry pets and smokers in the homes and negatively correlated to the home with window opening with a statistical significance during the periods of jumping on the bed and making the bed. In conclusion, significant increases of PM and bioaerosols during jumping on the bed and making the bed may need to be concerned.

Inactivation of airborne bacteria using different UV sources: Performance modeling, energy utilization, and endotoxin degradation

Airborne bacteria-containing bioaerosols have attracted increased research attention on account of their adverse effects on human health. Ultraviolet germicidal irradiation (UVGI) is an effective method to inactivate airborne microorganisms. The present study models and compares the inactivation performance of three UV sources in the UVGI for aerosolized Escherichia coli. Inactivation efficiency of 0.5, 2.2 and 3.1 logarithmic order was obtained at an exposure UV dose of 370 J/m3 under UVA (365 nm), UVC (254 nm) and UVD (185 nm) sources, respectively. A Beer–Lambert law-based model was developed and validated to compare the inactivation performances of the UV sources, and modeling enabled prediction of inactivation efficiency and analysis of the sensitivity of several parameters. Low influent E. coli concentrations and high UV doses resulted in high energy consumption (EC). The change in airborne endotoxin concentration during UV inactivation was analyzed, and UVC and UVA irradiation showed no marked effect on endotoxin degradation. By contrast, both free and bound endotoxins could be removed by UVD treatment, which is attributed to the ozone generated by the UVD source. The results of this study can provide a better understanding of the air disinfection and airborne endotoxin removal processes.

Effects of Gestation Pens Versus Stalls and Wet Versus Dry Feed on Air Contaminants in Swine Production

ABSTRACTObjective: Evolving production practices in the swine industry may alter the working environment. This research characterized the influence of stall versus pen gestation housing and wet versus dry feed in finishing on air contaminant concentrations. Methods: Eight-hour time-weighted ammonia, hydrogen sulfide, respirable dust, respirable endotoxin, and carbon dioxide concentrations and temperature were measured regularly at stationary locations throughout a year in a facility with parallel gestation stall and open pen housing and parallel finishing rooms using dry and wet feed delivery systems. Hazard indices were calculated using ammonia, hydrogen sulfide, and endotoxin concentrations and relevant occupational exposure limits. Statistical analyses were performed to assess the influence of time of year, housing, and feed on measured parameters. Results: Due to reductions in ventilation rates as outdoor temperatures decreased, season affected pollutant levels more than other factors, with concentrations approximately one order of magnitude greater in winter than during summer. Ammonia, dust, and endotoxin were 25%, 43%, and 67% higher, respectively, on average, in the room with gestation pens than in the room with stalls. Endotoxin concentrations were more than five times higher, on average, with the dry feed system than with wet feed. While individual contaminant concentrations were generally below regulatory limits, hazard index calculations suggest that the effects of combined exposures on respiratory health may present a risk to workers. Elevated levels of respirable endotoxin and hydrogen sulfide were observed during power washing. Conclusions: Ventilation changes in response to seasonal requirements influenced air contaminant concentrations more than production practices, especially housing type. Wet feed systems substantially reduced airborne endotoxin concentrations.

Performances of the BC-112 NIOSH cyclone for the measurement of endotoxins in bioaerosols: A study in laboratory conditions

The BC-112 cyclone is a personal bioaerosol sampler with of a metallic main body (2mm inlet), a first collection stage (1.5mL collection tube) and a final collection stage (37mm three pieces cassette). A laboratory study has been carried out with E. coli experimental bioaerosols in order to investigate the efficiency of the cyclone for the measurement of airborne endotoxins in laboratory conditions. A first set of experiments allowed the validation of a protocol for the removal of endotoxins from contaminated BC-112 cyclones. The study also showed that endotoxins deposited on the inner cassette walls during sampling. Endotoxins deposits accounted for 18–42% of the total endotoxins measured in the bioaerosols and an adaptation of the analytical protocol was necessary in order to take such deposits into account. Furthermore, the type of filter mounted in the cassette significantly (p < 10−4) influenced the concentration of airborne endotoxins measured in the experimental bioaerosol. Teflon and PVC filters led to the highest concentrations while, surprisingly, fiberglass filters led to the lowest ones. An optimal configuration was set for the sampling devices including a PVC filter as collecting medium and extraction of collected endotoxins directly into the cassette. In such a configuration and with our experimental conditions the side by side comparison of the closed-face cassette (CFC) and the BC-112 cyclone showed a significant correlation (r = 0.99; n = 16; p < 10−4) between measurements done with the two sampling devices. The results also highlight that experimental biases may occur when comparing the collection or the overall efficiency of bioaerosol samplers using microbial surrogates and bioaerosol chambers. We concluded that the BC-112 cyclone was suitable for the assessment of airborne endotoxins providing protocol adaptations and that the overall efficiency of the device for the measurement of airborne endotoxins should be investigated in real exposure conditions as well as in other laboratory conditions.

Exposure to airborne endotoxin in Italian greenhouses: environmental analyses.

The peculiar characteristics of the greenhouses as confined spaces, microclimate and poor air exchange with the outside environment, encourage the development of a large number of biological agents. Endotoxin, is probably a major causative agent of occupational health problems. The objective of this study was to measure the concentrations of airborne endotoxin in greenhouses with different cultures. The influence of microclimate was studied in correlation with endotoxin levels and type of cultured vegetables. The data indicate that workers employed greenhouses are exposed to low levels of inhalable endotoxins; endotoxin concentrations do not correlate with the temperature and relative humidity values. A strong correlation between the leaf size and endotoxin concentration was observed. The mean concentration of endotoxins in the air of greenhouses is relatively low, however, there could be peaks of exposure during harvesting and eradication of broadleaf plants.

The seasonal influence on airborne dust and endotoxin concentrations in a laying hen house

The seasonal influence on airborne dust and endotoxin concentrations in a laying hen house

Determination and risk assessment of airborne endotoxin concentrations in a university campus

Endotoxin is a cell-wall component of Gram-negative bacteria and is a hazardous biological substance that exerts adverse health effects. However, research on the determination and risk assessment of airborne endotoxins in university campuses is limited. In this study, the levels of airborne endotoxins were measured at different sites of a university campus in China. The arithmetic means for airborne endotoxin levels were 72 endotoxin units (EU)/m3 (range = 37.9–97.6EU/m3). The airborne endotoxin levels varied at different sites and were typically high in laboratories (wastewater control and resource recovery laboratories) and school hospitals. Education environments had higher dose rates and risks (e.g., office) than recreational living places (e.g., gyms). The dose rates and health risks of airborne endotoxins followed the order children > adult male > adult female. Compared with skin contact, inhalation was the main way of airborne endotoxin exposure. No statistical differences were observed among the different sampling times on the same day. Both concentrations of total volatile organic compound and PM2.5 show positive correlations with airborne endotoxins, whereas culturable bioaerosol concentration, temperature, and relative humidity, were less significantly correlated with airborne endotoxin levels (p < 0.05).

Association of Endotoxin and Allergens with Respiratory and Skin Symptoms: A Descriptive Study in Laboratory Animal Workers.

In laboratory animal work, allergens are classically considered to play a prominent role in generation of respiratory and skin symptoms. However, recent development may have changed working conditions and require an updating of preventive measures. In workers exposed to a range of animals besides laboratory mice and rats the relative role of endotoxin, irritants, and allergens in symptom generation was assessed for updating preventative measures and health surveillance. Eligible workers were recruited from university units in which exposure to rats and/or mice, occurrence of respiratory and/or skin symptoms, and/or a history of animal bites had been reported. Exposure to endotoxin and rat and mouse allergen was assessed (71 half-day personal samples). 'Symptomatic' was defined by work-related ocular, nasal, respiratory, or skin symptoms. A concentration of specific IgE against rat or mouse (e87 and e88) ≥0.35 kU/l defined sensitization. Sensitivity analyses examined the effect of alternative exposure indicators and definitions of 'sensitized' and 'symptomatic'. From 302 eligible workers, 177 participated. There were 121 and 41 workers in the asymptomatic and non-sensitized and symptomatic but non-sensitized group, respectively. Eight subjects were symptomatic and sensitized. Six sensitized subjects were asymptomatic. One participant could not be assigned to a subgroup. Airborne endotoxin and allergen concentrations were mostly below 20 EU m-3 or the detection limit, respectively. Clinical history showed that irritants and sensitizers other than mouse/rat allergen or endotoxin were a major cause of symptoms. Results were sensitive to the selected exposure indicator and the definition of 'symptomatic'. Health surveillance programs need to be adapted to include a larger range of allergens and pay more attention to irritants.

Airborne endotoxin concentrations in indoor and outdoor particulate matter and their predictors in an urban city.

Endotoxins are an important biological component of particulate matter and have been associated with adverse effects on human health. There have been some recent studies on airborne endotoxin concentrations. We collected fine (PM2.5 ) and coarse (PM10-2.5 ) particulate matter twice on weekdays and weekends each for 48 hour, inside and outside 55 homes in an urban city in Japan. Endotoxin concentrations in both fractions were measured using the kinetic Limulus Amebocyte Lysate assay. The relationships between endotoxin concentrations and household characteristics were evaluated for each fraction. Both indoor and outdoor endotoxin concentrations were higher in PM2.5 than in PM10-2.5 . In both PM2.5 and PM10-2.5 , indoor endotoxin concentrations were higher than outdoor concentrations, and the indoor endotoxin concentrations significantly correlated with outdoor concentrations in each fraction (R2 =0.458 and 0.198, respectively). Indoor endotoxin concentrations in PM2.5 were significantly higher in homes with tatami or carpet flooring and in homes with pets, and lower in homes that used air purifiers. Indoor endotoxin concentrations in PM10-2.5 were significantly higher in homes with two or more children and homes with tatami or carpet flooring. These results showed that the indoor endotoxin concentrations were associated with the household characteristics in addition to outdoor endotoxin concentrations.

Domestic exposure to endotoxin and respiratory morbidity in former smokers with COPD.

Indoor air pollution has been linked to adverse chronic obstructive pulmonary disease (COPD) health, but specific causative agents have not yet been identified. We evaluated the role of indoor endotoxin exposure upon respiratory health in former smokers with COPD. Eighty-four adults with moderate to severe COPD were followed longitudinally and indoor air and dust samples collected at baseline, 3 and 6months. Respiratory outcomes were repeatedly assessed at each time point. The associations between endotoxin exposure in air and settled dust and health outcomes were explored using generalizing estimating equations in multivariate models accounting for confounders. Dust endotoxin concentrations in the main living area were highest in spring and lowest in fall, while airborne endotoxins remained steady across seasons. Airborne and dust endotoxin concentrations were weakly correlated with one another (rs =+0.24, P=0.005). Endotoxin concentrations were not significantly associated with respiratory symptoms, rescue medication use, quality of life, or severe exacerbations. In vitro whole-blood assays of the pro-inflammatory capacity of PM10 filters with and without endotoxin depletion demonstrated that the endotoxin component of indoor air pollution was not the primary trigger for interleukin-1β release. Our findings support that endotoxin is not the major driver in the adverse effects of indoor PM upon COPD morbidity.

Relationship between concentrations of microbiological agents in the air of agricultural settings and occurrence of work-related symptoms in exposed persons.

For assessment of the dose-response relationship between concentrations of microbial agents in the air of various agricultural settings and occurrence of work-related symptoms in exposed workers, a meta-analysis of the results obtained in 1994-2007 on the territory of eastern Poland was performed. The studies on the airborne concentrations of total culturable microorganisms, mesophilic bacteria, Gram-negative bacteria, thermophilic actinomycetes, fungi, and bacterial endotoxins, as well as on the frequency of work-related respiratory and general symptoms in the exposed workers, were carried out at grain, thyme, valerian, flax, and hop handling on farms, in cow barns, piggeries, horse stables and in a modern hatchery. The airborne concentrations of the total microorganisms were in the range of 9.2-1236.5 × 10(3) CFU/m(3) , of the total mesophilic bacteria 3.5-1225.8 × 10(3) CFU/m(3) , of Gram-negative bacteria 0.0- 46.2 × 10(3) CFU/m(3) , of thermophilic actinomycetes 0.0-7.1 × 10(3) CFU/m(3) , of fungi 2.1-77.9 × 10(3) CFU/m(3) , and of bacterial endotoxin 0.00925-429.55 µg/m(3) . The frequency of work-related symptoms ranged between 21.7-63.8%. In a meta-analysis for assessment of the correlations between the log-transformed concentrations of airborne microbial agents and the occurrence of work-related symptoms, the multiple regression test was applied. Statistically significant correlations were found between the occurrence of work-related symptoms and the concentration of total airborne microorganisms (R=0.748555; P=0.020317), mesophilic bacteria (R=0.7573; P=0.029548), Gram-negative bacteria (R=0.835938; P=0.019129), and endotoxins (R=0.705356; P=0.03378). The correlations between the concentrations of thermophilic actinomycetes and fungi, on one side, and frequency of work-related symptoms on the other, did not attain the threshold of significance (P=0.087049 and P=0.062963, respectively). Results of the meta-analysis confirm harmful health effects of the total airborne microorganisms, total airborne mesophilic bacteria, airborne Gram-negative bacteria, and airborne bacterial endotoxin on the occupationally-exposed agricultural workers, and indicate a need for the establishment of internationally recognized occupational exposure limits for these microbial agents.

일부 종합 병원 로비의 공기 중 엔도톡신 농도에 미치는 환경 요인 평가

Backgrounds: Endotoxin, which found in the outer membrane of the gram-negative bacteria cell wall, makes up almost all of the lipopolysaccharide(LPS). When people are exposed to endotoxin,it can result in diverse health effects such as an airway irritation and inflammation, fever, malaise, bronchitis, allergic asthma, toxic pneumonitis, hypersensitivity lung disease. Cases among the elderly, children or pregnant can occur more frequently than a healthy adult if they are repeatedly exposed to the existing endotoxin. Therefore, we investigated and assessed the environmental characteristics associated with the airborne endotoxin concentration level in six hospital lobbies. Method: Endotoxin from indoor air in six hospital lobbies was measured by an area sampling method and analyzed according to American Society for Testing and Materials International(ASTM international) E2144-01. Total suspended particulate(TSP), carbon dioxide(<TEX>$CO_2$</TEX>), temperature and humidity were also measured by using direct reading measurements or airborne sampling equipment at the same time. Environmental characteristics were appropriately divided into two or three groups for a statistics analysis. One-way analysis variable(one-way ANOVA) was used to examine a difference of the endotoxin concentration, depending on the environmental characteristics. In addition, only variables with p-value(p<0.25) were eventually designed to the best model by using multiple regression analysis. Results: The correlation analysis result indicated that TSP(p=0.003) and <TEX>$CO_2$</TEX>(p<0.0001) levels were significantly associated with endotoxin concentration levels. In contrast, temperature(p<0.068) and humidity(p<0.365) were not associated with endotoxin concentration. Levels of endotoxin concentration were statistically different among the environmental characteristics of Service time(p=0.01), Establishment of hospital(p<0.001), Scale of hospital(p=0.01), Day average people using hospital(p=0.03), Cleaning time of lobby(p=0.05), Season(p<0.001), and Cleaning of ventilation system(p<0.001) according to ANOVA. Finally, the best model(Adjusted R-square=72%) that we designed through a multiple regression test included environmental characteristics related to Service time, Area of lobby, Season, Cleaning of ventilation system, and Temperature. Conclusions: According to this study, our result showed a normal level of endotoxin concentration in the hospital lobbies and found environmental management methods to reduce the level of endotoxin concentration to a minimum. Consequently, this study recognized to be requirement for the management of ventilation systems and an indoor temperature in order to reduce the level of endotoxin concentration in the hospital lobbies.