Minimal selective concentrations of tetracycline in complex aquatic bacterial biofilms
Journal article, 2016

Selection pressure generated by antibiotics released into the environment could enrich for antibiotic resistance genes and antibiotic resistant bacteria, thereby increasing the risk for transmission to humans and animals. Tetracyclines comprise an antibiotic class of great importance to both human and animal health. Accordingly, residues of tetracycline are commonly detected in aquatic environments. To assess if tetracycline pollution in aquatic environments promotes development of resistance, we determined minimal selective concentrations (MSCs) in biofilms of complex aquatic bacterial communities using both phenotypic and genotypic assays. Tetracycline significantly increased the relative abundance of resistant bacteria at 10 μg/L, while specific tet genes (tetA and tetG) increased significantly at the lowest concentration tested (1 μg/L). Taxonomic composition of the biofilm communities was altered with increasing tetracycline concentrations. Metagenomic analysis revealed a concurrent increase of several tet genes and a range of other genes providing resistance to different classes of antibiotics (e.g. cmlA, floR, sul1, and mphA), indicating potential for co-selection. Consequently, MSCs for the tet genes of ≤ 1 μg/L suggests that current exposure levels in e.g. sewage treatment plants could be sufficient to promote resistance. The methodology used here to assess MSCs could be applied in risk assessment of other antibiotics as well.

Environmental emission limits

Antibiotic contaminants

Minimal selective concentration

Antibiotic resistance

Risk assessment

Author

Sara Lundström

University of Gothenburg

M. Ostman

Umeå University

Johan Bengtsson-Palme

University of Gothenburg

Carolin Rutgersson

University of Gothenburg

Malin Thoudal

University of Gothenburg

Triranta Sircar

University of Gothenburg

Hans Blanck

University of Gothenburg

Martin Eriksson

Chalmers, Shipping and Marine Technology, Maritime Environmental Sciences

M. Tysklind

Umeå University

Carl-Fredrik Flach

University of Gothenburg

D. G. Joakim Larsson

University of Gothenburg

Science of the Total Environment

0048-9697 (ISSN) 1879-1026 (eISSN)

Vol. 553 587-95

Subject Categories

Cell and Molecular Biology

Microbiology

Genetics

DOI

10.1016/j.scitotenv.2016.02.103

PubMed

26938321

More information

Latest update

2/27/2018