**5. Conclusions**

Wastewater treatment plants serve as a collection basin of multiresistant bacteria. In the investigated activated sludge samples all three screened multiresistant phenotypes were present, with ESBL harbouring Gram negative bacilli representing the most common ones. The study shows for the first time in Austria, the presence of VRE in WWTP and the first detection of a PER-1 mediated ESBL. All these multiresistant bacteria have the potential to spread in other ecological niches and therefore further monitoring and measures for reduction should be taken into consideration.

**Supplementary Materials:** The following tables are available online at www.mdpi.com/1660-4601/15/3/479/s1, Table S1: Antibiotics, disk content and breakpoints used for disk susceptibility testing according to the EUCAST guidelines (EUCAST V2.0, 2012).

**Acknowledgments:** This project was funded by "Hygienefonds der Medizinischen Universität Graz", Auenbruggerplatz 2, 8010 Graz, Austria.

**Author Contributions:** Gebhard Feierl, Franz F. Reinthaler and Gernot Zarfel conceived and designed the study; Herbert Galler and Doris Haas took samples and provided background information of the samples. Herbert Galler, Gernot Zarfel, Christian Petternel and Josefa Luxner performed the bacterial isolation, microbiological experiments, and analyses. Gernot Zarfel and Josefa Luxner performed molecular biology experiments. Herbert Galler, Gebhard Feierl and Gernot Zarfel analysed the data. Herbert Galler and Gernot Zarfel wrote the manuscript. Juliana Habib and Clemens Kittinger edited the manuscript.

**Conflicts of Interest:** The authors declare no conflict of interest.
