Research: Environment as important as antibiotic exposure in resistance

July 24 (UPI) -- The environment and antibiotic exposure could be equally important in curbing the spread of drug resistance, according to research.

Researchers at the University of Exeter Medical School in Britain determined among bacteria exposed to very low concentrations of antibiotics, antibiotic resistance increases about as much as it does during high clinical concentrations. The findings, which were published Tuesday in the journal mBio, mean the environment is equally as important as antibiotic exposure in humans and animals.

"Antibiotic resistance is one of the greatest global issues facing society," the researchers wrote. "Still, comparatively little is known about selection for resistance at very low antibiotic concentrations. ... largely understudied ecological compartments could be just as important as clinical environments for selection of antibiotic resistance."

The World Health Organization has warned antibiotics won't be effective in treating pneumonia, tuberculosis and blood poisoning as well as preventing infection in routine medical procedures, such as joint replacements and chemotherapy.

In September 2016, the United Nations General Assembly approved "a broad coordinated approach to address the root causes of antimicrobial resistance across multiple sectors, especially human health, animal health and agriculture."

"Already, some commonly prescribed antibiotics are starting to prove ineffective for some infections," research leader Dr. Aimee Murray, of the University of Exeter Medical School, said in a press release. "Our research casts new light on how this problem may be spreading, and provides new evidence for the steps we may need to take in targeting the environment to try and stop this global problem."

She added additional research is needed, including whether microbes evolve resistance to antibiotics when exposed to low levels in other settings than waste water, such as in different areas of the body.

AstraZeneca, a drugmaker, co-funded the study with the Biotechnology and Biological Sciences Research Council.

Studied were the evolution of microbes from sewage waste water when exposed to the antibiotic cefotaxime.

Sewage contains bacteria resistant to antibiotics, which is included in toilet waste from people taking antibiotics and from medication disposal.

The researchers said their finding show that runoff from rivers, streams and the sea may be a breeding ground for resistant bacteria. People come in contact with the bacteria resistant to antibiotics in natural environments, including close contact with animals, through food or outdoor recreational activities.

"Our research shows just how important it is to take action to limit antibiotics entering the environment," Dr. William Gaze, who leads the University of Exeter Medical School research program on the environmental dimension of antibiotic resistance, said. "So far a lot of research effort to tackle this problem has been around hospitals and reducing clinical prescribing, but we now know that the environment is likely to play a part in how resistance to antibiotics can evolve and spread. We all need to think more holistically about environmental management of waste, including how we treat our waste water."