An Environmental Science and Engineering Framework for Combating Antimicrobial Resistance

On June 20, 2017, members of the environmental engineering and science (EES) community convened at the Association of Environmental Engineering and Science Professors (AEESP) Biennial Conference for a workshop on antimicrobial resistance. With over 80 registered participants, discussion groups focused on the following topics: risk assessment, monitoring, wastewater treatment, agricultural systems, and synergies. In this study, we summarize the consensus among the workshop participants regarding the role of the EES community in understanding and mitigating the spread of antibiotic resistance via environmental pathways. Environmental scientists and engineers offer a unique and interdisciplinary perspective and expertise needed for engaging with other disciplines such as medicine, agriculture, and public health to effectively address important knowledge gaps with respect to the linkages between human activities, impacts to the environment, and human health risks. Recommendations that propose priorities for research within the EES community, as well as areas where interdisciplinary perspectives are needed, are highlighted. In particular, risk modeling and assessment, monitoring, and mass balance modeling can aid in the identification of 'hot spots' for antibiotic resistance evolution and dissemination, and can help identify effective targets for mitigation. Such information will be essential for the development of an informed and effective policy aimed at preserving and protecting the efficacy of antibiotics for future generations

Microbiologically Enhanced Mixing across Scales during \u3ci\u3ein-situ\u3c/i\u3e Bioremediation of Uranium

Production of nuclear fuels for weapons and electric energy has resulted in groundwater uranium contamination at Department of Energy (DOE) sites. Reduction of uranium by dissimilatory metal-reducing bacteria (DMRB) is an effective approach for in-situ bioremediation of these sites. In this process, an organic electron donor is typically delivered through a well into groundwater in order to promote the biological reduction of soluble and toxic U(VI) to insoluble and less toxic U(IV). A key challenge is mixing the organic electron donor with U(VI) in groundwater where laminar flow conditions prevail. A potential solution is to enhance reaction beyond the scale of physical mixing by promoting extracellular electron shuttling. Growing evidence suggests that extracellular electron shuttling can occur by either diffusion of aqueous phase electron shuttles (e.g., H2, quinones) between syntrophs and/or DMRB, or through direct electron transfer between cells through metallic-like appendage (i.e., nanowires). In this project, we used pore scale, microfluidic experiments in order to elucidate cell-to-cell electron transport that can potentially enhance U(VI) reduction beyond the scale of physical mixing with an organic electron donor. Batch studies were performed to develop DMRB cultures, and to evaluate their growth with different electron acceptor and donor conditions. DMRB cultures from batch studies were used to inoculate pore scale, microfluidic reactors. The microfluidic experiments allowed direct imaging of microbial growth over various mixing length scales. Anaeromyxobacter dehalogenans Strain K and a mixed ground water culture were used, and we hypothesize that these organisms will enhance reaction beyond physical mixing scales by facilitated electron transfer

Geobiology reveals how human kidney stones dissolve in vivo

Abstract More than 10% of the global human population is now afflicted with kidney stones, which are commonly associated with other significant health problems including diabetes, hypertension and obesity. Nearly 70% of these stones are primarily composed of calcium oxalate, a mineral previously assumed to be effectively insoluble within the kidney. This has limited currently available treatment options to painful passage and/or invasive surgical procedures. We analyze kidney stone thin sections with a combination of optical techniques, which include bright field, polarization, confocal and super-resolution nanometer-scale auto-fluorescence microscopy. Here we demonstrate using interdisciplinary geology and biology (geobiology) approaches that calcium oxalate stones undergo multiple events of dissolution as they crystallize and grow within the kidney. These observations open a fundamentally new paradigm for clinical approaches that include in vivo stone dissolution and identify high-frequency layering of organic matter and minerals as a template for biomineralization in natural and engineered settings