Typologie et logique socio-économique des systèmes de culture associant céréales et légumineuses dans les agro-écosystèmes soudano-sahéliens du Burkina Faso

Dans la zone soudano-sahélienne du Burkina Faso, les associations mixtes céréales-légumineuses dominent les surfaces cultivées annuellement. Cependant, les rendements sont faibles et ne couvrent souvent pas les besoins alimentaires des exploitations qui les pratiquent. Afin d’améliorer la productivité de ces associations, il est nécessaire de comprendre la logique socio-économique de leurs mises en oeuvre. Dans cette optique, 60 exploitations agricoles familiales (EA) ont été enquêtées dans la région Nord du Burkina. Des analyses en correspondances multiples (ACM) font ressortir 4 types de systèmes de culture caractérisés d’une part par le niveau d’apport de matière organique et la fréquence de désherbage et d’autre part, par la présence de structures pérennes de conservation des eaux et des sols. La fertilisation organique et le désherbage fréquent sont associés aux EA les mieux pourvues en main d’oeuvre familiale, en petits ruminants et surfaces agricoles. L’âge de l’exploitant agricole et le nombre d’épouses sont de bons indicateurs des moyens économiques de l’EA. La plupart des recettes monétaires annuelles par EA varient dans la gamme très large de 25 à 300 KFCFA. Ces aspects doivent être pris en compte en vue de raisonner des propositions techniques adaptées à la diversité des EA de cette région.© 2016 International Formulae Group. All rights reserved.Mots clés: ACM, associations mixtes céréales-légumineuses, typologie des systèmes de culture, logique socioéconomique, Burkina FasoEnglish Title: Typology and socio-economic logic of cropping systems in Sub-Saharan agro-ecosystems of Burkina FasoEnglish AbstractIn Sub-Saharan zone of Burkina Faso, legumes and cereals mixed cultivation systems occupy most of the cultivated area. However, yields are low and often do not cover the food needs of farms that practise them. In order to improve the productivity of these intercropping systems, it is necessary to understand the socio-economic logic of their implementation. To this purpose, sixty family farms were surveyed in the northern region of Burkina Faso. Multiple correspondences analysis (MCA) showed four types of cropping systems characterized on one hand by the level of organic matter intake and weeding frequency and on the other hand, by the presence of permanent structures for water and soil conservation. Organic matter fertilization and frequent weeding are associated with farms with high family labor, livestock (especially small ruminants) and high cultivated area, while 70% of farmers have an off-farm activity. The age of household head and the number of their wives are good indicators of farmers’ income. Most of farmers’ monetary recipes vary widely from 25 to 300 KFCFA. These aspects must be taken into consideration for reasoning suitable technical recommendations for the farmer’s in this region.© 2016 International Formulae Group. All rights reserved.Keywords: MCA, legumes and cereals mixed cultivation systems, typology of cropping systems, socioeconomic logic, Burkina Fas

Rectal Carriage of Extended-Spectrum Beta-Lactamase-Producing Gram-Negative Bacilli in Community Settings in Madagascar

BACKGROUND: Extended-spectrum ß-lactamase-producing Enterobacteria (ESBL-PE) emerged at the end of the 1980s, causing nosocomial outbreaks and/or hyperendemic situations in hospitals and long-term care facilities. In recent years, community-acquired infections due to ESBL-PE have spread worldwide, especially across developing countries including Madagascar. OBJECTIVES: This study aimed to determine the prevalence and risk factors of intestinal carriage of ESBL-PE in the community of Antananarivo. METHODS: Non-hospitalized patients were recruited in three health centers in different socio economic settings. Fresh stool collected were immediately plated on Drigalski agar containing 3 mg/liter of ceftriaxone. Gram-negative bacilli species were identified and ESBL production was tested by a double disk diffusion (cefotaxime and ceftazidime +/- clavulanate) assay. Characterization of ESBLs were perfomed by PCR and direct sequencing . Molecular epidemiology was analysed by Rep-PCR and ERIC-PCR. RESULTS: 484 patients were screened (sex ratio  = 1.03, median age 28 years). 53 ESBL-PE were isolated from 49 patients (carrier rate 10.1%). The isolates included Escherichia coli (31), Klebsiella pneumoniae (14), Enterobacter cloacae (3), Citrobacter freundii (3), Kluyvera spp. (1) and Pantoae sp.(1). In multivariate analysis, only the socioeconomic status of the head of household was independently associated with ESBL-PE carriage, poverty being the predominant risk factor. CONCLUSIONS: The prevalence of carriage of ESBL in the community of Antananarivo is one of the highest reported worldwide. This alarming spread of resistance genes should be stopped urgently by improving hygiene and streamlining the distribution and consumption of antibiotics

Organised Genome Dynamics in the Escherichia coli Species Results in Highly Diverse Adaptive Paths

The Escherichia coli species represents one of the best-studied model organisms, but also encompasses a variety of commensal and pathogenic strains that diversify by high rates of genetic change. We uniformly (re-) annotated the genomes of 20 commensal and pathogenic E. coli strains and one strain of E. fergusonii (the closest E. coli related species), including seven that we sequenced to completion. Within the ∼18,000 families of orthologous genes, we found ∼2,000 common to all strains. Although recombination rates are much higher than mutation rates, we show, both theoretically and using phylogenetic inference, that this does not obscure the phylogenetic signal, which places the B2 phylogenetic group and one group D strain at the basal position. Based on this phylogeny, we inferred past evolutionary events of gain and loss of genes, identifying functional classes under opposite selection pressures. We found an important adaptive role for metabolism diversification within group B2 and Shigella strains, but identified few or no extraintestinal virulence-specific genes, which could render difficult the development of a vaccine against extraintestinal infections. Genome flux in E. coli is confined to a small number of conserved positions in the chromosome, which most often are not associated with integrases or tRNA genes. Core genes flanking some of these regions show higher rates of recombination, suggesting that a gene, once acquired by a strain, spreads within the species by homologous recombination at the flanking genes. Finally, the genome's long-scale structure of recombination indicates lower recombination rates, but not higher mutation rates, at the terminus of replication. The ensuing effect of background selection and biased gene conversion may thus explain why this region is A+T-rich and shows high sequence divergence but low sequence polymorphism. Overall, despite a very high gene flow, genes co-exist in an organised genome

Streptococcus agalactiae clones infecting humans were selected and fixed through the extensive use of tetracycline

Streptococcus agalactiae (Group B Streptococcus, GBS) is a commensal of the digestive and genitourinary tracts of humans that emerged as the leading cause of bacterial neonatal infections in Europe and North America during the 1960s. Due to the lack of epidemiological and genomic data, the reasons for this emergence are unknown. Here we show by comparative genome analysis and phylogenetic reconstruction of 229 isolates that the rise of human GBS infections corresponds to the selection and worldwide dissemination of only a few clones. The parallel expansion of the clones is preceded by the insertion of integrative and conjugative elements conferring tetracycline resistance (TcR). Thus, we propose that the use of tetracycline from 1948 onwards led in humans to the complete replacement of a diverse GBS population by only few TcR clones particularly well adapted to their host, causing the observed emergence of GBS diseases in neonates. \ua9 2014 Macmillan Publishers Limited. All rights reserved

Gene expression profiling of rat spermatogonia and Sertoli cells reveals signaling pathways from stem cells to niche and testicular cancer cells to surrounding stroma

Background: Stem cells and their niches are studied in many systems, but mammalian germ stem cells (GSC) and their niches are still poorly understood. In rat testis, spermatogonia and undifferentiated Sertoli cells proliferate before puberty, but at puberty most spermatogonia enter spermatogenesis, and Sertoli cells differentiate to support this program. Thus, pre-pubertal spermatogonia might possess GSC potential and pre-pubertal Sertoli cells niche functions. We hypothesized that the different stem cell pools at pre-puberty and maturity provide a model for the identification of stem cell and niche-specific genes. We compared the transcript profiles of spermatogonia and Sertoli cells from pre-pubertal and pubertal rats and examined how these related to genes expressed in testicular cancers, which might originate from inappropriate communication between GSCs and Sertoli cells. Results: The pre-pubertal spermatogonia-specific gene set comprised known stem cell and spermatogonial stem cell (SSC) markers. Similarly, the pre-pubertal Sertoli cell-specific gene set comprised known niche gene transcripts. A large fraction of these specifically enriched transcripts encoded trans-membrane, extra-cellular, and secreted proteins highlighting stem cell to niche communication. Comparing selective gene sets established in this study with published gene expression data of testicular cancers and their stroma, we identified sets expressed genes shared between testicular tumors and pre-pubertal spermatogonia, and tumor stroma and pre-pubertal Sertoli cells with statistic significance. Conclusions: Our data suggest that SSC and their niche specifically express complementary factors for cell communication and that the same factors might be implicated in the communication between tumor cells and their micro-enviroment in testicular cancer

Effect of angiotensin-converting enzyme inhibitor and angiotensin receptor blocker initiation on organ support-free days in patients hospitalized with COVID-19

IMPORTANCE Overactivation of the renin-angiotensin system (RAS) may contribute to poor clinical outcomes in patients with COVID-19. Objective To determine whether angiotensin-converting enzyme (ACE) inhibitor or angiotensin receptor blocker (ARB) initiation improves outcomes in patients hospitalized for COVID-19. DESIGN, SETTING, AND PARTICIPANTS In an ongoing, adaptive platform randomized clinical trial, 721 critically ill and 58 non–critically ill hospitalized adults were randomized to receive an RAS inhibitor or control between March 16, 2021, and February 25, 2022, at 69 sites in 7 countries (final follow-up on June 1, 2022). INTERVENTIONS Patients were randomized to receive open-label initiation of an ACE inhibitor (n = 257), ARB (n = 248), ARB in combination with DMX-200 (a chemokine receptor-2 inhibitor; n = 10), or no RAS inhibitor (control; n = 264) for up to 10 days. MAIN OUTCOMES AND MEASURES The primary outcome was organ support–free days, a composite of hospital survival and days alive without cardiovascular or respiratory organ support through 21 days. The primary analysis was a bayesian cumulative logistic model. Odds ratios (ORs) greater than 1 represent improved outcomes. RESULTS On February 25, 2022, enrollment was discontinued due to safety concerns. Among 679 critically ill patients with available primary outcome data, the median age was 56 years and 239 participants (35.2%) were women. Median (IQR) organ support–free days among critically ill patients was 10 (–1 to 16) in the ACE inhibitor group (n = 231), 8 (–1 to 17) in the ARB group (n = 217), and 12 (0 to 17) in the control group (n = 231) (median adjusted odds ratios of 0.77 [95% bayesian credible interval, 0.58-1.06] for improvement for ACE inhibitor and 0.76 [95% credible interval, 0.56-1.05] for ARB compared with control). The posterior probabilities that ACE inhibitors and ARBs worsened organ support–free days compared with control were 94.9% and 95.4%, respectively. Hospital survival occurred in 166 of 231 critically ill participants (71.9%) in the ACE inhibitor group, 152 of 217 (70.0%) in the ARB group, and 182 of 231 (78.8%) in the control group (posterior probabilities that ACE inhibitor and ARB worsened hospital survival compared with control were 95.3% and 98.1%, respectively). CONCLUSIONS AND RELEVANCE In this trial, among critically ill adults with COVID-19, initiation of an ACE inhibitor or ARB did not improve, and likely worsened, clinical outcomes. TRIAL REGISTRATION ClinicalTrials.gov Identifier: NCT0273570

Identification of Strains of <i>Alcaligenes</i> and <i>Agrobacterium</i> by a Polyphasic Approach

International audienceThe number of stable discriminant biochemical characters is limited in the genera Alcaligenes and Agrobacterium, whose species are consequently difficult to distinguish from one another by conventional tests. Moreover, genomic studies have recently drastically modified the nomenclature of these genera; for example, Alcaligenes xylosoxidans was transferred to the genus Achromobacter in 1998. Twenty-five strains of Achromobacter xylosoxidans, three strains of an Agrobacterium sp., five strains of an Alcaligenes sp., and four unnamed strains belonging to the Centers for Disease Control and Prevention group IVc-2 were examined. These strains were characterized by conventional tests, including biochemical tests. The assimilation of 99 carbohydrates, organic acids, and amino acids was studied by using Biotype-100 strips, and rRNA gene restriction patterns were obtained with the automated Riboprinter microbial characterization system after cleavage of total DNA with EcoRI or PstI restriction endonuclease. This polyphasic approach allowed the two subspecies of A. xylosoxidans to be clearly separated. Relationships between five strains and the Ralstonia paucula type strain were demonstrated. Likewise, three strains were found to be related to the Ochrobactrum anthropi type strain. We showed that substrate assimilation tests and automated ribotyping provide a simple, rapid, and reliable means of identifying A. xylosoxidans subspecies and that these two methods can be used as alternative methods to characterize unidentified strains rapidly when discriminant biochemical characters are missing

Identification of Strains of <i>Alcaligenes</i> and <i>Agrobacterium</i> by a Polyphasic Approach

International audienceThe number of stable discriminant biochemical characters is limited in the genera Alcaligenes and Agrobacterium, whose species are consequently difficult to distinguish from one another by conventional tests. Moreover, genomic studies have recently drastically modified the nomenclature of these genera; for example, Alcaligenes xylosoxidans was transferred to the genus Achromobacter in 1998. Twenty-five strains of Achromobacter xylosoxidans, three strains of an Agrobacterium sp., five strains of an Alcaligenes sp., and four unnamed strains belonging to the Centers for Disease Control and Prevention group IVc-2 were examined. These strains were characterized by conventional tests, including biochemical tests. The assimilation of 99 carbohydrates, organic acids, and amino acids was studied by using Biotype-100 strips, and rRNA gene restriction patterns were obtained with the automated Riboprinter microbial characterization system after cleavage of total DNA with EcoRI or PstI restriction endonuclease. This polyphasic approach allowed the two subspecies of A. xylosoxidans to be clearly separated. Relationships between five strains and the Ralstonia paucula type strain were demonstrated. Likewise, three strains were found to be related to the Ochrobactrum anthropi type strain. We showed that substrate assimilation tests and automated ribotyping provide a simple, rapid, and reliable means of identifying A. xylosoxidans subspecies and that these two methods can be used as alternative methods to characterize unidentified strains rapidly when discriminant biochemical characters are missing

Draft Genome Sequence of the Fish Pathogen Flavobacterium columnare Genomovar III Strain PH-97028 (=CIP 109753)

International audienceFlavobacterium columnare strain PH-97028 (=CIP 109753) is a genomovar III reference strain that was isolated from a diseased Ayu fish in Japan. We report here the analysis of the first available genomovar III sequence of this species to aid in identification, epidemiological tracking, and virulence studies

Streptomyces silvae sp. nov., isolated from forest soil

International audienceA bacterial strain, named For3 T , was isolated from forest soil sampled in Champenoux, France. Based on its 16S rRNA gene sequence, the strain was affiliated to the family Streptomycetaceae and, more specifically, to the genus Streptomyces . The strain had 99.93% 16S rRNA gene sequence similarity to its closest relative strains Streptomyces pratensis ATCC 33331 T , Streptomyces anulatus ATCC 27416 T , Streptomyces setonii NRRL ISP-5322 T and Kitasatospora papulosa NRRL B-16504 T . The phylogenomic tree using the genome blast distance phylogeny method showed that the closest relative strain was Streptomyces atroolivaceus NRRL ISP-5137 T and that For3 T represents a new branch among the Streptomyces . Genome relatedness indexes revealed that the average nucleotide identity and digital DNA–DNA hybridization values between For3 T and its closest phylogenomic relative ( S. atroolivaceus NRRL ISP-5137 T ) were 88.39 and 39.2 %, respectively. The G+C content of the genome was 71.4 mol% and its size was 7.96 Mb with 7492 protein-coding genes. Strain For3 T harboured complete metabolic pathways absent in the closest relative strains such as cellulose biosynthesis, glycogen degradation I, glucosylglycerate biosynthesis I. Anteiso-C 15:0 , iso-C 15:0 , anteiso-C 17:0 and MK-9(H4)/MK-9(H6) were the predominant cellular fatty acids and respiratory quinones, respectively. Phenotypic and genomic data supported the assignment of strain For3 T to a novel species Streptomyces silvae sp. nov., within the genus Streptomyces , for which the type strain is For3 T (=CIP 111908 T =LMG 32186 T )