Abstract
Antibiotics are vital in the treatment of bacterial infectious diseases but when released into the environment they may impact non-target organisms that perform vital ecosystem services and enhance antimicrobial resistance development with significant consequences for human health. We evaluate whether the current environmental risk assessment regulatory guidance is protective of antibiotic impacts on the environment, protective of antimicrobial resistance, and propose science-based protection goals for antibiotic manufacturing discharges. A review and meta-analysis was conducted of aquatic ecotoxicity data for antibiotics and for minimum selective concentration data derived from clinically relevant bacteria. Relative species sensitivity was investigated applying general linear models, and predicted no effect concentrations were generated for toxicity to aquatic organisms and compared with predicted no effect concentrations for resistance development. Prokaryotes were most sensitive to antibiotics but the range of sensitivities spanned up to several orders of magnitude. We show reliance on one species of (cyano)bacteria and the ‘activated sludge respiration inhibition test’ is not sufficient to set protection levels for the environment. Individually, neither traditional aquatic predicted no effect concentrations nor predicted no effect concentrations suggested to safeguard for antimicrobial resistance, protect against environmental or human health effects (via antimicrobial resistance development). Including data from clinically relevant bacteria and also more species of environmentally relevant bacteria in the regulatory framework would help in defining safe discharge concentrations for antibiotics for patient use and manufacturing that would protect environmental and human health. It would also support ending unnecessary testing on metazoan species.
Highlights
This may reflect the lack of pharmaceutical ERA datasets placed in the public domain and/or that few antibiotics have been approved since the existing European Medicines Agency guideline came into force in 2006 requiring full chronic toxicity testing on cyanobacteria/microalgae, invertebrates and fish and lack a full ecotoxicity data set
Our analysis suggests that the susceptibility of species in European Committee on Antimicrobial Susceptibility Testing is not always protective of environmental bacteria, such as cyanobacteria and a PNEC for AMR (PNECR)(T) using clinically relevant bacteria (CRB) MIC data as a surrogate for resistance may not be protective of the risk of antimicrobial resistance (AMR) development in environmental bacteria
Our analysis shows that frameworks for ERA and human health protection for antibiotics need to consider the impact of antibiotics on relevant vulnerable species and the essential ecosystem services they provide
Summary
They are used in the treatment of bacterial infectious diseases, supporting surgical interventions, and in cancer and prophylactic treatment. Antibiotics are used widely in livestock and domestic animal veterinary treatments and as growth promoters in aquaculture. Global production of antibiotics for human use is valued at $40 billion a year (O’Neill 2015) illustrating their societal and economic importance. Antibiotic consumption is on the rise and between the years 2000 and 2010 there was an estimated 36% increase in use globally for human healthcare (Van Boeckel et al.2014). Bacteria are most sensitive to antibiotics but there is high interspecies variation
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