Graham Environmental Sustainability Institute

Biofilms and the Spread of Antibiotic Resistance in Water

Principal Investigators: Chuanwu Xi, Carl F. Marrs, and Carl Simon.

Student Supported: Laxmi Modali.

Units Involved: School of Public Health, College of Literature, Arts, & Sciences, Ford School of Public Policy, and Center for the Study of Complex Systems.

Brief Project Description: The emergence of bacterial resistance to antibiotics is quite common in areas where antibiotics are heavily used, but antibiotic-resistant bacteria also increasingly occur in aquatic environments. The spread of antibiotic resistance is currently a big concern to public health. Horizontal gene transfer is one of the major mechanisms contributing to the spread of genetic elements encoding antibiotic resistance among even genetically-distant bacterial populations. Bacterial cells in biofilms are more resistant to antibiotics than free-living cells. Several factors related to biofilms may contribute to the spread of antibiotic resistance. One of the factors is high frequency of horizontal gene transfer in biofilms due to the high cell density, the close proximity, increased genetic competence and accumulated mobile genetic elements. Biofilms are ubiquitous in surface water environments and drinking water distribution systems. Our proposed project will use laboratory experimental study and mathematic modeling to investigate the role of biofilms in the spread of antibiotic resistance in surface water and drinking water. We will focus on the occurrence of Trimethoprim (TMP) and sulfonamide (SUL) resistance in source and drinking water and build a mathematical model describing natural gene transformation of SUL resistance gene(s) in Acinetobacter BD413 single-species biofilms in a laboratory system. Our long term goal is to use experimental approaches and mathematical modeling to quantify and predict the rate and pattern of spread of antibiotic resistance in biofilms in source water and drinking water and to develop innovative approaches to reduce risks associated with the spread of antibiotic resistance. The proposed research will have primarily contributions to one of the GESI focal areas of “Human Health and the Linkage to a Changing Environment”, and will have significant contributions to the other two GESI focal areas of “Freshwater and Marine System Sustainability” and “Sustainable Infrastructure, Built Environment, and Manufacturing Systems”.

The topic of this proposal is both timely and state-of-the-art. We will combine a laboratory model system and advanced imaging tools to investigate directly transfer of genetic elements among a bacterial community and will use mathematical modeling to describe quantitatively the process, while addressing a significant concern to public health. This project is significant and will have a broad impact for following reasons: 1), the approach we take is very innovative and interdisciplinary, which reflects the inherited needs to address problems of this type. We have assembled an interdisciplinary team of investigators from 3 departments and 2 schools and one of them is a junior faculty member. The success of this project will promote collaborations among faculty from different disciplines on the campus and will contribute significantly to the career development of the junior faculty member in the area of environmental microbiology and public health; 2), this project will involve one graduate student and one undergraduate student.

The graduate student will be trained in both disciplines of environmental microbiology and mathematic modeling and will act as a bridge to bring together both disciplines. The undergraduate student working on this project is very excited about pursuing her graduate study in the area of antibiotic resistance; 3), the results obtained from this project will be integrated into courses for training students at the UM and Eastern Michigan University and for training local and national public health professionals in the OJ/OC (On Job/On Campus) program in the School of Public Health; 4) the proposed project is addressing a big global health problem, i.e., antibiotic resistance.

In our future projects, we will try to link this environmental study of antibiotic resistance of Acinetobacter sp. with increasing hospital outbreaks of multi-drug resistant Acinetobacter sp. around the world. Data obtained from this research will also be used as preliminary studies for extramural grant applications to NIH and National Science Foundation (NSF) “Ecology of Infectious Diseases (EID)” program; In addition the PI will apply to the NSF “Faculty Early Career Development (CAREER) Program” for continued support for this research; 5) last but not least, the proposed research match perfectly the focal research areas of the Graham Environmental Sustainability Institute and will contribute significantly to the big GESI mission.

Significant Accomplishments (as of January 1, 2009)

External Funding:

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