title: Ecotoxicological assessment of antibiotics: A call for improved consideration of microorganisms.
abstract: Antibiotics play a pivotal role in the management of infectious disease in humans, companion animals, livestock, and aquaculture operations at a global scale. Antibiotics are produced, consumed, and released into the environment at an unprecedented scale causing concern that the presence of antibiotic residues may adversely impact aquatic and terrestrial ecosystems. Here we critically review the ecotoxicological assessment of antibiotics as related to environmental risk assessment (ERA). We initially discuss the need for more specific protection goals based on the ecosystem service concept, and suggest that the ERA of antibiotics, through the application of a mode of toxic action approach, should make more use of ecotoxicological endpoints targeting microorganisms (especially bacteria) and microbial communities. Key ecosystem services provided by microorganisms and associated ecosystem service-providing units (e.g. taxa or functional groups) are identified. Approaches currently available for elucidating ecotoxicological effects on microorganisms are reviewed in detail and we conclude that microbial community-based tests should be used to complement single-species tests to offer more targeted protection of key ecosystem services. Specifically, we propose that ecotoxicological tests should not only assess microbial community function, but also microbial diversity (‘species’ richness) and antibiotic susceptibility. Promising areas for future basic and applied research of relevance to ERA are highlighted throughout the text. In this regard, the most fundamental knowledge gaps probably relate to our rudimentary understanding of the ecological roles of antibiotics in nature and possible adverse effects of environmental pollution with subinhibitory levels of antibiotics.
authors.affiliation: Department of Plant and Environmental Sciences, University of Copenhagen, Frederiksberg, Denmark; Sino Danish Center for Education and Research, Beijing, China. Electronic address: kkb@plen.ku.dk.
authors.forename: Kristian K
authors.initials: KK
authors.lastname: Brandt
authors.affiliation: Unilever-Safety & Environmental Assurance Centre, Sharnbrook, United Kingdom.
authors.forename: Alejandro
authors.initials: A
authors.lastname: Amézquita
authors.affiliation: Department of Biological and Environmental Sciences, University of Gothenburg, Gothenburg, Sweden.
authors.forename: Thomas
authors.initials: T
authors.lastname: Backhaus
authors.affiliation: Environment Department, University of York, York, UK.
authors.forename: Alistair
authors.initials: A
authors.lastname: Boxall
authors.affiliation: ECT Oekotoxikologie GmbH, Flörsheim/Main, Germany.
authors.forename: Anja
authors.initials: A
authors.lastname: Coors
authors.affiliation: Federal Office of Consumer Protection and Food Safety, Department 3: Veterinary Drugs, Berlin, Germany.
authors.forename: Thomas
authors.initials: T
authors.lastname: Heberer
authors.affiliation: Environment Canada, Saskatoon, Saskatchewan, Canada.
authors.forename: John R
authors.initials: JR
authors.lastname: Lawrence
authors.affiliation: Office of Research and Development, U.S. Environmental Protection Agency, Cincinnati, OH, USA.
authors.forename: James
authors.initials: J
authors.lastname: Lazorchak
authors.affiliation: Umweltbundesamt, Federal Environment Agency, Dessau, Germany.
authors.forename: Jens
authors.initials: J
authors.lastname: Schönfeld
authors.affiliation: AstraZeneca Global Environment, Alderley Park, United Kingdom.
authors.forename: Jason R
authors.initials: JR
authors.lastname: Snape
authors.affiliation: Key Laboratory of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen, China.
authors.forename: Yong-Guan
authors.initials: YG
authors.lastname: Zhu
authors.affiliation: Agriculture and Agri-Food Canada, London, Ontario, Canada. Electronic address: Ed.Topp@AGR.GC.CA.
authors.forename: Edward
authors.initials: E
authors.lastname: Topp
mesh_terms: D000818:Animals; D000900:Anti-Bacterial Agents / Q000032:analysis / Q000633:toxicity*; D004463:Ecology; D017753:Ecosystem; D054750:Ecotoxicology; D004785:Environmental Pollutants / Q000032:analysis / Q000633:toxicity*; D006801:Humans; D059013:Microbial Consortia / Q000187:drug effects*; D018570:Risk Assessment; D012988:Soil Microbiology / Q000592:standards*; D014871:Water Microbiology / Q000592:standards*
chemical_list: D000900:Anti-Bacterial Agents; D004785:Environmental Pollutants
keywords: Antimicrobials; Ecosystem services; Ecotoxicology; Environmental risk assessment; Microbial ecology; Pharmaceuticals