Antimicrobial Resistance Genes in the Atmosphere: Emissions and Exposure

抗生素是用于治疗细菌性疾病的药物，如链球菌性咽喉炎、肺炎和尿路感染。过度使用抗生素导致耐药细菌的增加，这意味着药物不再有效。抗生素耐药性被认为是我们这个时代最大的公共卫生挑战之一。在美国，每年至少有200万人因耐药性感染而患病，23，000人死于耐药性感染。抗药性细菌及其基因在土壤和水中的传播被认为是造成这一问题的原因。它们在大气中的存在令人担忧，因为风可以帮助它们长距离传播。该项目的首要目标是确定城市和农村地区空气中存在多少抗药性细菌及其基因。第二个目标是测量它们如何从污水处理厂和农场释放到大气中。最终的目标是模拟它们能在空气中飞行多远。这项研究的成功完成将使我们能够评估吸入细菌及其基因作为运输途径的重要性，而不是通过水和土壤接触它们。这些信息可用于制定政策和指导方针，以尽量减少抗生素耐药性的进一步传播，保护公众健康。环境中抗菌素耐药基因（ARG）的传播可能在向人类传播耐药性方面发挥作用。大多数关于环境中的精氨酸的研究都集中在水和土壤上，但空气中的精氨酸尤其令人担忧，因为它们具有长距离迁移的潜力。该项目的总体目标是促进对大气中的ARG的来源、迁移和归宿的基本了解。具体目标是：（1）描述代表背景、城市和农村环境的空气、水和土壤样本中的ARG浓度和分布;（2）量化污水处理厂和动物饲养作业向大气中的ARG排放率;（3）估计吸入接触ARG的重要性。这项研究采用了跨学科的方法，利用了空气质量工程，微生物学和气溶胶科学的科学方法。通过两项实地研究，我们将获得城市和农村地区ARG和其他抗菌素耐药性标志物的测量结果，重点是污水处理厂和农场。研究结果将包括空气中按大小区分的精氨酸浓度和分布，以及它们与潜在来源的关系。我们还将使用实地研究的数据，通过逆扩散建模方法计算污水处理厂和农场的ARGs排放率，并评估空气、水和土壤对ARGs总暴露量的相对贡献。将产生关于空气中抗菌剂耐药性标志物的新知识，包括空气中特定ARGs和细菌的大小分辨浓度和丰度;空气，水和土壤中耐药基因的宏基因组概况;污水处理厂和动物饲养操作中ARGs的排放率和排放因子;以及吸入暴露于ARGs的估计。这项研究将通过产生关于ARG在大气中的流行率、暴露程度及其长途运输潜力的关键新信息，来解决我们对空气中抗菌素耐药性的理解方面的主要差距。通过提高对空气中ARG的认识，研究结果将提供一个更完整的ARG在环境中的情况，以帮助减少其传播和管理影响。该奖项反映了NSF的法定使命，并已被认为是值得通过使用基金会的知识价值和更广泛的影响审查标准进行评估的支持。

Antibiotics are medicines used to treat bacterial diseases such as strep throat, pneumonia, and urinary tract infections. Overuse of antibiotics has led to an increase in bacteria that are resistant, meaning that the medicines are no longer effective. Antibiotic resistance is considered one of the largest public health challenges of our time. In the US, at least 2 million people become sick with antibiotic-resistant infections and 23,000 people die from them each year. The spread of antibiotic-resistant bacteria and their genes in soil and water is thought to contribute to the problem. Their presence in the atmosphere is a concern because wind can help them spread long distances. The first aim of this project is to determine how many antibiotic-resistant bacteria and their genes are present in the air in urban and rural areas. The second aim is to measure how they are released into the atmosphere from sewage treatment plants and farms. The final aim is to model how far they can travel through the air. Successful completion of this research will allow us to assess the importance of inhalation of bacteria and their genes as a transport pathway compared to contacting them through water and soil. This information can be used to develop policies and guidelines to minimize further spread of antibiotic resistance and protect public health.The spread of antimicrobial resistance genes (ARGs) in the environment is likely to play a role in transmission of resistance to humans. Most studies of ARGs in the environment have focused on water and soil, but ARGs in air are especially concerning because of their potential for long-distance transport. The overall goal of this project is to advance fundamental understanding about the sources, transport, and fate of ARGs in the atmosphere. Specific objectives are to: (1) characterize ARG concentrations and profiles in air, water, and soil samples representing background, urban, and rural settings; (2) quantify ARG emission rates to the atmosphere from wastewater treatment plants (WWTPs) and animal feeding operations; and (3) estimate the significance of inhalation exposure to ARGs. This research employs an interdisciplinary approach that leverages state-of-the-science methods in air quality engineering, microbiology, and aerosol science. Through two field studies, we will obtain measurements of ARGs and other markers of antimicrobial resistance in urban and rural areas, with a focus on WWTPs and farms. Results will include size-resolved concentrations and profiles of ARGs in air and how they relate to potential sources. We will also use data from the field studies to calculate emission rates of ARGs from WWTPs and farms via an inverse dispersion modeling approach and to assess the relative contribution of air, water, and soil to total exposure to ARGs. New knowledge about markers of antimicrobial resistance in air will be generated, including size-resolved concentrations and abundances of specific ARGs and bacteria in air; metagenomic profiles of resistomes in air, water, and soil; emission rates and emission factors for ARGs from WWTPs and animal feeding operations; and estimates of inhalation exposure to ARGs. This research will address major gaps in our understanding of antimicrobial resistance in air by producing critical new information about the prevalence of ARGs in the atmosphere, the magnitude of exposure, and their potential for long-distance transport. By advancing knowledge about ARGs in air, results will provide a more complete picture of ARGs in the environment to help reduce their spread and manage impacts.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.