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1.
Waste Manag ; 105: 395-404, 2020 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-32126367

RESUMO

Mycotoxins are metabolites secreted by certain types of moulds, and some of them can be harmful to health. The objective of this study was to estimate the level of exposure to airborne aflatoxin B1, ochratoxin A, gliotoxin and sterigmatocystin in waste recycling and recovery facilities. An additional goal was to assess the related health risks for workers. Targeted mycotoxins were analysed quantitatively in 94 air samples collected in five sites using ultra-performance liquid chromatography coupled with high resolution mass spectrometry. The level of exposure to mycotoxin during working day scenarios was compared to benchmark values, either health-based guidelines when available or the concentration of no toxicological concern (CoNTC) when not. Eleven per cent of samples showed quantifiable measurement results. Aflatoxin B1 and sterigmatocystin were quantified at the mechanical separation area in mechanical-biological treatment (MBT) facilities and in the materials recovery facility (MRF), but not in composting plants and composting units in MBT facilities. The levels of exposure were all below 1 ng m-3. This is the first time exposure to sterigmatocystin in waste management facilities is reported and quantified. Ochratoxin A and gliotoxin were not quantified in any of the air samples. Health risk assessment approaches did not suggest a significant threat to workers' health. These data do not suggest the need for specific prevention measures in addition to those against other airborne biological agents.


Assuntos
Micotoxinas , Exposição Ocupacional , Microbiologia do Ar , Humanos , Reciclagem , Medição de Risco
3.
Environ Monit Assess ; 192(3): 196, 2020 Feb 22.
Artigo em Inglês | MEDLINE | ID: mdl-32086610

RESUMO

Traffic junctions are one of the crowded places where commuters are at high risk of developing respiratory infections, due to their greater exposure to airborne and human transmitted microbial pathogens. An airborne bioaerosol assessment study was carried out at a high traffic density junction focusing on their concentration, contribution in respirable particulate matter (PM), and factors influencing the distribution and microbial diversity. Andersen six-stage viable cascade impactor and a wide-range aerosol spectrometer were used for microbial and particulate matter measurements, respectively. Statistical analysis was conducted to evaluate the relationship between bioaerosol concentration, vehicular count, PM concentration, and meteorological parameters. The mean bacteria concentration (1962.95 ± 651.85 CFU/m3) was significantly different than fungi (1118.95 ± 428.34 CFU/m3) (p < 0.05). The temporal distribution showed maximum concentration for bacteria and fungi during monsoon and postmonsoon seasons, respectively. In terms of bioaerosol loading, a considerable fraction of fungi (3.25%) and bacteria (5.65%) contributed to the total airborne PM. Most abundant bioaerosols were Aspergillus (27.58%), Penicillium (23%), and Cladosporium (14.05%) (fungi), and Micrococcus (25.73%), Staphylococcus (17.98%), and Bacillus (13.8%) (bacteria). Traffic-induced roadside soil resuspension and microbial aerosolizations from the human body were identified as the chief sources of bioaerosol emissions. The risk of lower respiratory tract infections caused by anthroponotic (human transmitted) transfer of bacterial pathogens is very high. The results of the study can be used to trace sources of microbial mediated communicable diseases, and to recommend appropriate safety measures to avoid pathogenic bioaerosol exposure.


Assuntos
Microbiologia do Ar , Poluentes Atmosféricos , Aerossóis , Cidades , Monitoramento Ambiental , Fungos , Humanos , Índia , Irã (Geográfico) , Risco , Emissões de Veículos
4.
Environ Monit Assess ; 192(2): 82, 2020 Jan 02.
Artigo em Inglês | MEDLINE | ID: mdl-31897757

RESUMO

Bacterial contamination occurs in different occupational exposures. Although the level of colony-forming units in airborne samples reveals bacterial exposure, the bacterial origin is not specified. We applied Fourier transform infrared spectroscopy to investigate bacterial species in airborne samples and validated bacterial evaluation in an occupational exposure. As a pilot study, airborn of nurses station (n=40) was assessed according to National Institute of Occupational Safety and Health 0800 method. Bacterial strain in all samples was evaluated by diagnosis gallery tests. Simultaneously, Fourier transform infrared spectroscopy of sampled bacteria was prepared and then classified by principal component analysis. Spectroscopy method was validated for Staphylococcus aureus quantification. For this aim, spectrum band area in different wavenumbers was evaluated for calibration curve plotting and extraction of validation parameters. The second derivatization of spectroscopy data in 1200 to 1500 cm-1 presented the best determination for gram-type discrimination by principal component analysis modeling. Moreover 900-1200 cm-1 region modeling finely differentiated gram-negative bacteria in airborne samples. Adding spectroscopy area band in 2850 and 2906 cm-1 was validated to assess the level of Staphylococcus aureus contamination. Results showed appropriate correlation between the Staphylococcus aureus level in airborne samples analyzed by commercial counting evaluation and Fourier transform infrared spectroscopy method. Fourier transform infrared spectroscopy is a functional technique for assessment of airborne quality in occupational exposure. This analysis was recommended as an alternative method for quantitative and qualitative analysis of bio-aerosols.


Assuntos
Microbiologia do Ar , Bactérias , Monitoramento Ambiental/métodos , Exposição Ocupacional/análise , Aerossóis/análise , Bactérias Gram-Negativas , Humanos , Exposição Ocupacional/estatística & dados numéricos , Projetos Piloto , Análise de Componente Principal , Espectroscopia de Infravermelho com Transformada de Fourier , Staphylococcus aureus
5.
Environ Monit Assess ; 192(2): 87, 2020 Jan 03.
Artigo em Inglês | MEDLINE | ID: mdl-31900675

RESUMO

Exposure to outside air microorganisms especially fungi has been linked with illness such as allergic respiratory symptoms, rhinitis, asthma, and infection such as mycosis. Airborne fungal composition was sampled from five locations in Lagos State, Nigeria, between May 2014 and April 2016. Fungi spores were collected using the sedimentation plate method with the Petri dishes of dichloran-glycerol 18 (DG-18) and potato dextrose agar (PDA) media. Fungi sporulated faster on DG-18 agar plate as compared with PDA. The abundances of fungal spores collected monthly at the locations varied. The most abundant spores came from the fungi were Aspergillus niger (14.47%), Aspergillus sydowii (10.37%), and Aspergillus flavus (7.93%). Additional species were present in the collections including Ascomycetes: Penicillium funiculosum (5.49%), Neurospora crassa (5.32%), Penicillium oxalicum (4.71%), Penicillium pinophilum (2.88%), Fusarium verticillioides (3.05%), Penicillium simplicissimum (1.83%), Aphaderanum sp. (0.22%), Curvularia sp. (0.22%), Aspergillus oryzae (0.22%), and Paecilomyces sp. (0.61%) and the Mucoromycotina Zygomycetes: Rhizopus oryzae (4.10%) and Mucor sp. (3.44%). Fungal concentrations were significantly higher (P ≤ 0.05) during the rainy season compared with the dry season. Aspergillus and Penicillium were the most predominant airborne fungal genera while Mucor, Alternaria, and Cladosporium were some of the least observed. Generally, abundance of fungi was significantly high during the wet season in all the studied locations.


Assuntos
Microbiologia do Ar , Monitoramento Ambiental , Esporos Fúngicos , Alérgenos , Alternaria , Aspergillus , Asma , Cladosporium , Fungos/classificação , Hipersensibilidade , Nigéria , Penicillium , Estações do Ano
6.
Environ Sci Technol ; 54(3): 1353-1362, 2020 02 04.
Artigo em Inglês | MEDLINE | ID: mdl-31909609

RESUMO

Bioaerosols consisting of biologically originated airborne particles such as microbes, metabolites, toxins, and fragments of microorganisms are present ubiquitously in our living environment. The international interests in bioaerosols have rapidly increased because of their many potential health effects. Thus, accurate and fast detection of total bioaerosols in different environments has become an important task for safeguarding against biological threats and broadening the pool of bioaerosol knowledge. To quickly evaluate the total bioaerosol concentration, we developed a localized surface plasmon resonance biosensor based on succinimidyl-ester-functionalized gold nanoislands (SEF-AuNIs) for quantitative bioaerosol detection. The detection limit of our proposed SEF-AuNI sensors for model bacteria Escherichia coli and Bacillus subtilis can go to 0.5119 and 1.69 cells/mL, respectively. To demonstrate the capability of this bioaerosol sensing technique, we tested aerosol samples collected from Bern (urban station), Basel (suburban station), and Rigi mountain (rural and high altitude station) in Switzerland and further investigated the correlation with endotoxin and PM10. The results substantiated that our SEF-AuNI sensors could be a reliable candidate for total bioaerosol detection and air quality assessment.


Assuntos
Microbiologia do Ar , Escherichia coli , Aerossóis , Bacillus subtilis , Monitoramento Ambiental , Suíça
7.
Plant Dis ; 104(1): 82-93, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31738689

RESUMO

The lettuce downy mildew pathogen, Bremia lactucae, is an obligate oomycete that causes extensive produce losses. Initial chlorotic symptoms that severely reduce the market value of the produce are followed by the appearance of white, downy sporulation on the abaxial side of the leaves. These spores become airborne and disseminate the pathogen. Controlling lettuce downy mildew has relied on repeated fungicide applications to prevent outbreaks. However, in addition to direct economic costs, heterogeneity and rapid adaptation of this pathogen to repeatedly applied fungicides has led to the development of fungicide-insensitivity in the pathogen. We deployed a quantitative PCR assay-based detection method using a species-specific DNA target for B. lactucae coupled with a spore trap system to measure airborne B. lactucae spore loads within three commercial fields that each contained experimental plots, designated EXP1 to EXP3. Based upon these measurements, when the spore load in the air reached a critical level (8.548 sporangia per m3 air), we advised whether or not to apply fungicides on a weekly basis within EXP1 to EXP3. This approach saved three sprays in EXP1, and one spray each in EXP2 and EXP3 without a significant increase in disease incidence. The reduction in fungicide applications to manage downy mildew can decrease lettuce production costs while slowing the development of fungicide resistance in B. lactucae by eliminating unnecessary fungicide applications.


Assuntos
Agricultura , Microbiologia do Ar , Alface , Oomicetos , Reação em Cadeia da Polimerase , Esporos Fúngicos , Agricultura/métodos , Ar , Alface/microbiologia , Oomicetos/genética , Doenças das Plantas/microbiologia , Esporos Fúngicos/genética
8.
Int J Syst Evol Microbiol ; 70(1): 71-76, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31622233

RESUMO

Two Gram-stain-positive, motile, endospore-forming, aerobic strains, designated V44-8T and V47-23aT, were isolated from environmental air sampling at the vehicle assembly building at Cape Canaveral, Florida, where the Viking spacecraft were assembled. Growth was observed at pH 7-9 (optimum, pH 9) for strain V44-8T, and pH 5-10 (pH 9) for strain V47-23aT. Both strains displayed growth in 0-5 % NaCl with an optimum at 1 % for strain V44-8T; 0 % for strain V47-23aT. Strains V44-8T and V47-23aT grew optimally at 32 °C, (15-32 °C) and 25 °C (20-45 °C), respectively. The cell wall of both strains contained meso-diaminopimelic acid as the diagnostic diamino acid. Both strains contained phosphatidylglycerol, phosphatidylethanolamine and diphosphatidylglycerol. The predominant cellular fatty acids were anteiso-C15 : 0, iso-C14 : 0 and iso-C15 : 0. Strain V47.23aT shared its highest 16S rRNA sequence similarity with Bacillus cavernae DSM-105484T at 96.9%, and V44.8T with Bacillus zeae DSM-103964T at 96.6 %. Based on their phenotypic characteristics and phylogenetic position inferred from 16S rRNA gene sequence analyses, the isolates were identified as being a members of the genus Bacillus that forms a separate clade when compared to close relatives. Average nucleotide identity and average amino acid identity values between strains V44-8T and DSM-103964T were 72.1% and 67.5 %; V47-23aT and DSM-105484T were 62.4% and 69.1%, respectively. Based on the phenotypic, genomic and biochemical data, strains V44-8T and V47-23aT represent two novel species in the genus Bacillus for which the names Bacillus glennii sp. nov. [type strain, V44-8T (=ATCC BAA-2860T =DSM 105192T)], and Bacillus saganii sp. nov. [V47-23aT (=ATCC BAA-2861T=DSM 105190T)] are proposed.


Assuntos
Microbiologia do Ar , Bacillus/classificação , Filogenia , Astronave , Bacillus/isolamento & purificação , Técnicas de Tipagem Bacteriana , Composição de Bases , Parede Celular/química , DNA Bacteriano/genética , Ácido Diaminopimélico/química , Ambiente Controlado , Ácidos Graxos/química , Florida , Hibridização de Ácido Nucleico , Peptidoglicano/química , Fosfolipídeos/química , RNA Ribossômico 16S/genética , Análise de Sequência de DNA
9.
Sci Total Environ ; 701: 134684, 2020 Jan 20.
Artigo em Inglês | MEDLINE | ID: mdl-31704402

RESUMO

Growing epidemiological evidence links natural green space exposure with a range of health benefits, including for mental health. Conversely, greater urbanisation associates with increased risk of mental health disorders. Microbiomes are proposed as an important but understudied link that may help explain many green space-human health associations. However, there remains a lack of controlled experimental evidence testing possible beneficial effects from passive exposure to natural biodiversity via airborne microbiota. Previous mouse model studies have used unrealistic environmental microbial exposures-including excessive soil and organic matter contact, feed supplements and injections-to demonstrate host microbiota, immune biomarker, and behavioural changes. Here, in a randomised controlled experiment, we demonstrate that realistic exposures to trace-level dust from a high biodiversity soil can change mouse gut microbiota, in comparison to dust from low biodiversity soil or no soil (control) (n = 54 total mice, comprising 3 treatments × 18 mice, with 9 females + 9 males per group). Furthermore, we found a nominal soil-derived anaerobic spore-forming butyrate-producer, Kineothrix alysoides, was supplemented to a greater extent in the gut microbiomes of high biodiversity treatment mice. Also, increasing relative abundance of this rare organism correlated with reduced anxiety-like behaviour in the most anxious mice. Our results point to an intriguing new hypothesis: that biodiverse soils may represent an important supplementary source of butyrate-producing bacteria capable of resupplying the mammalian gut microbiome, with potential for gut health and mental health benefits. Our findings have potential to inform cost-effective population health interventions through microbiome-conscious green space design and, ultimately, the mainstreaming of biodiversity into health care.


Assuntos
Microbiologia do Ar , Biodiversidade , Exposição Ambiental , Microbioma Gastrointestinal , Animais , Feminino , Masculino , Camundongos
10.
Sci Total Environ ; 698: 134335, 2020 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-31518785

RESUMO

Moisture-indicative microbes in buildings are associated with a variety of symptoms, ranging from mild irritation to severe clinical illnesses. These symptoms are caused principally by dried, dormant and dead microbe material like spores, mycelium and microbe metabolites, leading to the activation of the immune system and formation of the antigen-specific immunoglobulins. This activation presumably takes place through the respiratory track and is a normal immune reaction against pathogenic invaders. During continuous exposure, a prolonged state of inflammation will follow, and this forms a considerable health risk for a building's occupant. A new ELISA system utilizing spores from two species Streptomyces albus and Aspergillus versicolor as an antigen was developed to reveal the related immunological processes. In 159 persons, microbial exposure was observed to increase the levels of spore-specific IgG, IgG1 and IgG3 serum antibody levels of individuals residing in microbe-dense buildings compared with the control reference buildings. No differences were detected in the levels of S. albus- and A. versicolor-specific serum IgA or IgM levels.


Assuntos
Microbiologia do Ar , Poluição do Ar em Ambientes Fechados/análise , Aspergillus , Exposição Ambiental/análise , Imunoglobulina G/metabolismo , Esporos Fúngicos , Streptomyces , Exposição Ambiental/estatística & dados numéricos , Ensaio de Imunoadsorção Enzimática , Humanos
11.
Waste Manag ; 101: 241-249, 2020 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-31630069

RESUMO

Waste collection is associated with various health symptoms. The aims of this study were to obtain knowledge about exposure to bacteria, fungi, and endotoxin during waste collection, and to study whether it is possible to reduce the exposures and the total inflammatory potential (TIP) of those exposures through simple interventions. The study was performed with an initial baseline exposure assessment, a second assessment with intervention workers only, and a third with intervention and reference workers. The waste collection workers were exposed to 7.8 × 103 cfu bacteria/m3, 1.4 × 104 cfu fungi/m3, and 92 endotoxin units/m3 (geometric mean values). The potential exposures in the truck cabs were up to 23 times higher than outdoor reference concentrations. For the intervention trucks and workers, airborne fungi in the truck cab were reduced; fungi, bacteria, and yeasts on the steering wheels were reduced; and the concentration of fungi on the workers' hands was reduced. Exposures were typically highest during collection of mixed household waste, in the summer, and for collection using trucks with low loading height. The TIP was highest for the reference group sampling mixed household waste, using trucks with low loading height, in the summer. Endotoxin, bacteria, and fungi contributed to the TIP of 42 personal exposure assessments. CONCLUSION: Motivating workers to reduce exposure through simple interventions improved hand and truck cab hygiene, but only slightly reduced personal exposure to airborne bioaerosols. Exposure can be reduced by only using trucks with high loading height.


Assuntos
Poluentes Ocupacionais do Ar , Exposição Ocupacional , Microbiologia do Ar , Poeira , Endotoxinas , Monitoramento Ambiental , Fungos , Humanos
12.
J Hosp Infect ; 104(3): 305-308, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-31877337

RESUMO

BACKGROUND: The role of laminar flow (LAF) is contradictory with several studies failing to replicate risk reduction. The 2016 World Health Organization guidelines identified this lack of good comparative studies. AIM: To analyse the use of LAF and the incidence of prosthetic joint infections (PJIs) in Asian patients undergoing total knee replacement (TKR). METHODS: Patients who underwent standard cemented posterior-stabilized TKR from 2004 to 2014 were reviewed from a prospectively collected single-surgeon database. Revision, traumatic and/or inflammatory cases were excluded. The type of airflow used was identified. The technique and surgical protocol for all procedures were similar. Tourniquets and inserted drains were routinely used. Patellar resurfacing was not performed. Patients were followed up at the outpatient clinics at regular intervals up to two years. At each visit, the patient was assessed for the occurrence of PJI. FINDINGS: Of the 1028 procedures, 453 (44.1%) were performed in an LAF operating theatre (OT) whereas 575 (55.9%) were performed in a non-LAF OT. There were no significant differences between the two groups in terms of age, gender, or side of procedure. The overall incidence of PJI was 0.6% (N = 6). Three (50%) occurred in an LAF OT whereas three (50%) occurred in a non-LAF OT. This was not statistically significant. CONCLUSION: Laminar flow systems are costly to procure and maintain. With modern aseptic techniques, patient optimization, and use of prophylactic antibiotics, laminar flow does not appear to further reduce risk of PJI in Asian patients after TKR.


Assuntos
Microbiologia do Ar , Artroplastia do Joelho/efeitos adversos , Controle de Infecções/métodos , Infecções Relacionadas à Prótese/epidemiologia , Infecção da Ferida Cirúrgica/prevenção & controle , Idoso , Movimentos do Ar , Ambiente Controlado , Feminino , Humanos , Masculino , Ventilação/instrumentação
13.
Ann Agric Environ Med ; 26(4): 555-565, 2019 Dec 19.
Artigo em Inglês | MEDLINE | ID: mdl-31885228

RESUMO

OBJECTIVE: The aim of this study was to assess microbial contamination of the air and surfaces at workplaces in commercial (CD) and traditional (TD) dairies. MATERIAL AND METHODS: Bioaerosol (impactor) and surface (swab) samples were collected in CD and in TD. Bacterial and fungal concentrations in the air and on surfaces were calculated and all isolated microorganisms taxonomically identified, based on their morphological, biochemical and molecular features. RESULTS: Average concentrations of bacterial aerosol ranged between 70-860 CFU/m3 and 265-14639 CFU/m3, while for fungal aerosol were between 50-290 CFU/m3 and 55-480 CFU/m3 in CD and TD, respectively. Average bacterial concentrations on surfaces ranged between 1.0-49.7 CFU/cm2 and 0.2-60.4 CFU/cm2, whereas average fungal surface contamination ranged between 0-2.7 CFU/cm2 and 0-4.6 CFU/cm2 in CD and TD, respectively. Qualitative analysis revealed mainly the presence of saprophytic microorganisms; however, several pathogenic strains (Staphylococcus aureus, Streptococcus intermedius, Clostridium perfringens, Actinomyces spp., Streptomyces spp., Candida albicans) were also isolated from both the air and surface samples in the studied dairies. CONCLUSIONS: The air and surfaces in TD were more polluted than those in CD; however, in both types of dairies, the levels of microbial contaminants did not exceed respective threshold limit values. Nevertheless, the presence of pathogenic microorganisms may increase health risk for dairy workers and influence the quality of products. Hence, proper hygienic measures should be introduced and performed to guarantee high microbial quality of both production processes and milk products.


Assuntos
Microbiologia do Ar , Bactérias/crescimento & desenvolvimento , Indústria de Laticínios/instrumentação , Fungos/crescimento & desenvolvimento , Exposição Ocupacional/análise , Aerossóis/química , Bactérias/classificação , Bactérias/genética , Bactérias/isolamento & purificação , Biodiversidade , Indústria de Laticínios/economia , Fungos/classificação , Fungos/genética , Fungos/isolamento & purificação , Humanos , Exposição por Inalação/efeitos adversos , Exposição por Inalação/análise , Exposição Ocupacional/efeitos adversos
14.
Huan Jing Ke Xue ; 40(8): 3470-3476, 2019 Aug 08.
Artigo em Chinês | MEDLINE | ID: mdl-31854752

RESUMO

Sanitary landfill is a commonly-used method for solid waste disposal. In the process of landfilling, e. g. dumping, stacking, pushing, and compacting, a large number of bioaerosols with pathogenic bacteria will be generated. That can result in air pollution and significant harm to human health if these pathogens are released into the air. Sampling sites were set up in a domestic waste sanitary landfill in North China to collect airborne bacteria in the air. Airborne bacteria, particle size distributions, and populations were analyzed, and the influence of meteorological parameters (temperature, relative humidity (RH), and wind speed (WS)) on the emission of airborne bacteria was also investigated. Results showed that the concentrations of airborne bacteria in the working area and the coverage area were (5437±572) CFU·m-3 and (2707±396) CFU·m-3, respectively. The emission level in the leachate treatment area was the highest, with an average of 9460 CFU·m-3. The concentration of airborne bacteria showed clear seasonal variation, being was much higher in summer than that in the other seasons. Redundancy analysis (RDA) demonstrated that RH, temperature, and WS affected the number of airborne bacteria in the air. The peaks in the airborne particle size distribution were 2.1-4.7 µm in the working area and 0.65-2.1 µm in the coverage area. Most of the airborne bacteria released from the leachate treatment processes were larger than 4.7 µm. Moraxellaceae, Bacillus aerius, Arcobacter, and Aeromonas were potential or opportunistic pathogens detected from the airborne bacteria samples. Effective measures should be taken to reduce the amount of bacterial aerosol emitted to the air in landfill working areas and in the leachate of treatment areas. Operators of landfill machinery and leachate treatment facilities should consider personal protection measures and should reduce their exposure to microbial aerosols in order to prevent disease.


Assuntos
Microbiologia do Ar , Bactérias , Monitoramento Ambiental , Instalações de Eliminação de Resíduos , China , Humanos , Tamanho da Partícula
15.
Huan Jing Ke Xue ; 40(8): 3477-3488, 2019 Aug 08.
Artigo em Chinês | MEDLINE | ID: mdl-31854753

RESUMO

In order to determine the concentrations and size distributions of total airborne microbes in atmospheric bioaerosols, bioaerosol samples were collected in the coastal region of Qingdao, China, from Sep. 2016 to Jul. 2017 using size-fractionated bioaerosol samplers. The concentrations of total airborne microbes were then measured using an epifluorescence microscope after staining with DAPI (4', 6-diamidino-2-phenylindole). The results showed that the concentrations of total airborne microbes were in the range of 1.86×105-2.54×106 cells·m-3 in Qingdao during the sampling period, with an average of (6.84±4.83)×105 cells·m-3. The concentrations of total airborne microbes showed seasonal variation, with the highest values occurring in spring and winter, and the lowest values in summer and fall. Statistical analysis showed that the concentrations of total airborne microbes in autumn had a significant seasonal difference with spring and summer (P<0.05). The monthly averaged concentrations of total airborne microbes ranged from 2.65×105 cells·m-3 to 1.12×106 cells·m-3, with the highest values in Feb. 2017 and the lowest in Sep. 2016. Total microbe concentrations also varied greatly over a diurnal timescale in fall and winter during the period of 2015 to 2017, but this variation was not statistically significant (P>0.05). Overall, the size distribution of total airborne microbes was skewed, with the highest ratio occurring at >7.0 µm with a ratio of 20.5%-27.3%. The monthly averaged size distribution of total airborne microbes varied between months, showing two main distribution types, specifically bimodal and skewed patterns, respectively. Spearman's rank correlation analysis showed that the AQI and the concentrations of CO, PM2.5, and PM10 had a significant positive correlation with the concentrations of total airborne microbes (P<0.05), while air temperature, wind speed and direction, NO2, SO2, and O3 were not significantly correlated with the airborne microbe concentration during the sampling period (P>0.05). Multiple linear regression showed that 20.6% of the variation in the total microbe concentrations in bioaerosols correlated with relative humidity and PM2.5.


Assuntos
Aerossóis , Poluentes Atmosféricos , Microbiologia do Ar , China , Monitoramento Ambiental , Tamanho da Partícula , Material Particulado , Estações do Ano
16.
J Microbiol ; 57(12): 1086-1094, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31680218

RESUMO

One of the advantages for initial survival of inhaled fungal spores in the respiratory tract is the ability for iron acquisition via hemolytic factor-production. To examine the ability of indoor Aspergillus and Penicillium affecting hemolysis, the secreted factors during the growth of thirteen strains from eight species were characterized in vitro for their hemolytic activity (HA) and CAMP-like reaction. The hemolytic index of HA on human blood agar of Aspergillus micronesiensis, Aspergillus wentii, Aspergillus westerdijkiae, Penicillium citrinum, Penicillium copticola, Penicillium paxilli, Penicillium steckii, and Penicillium sumatrense were 1.72 ± 0.34, 1.61 ± 0.41, 1.69 ± 0.16, 1.58 ± 0.46, 3.10 ± 0.51, 1.22 ± 0.19, 2.55 ± 0.22, and 1.90 ± 0.14, respectively. The secreted factors of an Aspergillus wentii showed high HA when grown in undernourished broth at 25°C at an exponential phase and were heat sensitive. Its secreted proteins have an estimated relative molecular weight over 50 kDa. Whereas, the factors of Penicillium steckii were secreted in a similar condition at a late exponential phase but showed low HA and heat tolerance. In a CAMP-like test with sheep blood, the synergistic hemolytic reactions between most tested mold strains and Staphylococcus aureus were identified. Moreover, the enhancement of α-hemolysis of Staphylococcus aureus could occur through the interaction of Staphylococcus aureus-sphingomyelinase and CAMP-like factors secreted from Aspergillus micronesiensis. Further studies on the characterization of purified hemolytic- and CAMP-like-factors secreted from Aspergillus wentii and Aspergillus micronesiensis may lead to more understanding of their involvement of hemolysis and cytolysis for fungal survival prior to pathogenesis.


Assuntos
Aspergillus/fisiologia , Hemólise , Interações Microbianas/fisiologia , Penicillium/fisiologia , Esfingomielina Fosfodiesterase/isolamento & purificação , Microbiologia do Ar , Animais , Aspergillus/isolamento & purificação , Toxinas Bacterianas , Sangue , Proteínas Hemolisinas , Temperatura Alta , Humanos , Técnicas In Vitro , Penicillium/isolamento & purificação , Ovinos , Esfingomielina Fosfodiesterase/metabolismo , Infecções Estafilocócicas , Staphylococcus aureus , Tailândia
17.
Environ Monit Assess ; 191(12): 720, 2019 Nov 06.
Artigo em Inglês | MEDLINE | ID: mdl-31691038

RESUMO

We evaluated the efficiency of an air purifier using the single-chamber method for the effective removal of airborne Staphylococcus epidermidis, a nosocomial infection-causing bacterium. In this experiment, the bacterial strain S. epidermidis was injected using a nebulizer into the test chamber, which was similar to a consumer living space (60 m3). The microbial sampling was conducted via the air sampler method, and the reduction in S. epidermidis growth was monitored by performing three consecutive tests. Initially, a blank test was conducted to determine the natural decay rate and calibrate the experimental setup. After injecting the bacterial strain from 1240 to 11180 CFU per unit volume (m3), the natural decay rate showed a maximum deviation of 3.1% with a sampling error of 1.1% p at a confidence level of 95%. In addition, the particle size distribution in the test chamber was found to range from 0.3 to 5.0 µm, and a subsequent decrease in large-sized particles was observed with the operation of the air purifier, which is the size similar to that of suspended airborne bacteria. This can be used to assess the performance of the air purifier by calibrating the natural reduction value to the reduced operation value. Thus, the single-chamber technique is a promising approach for analyzing the removal efficacy of airborne bacteria from indoor air.


Assuntos
Filtros de Ar/normas , Microbiologia do Ar , Staphylococcus epidermidis/isolamento & purificação , Monitoramento Ambiental , Tamanho da Partícula
18.
Sci Total Environ ; 694: 133802, 2019 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-31756794

RESUMO

Airborne fungi are a primary component of bioaerosols and proved to impact human health and climatic change. Deoxyribonucleic acid (DNA) is the essential component of most living organisms with relatively stable physicochemical properties. Little is known about day-night and pollution-episode differences of DNA mass ratio and fungal community in fine particles (PM2.5) during serious winter haze events in China. Here we collected twenty-nine PM2.5 samples every day and night during an entire winter haze evolution process in a megacity of Central China, Wuhan. DNA extraction and high-throughput sequencing methods were adopted to analyze fungal community. Results showed that mass ratio of DNA in PM2.5 (RD/P %) changed with pollution process and showed significant negative correlations with PM2.5 concentration (r = -0.72, P < 0.05) and temperature (r = -0.74, P < 0.05). RD/P became lower (4.40 × 10-4%) after haze episodes than before (7.16 × 10-4%). RD/P of night-samples (1.98 × 10-4-4.97 × 10-4%) were all lower than those for day-samples (3.05 × 10-4-9.99 × 10-4%) for the same period. The fungal species richness became much lower (76 operational taxonomic units (OTUs)) after haze episodes than before (198 OTUs). The species richness of night-samples (119-537 OTUs) were all higher than those of day-samples (71-198 OTUs) for the same period. The OTUs specially owned by night-samples were also more than those by day-samples. Fungal community diversity showed random variations. The fungal community composition of each sample was classified from phylum to genus level. Pathogenic fungi accounted for 8.60% of the entire fungal community. The significantly enriched fungal taxa in the night-sample group (29 taxa) were also much more than that in the day-sample group (9 taxa), which could explain the higher species richness of airborne fungi community in the night during the haze evolution episodes. These findings may serve as an important reference or inspiration to other aerosol studies focusing on human health and behavior of aerosols in the atmosphere.


Assuntos
Aerossóis/análise , Microbiologia do Ar , Monitoramento Ambiental , Material Particulado/análise , Atmosfera , Bactérias , China , DNA , Fungos , Estações do Ano
19.
Sci Total Environ ; 688: 1298-1307, 2019 Oct 20.
Artigo em Inglês | MEDLINE | ID: mdl-31726559

RESUMO

Patients with respiratory diseases in rural areas have been reported to have enhanced responsiveness to ambient particulate matter (PM). In addition to the physical and chemical components, ambient PM can contain microorganisms or parts thereof, referred here as BioPM, that can also contribute to the adverse health effects. This study aimed to characterize the microbial composition of BioPM originating from livestock, and to investigate whether these BioPM can trigger the activation of innate receptors and cells. Coarse (PM2.5-10 µm) and fine (PM<2.5 µm) BioPM samples were collected from indoor chicken, pig and goat farms using the versatile aerosol concentration enrichment system (VACES) connected to a Biosampler. The fungal and bacterial communities were assessed with an amplicon based approach using Next Generation Sequencing (NGS). In parallel, HEK-Blue cells expressing different pattern recognition receptors (Toll like receptors (TLR) 2, 3, 4, 5, 7, 8, 9 and NOD 1, 2) and a human monocytic cell line (MM6) were exposed to BioPM samples from these sites. Distinct airborne microbiota profiles associated with the corresponding animal farm were observed. Moreover, the various BioPM contained mainly ligands for TLR2 and TLR4 resulting in a concentration-dependent increase of pro-inflammatory cytokine secreted by MM6 cells. In addition, we show for the first time that only the pig-derived BioPM induced TLR5 activation. These findings suggest that animal farm specific BioPM trigger distinct inflammatory responses, which may contribute to airway diseases in humans.


Assuntos
Microbiologia do Ar , Monitoramento Ambiental , Material Particulado/análise , Animais , Linhagem Celular , Fazendas , Imunidade Inata , Gado , Microbiota
20.
Environ Sci Pollut Res Int ; 26(34): 34741-34753, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31654301

RESUMO

The aim of the literature review was to describe the environments where the presence of airborne Staphylococcus aureus was confirmed and to catalogue the most often used methods and conditions of bioaerosol sampling to identify the bacteria. The basis for searching of studies on S. aureus in the bioaerosol in different environments was PubMed database resources from the years 1990-2019 (May). The review included studies which were carried on in selected environments: hospitals and other health care facilities, large-scale animal breeding, wastewater treatment plants, residential areas, educational institutions, and other public places. The highest concentrations and genetic diversity of identified S. aureus strains, including MRSA (methicillin-resistant S. aureus), have been shown in large-scale animal breeding. The role of the airborne transmission in dissemination of infection caused by these pathogens is empirically confirmed in environmental studies. Commonly available, well-described, and relatively inexpensive methods of sampling, identification, and subtyping guarantee a high reliability of results and allow to obtain fast and verifiable outcomes in environmental studies on air transmission routes of S. aureus strains.


Assuntos
Microbiologia do Ar , Staphylococcus aureus , Animais , Antibacterianos , Humanos , Staphylococcus aureus Resistente à Meticilina , Testes de Sensibilidade Microbiana , Reprodutibilidade dos Testes , Infecções Estafilocócicas
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