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(M/EH045) Effects of antibiotics against environmental bacteria studied with simple tests. Alexy, Radka1, Kümpel, Tina1, Dörner, Martin 1, Kümmerer, Klaus1, 1 ABSTRACT- After administration antibiotics are excreted more or less unchanged by patients and animals from livestock. Antibiotics in the environment are of growing concern. In sewage treatment plants antibiotics may disturb the bacterial populations resulting in growing resistance and/or worse elimination of organic substances hereby affect the biological purification process. Only little is known about their effects against sewage treatment bacteria. A risk assessment is not possible on basis of current knowledge. Therefore simple tests with 18 important antibiotics were conducted to monitor the affection of bacterial growth and function. For Gram negative bacteria a Ps. putida growth inhibition test was used, for Gram positive ones a new test with Enterococcus faecalis was adapted. Additionally effects against nitrifying bacteria were monitored. The effect concentrations against were in the same order or higher as published for pathogenic bacteria. The nitrification inhibition test proofed not to be suitable for antibiotic testing. It will be discussed whether the standard tests used are appropriate for testing the affection of environmental bacteria. Key words: antibiotic, environmental bacteria, nitrification, inhibition |
