Multiresistant Enterobacteriaceae, like carbapenemase-producing strains, have their primary reservoir in medical institutions. They can also be found with increasing tendency in other reservoirs. One possible way for entrance of multiresistant Enterobacteriaceae into the environment is via waste water. The aim of the study was to screen isolates from a wastewater treatment plant for the presence of carbapenemase-producing Enterobacteriaceae. Three isolates harboured carbapenemase genes, one Klebsiella pneumoniae harboured KPC-2 and one K. pneumoniae and one Escherichia coli harboured OXA-48. This is the first report of carbapenemase-harbouring Enterobacteriaceae isolated outside medical institutions in Austria and the first detection of KPC-harbouring K. pneumonia MLST ST 1245.