Efficiency and sensitivity of the digital droplet PCR for the quantification of antibiotic resistance genes in soils and organic residues.

Droplet digital PCR (ddPCR) allows absolute quantification and tolerance to inhibitors and has been proposed as the method of choice to overcome limitations of qPCR. The aim of this study was to evaluate ddPCR and qPCR performances to detect low copy number and copy number variation of antibiotic resistance genes (sul1 and qnrB genes encoding for resistance to sulfonamides and quinolones, respectively) using bacterial genomic DNA (gDNA) and metagenomic DNA extracted from soil and organic residue samples. With gDNA, qPCR showed a better range of quantification but the lower limit of quantification was at 15 copies of qnrB target vs.

Impact of untreated urban waste on the prevalence and antibiotic resistance profiles of human opportunistic pathogens in agricultural soils from Burkina Faso.

This study examined the long-term effects of the landfill disposal of untreated urban waste for soil fertilization on the prevalence and antibiotic resistance profiles of various human opportunistic pathogens in soils from Burkina Faso. Samples were collected at three sites in the periphery of Ouagadougou during two campaigns in 2008 and 2011. At each site, amendment led to changes in physico-chemical characteristics as shown by the increase in pH, CEC, total C, total N, and metal contents.

Low occurrence of Pseudomonas aeruginosa in agricultural soils with and without organic amendment.

The occurrence of Pseudomonas aeruginosa was monitored at a broad spatial scale in French agricultural soils, from various soil types and under various land uses to evaluate the ability of soil to be a natural habitat for that species. To appreciate the impact of agricultural practices on the potential dispersion of P. aeruginosa, we further investigated the impact of organic amendment at experimental sites in France and Burkina Faso.

[African agriculture faced with global changes: researches and innovations based on ecological sciences].

In the context of environmental and socio-economic changes, the agriculture of Sub-Saharan African countries will have to ensure food security of the population, while reducing its environmental footprint. The biophysical and social systems of agricultural production are complex. Innovative agricultural practices will be based on an intensification of ecological processes that determine the functioning of the soil-plant system, farmers' fields and agro-ecosystems.

Effect of the raw materials and mixing ratio of composted wastes on the dynamic of organic matter stabilization and nitrogen availability in composts of Sub-Saharan Africa.

The effect of raw materials and their proportions in initial mixtures on organic matter (OM) stabilization and nitrogen (N) availability during pit composting in Sub-Saharan Africa was assessed using biochemical fractionation and laboratory incubations to characterize composts sampled throughout the composting process. Stabilization of OM occurred more rapidly in mixtures with slaughter-house wastes, it was progressive in mixture with household refuses while tree leaves compost remained unstable. Carbon mineralization from compost samples was positively correlated to water soluble and hemicellulose-like organic fractions.