The occurrence of antimicrobial substances in toilet, sink and shower drainpipes of clinical units: A neglected source of antibiotic residues

• Published in: International journal of hygiene and environmental health 2019-04, Vol.222 (3), p.455-467
• Main Authors: Voigt, A.M., Faerber, H.A., Wilbring, G., Skutlarek, D., Felder, C., Mahn, R., Wolf, D., Brossart, P., Hornung, T., Engelhart, S., Exner, M., Schmithausen, R.M.
• Format: Article
• Language: English
• Subjects: Anti-Infective Agents - analysis; Antibiotic residues; Antibiotic selection pressure; Bathroom Equipment; Biofilm; Clinical wastewater; Environmental Monitoring; Equipment and Supplies, Hospital; Germany; Hospitals; Housing; LC-MS/MS; Waste Water - analysis; Water Pollutants, Chemical - analysis
• ISSN: 1438-4639; 1618-131X
• DOI: 10.1016/j.ijheh.2018.12.013

Antibiotics represent one of the most important drug groups used in the management of bacterial infections in humans and animals. Due to the increasing problem of antibiotic resistance, assurance of the antibacterial effectiveness of these substances has moved into the focus of public health. The reduction in antibiotic residues in wastewater and the environment may play a decisive role in the development of increasing rates of antibiotic resistance. The present study examines the wastewater of 31 patient rooms of various German clinics for possible residues of antibiotics, as well as the wastewater of five private households as a reference. To the best of our knowledge, this study shows for the first time that in hospitals with high antibiotic consumption rates, residues of these drugs can be regularly detected in toilets, sink siphons and shower drains at concentrations ranging from 0.02 μg·L−1 to a maximum of 79 mg·L−1. After complete flushing of the wastewater siphons, antibiotics are no longer detectable, but after temporal stagnation, the concentration of the active substances in the water phases of respective siphons increases again, suggesting that antibiotics persist through the washing process in biofilms. This study demonstrates that clinical wastewater systems offer further possibilities for the optimization of antibiotic resistance surveillance. •High amounts of antibiotic residues were found in sanitary units of patient wards.•The spectrums and concentrations were related to the medical specialty of the clinics.•After sufficient rinsing, no antibiotics are detected in the aqueous phases.•After water stagnation, detectable antibiotics reoccurred in sanitary units.•Biofilm is suggested as a medium for accumulation and reoccurrence of antibiotics.