Measuring and mitigating the release of mobile antibiotic resistance genes from wastewater treatment plants in Canada.

Antibiotic resistance in bacterial pathogens undermines a physician's ability to control invasive bacterial infections, leading to serious consequences in patient health outcomes. The magnitude of the threat was highlighted by the recent G8 Science Ministers identified antimicrobial drug resistance as a major health security challenge of the twenty first century (G8 UK, June 12, 2013). The rise in antibiotic resistance has been linked to an increased use of antibiotics in clinical and agricultural settings. Consequently, recent policy development has focused on reducing antibiotic use. These efforts are important for public health; however, they do not consider other potential reservoirs of antibiotic resistance. In this context, research efforts have identified wastewater treatment plants (WWTPs) as global hot-spots for high concentrations of antibiotic resistant bacteria (ARB) and antibiotic resistance genes. WWTPs receive human fecal wastes from households containing excreted gut bacteria including ARB. Individuals required to orally ingest antibiotics as a medical treatment will enrich for ARB in the gastrointestinal tract. These ARB and antibiotic residues are excreted in urine and feces, and are ultimately transported to wastewater treatment plants. Moreover, the antibiotic resistance genes are often associated with mobile genetic elements, furthering the potential for these clinically relevant antibiotic resistance genes to be horizontally mobilized to opportunistic pathogens found in the environment. WWTPs may represent a critical control point in the reduction of antibiotic resistance reservoirs. The proposed research will be in collaboration with our municipal WWTP partners in three provinces (SK, PEIand NS) and one territory (NU) whereby we will measure the diversity and quantify the release of clinically relevant mobile resistance genes from different WWTPs in Canada. Analysis of these data will help to determine if certain treatment processes either enhance release of new antibiotic resistance plasmids, or if certain processes, such as membrane use can help to reduce release of these mobile resistance elements in the effluent.