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Personne :
Duchaine, Caroline

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Duchaine

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Caroline

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Université Laval. Département de biochimie, de microbiologie et de bio-informatique

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ncf10370881

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Résultats de recherche

Voici les éléments 1 - 10 sur 11
  • PublicationAccès libre
    Organic components of airborne dust influence the magnitude and kinetics of dendritic cell activation
    (Elsevier Science, 2018-04-27) Duchaine, Caroline; Veillette, Marc; Marsolais, David; Blais Lecours, Pascale; Létourneau, Valérie.; Boucher, Magali
    Bioaerosol exposure in highly contaminated occupational settings is associated with an increased risk of disease. Yet, few determinants allow for accurate prediction of the immunopathogenic potential of complex bioaerosols. Since dendritic cells are instrumental to the initiation of immunopathological reactions, we studied how dendritic cell activation was modified in response to individual agents, combined microbial agents, or air sample eluates from highly contaminated environmental settings. We found that combinations of agents accelerated and enhanced the activation of in vitro-generated murine bone marrow-derived dendritic cell cultures, when compared to individual agents. We also determined that endotoxins are not sufficient to predict the potential of air samples to induce bone marrow-derived dendritic cell activation, especially when endotoxin levels are low. Importantly, bone marrow-derived dendritic cell activation stratified samples from three environmental settings (swine barns, dairy barns, and wastewater treatment plants) according to their air quality status. As a whole, these results support the notion that the interplay between bioaerosol components impacts on their ability to activate dendritic cells and that bone marrow-derived dendritic cell cultures are promising tools to study the immunomodulatory impact of air samples and their components.
  • PublicationAccès libre
    Detection of streptococcus suis in bioaerosols of swine confinement buildings
    (American Society for Microbiology, 2014-03-14) Duchaine, Caroline; Veillette, Marc; Grenier, Daniel; Létourneau, Valérie.; Bonifait, Laetitia
    Streptococcus suis is an important swine pathogen that can cause septicemia, meningitis, and pneumonia. Also recognized as an emerging zoonotic agent, it is responsible for outbreaks of human infections in Asian countries. Serotype 2 is the predominant isolate from diseased animals and humans. The aerosolization of S. suis in the air of swine confinement buildings (SCB) was studied. The presence of S. suis in bioaerosols was monitored in SCB where cases of infection had been reported and in healthy SCB without reported infections. Using a quantitative-PCR (qPCR) method, we determined the total number of bacteria (1 × 108 to 2 × 108 airborne/m3), total number of S. suis bacteria (4 × 105 to 10 × 105 airborne/m3), and number of S. suis serotype 2 and 1/2 bacteria (1 × 103 to 30 × 103 airborne/m3) present in the air. S. suis serotypes 2 and 1/2 were detected in the air of all growing/finishing SCB that had documented cases of S. suis infection and in 50% of healthy SCB. The total number of bacteria and total numbers of S. suis and S. suis serotype 2 and 1/2 bacteria were monitored in one positive SCB during a 5-week period, and it was shown that the aerosolized S. suis serotypes 2 and 1/2 remain airborne for a prolonged period. When the effect of aerosolization on S. suis was observed, the percentage of intact S. suis bacteria (showing cell membrane integrity) in the air might have been up to 13%. Finally S. suis was found in nasal swabs from 14 out of 21 healthy finishing-SCB workers, suggesting significant exposure to the pathogen. This report provides a better understanding of the aerosolization, prevalence, and persistence of S. suis in SCB.
  • PublicationRestreint
    Airborne porcine circovirus in Canadian swine confinement buildings
    (Oxford, 2009-09-11) Duchaine, Caroline; Massé, Daniel; Verreault, Daniel; Létourneau, Valérie.; Gagnon, Carl A.; Gendron, Louis
    Porcine circovirus type 2 has been linked to many diseases, such as postweaning multisystemic wasting syndrome and can be found in most commercial swine confinement buildings around the world. Although the exact role of the virus in the appearance of disease in animals is not fully understood, the mechanisms responsible for the transmission of the virus are currently believed to happen mostly by contact. Nevertheless, the possibility of airborne transmission cannot be rejected. This study investigated the presence of the virus, total bacteria and total dusts in aerosols. Air samples were taken with gelatin filters in swine confinement buildings and were analyzed by quantitative polymerase chain reaction. Interestingly, concentrations of airborne PCV2 of up to 10(7) genomes per cubic meter of air were detected. Airborne dust concentrations were correlated to airborne concentrations of PCV2 and total bacteria. Although the infectivity potential of the airborne viral loads were not evaluated, it is clear that the virus can become airborne in detectable concentrations in commercial swine confinement building environments. The significance of this finding in an epidemiological point of view will need further investigation.
  • PublicationRestreint
    Impact of production systems on swine confinement buildings bioaerosols
    (Taylor and Francis, 2009-12-15) Duchaine, Caroline; Mériaux, Anne; Massé, Daniel; Létourneau, Valérie.; Nehmé, Benjamin
    Hog production has been substantially intensified in Eastern Canada. Hogs are now fattened in swine confinement buildings with controlled ventilation systems and high animal densities. Newly designed buildings are equipped with conventional manure handling and management systems, shallow or deep litter systems, or source separation systems to manage the large volumes of waste. However, the impacts of those alternative production systems on bioaerosol concentrations within the barns have never been evaluated. Bioaerosols were characterized in 18 modern swine confinement buildings, and the differences in bioaerosol composition in the three different production systems were evaluated. Total dust, endotoxins, culturable actinomycetes, fungi, and bacteria were collected with various apparatuses. The total DNA of the air samples was extracted, and quantitative polymerase chain reaction (PCR) was used to assess the total number of bacterial genomes, as a total (culturable and nonculturable) bacterial assessment. The measured total dust and endotoxin concentrations were not statistically different in the three studied production systems. In buildings with sawdust beds, actinomycetes and molds were found in higher concentrations than in the conventional barns. Aspergillus, Cladosporium, Penicillium, and Scopulariopsis species were identified in all the studied swine confinement buildings. A. flavus, A. terreus, and A. versicolor were abundantly present in the facilities with sawdust beds. Thermotolerant A. fumigatus and Mucor were usually found in all the buildings. The culturable bacteria concentrations were higher in the barns with litters than in the conventional buildings, while real-time PCR revealed nonstatistically different concentrations of total bacteria in all the studied swine confinement buildings. In terms of workers' respiratory health, barns equipped with a solid/liquid separation system may offer better air quality than conventional buildings or barns with sawdust beds. The impact of ventilation rates, air distribution, or building design still has to be explored.
  • PublicationRestreint
    Presence of zoonotic pathogens in physico-chemically characterized manures from hog finishing houses using different production systems
    (Elsevier Applied Science, 2010-02-04) Duchaine, Caroline; Massé, Daniel; Létourneau, Valérie.; Letellier, Ann; Côté, Caroline; Topp, Edward
    Hog production has been intensified in Eastern Canada, by 50% over the last 20years. Wastes are now managed with conventional production systems (slatted floor), litter systems or source separation systems. We studied the presence of total and fecal coliforms, Campylobacter, Clostridium perfringens, Enterococcus, Escherichia coli, Salmonella, Yersinia enterocolitica, Giardia and Cryptosporidium in the manure of all of these production systems. The concentrations of the studied zoonotic pathogens did not differ between the conventional and the litter systems investigated. The source separation system yielded separated solid and liquid fractions. Total and fecal coliforms, C. perfringens, Enterococcus, E. coli, and Y. enterocolitica were found in the solids and the liquid fractions of a source separation system.Campylobacter species were not detected in the liquid fractions. Zoonotic pathogens are therefore, found in the manure of Eastern Canadian hog finishing houses equipped either with conventional, sawdust litter or source separation systems. Pathogens inactivation will require changes in manure management practices or the use of manure disinfection methods.
  • PublicationRestreint
    Biological activities of respirable dust from Eastern Canadian peat moss factories
    (Pergamon, 2010-04-14) Duchaine, Caroline; Mériaux, Anne; Goyer, Nicole; Chakir, Jamila; Létourneau, Valérie.; Cormier, Yvon
    Bacteria, moulds, endotoxin and quartz from respirable dust of agricultural and industrial buildings are typically incriminated for the respiratory health decline of exposed workers despite that dust being an undefined mixture and quantification methods of aerosolized bacteria, moulds or endotoxin not being standardized yet. We developed an in vitro alveolar epithelial cell system in which biological activities of peat moss factories' dust might be correlated to bacteria, mould, endotoxin and quartz concentrations of the analyzed samples. Following exposure, interleukin-8 protein secretion, necrosis and apoptosis of the exposed A549 cells were monitored respectively with ELISA on cell supernatants, trypan blue exclusion and DNA fragmentation detection by flow cytometry. Respirable dust was collected with liquid impingers and respirable quartz with 10mm Dorr-Oliver cyclones. We quantified mesophilic bacteria, mesophilic moulds and endotoxins from liquid impinger samples. No correlation was observed between biological activities of dust and bacteria, mould, endotoxin or quartz concentrations under our experimental conditions. Our speculation is that simple measurements, such as dust concentrations, may not be adequate indicators of the human respiratory health hazard for a given environment.
  • PublicationRestreint
    Human pathogens and tetracycline-resistant bacteria in bioaerosols of swine confinement buildings and in nasal flora of hog producers
    (Elsevier, 2010-10-23) Duchaine, Caroline; Mériaux, Anne; Massé, Daniel; Létourneau, Valérie.; Nehmé, Benjamin; Cormier, Yvon
    Swine confinement buildings in eastern Canada are enclosed and equipped with modern production systems to manage waste. Bioaerosols of these swine confinement buildings could be contaminated by human pathogens and antimicrobial resistant bacteria which could colonize exposed workers. We therefore wanted to analyze bioaerosols of swine confinement buildings and nasal flora of Canadian hog producers to evaluate possible colonization with human pathogens and tetracycline-resistant bacteria. Culturable and non-culturable human pathogens and tet genes were investigated in the bioaerosols of 18 barns. The nasal passages of 35 hog producers were sampled and total DNA was extracted from the calcium-alginate swabs to detect, by PCR, Campylobacter, C. perfringens, Enterococcus, E. coli, Y. enterocolitica, tetA/tetC, tetG and ribosomal protection protein genes. Airborne culturable C. perfringens, Enterococcus, E. coli, and Y. enterocolitica were present in the bioaerosols of 16, 17, 11 and 6 of the 18 facilities. Aerosolized total (culturable/non culturable) Campylobacter, C. perfringens, Enterococcus, E. coli and Y. enterocolitica were detected in 10, 6, 15, 18 and 2 barns, respectively. Tet genes were found in isolates of culturable human pathogens. TetA/tetC, tetG and ribosomal protection protein genes were detected in the bioaerosols of all 18 studied buildings. Campylobacter, C. perfringens, Enterococcus, E. coli, and Y. enterocolitica were found respectively in 4, 9, 17, 14 and one nasal flora of workers. One and 10 workers were positive for tetA/tetC and tetG genes, respectively. In swine confinement buildings, hog producers are exposed to aerosolized human pathogens and tetracycline-resistant bacteria that can contaminate the nasal flora.
  • PublicationRestreint
    Culture-independent approach of the bacterial bioaerosol diversity in the standard swine confinement buildings, and assessment of the seasonal effect
    (Blackwell Science., 2008-01-25) Duchaine, Caroline; Veillette, Marc; Forster, Robert John; Létourneau, Valérie.; Nehmé, Benjamin
    The bacterial bioaerosol community of eight swine confinement buildings (SCB) was monitored during two visits in the winter, and one during the summer. To our knowledge, culture-independent approaches and molecular biology tools such as biomass quantification and biodiversity analyses have never been applied to swine building bioaerosol analyses. Total DNA of each sample was extracted and analysed by quantitative real-time polymerase chain reaction, denaturing gradient gel electrophoresis (DGGE) and phylogenetic analysis using primers targeting the bacterial 16S rRNA gene. Even though the total bacterial concentration was higher in winter than in summer, the total bacterial concentration for both seasons was 100 to1000 times higher than the total cultural bacteria. The concentration of bioaerosol was influenced by the temperature indoors, which was regulated with an electronic fan system driving warm air and particles outside of the SCB. Comparison of the DGGE profiles showed the same biodiversity in each SCB during both seasons. The phylogenetic analysis revealed a large number of sequences (93.8%) related to Gram-positive anaerobic bacteria, such as Clostridia, and dominated by the Clostridia cluster I (C. disporicum) and the Clostridia cluster XI (C. glycolycum). The bioaerosol diversity also contained also a low proportion of Bacteroidetes and Lactobacillales–Streptococcales sequences. Analyses of the global community and phylotype diversity showed that the main source of bioaerosols could come from the pig manure slurry.
  • PublicationAccès libre
    Culture-independent characterization of archaeal biodiversity in swine confinement building bioaerosols
    (American Society for Microbiology., 2009-09-01) Duchaine, Caroline; Veillette, Marc; Létourneau, Valérie.; Forster, Robert John; Nehmé, Benjamin; Gilbert, Yan.; Villemur, Richard
    It was previously demonstrated that microbial communities of pig manure were composed of both bacteria and archaea. Recent studies have shown that bacteria are aerosolized from pig manure, but none have ever focused on the airborne archaeal burden. We sought here to develop and apply molecular ecology approaches to thoroughly characterize airborne archaea from swine confinement buildings (SCBs). Eight swine operations were visited, twice in winter and once during summer. Institute of Occupational Medicine cassettes loaded with 25-mm gelatin filters were used to capture the inhalable microbial biomass. The total genomic DNA was extracted and used as a template for PCR amplification of the archaeal 16S rRNA gene. High concentrations of archaea were found in SCB bioaerosols, being as high as 108 16S rRNA gene copies per cubic meter of air. Construction and sequencing of 16S rRNA gene libraries revealed that all sequences were closely related to methanogenic archaea, such as Methanosphaera stadtmanae (94.7% of the archaeal biodiversity). Archaeal community profiles were compared by 16S rRNA gene denaturing gradient gel electrophoresis. This analysis showed similar fingerprints in each SCB and confirmed the predominance of methanogenic archaea in the bioaerosols. This study sheds new light on the nature of bioaerosols in SCBs and suggests that archaea are also aerosolized from pig manure.
  • PublicationRestreint
    Endotoxin levels and contribution factors of endotoxins in resident, school, and office environments - a review
    (Pergamon, 2016-08-06) Salonen, Heidi; Duchaine, Caroline; Létourneau, Valérie.; Mazaheri, Mandana; Laitinen, Sirpa; Clifford, Sam; Mikkola, Raimo; Lappalainen, Sanna; Reijula, Kari; Morawska, Lidia
    As endotoxin exposure has known effects on human health, it is important to know the generally existing levels of endotoxins as well as their contributing factors. This work reviews current knowledge on the endotoxin loads in settled floor dust, concentrations of endotoxins in indoor air, and different environmental factors potentially affecting endotoxin levels. The literature review consists of peer-reviewed manuscripts located using Google and PubMed, with search terms based on individual words and combinations. References from relevant articles have also been searched. Analysis of the data showed that in residential, school, and office environments, the mean endotoxin loads in settled floor dust varied between 660 and 107,000 EU/m2, 2180 and 48,000 EU/m2, and 2700 and 12,890 EU/m2, respectively. Correspondingly, the mean endotoxin concentrations in indoor air varied between 0.04 and 1610 EU/m3 in residences, and 0.07 and 9.30 EU/m3 in schools and offices. There is strong scientific evidence indicating that age of houses (or housing unit year category), cleaning, farm or rural living, flooring materials (the presence of carpets), number of occupants, the presence of dogs or cats indoors, and relative humidity affect endotoxin loads in settled floor dust. The presence of pets (especially dogs) was extremely strongly associated with endotoxin concentrations in indoor air. However, as reviewed articles show inconsistency, additional studies on these and other possible predicting factors are needed.