Horizontal transfer, selection and maintenance of antibiotic resistance determinants

Scientific abstract Antibiotic resistance, especially in Gram-negative pathogens, represents a substantial clinical and financial burden to our society. The presented work investigated mechanisms and evolutionary dynamics that promote the emergence and maintenance of resistance in bacteria. In the first study, conserved collateral susceptibility changes were identified across resistant uropathogenic Escherichia coli, which included also changes towards increased sensitivity of these isolates to certain antibiotics. This so-called collateral sensitivity potentiated the effect of antibiotics and prevented the selection of resistant isolates compared to wildtype strains. The mechanism and fitness cost of resistance were important predictors of collateral responses in resistant bacteria, and their rapid clinical identification could inform future evolution-based infection treatment. The second study demonstrated the potential of a transposable element (Tn1) to spread antibiotic resistance during natural transformation of Acinetobacter baylyi. In the course of this horizontal gene transfer mechanism, Tn1-containing DNA entered the bacterial cell, and specific host, as well as transposon proteins, facilitated Tn1-insertion into the recipient chromosome. A mechanistic model of transposition-mediated natural transformation from a circular, cytoplasmic intermediate is presented. In the third study, uropathogenic E. coli improved its permissiveness towards two unrelated multidrug resistance plasmids while adapting to a new environmental niche. Mutations in the CCR and ArcAB regulatory systems resulted in transcriptional downregulation of plasmid genes and explained plasmid cost reduction. The presented evolutionary dynamics improve our understanding of successful associations between bacterial pathogens and resistance plasmids and provide a novel solution to the so-called ‘plasmid paradox’. In a broader perspective, the findings of this thesis advanced our knowledge on the selection, spread and maintenance of antibiotic resistance in bacteria, which is important to counteract its evolution

Improving water use efficiency under worsening scarcity: Evidence from the Middle Olifants sub-basin in South Africa

With the political changes in South Africa in the early 1990s, the South African government introduced a reform process in the entire water sector with the goal of a more enhanced and equitable water management system. This paper analyzes existing water allocation situations and applies a nonlinear optimization model to investigate the optimal intra- and inter-regional allocations in the Middle Olifants sub-basin of South Africa. Results show higher benefit from inter-regional water allocation. Reducing water supply levels to conform to the sustainable water supply policy, it can be shown that although water supply is reduced by approximately 50%, total benefits from water are only reduced by 5% and 11% for inter- and intra-regional allocation regimes respectively. These results indicate that alternative water allocation mechanisms can serve as instruments to offset for the effects of water scarcity.Water allocation, IWRM, Olifants basin, South Africa, Africa, Resource /Energy Economics and Policy,

Development and validation of risk profiles of West African rural communities facing multiple natural hazards

West Africa has been described as a hotspot of climate change. The reliance on rain-fed agriculture by over 65% of the population means that vulnerability to climatic hazards such as droughts, rainstorms and floods will continue. Yet, the vulnerability and risk levels faced by different rural social-ecological systems (SES) affected by multiple hazards are poorly understood. To fill this gap, this study quantifies risk and vulnerability of rural communities to drought and floods. Risk is assessed using an indicator-based approach. A stepwise methodology is followed that combines participatory approaches with statistical, remote sensing and Geographic Information System techniques to develop community level vulnerability indices in three watersheds (Dano, Burkina Faso; Dassari, Benin; Vea, Ghana). The results show varying levels of risk profiles across the three watersheds. Statistically significant high levels of mean risk in the Dano area of Burkina Faso are found whilst communities in the Dassari area of Benin show low mean risk. The high risk in the Dano area results from, among other factors, underlying high exposure to droughts and rainstorms, longer dry season duration, low caloric intake per capita, and poor local institutions. The study introduces the concept of community impact score (CIS) to validate the indicator-based risk and vulnerability modelling. The CIS measures the cumulative impact of the occurrence of multiple hazards over five years. 65.3% of the variance in observed impact of hazards/CIS was explained by the risk models and communities with high simulated disaster risk generally follow areas with high observed disaster impacts. Results from this study will help disaster managers to better understand disaster risk and develop appropriate, inclusive and well integrated mitigation and adaptation plans at the local level. It fulfills the increasing need to balance global/regional assessments with community level assessments where major decisions against risk are actually taken and implemented

The Economics of Desertification, Land Degradation, and Drought; Toward an Integrated Global Assessment

Land degradation has not been comprehensively addressed at the global level or in developing countries. A suitable economic framework that could guide investments and institutional action is lacking. This study aims to overcome this deficiency and to provide a framework for a global assessment based on a consideration of the costs of action versus inaction regarding desertification, land degradation, and drought (DLDD). Most of the studies on the costs of land degradation (mainly limited to soil erosion) give cost estimates of less than 1 percent up to about 10 percent of the agricultural gross domestic product (GDP) for various countries worldwide. But the indirect costs of DLDD on the economy (national income), as well as their socioeconomic consequences (particularly poverty impacts), must be accounted for, too. Despite the numerous challenges, a global assessment of the costs of action and inaction against DLDD is possible, urgent, and necessary. This study provides a framework for such a global assessment and provides insights from some related country studies.Agricultural Finance, Crop Production/Industries, Environmental Economics and Policy, Land Economics/Use, Resource /Energy Economics and Policy,

The economics of desertification, land degradation, and drought: Toward an integrated global assessment

cost of inaction, desertification, drought, Economics, Land degradation, prevention of land degradation,

Piggybacking on Niche Adaptation Improves the Maintenance of Multidrug-Resistance Plasmids

The persistence of plasmids in bacterial populations represents a puzzling evolutionary problem with serious clinical implications due to their role in the ongoing antibiotic resistance crisis. Recently, major advancements have been made toward resolving this “plasmid paradox” but mainly in a nonclinical context. Here, we propose an additional explanation for the maintenance of multidrug‐resistance plasmids in clinical Escherichia coli strains. After coevolving two multidrug‐resistance plasmids encoding resistance to last resort carbapenems with an extraintestinal pathogenic E. coli strain, we observed that chromosomal media adaptive mutations in the global regulatory systems CCR (carbon catabolite repression) and ArcAB (aerobic respiration control) pleiotropically improved the maintenance of both plasmids. Mechanistically, a net downregulation of plasmid gene expression reduced the fitness cost. Our results suggest that global chromosomal transcriptional rewiring during bacterial niche adaptation may facilitate plasmid maintenance

Making SDGs work for climate change hotspots

The impacts of climate change on people's livelihoods have been widely documented. It is expected that climate and environmental change will hamper poverty reduction, or even exacerbate poverty in some or all of its dimensions. Changes in the biophysical environment, such as droughts, flooding, water quantity and quality, and degrading ecosystems, are expected to affect opportunities for people to generate income. These changes, combined with a deficiency in coping strategies and innovation to adapt to particular climate change threats, are in turn likely to lead to increased economic and social vulnerability of households and communities, especially amongst the poorest

Interdisciplinary assessment of sea-level rise and climate change impacts on the lower Nile delta, Egypt

Copyright © 2015 Elsevier. NOTICE: this is the author’s version of a work that was accepted for publication in Science of the Total Environment. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published in Science of the Total Environment Vol. 503-504 (2015), DOI: 10.1016/j.scitotenv.2014.06.111CLImate-induced changes on WAter and SECurity (CLIWASEC) was a cluster of three complementary EC-FP7 projects assessing climate-change impacts throughout the Mediterranean on: hydrological cycles (CLIMB - CLimate-Induced changes on the hydrology of Mediterranean Basins); water security (WASSERMed - Water Availability and Security in Southern EuRope and the Mediterranean) and human security connected with possible hydro-climatic conflicts (CLICO - CLImate change hydro-COnflicts and human security). The Nile delta case study was common between the projects. CLIWASEC created an integrated forum for modelling and monitoring to understand potential impacts across sectors. This paper summarises key results from an integrated assessment of potential challenges to water-related security issues, focusing on expected sea-level rise impacts by the middle of the century. We use this common focus to illustrate the added value of project clustering. CLIWASEC pursued multidisciplinary research by adopting a single research objective: sea-level rise related water security threats, resulting in a more holistic view of problems and potential solutions. In fragmenting research, policy-makers can fail to understand how multiple issues can materialize from one driver. By combining efforts, an integrated assessment of water security threats in the lower Nile is formulated, offering policy-makers a clearer picture of inter-related issues to society and environment. The main issues identified by each project (land subsidence, saline intrusion - CLIMB; water supply overexploitation, land loss - WASSERMed; employment and housing security - CLICO), are in fact related. Water overexploitation is exacerbating land subsidence and saline intrusion, impacting on employment and placing additional pressure on remaining agricultural land and the underdeveloped housing market. All these have wider implications for regional development. This richer understanding could be critical in making better policy decisions when attempting to mitigate climate and social change impacts. The CLIWASEC clustering offers an encouraging path for the new European Commission Horizon 2020 programme to follow.European Commission Seventh Framework Program CLICOEuropean Commission Seventh Framework Program CLIMBEuropean Commission Seventh Framework Program WASSERMe

Proceedings of the ANDROID Doctoral School

The Doctoral School initiative which was set up by the ANDROID network is a core element of the overall project that aims to strengthen the link between research and teaching in the area of disaster resilience. The mixed teaching space that we have developed as part of this ongoing project has attempted to encourage and promote the work of doctoral students in this field. The ANDROID disaster resilience network doctoral school consists of two programmes: 1. Online Doctoral School (ODS) and 2. Residential Doctoral School (RDS) The interlinked programmes work together to deliver on a varied number of teaching and research driven objectives. The online doctoral school which was conducted in Spring 2013 provided an innovative platform to transfer and develop the knowledge base of doctoral candidates. This was achieved through the conduct of a series of domain expert presentations along with thematic sessions aimed at engaging the doctoral researchers in knowledge discovery through detailed discussion. The online doctoral school will be rolled out again in Spring 2014