Water JPI Stare Project present the first Trans-Europe surveillance on antibiotic resistance in wastewater treatment plants

In a recent study published on Science Advances the team of the Water JPI project - StARE, led by the coordinator Célia Manaia, presented the results of a pioneering European study on the antibiotic resistance prevalence in urban wastewater treatment plants (UWTPs) in seven European countries (Portugal, Spain, Ireland, Cyprus, Germany, Finland and Norway) and 12 municipal WWTPs.

According to the World Health Organization (WHO) resistance to antibiotics is considered one of the greatest threats to public health worldwide. In Europe, levels of antibiotic resistance in clinical settings, particularly in hospitals, have been monitored for more than a decade and have shown that southern European countries have higher prevalence values ​​than those in the North.  Over the last decades, antibiotic-resistant bacteria have also become an important environmental contaminant, being the potential transmission to humans, for example through recreational activities or food, which has serious potential implications. In urban areas, domestic sewage treatment plants, including hospital sewage, are a major source of antibiotic-resistant bacteria for the environment.

StARE aimed to understand whether the scenario of European distribution of antibiotic resistance in the clinical environment was also observed in raw sewage and in such cases if wastewater treatment would attenuate any differences.  Although wastewater treatment was efficient in the reduction of antibiotic resistance prevalence, the load of resistance was higher in southern countries in comparison to  northern countries. The results illustrated that observations in clinical settings, environmental antibiotic resistance follows an increasing north-to-south gradient of antibiotic resistance prevalence. This was observed in raw sewage not attenuated by wastewater treatment. Factors such as the temperature, precipitation, and dimensions of the UWTP may contribute to the persistence and dissemination of antibiotic resistance to the receptor environment. Another important outcome from this study is the proposed design and implementation of  simplified and low-cost surveillance protocols, based on high-throughput data as the quantification of antibiotic resistance genes instead of the traditional faecal indicators detection. In any case, the surveillance programmes should always consider and be adapted to the different geographical regions.

Global implementation of integrated environmental resistance monitoring programs will be crucial if control measures are to be implemented, if appropriate, adapted in accordance to the different geographic regions.