Minimal selective concentrations of tetracycline in complex aquatic bacterial biofilms
Artikel i vetenskaplig tidskrift, 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


Sara Lundström

Göteborgs universitet

M. Ostman

Umeå universitet

Johan Bengtsson-Palme

Göteborgs universitet

Carolin Rutgersson

Göteborgs universitet

Malin Thoudal

Göteborgs universitet

Triranta Sircar

Göteborgs universitet

Hans Blanck

Göteborgs universitet

Martin Eriksson

Chalmers, Sjöfart och marin teknik, Maritim miljövetenskap

M. Tysklind

Umeå universitet

Carl-Fredrik Flach

Göteborgs universitet

D. G. Joakim Larsson

Göteborgs universitet

Science of the Total Environment

0048-9697 (ISSN)

Vol. 553 587-95


Cell- och molekylärbiologi







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