Antibiotic resistance research at UWM helps to assess potential public health risks

A researcher uses a pipette under a fume hood while a student researcher looks on.

Annually, medical professionals in the United States combat about two million cases where patients have antibiotic resistant diseases. These resistant diseases have claimed thousands of lives and have had a substantial economic impact.

With this problem in mind, Assistant Professor Troy Skwor, PhD, from the Department of Biomedical Sciences, and undergraduate student Brandon Bojar are working to understand how this national problem manifests in Milwaukee. They are conducting research on the antibiotic resistant bacterial populations in Milwaukee’s hospital and urban wastewater.

Antibiotic resistant bacteria research

Of the antibiotic resistant bacteria, the Centers for Disease Control and Prevention (CDC) have identified two populations as serious to urgent public health threats. The populations, called carbapenem-resistant and extended-spectrum beta-lactamase producing Enterobacteriaceae, are a family of bacteria that include Escherichia coli, or E. coli.

Using the CDC classification, Skwor, Bojar and collaborators from Marquette University and the Medical College of Wisconsin put together a study specific to Milwaukee.

They gathered data from Milwaukee’s hospital and urban wastewater with the goal of characterizing and assessing antibiotic resistant bacterial populations from human sources and their potential impact on the environment.

In their research, they focused on three objectives. The first aim of their study was to determine the prevalence of antibiotic resistant populations in hospital wastewater in comparison to urban wastewater.

Their research team’s second goal was to ascertain how current urban wastewater treatment impacted these resistance levels. Third, they wanted to determine if these antibiotic resistant populations have the potential to cause disease.

Preliminary research findings

In Fall 2018, wastewater samples were obtained and tested from hospital wastewater and urban wastewater. For the latter, samples were taken throughout the urban wastewater treatment process, including a test of the final, post-chlorinated effluent that is disseminated into Lake Michigan following Environmental Protection Agency regulations.

After analyzing samples from all the water sources, Skwor and Bojar found that the average multiple antibiotic resistance (MAR) index, which measures the extent of resistance for each bacterial isolate, was significantly greater in hospital wastewater compared to urban water samples, which is what they predicted.

They further identified multiple mechanisms that the bacteria use to acquire resistance and demonstrated that these genes could potentially be passed between different bacteria, thus spreading resistance.

“This research is just the beginning”

The team is finishing up the project and putting together an article for publication. The specific details of their findings will be available after they publish their research. However, this summer Skwor and Bojar presented some of their findings at the annual American Society for Microbiology Microbe Conference.

For Bojar, this was his first conference poster presentation outside of UWM. Bojar explained, “As an undergraduate student, it was a huge honor for me to present. Receiving feedback from scientists from around the world was inspiring.”

Skwor and Bojar both emphasized that this research was just the first step in a long-term research project. They have many questions they still need answered, such as how is the resistance acquired on a molecular level? Are the same resistant genes found environmentally and within the clinic? Are these resistant isolates potentially pathogenic or capable of causing disease in humans?

Skwor’s lab also performs research that analyzes alternative treatments to combat these antibiotic resistant bacteria, such as photodynamic therapy – the use of visible light combined with different photosensitizers to kill bacteria.

Skwor explains, “This research is just the beginning, and we are currently analyzing numerous avenues to further understand the acquisition of resistance, as well as its potential impact on environmental levels.”