Éditeur(s) : HAL CCSD Public Library of Science
Résumé : International audience
We assessed the occurrence of algae in five species of tank-bromeliads found in contrasting environmental sites in a Neotropical, primary rainforest around the Nouragues Research Station, French Guiana. The distributions of both algal abundance and biomass were examined based on physical parameters, the morphological characteristics of bromeliad species and with regard to the structure of other aquatic microbial communities held in the tanks. Algae were retrieved in all of the bromeliad species with mean densities ranging from ∼10(2) to 10(4) cells/mL. Their biomass was positively correlated to light exposure and bacterial biomass. Algae represented a tiny component of the detrital food web in shaded bromeliads but accounted for up to 30 percent of the living microbial carbon in the tanks of Catopsis berteroniana, located in a highly exposed area. Thus, while nutrient supplies are believed to originate from wind-borne particles and trapped insects (i.e., allochtonous organic matter), our results indicate that primary producers (i.e., autochtonous organic matter) are present in this insectivorous bromeliad. Using a 24-h incubation of size-fractionated and manipulated samples from this plant, we evaluated the impact of mosquito foraging on algae, other microorganisms and rotifers. The prey assemblages were greatly altered by the predation of mosquito larvae. Grazing losses indicated that the dominant algal taxon, Bumilleriopsis sp., like protozoa and rotifers, is a significant part of the diet of mosquito larvae. We conclude that algae are a relevant functional community of the aquatic food web in C. berteroniana and might form the basis of a complementary non-detrital food web.
ISSN: 1932-6203

hal-00819161
https://hal.archives-ouvertes.fr/hal-00819161
https://hal.archives-ouvertes.fr/hal-00819161/document
https://hal.archives-ouvertes.fr/hal-00819161/file/Brouard2011_AreAlgae.pdf
DOI : 10.1371/journal.pone.0020129

Éditeur(s) : HAL CCSD Springer Verlag
Résumé : International audience
The purpose of this investigation was to characterize the management and prognosis of severe Pneumocystis jirovecii pneumonia (PJP) in human immunodeficiency virus (HIV)-negative patients. An observational cohort study of HIV-negative adults with PJP documented by bronchoalveolar lavage (BAL) through Gomori-Grocott staining or immunofluorescence, admitted to one intensive care unit (ICU) for acute respiratory failure, was undertaken. From 1990 to 2010, 70 patients (24 females, 46 males) were included, with a mean age of 58.6 ± 18.3 years. The mean Simplified Acute Physiology Score (SAPS)-II was 36.9 ± 20.4. Underlying conditions included hematologic malignancies (n = 21), vasculitis (n = 13), and solid tumors (n = 13). Most patients were receiving systemic corticosteroids (n = 63) and cytotoxic drugs (n = 51). Not a single patient received trimethoprim-sulfamethoxazole as PJP prophylaxis. Endotracheal intubation (ETI) was required in 42 patients (60.0 %), including 38 with acute respiratory distress syndrome (ARDS). In-ICU mortality was 52.9 % overall, reaching 80.9 % and 86.8 %, respectively, for patients who required ETI and for patients with ARDS. In the univariate analysis, in-ICU mortality was associated with SAPS-II (p = 0.0131), ARDS (p < 0.0001), shock (p < 0.0001), and herpes simplex virus (HSV) or cytomegalovirus (CMV) on BAL (p = 0.0031). In the multivariate analysis, only ARDS was associated with in-ICU mortality (odds ratio [OR] 23.4 [4.5-121.9], p < 0.0001). PJP in non-HIV patients remains a serious disease with high in-hospital mortality. Pulmonary co-infection with HSV or CMV may contribute to fatal outcome.
ISSN: 0934-9723

inserm-00872789
http://www.hal.inserm.fr/inserm-00872789
DOI : 10.1007/s10096-012-1730-7
PUBMED : 22930407

Éditeur(s) : HAL CCSD Wiley
Résumé : International audience
ISSN: 1758-2229

hal-01623623
https://hal.archives-ouvertes.fr/hal-01623623
DOI : 10.1111/1758-2229.12426