Résumé
CTX-M (extended spectrum beta-lactamase- ESBL) producing Escherichia coli are increasingly involved in human infections worldwide. The aim of this study was to investigate potential reservoirs for such strains: soils, cattle and farm environment. The prevalence of blaCTX-M genes was determined directly from soil DNA extracts obtained from 120 sites in Burgundy (France) using real time PCR. blaCTX-M targets were found in 20% of the DNA extracts tested. Samples of cattle feces (n=271) were collected from 182 farms in Burgundy. Thirteen ESBL-producing isolates were obtained from 12 farms and further characterized for the presence of bla genes. Of the 13 strains, five and eight strains carried blaTEM-71 genes and blaCTX-M-1 genes respectively. Ten strains of CTX-M-1 producing E. coli were isolated from cultivated and pasture soils as well as from composted manure within 2 of these farms. The genotypic analysis revealed that environmental and animal strains were clonally related. Our study confirms the occurrence of CTX-M producing E. coli in cattle and reports for the first time the occurrence of such strains in cultivated soils. The environmental competence of such strains has to be determined and might explain their long term survival since CTX-M isolates were recovered from a soil that was last amended with manure one year before sampling.
Auteurs, date et publication :
Auteurs Alain Hartmann , Lucie Amoureux , Aude Locatelli , Geraldine Depret , Claudy Jolivet , Eric Gueneau , Catherine Neuwirth
Publication : Frontiers in Microbiology
Date : 2025
Volume : 3
Catégorie(s)
#Genosol #INRAEAuteurs, date et publication :
Auteurs V. Brochier , P. Gourland , M. Kallassy , M. Poitrenaud , S. Houot
Publication : Agriculture, Ecosystems and Environment
Date : 2025
Volume : 160
Issue : 1
Pages : 91-98 (no. sp. Recycling of organic residues to agriculture)
Catégorie(s)
#INRAE #PRO #PRO QualiAgroAuteurs, date et publication :
Auteurs A. Deredjian , N. Alliot , L. Blanchard , E. Brothier , M. Amane , P. Cambier , C. Jolivet , M.N. Khelil , S. Nazaret , N. Saby , J. Thioulouse , S. Favre-Bonté
Publication : Research in Microbiology
Date : 2025
Volume : 167
Issue : 4
Pages : 313–324
Catégorie(s)
#INRAE #PRO #PRO Colmar #PRO EFELERésumé
Plan de Gestion de Données de l'infrastructure OLA (Umr Carrtel - INRAE)
Auteurs, date et publication :
Auteurs Ghislaine Monet , Denis Barbet , Viet Tran-Khac , Ghislaine Monet
Date : 2025
Catégorie(s)
#INRAE #OLAAuteurs, date et publication :
Auteurs Andrea A. Cimatoribus , U. Lemmin , D. Bouffard , D. A. Barry
Publication : Journal of Geophysical Research: Oceans
Date : 2025
Volume : 123
Issue : 2
Pages : 1016-1031
Catégorie(s)
#INRAE #OLARésumé
Effective indicators of plant nitrogen (N) nutrition are needed to improve N management in grasslands. This is particularly the case for mixtures that rely on N fixation by legumes as a major N input, because no reference tool such as the nitrogen nutrition index (NNI) exists under these conditions. The aims of this study were to test the reliability of a plant-based index, the N concentration of upper leaves in the canopy (Nup), as a possible alternative for NNI in both pure and mixed grasslands. Data were gathered from four experiments covering a range of pure and mixed grasslands under different N fertilization levels. A cross-validation of Nup predictions against NNI in pure stands, and against two NNI-derived indices in mixtures, was performed. The Nup values appeared to be linearly related to NNI in pure stands of both grasses and legumes. The relationship was identical for the two groups of species and explained up to 86% of NNI variability. In mixtures, Nup also displayed a linear relationship with the two other tested indices, explaining 65% and 78% of variability. The conclusions of the three indices diverged with respect to strongly unbalanced mixtures, where the assumptions regarding the computation of NNI-derived indices were not met. Excluding these situations, the overall relationship between Nup and NNI proved to be identical for mixtures and pure stands. The results suggest that Nup is a valid criterion for plant N nutrition which applies to a broad range of grassland species and to mixture conditions.
Auteurs, date et publication :
Auteurs Gaëtan Louarn , Abad Chabbi , François Gastal
Publication : Grass and Forage Science
Date : 2025
Volume : 75
Issue : 1
Pages : 127-133
Catégorie(s)
#ACBB #ACBB Lusignan #ANR-Citation #INRAERésumé
Key message Inter-specific interactions with eucalypts in mixed plantations increased N2 fixation rate of acacia trees compared to monocultures. N2 fixation was higher during the wet summer than during the dry winter both in acacia monocultures and in mixed plantations.
Auteurs, date et publication :
Auteurs Ranieri R. Paula , Jean-Pierre Bouillet , José L. de M. Gonçalves , Paulo C. O. Trivelin , Fabiano de C. Balieiro , Yann Nouvellon , Julianne de C. Oliveira , José C. de Deus Júnior , Bruno Bordron , Jean-Paul Laclau
Publication : Annals of Forest Science
Date : 2025
Volume : 75
Issue : 1
Catégorie(s)
#CIRAD #FORET Itatinga #FORET Rubberflux #INRAERésumé
An increase in soil N availability by Acacia mangium in pure or mixed-species stands may reduce soil organic matter (SOM) mineralization compared to eucalypt stands. We measured the isotope composition (δ13C) of coarse particulate organic matter (cPOM, 4–0.25 mm), of fine POM (fPOM, 0.25–0.05 mm) and of the remaining organo-mineral fraction (OMF, <0.05 mm), and of the forest floor in plantations established on a tropical C4-grass savannah. In contrast to our hypothesis, the presence of acacia either alone or in mixture did not impact δ13C of the most stable SOM fractions derived from the previous savannah vegetation, which suggests similar rates of native SOM mineralization under acacia and eucalypt trees.
Auteurs, date et publication :
Auteurs D. Epron , Sogni Viviane Tchichelle , Y. Nouvellon , L. Mareschal , L.-S. Koutika
Publication : European Journal of Soil Biology
Date : 2025
Volume : 76
Pages : 92-94
Catégorie(s)
#CIRAD #FORET Itatinga #INRAERésumé
Agricultural practices affect the physical and chemical characteristics of the soil, which in turn may influence soil microorganisms with consequences on soil biological functioning. However, there is little knowledge on the interactions between agricultural management, soil physicochemical properties, and soil microbial communities, notably in tropical ecosystems with few studies conducted in strongly weathered and acid soils. Here, we investigated the early effect of tillage and crop residues management on top soil physical, chemical, and microbial properties in an acid savannah grassland of northeastern Laos. We initiated a 3-year rotation of rice/corn/soybean under three no-till systems (NTs) distinguished by the cover crops associated prior to and with the main crops, and one conventional tillage-based system (CT). The effect of agricultural management was evaluated 2 years after land reclamation in reference to the surrounding natural pasture (PAS). Our results demonstrate that NTs improve soil physicochemical characteristics (aggregate stability, organic carbon, and cation exchange capacity) as well as microbial abundance (total biomass, bacterial and fungal densities). A significant discrimination of the genetic structure of soil bacterial community was also observed between NTs, CT, and PAS. Interestingly, bacterial abundance and diversity were differently influenced by soil environment changes: microbial density was affected by the quantity and diversity of crop residues, soil organic carbon, and exchangeable base contents, whereas soil bacterial genetic structure was mainly determined by exchangeable aluminum content, pH, cation exchange capacity, and C/N ratio. Altogether, our study represents one of the most complete environmental evaluations of agricultural practices in tropical agrosystems and leads to recommend no-till systems with high residue restitutions to improve the physical, chemical, and microbial properties of tropical acid soils and thus contribute to the sustainability of agriculture in these ecosystems.
Auteurs, date et publication :
Auteurs Pascal Lienhard , Florent Tivet , André Chabanne , Samuel Dequiedt , Mélanie Lelièvre , Sengphanh Sayphoummie , Bounma Leudphanane , Nicolas Chemidlin Prévost-Bouré , Lucien Séguy , Pierre-Alain Maron , Lionel Ranjard
Publication : Agronomy for Sustainable Development
Date : 2013
Volume : 33
Issue : 2
Pages : 375-384
Catégorie(s)
#Genosol #INRAEAuteurs, date et publication :
Auteurs K M Haider , R Ciuraru , F Lafouge , C Decuq , L F Kebalo , B Esnault , A Fourtineau , F Levavasseur , B Loubet , C Focsa
Date : 1970