New research from the University of Stirling indicates that levels of antibiotic pollution in the environment may lead to an increase in the prevalence of antibiotic resistance, making it a Public Health concern.
The research, to be published in the American journal Environmental Health Perspectives, was led by PhD student Alfredo Tello, from the University’s Institute of Aquaculture. The study concludes that guidelines established for assessing environmental risks of veterinary antibiotics could be too high. These guidelines are set by VICH, the international programme founded to evaluate the safety of veterinary medicines.
Commenting on the research, Alfredo Tello said: “This study looks at the link between antibiotic pollution and antibiotic resistance from a new perspective. It reinforces previous studies which highlight that antibiotic contaminants in the environment may be leading to the development of antibiotic resistance.
“Antibiotics are being overused and we’re seeing the emergence of resistance to infections that we used to be able to treat. Their overuse has caused a constant ‘selective pressure’ - whereby antibiotic-resistant bacteria have increased within bacterial populations.”
The study was the first of its kind known to analyse the effect of concentrations of antibiotics actually measured in the environment on the prevalence of resistance in clinically-relevant bacteria, including the well-known E. coli.
Antibiotics are used extensively in human and veterinary medicine, as well as in aquaculture, to prevent or treat microbial infections. They can enter the environment via waste water treatment plant effluents, hospital and processing plant effluents, agricultural waste, and leakage from waste-storage and landfills. In addition, antibiotic resistance genes can be co-released into the environment with antibiotic compounds.
Stirling’s study suggests that concentrations of antibiotic contaminants that occur in the environment are high enough to increase the prevalence of antibiotic resistance in clinically-relevant bacteria.
The researchers also compared the levels of antibiotic sensitivity they identified to existing action limits - the guidelines drawn up by VICH to estimate the ecological risks of veterinary medicines on the environment. Their findings suggest that these action limits are set inappropriately high and need to be reconsidered.
Mr Tello added, “The VICH guidelines should be reviewed to address the emergence of antibiotic resistance due to antibiotic pollution in the environment. An effort should also be made to reduce antibiotic pollution, either by limiting the use of antibiotics or improving the treatment of liquid and solid wastes.