An ANSWER to the risks of antibiotics (resistance) with water reuse

Reuse of municipal wastewater can significantly contribute to reducing water scarcity. But the use of reclaimed water can also involve risks. For example, there are concerns about the negative effects of chemical and biological contaminants, such as antibiotics and antibiotic-resistant bacteria and the genetic transfer of antibiotic resistance among different bacteria. The Horizon 2020-project ANSWER was started around this issue in 2015, which expires later this year.

Interdisciplinary approach

The European Commission and other international organisations consider antibiotics and antibiotic resistance to be serious public health threats, for which there is an urgent need for scientists with an interdisciplinary research and education background. ANSWER meets this need by training a new generation of researchers. One of those researchers was Gabriela Karina Paulus, who conducts research at KWR into the transfer of genes that are resistant to antibiotics in water systems. Paulus: ‘That can happen, for example, in biological wastewater treatment. When bacteria are under stress conditions, they are more likely to exchange genetic information. That is exactly when bacteria that did not used to be resistant to a particular antibiotic, acquire that resistance. If such a bacterium is a pathogen, you suddenly have less effective antibiotics at your disposal.’

Paulus: ‘At the moment, purifying at the source is not used on a large scale in the Netherlands, which means that wastewater treatment plants make a substantial contribution to antibiotics and antibiotic resistance in the environment. ‘

Removal at source

For her research, Paulus used several molecular methods, such as qPCR and next generation sequencing, combined with bioinformatic analysis. Her research showed among other things that it is much more effective in the Netherlands to remove antibiotics and antibiotic resistance from wastewater on the sites where they are discharged in the largest quantities, such as hospitals. Removal in the wastewater treatment plants might be less efficient.

Global problem

Paulus: ‘At the moment, purifying at the source is not used on a large scale in the Netherlands, which means that wastewater treatment plants make a substantial contribution to antibiotics and antibiotic resistance in the environment. This is an issue in other countries too. Because we really must consider antibiotic resistance to be a global problem, it is important that we treat wastewater better, and make sure treatment is introduced into areas where there is now no wastewater treatment.’

Information and education

It is also important to inform the public properly about the risks of improper use of antibiotics. ‘You should of course always finish a course of antibiotics as the doctor says, but it is equally as important that people know that they should not flush leftover medicine through the toilet or discharge it into the natural water system! This increases the risk of the spread of antibiotic resistance.’

Emission limits

At ANSWER, a multidisciplinary research team from the private sector and policymakers are working together to tackle antibiotic resistance and communication with interested parties and the public as part of their work package. They are also working on setting up relevant Emission Limit Values, which are indispensable for the development and application of rules and measures to limit the spread of antibiotic (resistance).