A researcher holds up a lab sample.

Exploring a nesting ground for antibiotic resistance

Over 2.8 million people in the United States get antibiotic-resistant infections each year, so understanding how resistance is acquired is a top health concern.

Troy Skwor, an assistant professor of biomedical sciences, is studying whether resistant populations of bacteria can survive the wastewater treatment process and enter into the environment, where they can affect people’s health.

Skwor’s work involves investigating antibiotic resistance within aeromonads – bacteria that live in many environments, including wastewater, and are linked to a wide array of human diseases. “If this organism can adapt to live in so many environments,” Skwor says, “it’s the perfect transfer vehicle for keeping antibiotic-resistant organisms in circulation.”

Skwor is exploring a second facet of the problem, too: determining whether antibiotic residue in wastewater increases the likelihood of genetic mutations that cause resistance, as well as which genes are involved. Low levels of antibiotic drugs end up in sewage after passing through the human digestive tract or because of improper waste disposal. In wastewater, they join a brew of substances that can cause genetic mutations in bacteria, which changes how the microbes behave.

Drugs in wastewater are highly diluted, so they aren’t strong enough to kill the bacteria. But that’s the problem, Skwor says. The microbes react to the presence of such low concentrations by mutating at a faster rate. They also exchange genes with nearby microbes, looking for new traits that give them the upper hand in these stressful environments.

A better sense of what happens to microbial genetic pathways in wastewater could lead to new drugs for bacterial infections that don’t contribute to antibiotic resistance.