Concentration and determinants of molds and allergens in indoor air and house dust of French dwellings

International audienceMolds and allergens are common indoor biocontaminants. The aims of this study were to assess the concentrations of common molds in indoor air and floor dust and the concentrations of house dust mite, cat and dog allergens in mattress dust in French dwellings, and to assess predictors of these concentrations. A sample of 150 houses in Brittany (western France) was investigated. Airborne Cladosporium and Penicillium were detected in more than 90% of the dwellings, Aspergillus in 46% and Alternaria in only 6% of the housings. Regarding floor dust samples, Cladosporium and Penicillium were detected in 92 and 80% of the housings respectively, Aspergillus in 49% and Alternaria in 14%. House dust mite allergens Der p1 and Der f1 were detected in 90% and 77% of the mattress dust samples respectively and Can f1 and Fel d1 in 37% and 89% of the homes. Airborne and dustborne mold concentrations, although not statistically correlated (except for Aspergillus) shared most of their predictors. Multivariate linear models for mold levels, explaining up to 62% of the variability, showed an influence of the season, of the age of the dwelling, of aeration habits, presence of pets, smoking, signals of dampness, temperature and relative humidity. Allergens in the dust of the mattress were strongly related to the presence of pets and cleaning practices of bedsheets, these factors accounting for 60% of the variability. This study highlights ubiquitous contamination by molds and underlines complex interaction between outdoor and indoor sources and factor

Influence de l'arrangement granulaire d'un sédiment polydisperses sur le seuil de mise en mouvement

La prédiction du transport d'un mélange de particules de plusieurs tailles est un point sensible d'une représentation de la dynamique sédimentaire sur de nombreux faciès en rivière ou en mer. Afin de déterminer les processus critiques qui régissent la mise en mouvement de tels mélanges et de quantifier leur contributions, des essais ont été réalisés dans un petit canal à courant. Ils ont porté sur des échantillons reconstitués, formés de sables naturels lithoclastiques bien triés ou de mélanges sableux bimodaux. L'objectif est d'observer et de quantifier les différences de comportement à l'entrainement entre un sédiment unimodal et un sédiment mélangé. Les résultats obtenus sont comparés à une sélection de formulations issues de la littérature. La série de tests a permis de mettre en évidence quelques processus particuliers du début du transport sédimentaire multiclasse dans un écoulement stationnaire. La granulométrie utilisée s'étend des sables fins aux sables très grossiers. Des paramètres du mélange tels que le rapport de taille des particules, le taux de saturation des échantillons par les grains dont la taille est la plus fine ou la porosité influent sur la modulation de la contrainte de frottement critique. Les comparaisons mesures / formules ont mis en évidence la difficulté de prédire le seuil de mise en mouvement des particules d'un mélange hétérométrique. Par conséquent, l'incertitude sur la granulométrie transportée s'accroît lorsque le frottement est proche du frottement critique d'une certaine classe de taille

High-resolution mass spectrometry identifies delayed biomarkers for improved precision in acetaminophen/paracetamol human biomonitoring

Paracetamol/acetaminophen (N-acetyl-p-aminophenol, APAP) is a top selling analgesic used in more than 600 prescription and non-prescription pharmaceuticals. To study efficiently some of the potential undesirable effects associated with increasing APAP consumption (e.g., developmental disorders, drug-induced liver injury), there is a need to improve current APAP biomonitoring methods that are limited by APAP short half-life. Here, we demonstrate using high-resolution mass spectrometry (HRMS) in several human studies that APAP thiomethyl metabolite conjugates (S-methyl-3-thioacetaminophen sulfate and S-methyl-3-thioacetaminophen sulphoxide sulfate) are stable biomarkers with delayed excretion rates compared to conventional APAP metabolites, that could provide a more reliable history of APAP ingestion in epidemiological studies. We also show that these biomarkers could serve as relevant clinical markers to diagnose APAP acute intoxication in overdosed patients, when free APAP have nearly disappeared from blood. Using in vitro liver models (HepaRG cells and primary human hepatocytes), we then confirm that these thiomethyl metabolites are directly linked to the toxic N-acetyl-p-benzoquinone imine (NAPQI) elimination, and produced via an overlooked pathway called the thiomethyl shunt pathway. Further studies will be needed to determine whether the production of the reactive hepatotoxic NAPQI metabolites is currently underestimated in human. Nevertheless, these biomarkers could already serve to improve APAP human biomonitoring, and investigate, for instance, inter-individual variability in NAPQI production to study underlying causes involved in APAP-induced hepatotoxicity. Overall, our findings demonstrate the potential of exposomics-based HRMS approach to advance towards a better precision for human biomonitoring.</p

Les contaminants biologiques dans l'environnement intérieur: Élaboration d’un indice environnemental d’exposition aux biocontaminants en environnement intérieur

National audienceLes contaminants biologiques à l’origine de troubles respiratoires sont, par ordre d’importance, les allergènes, les moisissures et les bactéries. Pour avoir une idée globale de la contamination biologique d’un logement, nous proposons de mettre au point un nouvel indice d’exposition vis-à-vis des contaminants biologiques, y compris les allergènes susceptibles d’être responsables de troubles respiratoires. Pour avoir une idée globale de la contamination biologique d’un logement, nous proposons de mettre au point un nouvel indice d’exposition vis-à-vis des contaminants biologiques, y compris les allergènes susceptibles d’être responsables de troubles respiratoires

[Covid-19 et transmission par aérosols: état des lieux]

International audienceSARS-CoV 2, the agent of the disease known as COVID-19, appeared in China at the end of 2019. The virus is transmitted primarily through the air in droplets or microdroplets emitted by symptomatic (through coughing or sneezing or during aerosol-generating procedures) or asymptomatic (through breathing or speaking) infected persons. This article reviews the current knowledge about the sizes of droplets emitted, the quantity of viral particles potentially emitted, the parameters influencing the conditions of transport and survival of these viral particles, including atmospheric conditions, and the impact on the development of the disease. It also discusses the parameters of risk assessment and recommendations for ventilation of indoor spaces. © 2021 John Libbey Eurotext. All rights reserved

Quantification rapide des champignons viables dans les environnements hospitaliers : analyse d'échantillons d'air et de surface par cytométrie en phase solide

International audienceQuantification rapide des champignons viables dans les environnements hospitaliers : analyse d'échantillons d'air et de surface par cytométrie en phase solid

Rapid quantification of viable fungi in hospital environments: analysis of air and surface samples using solid-phase cytometry.

International audienceBACKGROUND: Environmental surveillance is important in high-risk areas of hospitals to prevent fungal infections in immunosuppressed patients. Conventional culture methods for enumerating environmental fungi are time-consuming. AIM: In this field study, a solid-phase cytometry technique (SPC) and a more conventional culture-based method to quantify fungal contamination of hospital air and surface samples were compared. METHODS: For the air sampling, a liquid cyclone air sampler was used with a flow rate of 300 L/min for 10 min in each of four hospital locations. Surface swabbing was done in two locations, with two different swab types. Samples from all areas were processed by SPC and by culture on malt extract agar. FINDINGS: The mean airborne concentrations of viable fungi determined by SPC were about 1.5-fold higher than the mean concentrations obtained with the culture-based method. These differences for air samples were significant in three hospital environments. No significant difference was observed for surface samples between the two swab types and between the two analytical methods. One of the prominent advantages of SPC was its rapidity in comparison with the culture-based method (5 h versus 5 days). CONCLUSION: In this study, we showed that SPC allows for rapid monitoring of viable fungi in hospital environments. SPC can thus be used to provide an early warning and a rapid implementation of corrective measures. Viable fungi detection may be an important tool to assess infectious risk in wards with immunosuppressed patients

Comparative evaluation of impactor air samplers and of culture conditions for quantification of fungal contamination.

International audiencePortable microbial samplers are useful for detecting microorganisms in the air. However, limited data are available on their performance when sampling airborne biological agents in a routine practice. We compared bacterial and fungal concentrations obtained in field conditions using three impactor samplers with different designs (AES Chemunex Sampl’Air, bioMérieux Air Ideal, and Sartorius AirPort MD8/BACTair). The linearity of mold collection was tested in the range of 100 L to 1000 L, and all the devices had a correlation coefficient higher than 0.95. For optimal comparison of the samplers, we performed experiments in different hospital rooms with varying levels of air biocontamination. Each sampling procedure was repeated to assess reproducibility. No significant difference between the samplers was observed for the mold concentrations on Sabouraud agar, whereas Sampl’Air collected significantly more bacteria on tryptic soy agar than Air Ideal or BACTair at one of the sites. Impactor location in the room was nevertheless associated with the variability observed with the three samplers at the highest microbial concentration levels. On the basis of their performance, autonomy and simplicity of use, these three impactors are suitable for routine indoor evaluation of microbial air contamination

ARCANE - Volume 2 : Rapport de données eulériennes (1996-1999)

The Research Project ARCANE (Actions de Recherche sur la Circulation dans l'Atlantique Nord-Est) is designed to determine the transport of mass, heat and salt in the intergyre region of the North-East Atlantic. The specific objectives are the experimental study of the oceanic circulation in the neighbourhood of the Iberian Peninsula Continental Slope and of the circulation and dispersion of the Mediterranean Water in the North-East Atlantic. It is a joint project between the Centre Militaire d'Océanographie (CMO) of the Service Hydrographique et Océanographique de la Marine (SHOM) and the Laboratoire de Physique des Océans (LPO, Unité Mixte de Recherche IFREMERlCNRS/UBO), and tookplace between September 1996 and October 1999. Acoustic jloats, of Marvor and Rafos types, drifting buoys have been deployed. An acoustic sources network was maintained during 3 years. Currentmeter moorings and hydrological and geochemical tracers studies have been carried out. Several cruises on SHOM and IFREMER vessels have been conducted. Other partners are involved in the project: • the Laboratoire de Chimie Océanique (LCO/UBO), for geochemical measurements; • the « Instituto Hidrografico il (IH) from Lisbon, for eulerian currentmeter and hydrological measurements; • the « Empresa Publica Puertos deI Estado il (EPPE) from Madrid, for sea level and eulerian currentmeter measurements. This report presents the eulerian measurements collected by the LPO between November 1996 and October 1999, at three currentmeter moorings located northwest of the Iberian Peninsula. During the same period, the CMO maintained three currentmeter moorings on the nearby continental slope. These measurements, as weil as those resulting from other ARCANE activities (lagrangian measurements, hydrological, geochemical and tracer studies) have been or will be presented in particular reports.Le projet ARCANE (Actions de Recherche sur la Circulation dans l'Atlantique Nord-Est) a pour thématique la détermination des transports de masse, de chaleur et de sel dans la zone intergyre de l' Atlantique Nord-Est. Ses objectifs spécifiques sont l'étude expérimentale de la circulation océanique au voisinage de la pente continentale à l'Ouest et au Nord de la Péninsule Ibérique, et de la circulation et de la dispersion de l'Eau Méditerranéenne aux moyennes latitudes de l'Atlantique Nord-Est. Il s'agit d'un projet commun entre le Centre Militaire d'Océanographie (CMO) du Service Hydrographique et Océanographique de la Marine (SHOM) et le Laboratoire de Physique des Océans (LPO), Unité Mixte de Recherche IFREMER/CNRS/UBO, dont la phase expérimentale s'est déroulée entre septembre 1996 et octobre 1999. Il a consisté en la mise à l'eau de flotteurs acoustiques, de type Marvor et Rafos et de bouées dérivantes, et en le maintien pendant une durée de 3 ans d'un réseau de sources acoustiques. La mise à l'eau de mouillages courantométriques, et des mesures d'hydrologie et de traceurs géochimiques ont été réalisées. Plusieurs campagnes sur des navires du SHOM et de l'IFREMER ont été conduites pour mener à bien ce projet. D'autres partenaires sont impliqués, comme : . le Laboratoire de Chimie Océanique (LCO) de l'UBO, pour les mesures géochimiques ; . l'« Instituto Hidrografico » (IH) de Lisbonne, pour des mesures de courantométrie eulérienne et d'hydrologie ; . l'« Empresa Publica Puertos del Estado » (EPPE) de Madrid, pour des mesures de niveaux de la mer et de courantométrie eulérienne. Le rapport présente les mesures eulériennes réalisées par le LPO entre novembre 1996 et octobre 1999, en trois mouillages courantométriques situés au Nord-Ouest de la péninsule Ibérique. Le CMO a maintenu, pendant la même période, trois mouillages courantométriques sur la pente continentale voisine. Ces mesures, ainsi que celles qui résultent des autres activités entreprises dans le cadre du projet ARCANE (courantométrie lagrangienne, mesures d'hydrologie et de traceurs géochimiques) ont fait, ou feront, l'objet de rapports particuliers

The persistence of respiratory viruses on filters of air handling units

International audienc