CAREER: A Systematic Understanding of Accelerated Emergence and Transmission of Antibiotic Resistance under Non-antibiotic Micropollutant Exposure

抗生素耐药性对全球公共卫生构成重大威胁。世界卫生组织估计，如果不采取行动，到2050年，每年因抗生素耐药性感染而死亡的人数将达到1000万。耐药细菌（ARB）存在于地表水、土壤和废水中的许多自然和工程环境中。这些环境中的ARB可能进入饮用水供应和食物链，导致人类接触并增加风险。因此，了解和控制ARB在这些环境中的出现和传播对于更好地保护人类健康至关重要。这项CAREER研究项目的目标是了解微污染物的存在如何影响环境相关条件下抗生素耐药性的发展、扩散和传播。这将通过具体的研究来实现，通过化学和分子生物学的新结合来跟踪暴露于微污染物的微生物对抗生素耐药性的诱导。这项研究的成功完成将促进对微污染物如何诱导抗生素耐药性的认识。结果也有很大的潜力，以改善努力监测和防止抗生素耐药性的传播。向公众传播抗生素耐药性问题的结果是与南加州内陆帝国地区当地污水处理厂、高中和大学合作开展外展工作的基础。这些努力将通过教育公众了解一个关键的公共卫生问题并提高国家的科学素养，从而使社会受益。虽然通过增加抗生素浓度选择的抗生素耐药性已经得到了很好的研究，但对于环境中非抗生素微污染物和抗生素的共同存在如何影响抗生素耐药性的发展，存在一个关键的知识缺口。初步研究发现，非抗生素微污染物以协同方式影响抗生素耐药性的发展和传播。本CAREER项目的目标是发展对这一过程的机制理解，特别是关注支撑抗生素耐药性发展和传播的基因型-表型关系。这一目标将通过将选择性生长实验与系统和分子生物学工具相结合的具体研究来实现。导致协同抗生素耐药性选择的遗传基础将首先通过分子生物学工具确定和验证。接下来，将研究从抗生素和非抗生素微污染物共同暴露中选择的促进耐药突变体增殖的环境因素。短期生长竞争试验将使用含有两种具有不同抗生素抗性的细菌菌株的共培养物。每个菌株的适合度将在生长过程中使用单核苷酸多态性（SNP）基因分型进行评估。最后，暴露于非抗生素微污染物对共轭水平基因转移（HGT）的影响将通过相同和不同细菌物种之间的交配实验来确定。导致HGT加速的分子机制将通过比较转录组学和蛋白质组学来确定。该研究计划将与教育和推广组成部分相结合，强调通过为不同的学习者群体设计的活动的多样性。将组织本科生研讨会（“WeAreIn”），鼓励女性本科生参与STEM，并利用研究培训项目从代表性不足的群体中招募本科生。将为K-12、本科生和研究生开发在线教育资源，并将开放房屋和公共网站以当地社区为目标，教育公众抗生素耐药性，并促进抗生素的正确使用和处置，以控制其传播。该奖项反映了美国国家科学基金会的法定使命，并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，被认为值得支持。

Antibiotic resistance poses a major global threat to public health. The World Health Organization estimates that annual deaths due to antibiotic resistant infections could reach 10 million by 2050 if no actions are taken. Antibiotic-resistant bacteria (ARB) are found in many natural and engineered environments in surface water, soil, and wastewater. ARB in these environments may enter potable water supply and food chains, resulting in human exposure and increased risk. Thus, it is critical to understand and control the emergence and spread of ARB in these environments to better protect human health. The goal of this CAREER research project is to understand how the presence of micropollutants affects the development, proliferation, and transmission of antibiotic resistance under environmentally relevant conditions. This will be achieved by specific research to track the induction of antibiotic resistance in microorganisms exposed to micropollutants through a novel combination of chemistry and molecular biology. Successful completion of this research will advance knowledge of how micropollutants induce antibiotic resistance. Results also have strong potential to improve efforts to monitor and prevent the spread of antibiotic resistance. Dissemination of results to the public on antibiotic resistance issues form the basis of outreach efforts in collaboration with local wastewater treatment plants, high schools, and colleges in the Inland Empire Region of southern California. These efforts will benefit society by educating the public about a critical public health issue and increase the scientific literacy of the Nation. Although antibiotic resistance selected by increasing concentration of antibiotics has been well studied, there is a critical knowledge gap concerning how the co-occurrence of non-antibiotic micropollutants and antibiotics in the environment influence the development of antibiotic resistance. Preliminary work found that non-antibiotic micropollutants influence the development and transmission of antibiotic resistance in a synergistic manner. The goal of this CAREER project is to develop a mechanistic understanding of this process specifically focusing on the genotype-to-phenotype relationships that underpin the development and transmission of antibiotic resistance. This goal will be achieved through specific research integrating selective growth experiments with systems and molecular biology tools. The genetic basis leading to synergistic antibiotic resistance selection will be first identified and validated via molecular biological tools. Next, the environmental factors that promote the proliferation of resistant mutants selected from the co-exposure of antibiotics and non-antibiotic micropollutants will be examined. Short-term growth competition tests will use co-cultures containing two strains of bacteria with different antibiotic resistance capacity. The fitness of each strain will be assessed during growth using single nucleotide polymorphism (SNP) genotyping. Lastly, the effect of exposure to non-antibiotic micropollutants on conjugative horizontal gene transfer (HGT) will be determined via mating experiments between the same and different bacterial species. The molecular mechanisms leading to accelerated HGT will be identified by comparative transcriptomics and proteomics. The research program will be integrated with an education and outreach component that emphasizes diversity through activities designed for different groups of learners. Undergraduate workshops (“WeAreIn”) will be organized to encourage participation of women undergraduates in STEM, and research training programs will be utilized for recruiting undergraduates from underrepresented groups. Online education resources will be developed for K-12, undergraduate, and graduate students, and open houses and a public website will target local communities to educate the public on antibiotic resistance and promote the proper use and disposal of antibiotics to control its spread.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.