73 research outputs found
Isolement et caractĂ©risation morphologique de moisissures productrices de substances antibactĂ©riennes Ă partir dâaliments locaux au Burkina Faso
En vue du risque augmentĂ© jour aprĂšs jour des bactĂ©ries rĂ©sistantes aux antibiotiques, nous nous sommes intĂ©ressĂ©s dans cette Ă©tude Ă lâisolement et Ă la caractĂ©risation des isolats de moisissures productrices dâantibiotique Ă partir dâaliments locaux du Burkina Faso. Cinquante (50) isolats fongiques isolĂ©s ont servis au test dâantibiose qui a rĂ©vĂ©lĂ© vingt (20) isolats producteurs de substances antimicrobiennes. Ce test a concernĂ©Â les cellules des isolats ainsi que des extraits aqueux et organiques issues de ceux-ci. Trois (03) isolats ont prĂ©sentĂ© des diamĂštres dâinhibitions moyens de 20 mm sur les germes tests. Leur caractĂ©risation a portĂ© sur les critĂšres morphologiques et culturaux. Lâisolat S1 prĂ©sente en 5 jours dâincubation sur la gĂ©lose de Pomme de Terre Dextrose (PDA) une colonie plate, de couleur blanche au recto, avec un revers jaune, lâisolat S2 une colonie vert-olive, de texture veloutĂ©e, plus dense au centre et lâisolat S3 une petite colonie de couleur verte et ronde. En microscopie optique les isolats S1 et S2 ont prĂ©sentĂ© des conidies rondes, rĂ©fringentes et nombreuses, les conidiophores sont hyalins, longs et non cloisonnĂ©s. Lâisolat S3 a prĂ©sentĂ© des conidies rares, des pĂ©nicilles constituĂ©s de phialides branchĂ©s directement Ă lâextrĂ©mitĂ© des conidiophores cloisonnĂ©s. Lâanalyse de ces caractĂ©ristiques indique que S1, S2 et S3 appartiennent respectivement aux genres Aspergillus et Penicillium.© 2016 International Formulae Group. All rights reserved.Mots clĂ©s: Substances antimicrobiennes, Aspergillus, Penicillium, Burkina FasoEnglish Title: Isolation and morphological characterization of fungi producing antibacterial substances from local food in Burkina FasoEnglish AbstractBacterial resistance to the actual antibiotic is mostly in dangerous progress, why we have interest in isolation and characterization of fungi strains producing antibiotics using local food in Burkina Faso. Fifty (50) isolated strains were used in the antibiosis trial which revealed twenty (20) strains producing antimicrobial substances. This trial concerned the strains cell as well as its aqueous and organic extracts. Three (03) strains had average inhibition diameters of 20 mm on the testing germs. Their characterization focused on the  morphological and culture criteria. After five days of incubation in Potato Dextrose Agar (PDA), the strain S1 shows a flat colony, white on the front, with a yellow reverse. The strain S2 shows an olive-green colony, velvety texture, more dense in the center. As for the strain S3, it shows a round green colored colony. In optical microscopy, strains S1 and S2 showed numerous round and refractive conidia, conidiophores are hyaline, long and not partitioned. S3 strain showed uncommon conidia, penicillus made of phialides which are directly linked to the end of partitioned conidiophores. Analysis of these characteristics indicates that S1, S2 and S3 belong respectively to the Aspergillus and Penicillium genera.© 2016 International Formulae Group. All rights reservedKeywords: Antimicrobial substances, Aspergillus, Penicillium, Burkina Fas
Fertilisation des sols avec la litiere foliaire en zone Subsahelienne du Burkina Faso: Diversite des especes, effets sur les rendements du sorgho
Organic matter sources management for soil fertility improvement has
been the subject of many researches. Agroforestry is one of the topics
addressed by these researches. In Burkina Faso\u2019s Northern Center,
leaf litter of woody species is collected, piled, crumbled before
spreading in fields. This practice is not well known in the rest of the
country. The present study aims to provide information on the diversity
of spontaneous plant species concerned, farmers\u2019 motivations of
litter crumbling and to evaluate, empirically the effects of litter
spreading on sorghum yields. A participatory study, using qualitative
surveys and biometric field measurements, was conducted in five
villages in the Northern Center of Burkina Faso. Because of their
availability, accessibility, and agronomic performance, plants such as
Vitellaria paradoxa , Anogeissus leiocarpa , Combretum micranthum ,
Lannea microcarpa and Diospyros mespiliformis were the species
whose leaf litter was valued most. Measurements achieved in situ
indicate that sorghum yields from fields that received Vitellaria leaf
litter for the first time were lower than those in the control plots.
On the other hand, fields that received this litter for three
consecutive years were more productive. A scientific study on leaf
litter chemical characteristics and their influence on soil fertility
parameters should be considered in order to validate local knowledge
and to improve knowledge about these practices.La gestion des sources de mati\ue8res organiques, pour am\ue9liorer
la fertilit\ue9 des sols, a fait l\u2019objet de nombreuses
recherches. L\u2019agroforesterie est une des th\ue9matiques
abord\ue9es par ces recherches. Dans le Centre-Nord du Burkina Faso,
la liti\ue8re foliaire des esp\ue8ces ligneuses est ramass\ue9e,
mise en tas, \ue9miett\ue9e avant d\u2019\ueatre \ue9pandue
dans les champs. Cette pratique est peu connue dans le reste du pays.
La pr\ue9sente \ue9tude visait \ue0 fournir des informations sur
la diversit\ue9 des esp\ue8ces v\ue9g\ue9tales spontan\ue9es
concern\ue9es, les motivations paysannes de l\u2019\ue9miettement
de la liti\ue8re et \ue0 \ue9valuer, empiriquement et par des
mesures, les effets de l\u2019\ue9pandage de ces liti\ue8res sur
les rendements du sorgho. Une \ue9tude participative, \ue0
l\u2019aide d\u2019enqu\ueates qualitatives et des mesures
biom\ue9triques dans des champs, a \ue9t\ue9 men\ue9e dans cinq
villages du Centre Nord du Burkina Faso. A cause de leur
disponibilit\ue9, leur accessibilit\ue9, leur performance
agronomique, les plantes telles que Vitellaria paradoxa , Anogeissus
leiocarpa , Combretum micranthum , Lannea microcarpa , Diospyros
mespiliformis ont \ue9t\ue9 cit\ue9es comme \ue9tant les
esp\ue8ces dont la liti\ue8re des feuilles est valoris\ue9e. Les
mesures r\ue9alis\ue9es in situ montrent que, les rendements du
sorgho dans les champs ayant re\ue7u de la liti\ue8re foliaire de
Vitellaria pour la premi\ue8re fois, ont \ue9t\ue9
inf\ue9rieurs \ue0 ceux des parcelles t\ue9moin. Par contre, les
champs ayant re\ue7u cette liti\ue8re pendant trois ann\ue9es
cons\ue9cutives ont \ue9t\ue9 plus productifs. Dans
l\u2019optique de valider les savoirs locaux et d\u2019approfondir
les connaissances sur l\u2019effet des liti\ue8res foliaires sur la
fertilit\ue9 du sol, une \ue9tude scientifique sur leur
caract\ue9ristique chimique et sur leur influence sur les
param\ue8tres de fertilit\ue9 du sol, est \ue0 envisager
Les risques sanitaires lies a l\u2019utilisation des pesticides dans les bas-fonds rizicoles de la commune de dano, Province du Ioba Burkina Faso
Pesticides are an essential component of agricultural production
techniques for pests and weeds control. In Burkina Faso, failure to
observe good practices for pesticides use exposes farmers to health
risks. The study presents health risks related to pesticide management
in rice fields in Dano through a survey of 158 rice farmers working in
inland valleys. Socio-demographic characteristics of farmers, the types
of pesticides used and their effects on health were documented. Rice
farming in Dano is mainly done by an ageing population with an average
of over 50 years (60%). In addition, farmers\u2019 education level is
low, with an illiteracy rate of 61 and only 32% of farmers attaining
primary school education. Risky behaviours of pesticides use are
common, especially inadequate of farmer protection, poor practices of
storage and re-use of pesticide products. Twelve types of pesticides
were identified, of which 40% are not officially registered. The main
active components in herbicides are Glyphosate, Paraquat, Bensulfuron
methyl and Bispyribac-sodium. Health risks of pesticide use reported by
farmers included various poisoning symptoms. To mitigate pesticide
poisoning prevalence associated with poor farming practices, awareness
campaigns should be conducted to inform farmers to use pesticides
safely.Les produits pesticides constituent de nos jours une composante
essentielle des techniques de production agricole pour le contr\uf4le
des ravageurs et des mauvaises herbes. Au Burkina Faso, le non respect
des bonnes pratiques d\u2019utilisation des pesticides pose un
v\ue9ritable probl\ue8me de sant\ue9 des populations.
L\u2019\ue9tude pr\ue9sente les risques sanitaires de gestion des
pesticides agricoles. Une enqu\ueate de terrain a \ue9t\ue9
r\ue9alis\ue9e dans la Commune de Dano aupr\ue8s de 158
producteurs rizicoles. Le questionnaire a port\ue9 sur les
caract\ue9ristiques sociod\ue9mographiques des producteurs
rizicoles, les types de pesticides utilis\ue9s et leurs effets sur la
sant\ue9. L\u2019\ue9tude montre que la riziculture \ue0 Dano
est une activit\ue9 principalement exerc\ue9e par une population
vieillissante dont les plus de 50 ans repr\ue9sentent pr\ue8s de
60%. De plus, la population est analphab\ue8te \ue0 61% contre 32%
des producteurs ayant fr\ue9quent\ue9 l\u2019\ue9cole primaire.
Les mauvaises pratiques d\u2019utilisation des pesticides sont
fr\ue9quentes et concernent surtout l\u2019insuffisance des
\ue9quipements de protection individuels des producteurs, les
pratiques de stockage et de r\ue9utilisation des reliquats de
pesticides. Douze types de pesticides ont \ue9t\ue9 identifi\ue9s
dont 40% ne sont pas homologu\ue9s. Les principales mati\ue8res
actives dans les herbicides sont le Glyphosate, le Paraquat, le
Bensulfuron methyl et le Bispyribac-sodium. Les effets sanitaires de
l\u2019utilisation des pesticides sont ressentis par les producteurs
agricoles \ue0 travers divers sympt\uf4mes des intoxications. Pour
r\ue9duire la pr\ue9valence des intoxications aux pesticides, des
campagnes d\u2019information et de sensibilisation doivent \ueatre
men\ue9es \ue0 l\u2019endroit des populations et des producteurs
pour une utilisation s\ue9curis\ue9e des pesticides
Molecular diagnosis of Shigella, Salmonella and Campylobacter by multiplex Real-time PCR in stool culture samples in Ouagadougou (Burkina Faso)
ABSTRACT:Background: Bacteriological diagnosis of Campylobacter spp, Salmonella spp and Shigella spp could be necessary in the case of infectious gastroenteritis syndrome.The objective of this study was to diagnose concomitantly the three enteropathogenic bacteria by multiplex Real-Time PCR in stool culture samples in Ouagadougou (Burkina Faso).Materials and Methods: The study was conducted from February 5th to March 9th, 2013. Two hundred stool samples were received during the study period. The bacteria were identified by bacterial culture following by multiplex Real-Time PCR.Results: Shigella spp and Campylobacter spp were sought by culture in all 200 samples. Enteropathogenic E. coli was sought only in 37 samples from all children under 2 years old. The bacterial culture was positive in 12 stool samples. Shigella spp and Salmonella spp. were isolated respectively in 5 (2.5%) and 3 samples (1.5%). Enteropathogenic E. coli was isolated in 10.8% (4/37) of the samples tested.The multiplex real-time PCR identified bacteria in 20 patients, including 17 cases of Shigella spp., 1 case of Salmonella spp. and 2 cases of Campylobacter spp.Conclusions: This study has highlighted the low frequency of 3 sought bacterial genera in stool samples. It has also demonstrated a significant difference between the culture and the multiplex Real-Time PCR method in the diagnosis of Shigella
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A Randomized Trial to Assess the Impact of a Package of Diagnostic Tools and Diagnostic Algorithm on Antibiotic Prescriptions for the Management of Febrile Illnesses Among Children and Adolescents in Primary Health Facilities in Burkina Faso.
BACKGROUND: Low- and middle-income countries face significant challenges in differentiating bacterial from viral causes of febrile illnesses, leading to inappropriate use of antibiotics. This trial aimed to evaluate the impact of an intervention package comprising diagnostic tests, a diagnostic algorithm, and a training-and-communication package on antibiotic prescriptions and clinical outcomes. METHODS: Patients aged 6 months to 18 years with fever or history of fever within the past 7 days with no focus, or a suspected respiratory tract infection, arriving at 2 health facilities were randomized to either the intervention package or standard practice. The primary outcomes were the proportions of patients who recovered at day 7 (D7) and patients prescribed antibiotics at day 0. RESULTS: Of 1718 patients randomized, 1681 (97.8%; intervention: 844; control: 837) completed follow-up: 99.5% recovered at D7 in the intervention arm versus 100% in standard practice (P = .135). Antibiotics were prescribed to 40.6% of patients in the intervention group versus 57.5% in the control arm (risk ratio: 29.3%; 95% CI: 21.8-36.0%; risk difference [RD]: -16.8%; 95% CI: -21.7% to -12.0%; P < .001), which translates to 1 additional antibiotic prescription saved every 6 (95% CI: 5-8) consultations. This reduction was significant regardless of test results for malaria, but was greater in patients without malaria (RD: -46.0%; -54.7% to -37.4%; P < .001), those with a respiratory diagnosis (RD: -38.2%; -43.8% to -32.6%; P < .001), and in children 6-59 months old (RD: -20.4%; -26.0% to -14.9%; P < .001). Except for the period July-September, the reduction was consistent across the other quarters (P < .001). CONCLUSIONS: The implementation of the package can reduce inappropriate antibiotic prescription without compromising clinical outcomes. CLINICAL TRIALS REGISTRATION: clinicaltrials.gov; NCT04081051
Structural, physiognomic and above-ground biomass variation in savanna-forest transition zones on three continents - How different are co-occurring savanna and forest formations?
Through interpretations of remote-sensing data and/or theoretical propositions, the idea that forest and savanna represent "alternative stable states" is gaining increasing acceptance. Filling an observational gap, we present detailed stratified floristic and structural analyses for forest and savanna stands located mostly within zones of transition (where both vegetation types occur in close proximity) in Africa, South America and Australia. Woody plant leaf area index variation was related to tree canopy cover in a similar way for both savanna and forest with substantial overlap between the two vegetation types. As total woody plant canopy cover increased, so did the relative contribution of middle and lower strata of woody vegetation. Herbaceous layer cover declined as woody cover increased. This pattern of understorey grasses and herbs progressively replaced by shrubs as the canopy closes over was found for both savanna and forests and on all continents. Thus, once subordinate woody canopy layers are taken into account, a less marked transition in woody plant cover across the savanna-forest-species discontinuum is observed compared to that inferred when trees of a basal diameter > 0.1 m are considered in isolation. This is especially the case for shrub-dominated savannas and in taller savannas approaching canopy closure. An increased contribution of forest species to the total subordinate cover is also observed as savanna stand canopy closure occurs. Despite similarities in canopy-cover characteristics, woody vegetation in Africa and Australia attained greater heights and stored a greater amount of above-ground biomass than in South America. Up to three times as much above-ground biomass is stored in forests compared to savannas under equivalent climatic conditions. Savanna-forest transition zones were also found to typically occur at higher precipitation regimes for South America than for Africa. Nevertheless, consistent across all three continents coexistence was found to be confined to a well-defined edaphic-climate envelope with soil and climate the key determinants of the relative location of forest and savanna stands. Moreover, when considered in conjunction with the appropriate water availability metrics, it emerges that soil exchangeable cations exert considerable control on woody canopy-cover extent as measured in our pan-continental (forest + savanna) data set. Taken together these observations do not lend support to the notion of alternate stable states mediated through fire feedbacks as the prime force shaping the distribution of the two dominant vegetation types of the tropical lands
Pantropical variability in tree crown allometry
Aim:
Tree crowns determine light interception, carbon and water exchange. Thus, understanding the factors causing tree crown allometry to vary at the tree and stand level matters greatly for the development of future vegetation modelling and for the calibration of remote sensing products. Nevertheless, we know little about largeâscale variation and determinants in tropical tree crown allometry. In this study, we explored the continental variation in scaling exponents of siteâspecific crown allometry and assessed their relationships with environmental and standâlevel variables in the tropics. /
Location:
Global tropics. /
Time period:
Early 21st century. /
Major taxa studied:
Woody plants. /
Methods:
Using a dataset of 87,737 trees distributed among 245 forest and savanna sites across the tropics, we fitted siteâspecific allometric relationships between crown dimensions (crown depth, diameter and volume) and stem diameter using powerâlaw models. Standâlevel and environmental drivers of crown allometric relationships were assessed at pantropical and continental scales. /
Results:
The scaling exponents of allometric relationships between stem diameter and crown dimensions were higher in savannas than in forests. We identified that continental crown models were better than pantropical crown models and that continental differences in crown allometric relationships were driven by both standâlevel (wood density) and environmental (precipitation, cation exchange capacity and soil texture) variables for both tropical biomes. For a given diameter, forest trees from Asia and savanna trees from Australia had smaller crown dimensions than trees in Africa and America, with crown volumes for some Asian forest trees being smaller than those of trees in African forests. /
Main conclusions:
Our results provide new insight into geographical variability, with large continental differences in tropical tree crown allometry that were driven by standâlevel and environmental variables. They have implications for the assessment of ecosystem function and for the monitoring of woody biomass by remote sensing techniques in the global tropics
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