Sandrine Roussel

High-resolution imaging of the Pyrenees and Massif Central from the data of the PYROPE and IBERARRAY portable array deployments

The lithospheric structures beneath the Pyrenees, which holds the key to settle long-standing controversies regarding the opening of the Bay of Biscay and the formation of the Pyrenees, are still poorly known. The temporary PYROPE and IBERARRAY experiments have recently filled a strong deficit of seismological stations in this part of western Europe, offering a new and unique opportunity to image crustal and mantle structures with unprecedented resolution. Here we report the results of the first tomographic study of the Pyrenees relying on this rich data set. The important aspects of our tomographic study are the precision of both absolute and relative traveltime measurements obtained by a nonlinear simulated annealing waveform fit and the detailed crustal model that has been constructed to compute accurate crustal corrections. Beneath the Massif Central, the most prominent feature is a widespread slow anomaly that reflects a strong thermal anomaly resulting from the thinning of the lithosphere and upwelling of the asthenosphere. Our tomographic images clearly exclude scenarios involving subduction of oceanic lithosphere beneath the Pyrenees. In contrast, they reveal the segmentation of lithospheric structures, mainly by two major lithospheric faults, the Toulouse fault in the central Pyrenees and the Pamplona fault in the western Pyrenees. These inherited Hercynian faults were reactivated during the Cretaceous rifting of the Aquitaine and Iberian margins and during the Cenozoic Alpine convergence. Therefore, the Pyrenees can be seen as resulting from the tectonic inversion of a segmented continental rift that was buried by subduction beneath the European plate.

Hypersensitivity pneumonitis and metalworking fluids contaminated by mycobacteria

Metalworking fluids (MWF) are responsible for hypersensitivity pneumonitis (HP). The aim of the present study was to identify the antigen (Ag) responsible for MWF-associated HP, and to optimise serological diagnosis by definition of a threshold allowing discrimination between HP patients and asymptomatic exposed workers. 13 patients, who were workers at a car engine manufacturing plant, were suspected of MWF-associated HP. Microbial analysis of 83 used MWFs was carried out. Sera from 13 MWF-associated HP patients, 12 asymptomatic exposed workers and 18 healthy unexposed controls were tested to determine their immunological responses to three Ags, including Mycobacterium immunogenum. M. immunogenum was identified in 40% of used fluids by culture and confirmed by DNA sequencing. The threshold for differentiating MWF-associated HP patients from asymptomatic exposed workers was five arcs of precipitation (sensitivity 77% and specificity 92%), as determined by electrosyneresis (ES). Using ELISA methods with protein extract from M. immunogenum, a threshold leading to 92% sensitivity and 100% specificity was established. The detection of specific antibodies against M. immunogenum Ag at high levels in case sera suggests that M. immunogenum-contaminated MWF is responsible for MWF-associated HP. To discriminate MWF-associated HP patients from asymptomatic exposed workers, we suggest a five-arc threshold for ES and a 1.6-AU threshold for ELISA methods.

Indoor mold concentration in Eastern France

UNLABELLED Our prospective case-control study of 118 dwellings in Eastern France examined fungal contamination in unhealthy dwellings (n = 32) (homes with visible mold contamination and adverse health outcomes reported by the occupants), dwellings occupied by allergic patients (with medical diagnostic and positive prick-tests for molds) (n = 27) and matched control dwellings (n = 59). Unhealthy dwellings present higher airborne concentrations of Aspergillus, Penicillium, and Cladosporium than control dwellings, irrespective of the room sampled. Bedroom walls were more highly contaminated by molds than others. Dwellings occupied by allergic patients differed significantly for airborne concentrations of Penicillium only, but not for wall surface contamination, whereas bathroom walls were more highly contaminated than other rooms. Molecular identification of 12 Penicillium species showed Penicillium chrysogenum and Penicillium olsonii to be the two main species. From the total average of molds, by impaction method, useful thresholds can be given: below 170 CFU/m(3), between 170 and 560 CFU/m(3), 560 and 1000 CFU/m(3) and above 1000 CFU/m(3), respectively for dwellings with low, moderate, high, and very high concentrations. The latter would be considered a potential health hazard. PRACTICAL IMPLICATIONS A single measure of airborne concentrations of molds by impaction allows to establish useful thresholds by social services to estimate in a objective way the housing moldiness. Excluding the summer period, reproducibility of this kind of measure on 3 months, in the fixed limits, is 94.3%. The differences in terms of biodiversity of the unhealthy housing and those accommodating allergic patients imply a specific approach to decrease fungi airborne concentrations. The biodiversity of Penicillium raises the problem of the use of the single extract of Penicillium chrysogenum for skin-tests. The extent of the contaminated surfaces must be measured to assess the potential risk linked to spore contamination. Indeed, surface sampling mostly allows qualitative assessment of the environment.

Characteristics of dwellings contaminated by moulds

Dwellings showing a presence of moulds are considered to be unhealthy both by the inhabitants and by sanitary authorities. Although the thresholds of pathogenicity have not yet been established, the toxic, allergic and infectious risk of indoor moulds is better understood today. A study on indoor fungi contamination for 128 dwellings was done between October and May in France. It concerned 69 dwellings, the occupants of which either complained to the sanitary authorities about problems of moulds and humidity or consulted a doctor who related their symptoms to housing conditions. Fifty-nine other dwellings, the occupants of which were healthy, constituted the control group. We present the statistical analysis of questionnaires, which aimed to clarify characteristics of dwellings associated with high concentrations of airborne moulds. Air samples were taken with an impactor in 500 rooms. On visiting dwellings, investigators obtained answers to 25 questions concerning characteristics of inhabitants and living space, as well as the presence of mould indicators. Indoor and outdoor temperature and indoor relative humidity of air measurements were taken. The total concentration of fungi in the air was significantly higher in ground floor apartments versus those on other floors (p = 0.047), in small and highly occupied dwellings (p = 0.03 and 0.003), in dwellings with electric heating (p = 0.04), without a ventilation system (p = 0.003), with water damage (p = 0.003), and finally, in those where the investigator noted an odour of moisture or visible moulds (p < 0.001). The efficacy of the latter criteria in the evaluation of insalubrity is discussed.

Indoor fungal contamination of moisture-damaged and allergic patient housing analysed using real-time PCR.

Aims:  The aim of our study was to compare, using real‐time (Rt) PCR, quantitative levels of five fungal species in three kinds of dwellings.

[Moulds in dwellings: health risks and involved species].

INTRODUCTION In industrialized countries the population spends 90% of its time in enclosed spaces. Since 1973, energy consumption for heating decreased on average by 36% per dwelling. Low-quality insulation, a fall in temperature and inadequate ventilation translated into high humidity in dwellings, which led to proliferation of moulds. BACKGROUND The allergenic, toxic and infectious effects of moulds on human health are documented. However, the potential dose/effect relationship between measured concentrations of indoor moulds and respiratory disorders often remains difficult to assess accurately. In several cases, fungi were demonstrated only as a promoter of health disorders. In a few cases (hypersensitivity pneumonitis, invasive fungal infections), the pathogenesis is without doubt due to environmental fungal exposure in a limited number of patients. On the other hand, the role of fungi was suspected but not proven for some well-defined pathologies, and some ill-defined health disorders, affecting large numbers of patients, such as the Sick Building Syndrome, rhinitis, sinusitis and conjunctivitis, as well as asthma and exacerbations of bronchitis. Eighteen fungal species, suspected of playing a role in public health, have been listed by the French Superior Council of Public Health. For each species, the proliferation conditions, type of substrates contaminated and heath effects reported in the literature are described. VIEWPOINT The lack of standardization of measurements of concentrations of fungal species, the interactions with chemical compounds (formaldehydes), organic compounds (mycotoxins, endotoxins) and between species, makes the analysis of indoor fungal contamination complicated. The time has come to establish clearly a relationship between exposure to fungi and health disorders, rather than continuing to investigate factors related to the level of indoor fungal contamination.

Farmer’s Lung Disease and Microbiological Composition of Hay: A Case–Control Study

Previous studies performed in France have suggested that handling hay contaminated with high amounts of moulds, and especially Absidia corymbifera and Eurotium amstelodami, may favour farmer’s lung disease. The circumstances favouring farmer’s lung disease and the distinctive microbiological composition of hay samples that provoke attacks need to be specified. We present a case–control study which investigates the agricultural practices and the microbiological composition of hay handled in patients with farmer’s lung disease as compared to those of a representative control population. Ten cases identified the hay they were handling at the onset of symptoms. The location, type of farm and working conditions were similar to those of the control farms. Conversely, the microbiological composition of hay differed, with significantly higher amounts of E. amstelodami (P < 0.01), A. corymbifera (P = 0.003), mesophilic Streptomyces (P < 0.01), thermophilic Streptomyces (P < 0.01) and Saccharomonospora viridis (P < 0.01) than in the control population. Our results demonstrate that hay identified by patients as having a harmful effect is characterized by a higher total amount of microorganisms, notably five microorganisms that seem discriminative. Mean concentrations are 2- to 115-fold higher in hay suspected to cause symptoms than in hay from a representative panel of farms. Handling hay with high amounts of these five microorganisms constitutes a risk factor for farmer’s lung disease that should be considered for the development of prophylactic measures.

Multiple-Locus Variable-Number Tandem-Repeat Analysis for Rapid Typing of Candida glabrata

ABSTRACT A multiple-locus variable-number tandem-repeat analysis (MLVA) using six microsatellite markers was assessed in 127 Candida glabrata isolates. Thirty-seven different genotypes, stable both in vitro and in vivo, were observed. The highest discriminatory power (D = 0.902) was reached by using only four markers. MLVA seems to be relevant for C. glabrata typing.

Immuno-reactive proteins from Mycobacterium immunogenum useful for serodiagnosis of metalworking fluid hypersensitivity pneumonitis

Metalworking fluid-associated hypersensitivity pneumonitis (MWF-HP) is a pulmonary disease caused by inhaling microorganisms present in the metalworking fluids used in the industrial sector. Mycobacterium immunogenum is the main etiological agent. Among the clinical, radiological and biological tools used for diagnosis, serological tests are important. The aim of this study was to identify immunogenic proteins in M. immunogenum and to use recombinant antigens for serological diagnosis of MWF-HP. Immunogenic proteins were detected by two-dimensional Western blot and candidate proteins were identified by mass spectrometry. Recombinant antigens were expressed in Escherichia coli and tested by enzyme-linked immunosorbent assay (ELISA) with the sera of 14 subjects with MWF-HP and 12 asymptomatic controls exposed to M. immunogenum. From the 350 spots visualized by two-dimensional gel electrophoresis with M. immunogenum extract, 6 immunogenic proteins were selected to be expressed as recombinant antigens. Acyl-CoA dehydrogenase antigen allowed for the best discrimination of MWF-HP cases against controls with an area under the receiver operating characteristics (ROC) curve of 0.930 (95% CI=0.820-1), a sensitivity of 100% and a specificity of 83% for the optimum threshold. Other recombinant antigens correspond to acyl-CoA dehydrogenase FadE, cytosol aminopeptidase, dihydrolipoyl dehydrogenase, serine hydroxymethyltransferase and superoxide dismutase. This is the first time that recombinant antigens have been used for the serodiagnosis of hypersensitivity pneumonitis. The availability of recombinant antigens makes it possible to develop standardized serological tests which in turn could simplify diagnosis, thus making it less invasive.

New evidence of the involvement of Lichtheimia corymbifera in farmer's lung disease

Farmers lung disease (FLD) is a form of hypersensitivity pneumonitis resulting from recurrent exposure to moldy plant materials. We investigated and compared the initial response of respiratory epithelium after exposure to extracts of Sacharopolyspora rectivirgula, Lichtheimia corymbifera (formerly Absidia corymbifera), Eurotium amstelodami and Wallemia sebi. The two criteria for selection of these species were their high prevalence in the hay handled by FLD patients and the presence of high levels of specific precipitins to these molds in FLD patients’ sera. Hydrosoluble extracts were prepared from spores and hyphae grown in culture under optimal conditions for each of the four species. Confluent A549 cells were inoculated with one of the four calibrated soluble extracts. Two mediators, one inflammatory (Interleukin (IL)-8) and one allergic (IL-13), were quantified using real-time PCR and ELISA assay, after four exposure periods (30 min, 2 h, 4 h and 8 h). S. rectivirgula and L. corymbifera extracts were the only ones which induced a marked upregulation of IL-8, as shown by both real-time PCR and ELISA assay 8 h after the initial contact. This study adds to the growing body of evidence that L. corymbifera should be recognized as an etiologic agent of FLD along with S. rectivirgula.