Researchers from the University of North Carolina-Charlotte say that treatments to clean waste water may actually create new antibiotics, further adding to the problem of antibiotic resistance in the environment.

The discovery builds on previous work by civil and environmental engineering assistant professor Olya Keen who began research into the behavior of antibiotics in wastewater in summer 2014.

(Read “Wastewater Treatment Technologies for Developing Countries.”)

Dr. Keen (right) and Ph.D. student Nicole Kennedy-Neth working with a lab sample. Source: UNCC“This research is a small piece of a larger question,” Keen says. “There are varieties of antibiotics found in wastewater, and, at this point, we are just testing one.” Keen says the antibiotic is in a class of antibiotics that all have similar compositions, so other antibiotics in this class may respond the same way.

The antibiotic Keen and her student are studying is doxycycline, which falls into one of the more widely used classes of antibiotics. Their research shows that chlorine used to treat wastewater changes the makeup of the doxycycline and forms new antibiotics.

“Wastewater treatment is designed to break down biological substances but not antibiotics,” says Keen.

Antibiotics end up in wastewater in several ways; those not broken down by the human body are passed to wastewater, expired antibiotics from homes and hospitals are dumped into wastewater, and antibiotic materials is discharged by pharmaceutical companies.

“Wastewater tests have found every type of antibiotic known,” Keen says. “The problems antibiotics cause when they are not broken down by treatment is they get into streams where bacteria are becoming immune to them.” More dangerous, she says, are that super-bug bacteria can be formed.

Keen’s lab uses a mass spectrometer to work with controlled samples. The researchers treat doxycycline with chlorine, then separate samples by the mass of molecules to identify their composition. The next step is to treat and test water samples taken from real wastewater.

The university research team hopes eventually to find better ways of breaking down the antibiotics during wastewater treatment or developing preventative solutions to keep antibiotics out of wastewater streams.