The effects of low-level ionizing radiation and copper exposure on the incidence of antibiotic resistance in lentic biofilm bacteria

• Published in: Environmental pollution (1987) 2017-09, Vol.228 (C), p.390-397
• Main Authors: McArthur, J. Vaun, Dicks, Christian A., Bryan, A. Lawrence, Tuckfield, R. Cary
• Format: Article
• Language: English
• Subjects: Bacteria - drug effects; Bacteria - genetics; Bacteria - radiation effects; Biofilms - drug effects; Biofilms - radiation effects; Copper - toxicity; Drug Resistance, Bacterial - drug effects; Drug Resistance, Bacterial - genetics; Drug Resistance, Bacterial - radiation effects; Incidence; Radiation, Ionizing; Water Pollutants - toxicity
• ISSN: 0269-7491; 1873-6424
• DOI: 10.1016/j.envpol.2017.03.081

Environmental reservoirs of antibiotic resistant bacteria are poorly understood. Understanding how the environment selects for resistance traits in the absence of antibiotics is critical in developing strategies to mitigate this growing menace. Indirect or co-selection of resistance by environmental pollution has been shown to increase antibiotic resistance. However no attention has been given to the effects of low-level ionizing radiation or the interactions between radiation and heavy metals on the maintenance or selection for antibiotic resistance (AR) traits. Here we explore the effect of radiation and copper on antibiotic resistance. Bacteria were collected from biofilms in two ponds – one impacted by low-level radiocesium and the other an abandoned farm pond. Through laboratory controlled experiments we examined the effects of increasing concentrations of copper on the incidence of antibiotic resistance. Differences were detected in the resistance profiles of the controls from each pond. Low levels (0.01 mM) of copper sulfate increased resistance but 0.5 mM concentrations of copper sulfate depressed the AR response in both ponds. A similar pattern was observed for levels of multiple antibiotic resistance per isolate. The first principal component response of isolate exposure to multiple antibiotics showed significant differences among the six isolate treatment combinations. These differences were clearly visualized through a discriminant function analysis, which showed distinct antibiotic resistance response patterns based on the six treatment groups. [Display omitted] •Effects of radiocesium and copper in the environment on antibiotic resistance in lentic biofilm bacteria are determined.•Differences in antibiotic resistance profiles differ initially between ponds with and without chronic radiation pollution.•Resistance profile converge with increasing levels of copper exposure. The effects of chronic ionizing radiation and heavy metal pollution are determined on the incidence of antibiotic resistance traits in lentic biofilm bacteria.