Craig Baker-Austin^{a, *}, Meredith S. Wright^{a, b}, Ramunas Stepanauskas^c and J V. McArthur^a

^aSavannah River Ecology Laboratory, Drawer E, SC 29803, USA
^bInstitute of Ecology, University of Georgia, Athens, GA 30602, USA
^cBigelow Laboratory for Ocean Sciences, West Boothbay Harbor, ME 04575, USA

Abstract
There is growing concern that metal contamination functions as a selective agent in the proliferation of antibiotic resistance. Documented associations between the types and levels of metal contamination and specific patterns of antibiotic resistance suggest that several mechanisms underlie this co-selection process. These co-selection mechanisms include co-resistance (different resistance determinants present on the same genetic element) and cross-resistance (the same genetic determinant responsible for resistance to antibiotics and metals). Indirect but shared regulatory responses to metal and antibiotic exposure such as biofilm induction also represent potential co-selection mechanisms used by prokaryotes. Metal contamination, therefore, represents a long-standing, widespread and recalcitrant selection pressure with both environmental and clinical importance that potentially contributes to the maintenance and spread of antibiotic resistance factors.

*Corresponding author: Baker-Austin, C. (baker@srel.edu).

SREL Reprint #2973