Municipal wastewater treatment and the proliferation of antibiotic resistance

University Of Minnesota-Twin Cities, Minneapolis MN

Investigators

Abstract

Proposal Title: Municipal wastewater treatment and the proliferation of antibiotic resistance Principal Investigator: LaPara, Timothy Institution: University of Minnesota-Twin Cities Proposal No: CBET-0967176 Antibiotics have profoundly impacted medical practice, as these drugs can successfully eradicate most bacterial infections. While the medical community now recognizes the growing problem of antibiotic resistance, effective solutions are currently lacking and there is an urgent need to find new approaches to help solve the problem of broadly disseminated antibiotic resistant bacteria. This research proposal focuses on the importance of municipal wastewater and municipal wastewater treatment on the proliferation of antibiotic resistance. Even though municipal wastewater has been clearly and repeatedly shown to contain antibiotic resistant bacteria, the scientific community has generally failed to recognize municipal wastewater as a principal reservoir of antibiotic resistance. There are two primary routes by which antibiotic resistant bacteria can leave a municipal wastewater treatment facility: (1) with the treated effluent, and (2) with the residual wastewater solids. Of these two routes, residual wastewater solids are much more likely to be important for the spread of resistance ? and thus the primary focus of this proposal. The proposed research will provide seminal knowledge, allowing design engineers to select technologies that will optimize pathogen inactivation, the elimination of antibiotic resistant bacteria, the reduction of antibiotic resistance genes, and the stabilization of wastewater solids. The proposed research will test two hypotheses concerning the ecology of antibiotic resistance: (1) municipal wastewater treatment facilities can be intentionally designed to inactivate antibiotic resistant bacteria and to eliminate the genetic determinants that encode resistance, and (2) municipal wastewater treatment facilities are a source of antibiotic resistant bacteria because the conditions intentionally designed by environmental engineers to treat municipal wastewater are simultaneously (albeit unintentionally) conducive for horizontal gene transfer. The first hypothesis will be tested by quantifying the reductions of genes encoding antibiotic resistance in anaerobic digestors and other unit operations used to treat residual wastewater solids (Objective 1) and by determining the fate of genes encoding antibiotic resistance when treated wastewater solids are applied to agricultural soils (Objective 2). The second hypothesis will be tested by elucidating the rates of horizontal gene transfer and characterizing the genes that are horizontally transferred within the aeration tanks and anaerobic digestors of several municipal wastewater treatment facilities (Objective 3). The proposed project will have broad impacts that extend beyond the scientific research. The most pertinent of these broader impacts will focus on developing future scientists and engineers whose professional efforts will benefit society. The proposed project will directly support the education of a doctoral student at the University of Minnesota. In addition, the principal investigators will leverage the proposed project to augment the educational experience of two formal lecture/laboratory courses offered by the University of Minnesota. Similarly, the principal investigators will leverage the proposed project to mentor undergraduate students that will be financially supported the Research Experience for Undergraduates (REU) program at the University of Minnesota. These REU programs have been particularly successful at recruiting students from underrepresented groups to the University of Minnesota, thus likely providing another broader impact as defined by the National Science Foundation. Finally, the results of the proposed research will be broadly disseminated to the peer-reviewed technical literature, various agencies who operate municipal wastewater treatment facilities throughout the state of Minnesota, and to Minnesota State legislators.