Effet des dates de semis sur les niveaux de sévérité de la pustule bactérienne (Xanthomonas axonopodis pv. glycines) de soja (Glycine max) au Nord Bénin

Au Bénin, la pustule bactérienne du soja (Xanthomonas axonopodis pv. glycines) est à l’origine de la réduction du rendement de la culture. La présente étude vise à réduire les effets néfastes de la pustule bactérienne sur la culture du soja. Pour ce faire, cinq variétés de soja ont été semées à différentes dates suivant un dispositif en split-plot avec comme facteur principal la date de semis et comme facteur secondaire la variété. Les semis ont été réalisés le 1er juillet (semis précoce), le 15 juillet (semis normal) et le 1er août (semis tardif). Les résultats obtenus montrent une réduction significative des symptômes de la pustule bactérienne du soja au semis normal et au semis tardif comparée au semis précoce pour les variétés JUPITER, TGX1910-2F, ISRA 25/72 et TGX1985-11F. Le semis normal et le semis tardif réduisent le rendement des variétés comparé au semis précoce. La variété TGX1984-77F apparaît plus résistante et la variété JUPITER plus sensible que les variétés TGX1910-2F, ISRA 25/72 et TGX1985-11F à l’infection naturelle. Ainsi, l’utilisation des variétés résistantes ou tolérantes au semis normal ou tardif permettrait de lutter efficacement contre la maladie.© 2015 International Formulae Group. All rights reserved.Mots clés: Bénin, date de semis, pustule bactérienne, sévérité, sojaEnglish Title: Effect of sowing date on soybean (Glycine max) bacterial pustule (Xanthomonas axonopodis pv. glycines) severity level in northern BeninEnglish AbstractIn Benin, bacterial pustule (Xanthmonas axonopodis pv. glycines) significantly reduced soybean yield. The present study aims at reducing the effect of bacterial pustule on soybean culture. Then, seeds of five soybean varieties were sown in a split-plot design with sowing date as the main factor and variety as the secondary factor. Sowing was respectively made on 1st July (early planting), 15th July (normal planting) and  August 1st (late planting). The results showed a significant reduction in symptoms of soybean bacterial pustule for a normal and a late sowing date compared to the early sowing with the varieties JUPITER, TGX1910-2F, ISRA 25/72 and TGX1985-11F. The normal and late sowing reduce yield varieties compared to early sowing. The variety TGX1984-77F was resistant/tolerant and variety JUPITER was susceptible than varieties TGX1910-2F, ISRA 25/72 and TGX1985-11F under natural infection. Thus, the use of resistant or tolerant varieties to a normal or late sowing date will be helpful to control the disease in soybean culture.Keywords: Benin, bacterial pustule, sowing date, severity, soybea

Whole-genome sequencing-based antimicrobial resistance characterization and phylogenomic investigation of 19 multidrug-resistant and extended-spectrum beta-lactamase-positive Escherichia coli strains collected from hospital patients in Benin in 2019

The increasing worldwide prevalence of extended-spectrum beta-lactamase (ESBL) producing Escherichia coli constitutes a serious threat to global public health. Surgical site infections are associated with high morbidity and mortality rates in developing countries, fueled by the limited availability of effective antibiotics. We used whole-genome sequencing (WGS) to evaluate antimicrobial resistance and the phylogenomic relationships of 19 ESBL-positive E. coli isolates collected from surgical site infections in patients across public hospitals in Benin in 2019. Isolates were identified by MALDI-TOF mass spectrometry and phenotypically tested for susceptibility to 16 antibiotics. Core-genome multi-locus sequence typing and single-nucleotide polymorphism-based phylogenomic methods were used to investigate the relatedness between samples. The broader phylogenetic context was characterized through the inclusion of publicly available genome data. Among the 19 isolates, 13 different sequence types (STs) were observed, including ST131 (n = 2), ST38 (n = 2), ST410 (n = 2), ST405 (n = 2), ST617 (n = 2), and ST1193 (n = 2). The blaCTX-M-15 gene encoding ESBL resistance was found in 15 isolates (78.9%), as well as other genes associated with ESBL, such as blaOXA-1 (n = 14) and blaTEM-1 (n = 9). Additionally, we frequently observed genes encoding resistance against aminoglycosides [aac-(6')-Ib-cr, n = 14], quinolones (qnrS1, n = 4), tetracyclines [tet(B), n = 14], sulfonamides (sul2, n = 14), and trimethoprim (dfrA17, n = 13). Nonsynonymous chromosomal mutations in the housekeeping genes parC and gyrA associated with resistance to fluoroquinolones were also detected in multiple isolates. Although the phylogenomic investigation did not reveal evidence of hospital-acquired transmissions, we observed two very similar strains collected from patients in different hospitals. By characterizing a set of multidrug-resistant isolates collected from a largely unexplored environment, this study highlights the added value for WGS as an effective early warning system for emerging pathogens and antimicrobial resistance.The ARES (Académie de la Recherche pour l’Enseignement Supérieur), Belgium.http://www.frontiersin.org/Microbiologyam2022Genetic

Seroprevalence of malaria in inhabitants of the urban zone of Antananarivo, Madagascar

BACKGROUND: Antananarivo, the capital of Madagascar, is located at an altitude of over 1,200 m. The environment at this altitude is not particularly favourable to malaria transmission, but malaria nonetheless remains a major public health problem. The aim of this study was to evaluate exposure to malaria in the urban population of Antananarivo, by measuring the specific seroprevalence of Plasmodium falciparum. METHODS: Serological studies specific for P. falciparum were carried out with an indirect fluorescent antibody test (IFAT). In a representative population of Antananarivo, 1,059 healthy volunteers were interviewed and serum samples were taken. RESULTS: The seroprevalence of IgG+IgA+IgM was 56.1% and that of IgM was 5.9%. The major risk factor associated with a positive IgG+IgA+IgM IFAT was travel outside Antananarivo, whether in the central highlands or on the coast. The abundance of rice fields in certain urban districts was not associated with a higher seroprevalence. CONCLUSION: Malaria transmission levels are low in Antananarivo, but seroprevalence is high. Humans come into contact with the parasite primarily when travelling outside the city. Further studies are required to identify indigenous risk factors and intra-city variations more clearly

BMJ Open

Introduction Neonatal sepsis outreaches all causes of neonatal mortality worldwide and remains a major societal burden in low and middle income countries. In addition to limited resources, endemic morbidities, such as malaria and prematurity, predispose neonates and infants to invasive infection by altering neonatal immune response to pathogens. Nevertheless, thoughtful epidemiological, diagnostic and immunological evaluation of neonatal sepsis and the impact of gestational malaria have never been performed. Methods and analysis A prospective longitudinal multicentre follow-up of 580 infants from birth to 3 months of age in urban and suburban Benin will be performed. At delivery, and every other week, all children will be examined and clinically evaluated for occurrence of sepsis. At delivery, cord blood systematic analysis of selected plasma and transcriptomic biomarkers (procalcitonin, interleukin (IL)-6, IL-10, IP10, CD74 and CX3CR1) associated with sepsis pathophysiology will be evaluated in all live births as well as during the follow-up, and when sepsis will be suspected. In addition, whole blood response to selected innate stimuli and extensive peripheral blood mononuclear cells phenotypic characterisation will be performed. Reference intervals specific to sub-Saharan neonates will be determined from this cohort and biomarkers performances for neonatal sepsis diagnosis and prognosis tested. Ethics and dissemination Ethical approval has been obtained from the Comité d’Ethique de la Recherche – Institut des Sciences Biomédicales Appliquées (CER-ISBA 85 - 5 April 2016, extended on 3 February 2017). Results will be disseminated through international presentations at scientific meetings and publications in peer-reviewed journals

Evaluation of acute toxicity and histology effect on liver of glyphosate and atrazine in the African catfish Clarias gariepinus (Burchell 1822).

peer reviewedAquatic organisms are exposed to chemical pesticides including glyphosate (Sharp 480 SL) and atrazine (Atraforce), two phytocidal molecules used for agriculture purposes in Benin. In this study, we assessed the acute toxicity of these two herbicides with emphasis on their histopathological effects on the liver of catfish Clarias gariepinus. One hundred and eighty juveniles of C. gariepinus (mean length 7.26 ± 0.59 cm and mean weight 5.21 ± 3.22 g) were exposed over 96 h to increasing concentrations of each phytocide. The values of 96 h-LC50 were 6.175 × 103 and 3.165 ppm, respectively for Sharp 480 SL and Atraforce. This indicates that Sharp 480 SL was nontoxic, while Atraforce displayed a moderate toxicity to C. gariepinus juveniles. During the tests, the behavioral responses (hyperexcitation, lethargy, loss of balance, discoloration of skin, etc.) that usually precede death were observed in exposed fishes, confirming the neurotoxicity of these phytocides. Histological alterations observed in liver of contaminated fishes were regressive changes, such as necrosis, hepatocyte vacuolation, nuclear degeneration, hepatocytes degeneration, sinusoids dilatation, etc. These results indicate that exposure to these herbicides had destructive effects on the liver of C. gariepinus

Molecular Tools to Infer Resistance-Breaking Abilities of Rice Yellow Mottle Virus Isolates

Rice yellow mottle virus (RYMV) is a major biotic constraint to rice cultivation in Africa. RYMV shows a high genetic diversity. Viral lineages were defined according to the coat protein (CP) phylogeny. Varietal selection is considered as the most efficient way to manage RYMV. Sources of high resistance were identified mostly in accessions of the African rice species, Oryza glaberrima. Emergence of resistance-breaking (RB) genotypes was observed in controlled conditions. The RB ability was highly contrasted, depending on the resistance sources and on the RYMV lineages. A molecular marker linked to the adaptation to susceptible and resistant O. glaberrima was identified in the viral protein genome-linked (VPg). By contrast, as no molecular method was available to identify the hypervirulent lineage able to overcome all known resistance sources, plant inoculation assays were still required. Here, we designed specific RT-PCR primers to infer the RB abilities of RYMV isolates without greenhouse experiments or sequencing steps. These primers were tested and validated on 52 isolates, representative of RYMV genetic diversity. The molecular tools described in this study will contribute to optimizing the deployment strategy of resistant lines, considering the RYMV lineages identified in fields and their potential adaptability

Carbapenem-Resistant Organisms Isolated in Surgical Site Infections in Benin: A Public Health Problem

An alarming worldwide increase in antimicrobial resistance is complicating the management of surgical site infections (SSIs), especially in low-middle income countries. The main objective of this study was to describe the pattern of carbapenem-resistant bacteria in hospitalized patients and to highlight the challenge of their detection in Benin. We collected pus samples from patients suspected to have SSIs in hospitals. After bacterial identification by MALDI-TOF mass spectrometry, antimicrobial susceptibility was performed according to the Kirby–Bauer method. Carbapenemresistant strains were characterized using, successively, the Modified Hodge Test (MHT), the RESIST-5 O.K.N.V.I: a multiplex lateral flow and finally the polymerase chain reaction. Six isolates were resistant to three tested carbapenems and almost all antibiotics we tested but remained susceptible to amikacin. Four (66.7%) of them harbored some ESBL genes (blaCTX-M-1 and blaTEM-1). The MHT was positive for Carbapenems but not for Pseudomonas aeruginosa and Acinetobacter baumannii. As surgical antimicrobial prophylaxis, five of the six patients received ceftriaxone. The following carbapenems genes were identified: bla OXA-48(33.3%, n = 2), blaNDM (33.3%, n = 2) and blaVIM (33.3%, n = 2). These findings indicate a need for local and national antimicrobial resistance surveillance and the strengthening of antimicrobial stewardship programs in the country

Whole-Genome Sequencing-Based Screening of MRSA in Patients and Healthcare Workers in Public Hospitals in Benin

Methicillin-resistant Staphylococcus aureus (MRSA) constitutes a serious public health concern, with a considerable impact on patients’ health, and substantial healthcare costs. In this study, patients and healthcare workers (HCWs) from six public hospitals in Benin were screened for MRSA. Strains were identified as MRSA using conventional microbiological methods in Benin, and confirmed using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry in Belgium. Whole-genome sequencing (WGS) was used on the confirmed MRSA isolates, to characterize their genomic content and study their relatedness. Amongst the 305 isolates (304 wound swabs and 61 nasal swabs) that were collected from patients and HCWs, we detected 32 and 15 cases of MRSA, respectively. From this collection, 27 high-quality WGS datasets were obtained, which carried numerous genes and mutations associated with antimicrobial resistance. The mecA gene was detected in all the sequenced isolates. These isolates were assigned to five sequence types (STs), with ST8 (55.56%, n = 15/27), ST152 (18.52%, n = 5/27), and ST121 (18.52%, n = 5/27) being the most common. These 27 isolates carried multiple virulence genes, including the genes encoding the Panton–Valentine leukocidin toxin (48.15%, n = 13/27), and the tst gene (29.63%, n = 8/27), associated with toxic shock syndrome. This study highlights the need to implement a multimodal strategy for reducing the risk of the cross-transmission of MRSA in hospitals

Whole-Genome Sequencing-Based Antimicrobial Resistance Characterization and Phylogenomic Investigation of 19 Multidrug-Resistant and Extended-Spectrum Beta-Lactamase-Positive Escherichia coli Strains Collected From Hospital Patients in Benin in 2019

The increasing worldwide prevalence of extended-spectrum beta-lactamase (ESBL) producing Escherichia coli constitutes a serious threat to global public health. Surgical site infections are associated with high morbidity and mortality rates in developing countries, fueled by the limited availability of effective antibiotics. We!used whole-genome sequencing (WGS) to evaluate antimicrobial resistance and the phylogenomic relationships of 19 ESBL-positive E. coli isolates collected from surgical site infections in patients across public hospitals in Benin in 2019. Isolates were identi"ed by MALDI-TOF mass spectrometry and phenotypically tested for susceptibility to 16 antibiotics. Core-genome multi-locus sequence typing and single-nucleotide polymorphism-based phylogenomic methods were used to investigate the relatedness between samples. The broader phylogenetic context was characterized through the inclusion of publicly available genome data. Among the 19 isolates, 13 different sequence types (STs) were observed, including ST131 (n = 2), ST38 (n = 2), ST410 (n = 2), ST405 (n = 2), ST617 (n = 2), and ST1193 (n = 2). The blaCTX-M-15 gene encoding ESBL resistance was found in 15 isolates (78.9%), as well as other genes associated with ESBL, such as blaOXA-1 (n = 14) and blaTEM-1 (n = 9). Additionally, we!frequently observed genes encoding resistance against aminoglycosides [aac-(6')-Ib-cr, n = 14], quinolones (qnrS1, n = 4), tetracyclines [tet(B), n = 14], sulfonamides (sul2, n = 14), and trimethoprim (dfrA17, n = 13). Nonsynonymous chromosomal mutations in the housekeeping genes parC and gyrA associated with resistance to #uoroquinolones were also detected in multiple isolates. Although the phylogenomic investigation did not reveal evidence of hospital-acquired transmissions, we!observed two very similar strains collected from patients in different hospitals. By characterizing a set of multidrug-resistant isolates collected from a largely unexplored environment, this study highlights the added value for WGS as an effective early warning system for emerging pathogens and antimicrobial resistance

Indicateurs et biomarqueurs pour la sélection génétique de la qualité du poussin.

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