Hétérogénéité génétique et résistance des vecteurs du paludisme (Anopheles gambiae s.l) aux insecticides en zone cotonnière au Benin

La résistance des vecteurs du paludisme aux insecticides utilisés dans la lutte anti vectorielle est un obstacle majeur pour les programmes nationaux de lutte contre le paludisme. La présente étude avait pour but d’évaluer la diversité génétique des populations de Anopheles gambiae et la résistance aux insecticides (mutation Kdr et Ace-1) en zone cotonnière au Bénin. Deux méthodes de capture ont été utilisées pour la collecte d’échantillon. La capture sur appât humain et la récolte de la faune résiduelle matinale par spray. La PCR SINE a permis de distinguer deux espèces jumelles et d’obtenir les différents génotypes pour les deux gènes. Deux espèces du complexe An. gambiae s.l ont été trouvées en sympatrie (Anopheles coluzzii et Anopheles gambiae). La résistance kdr et Ace-1 connaissent un flux saisonnier. L’allèle résistant du gène kdr est fixé dans la population de vecteurs (Fis>0). Par contre, un déficit de l’allèle résistant est noté au niveau du gène Ace-1 (Fis<0).Mots clés : Hétérogénéité, génétique, résistance, vecteur, paludisme. English Title: Genetic heterogeneity and resistance to insecticides in malaria vector Anopheles gambiae s.l in the cotton growing area in Benin Resistance of malaria vectors to insecticides used in vector control is a major threat for national malaria control programs. The purpose of this study was to assess the genetic diversity of Anopheles gambiae populations and resistance to insecticides (Kdr Ace-1 mutation) in the cotton growing area in Benin. Two samples methods were used for mosquito collection: Human Landing catch (HLC) and the residual fauna collection by spray. The SINE PCR allow to identify species the different genotypes resistance genes. Two species of the An. gambiae s.l complex have been found in sympatry (Anopheles coluzzii and Anopheles gambiae). kdr and Ace-1 resistance had seasonal variation trend. The kdr resistance allele is fixed in the vector population (Fis> 0). Moreover, a deficit of the Ace-1 resistance allele was observed (Fis <0). Keywords: Heterogeneity, genetic, resistance, vector, malaria

Morphological diversities and associated preference traits in Peanut (Arachis hypogaea L.) landraces from central and southern Benin

Peanut (Arachis hypogaea L.) production in Benin is limited by several biotic and abiotic stresses. The objectives of this study were to document varietal trait preferences and peanut genetic diversity for breeding programs. A survey in the South and Center of Benin and an agro-morphological characterization was carried out. Results showed that farmers used five criteria, namely yield (seeds and pods), size of seeds, number of seeds per pod, oil content, and quality of the paste for selecting a variety. The clustering based on ten qualitative traits showed a variability structure in three groups based on the leaflets shape, plant habit, and branching pattern. The principal component analysis carried out on the quantitative traits indicated six groups of accessions. The group 3 of the latest analysis is composed of Azii alorga and Kamalo with interesting characteristics and showing a good criteria as seeds size (SDL= 14.62 ± 0.48 mm), and pods size (average pod length and width respectively PoL = 33.70 ± 1.14 mm, Pow = 14.87 ± 0.29 mm). The results should be prioritized for breeding programs to improve the good criteria found in other peanut varieties. It will be helpful for farmers in selecting performant varieties

Molecular characterization of Enterobacteriaceae producing β-lactamase and methicillin-resistant staphylococci isolated from the hospital environment and catheters in two public hospitals in Benin, Republic of Benin

Antimicrobial resistance is a real public health problem. All over the world, it has a considerable impact in hospitals. The present study was conducted to ascertain the bacterial ecology in two hospitals in Benin as well as the resistance genes present in the recovered isolates. A total of 146 environmental and catheter samples were collected at the University Hospital Center of Abomey-Calavi / So-Ava and at the Beninese Army Hospital of Cotonou. These samples were inoculated on Mannitol Salt and Eosin Methylene Blue agars. The colonies obtained were identified and their sensitivity to antibiotics were tested, using the Kirby Bauer technique. Four resistance genes encoding the production of extended-spectrum beta-lactamases (blaCTX-M1, blaCTX-M2, blaCTX-M9, blaCTX-M15) and the gene coding for methicillin resistance (mecA) were screened.  The gene coding for methicillin resistance (mecA) was sought in staphylococci. A total of 69 (53,49%) and 60 (46,51%) strains belonging to Enterobacteriaceae family and staphylococci were identified, respectively. A predominance of Staphylococcus aureus (25.6%) followed by Enterobacter cloacae (21.0%) and coagulase negative staphylococci (21.0%) was observed. These bacterial strains showed multidrug-resistance, particularly to beta-lactams, fluoroquinolones, aminoglycosides, and macrolides. Beta-lactamases were identified in the genome of bacterial strains with a predominance of blaCTX-M15 (42.8%). The frequency of the mecA gene in staphylococci was 50%. These results show the magnitude of the antimicrobial resistance situation in the hospitals investigated. They can be used to support advocacy for urgent action at the national level, especially with regards to the management and efficient use of antimicrobials in Benin

Genetic Divergence in Northern Benin Sorghum ( Sorghum bicolor

Sorghum [Sorghum bicolor (L.) Moench] is an important staple food crop in northern Benin. In order to assess its diversity in Benin, 142 accessions of landraces collected from Northern Benin were grown in Central Benin and characterised using 10 qualitative and 14 quantitative agromorphological traits. High variability among both qualitative and quantitative traits was observed. Grain yield (0.72–10.57 tons/ha), panicle weight (15–215.95 g), days to 50% flowering (57–200 days), and plant height (153.27–636.5 cm) were among traits that exhibited broader variability. Correlations between quantitative traits were determined. Grain yield for instance exhibited highly positive association with panicle weight (r=0.901, P=0.000) and 100 seed weight (r=0.247, P=0.000). UPGMA cluster analysis classified the 142 accessions into 89 morphotypes. Based on multivariate analysis, twenty promising sorghum genotypes were selected. Among them, AT41, AT14, and AT29 showed early maturity (57 to 66 days to 50% flowering), high grain yields (4.85 to 7.85 tons/ha), and shorter plant height (153.27 to 180.37 cm). The results obtained will help enhancing sorghum production and diversity and developing new varieties that will be better adapted to the current soil and climate conditions in Benin

Efficacy of Pyrethroid-Pyriproxyfen and Pyrethroid-Chlorfenapyr Long-Lasting Insecticidal Nets (LLINs) for the Control of Non-Anopheles Mosquitoes: Secondary Analysis from a Cluster Randomised Controlled Trial (cRCT)

The efficacy of a vector control tool in reducing mosquito biting is crucial for its acceptability. The present study compared the vector density of Culex spp. And Mansonia spp. across clusters, which received two dual-active ingredient (a.i.) long-lasting insecticidal nets (LLINs) and a standard pyrethroid-only LLIN, and assessed the seasonality of these mosquito genera. A total of 85,723 Culex spp. and 144,025 Mansonia spp. were caught over the study period. The density of Culex and Mansonia was reduced in all three arms over the study period. There was no evidence of a significant reduction in the indoor or outdoor density of Culex spp. in either dual-a.i. LLIN arm as compared to the standard pyrethroid-only net arm. A similar trend was observed with Mansonia spp. A high density of Culex spp. was found both in rainy and dry seasons, while for Mansonia spp., this was mainly observed during the rainy season. These results suggest that the novel insecticides in the dual-a.i. LLINs did not have an additional impact on these species and that pyrethroids might still be effective on them. Further work is required to determine whether these species of mosquitoes have resistance to the insecticides tested in this trial

Production and microbiological evaluation of three types of "Dèguè", a local fermented drink made from milk in Benin

This study consists to finalize some technologies for the production of a fermented drink called dèguè. This drink is widely consumed in Benin and other countries in sub-Saharan Africa. Following three different technologies, we had produced three (03) types of dèguè respectively with maize flour, sorghum and millet. These types have been analyzed and their microbiological characteristics were evaluated. The microbiological analysis results obtained from the experiments have shown that lactic acid bacteria, yeasts and molds were the dominant microflora of dèguè and varied respectively 7.22log10UFC/g to 7.55log10UFC/g for lactic acid bacteria and 7.78log10UFC/g to 8.44log10UFC/g for yeasts and molds. Moreover, the statistical analysis of these results showed that there was no significant difference at 5% (p <0.05) between the three types of dèguè. The values of lactic acid bacteria obtained were consistent with the standard (≥ 107/g) attached to the yoghurt. No type contained neither total coliforms nor thermotolerant coliforms. The products (dèguès) were also free of pathogenic microorganisms such as Escherichia coli, Staphylococcus aureus and Salmonella