Int. J. Environ. Res. Public Health 2011, 8(2), 480-497; doi:10.3390/ijerph8020480
Article

A Simple Model of Tetracycline Antibiotic Resistance in the Aquatic Environment (with Application to the Poudre River)

Ferdi L. Hellweger* email, Xiaodan Ruanemail and Sarah Sanchezemail
Center for Urban Environmental Studies, Department of Civil & Environmental Engineering, Northeastern University, 360 Huntington Ave, Boston, MA 02115, USA
* Author to whom correspondence should be addressed.
Received: 1 January 2011; in revised form: 20 January 2011 / Accepted: 10 February 2011 / Published: 15 February 2011
(This article belongs to the Special Issue Advances in Environmental Modelling)
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Abstract: Antibiotic resistance is a major concern, yet it is unclear what causes the relatively high densities of resistant bacteria in the anthropogenically impacted environment. There are various possible scenarios (hypotheses): (A) Input of resistant bacteria from wastewater and agricultural sources is significant, but they do not grow in the environment; (B) Input of resistant bacteria is negligible, but the resistant bacteria (exogenous or endogenous) grow due to the selection pressure of the antibiotic; (C) Exogenous bacteria transfer the resistance to the endogenous bacteria and those grow. This paper presents a simple mechanistic model of tetracycline resistance in the aquatic environment. It includes state variables for tetracyclines, susceptible and resistant bacteria, and particulate and dissolved organic matter in the water column and sediment bed. The antibiotic partitions between freely dissolved, dissolved organic matter (DOM)-bound and solids-bound phases, and decays. Bacteria growth is limited by DOM, inhibited by the antibiotic (susceptible bacteria only) and lower due to the metabolic cost of carrying the resistance (resistant bacteria only). Resistant bacteria can transfer resistance to the susceptible bacteria (conjugation) and lose the resistance (segregation). The model is applied to the Poudre River and can reproduce the major observed (literature data) patterns of antibiotic concentration and resistance. The model suggests observed densities of resistant bacteria in the sediment bed cannot be explained by input (scenario A), but require growth (scenarios B or C).
Keywords: antibiotic; antibiotic resistance; model; tetracycline; Poudre River

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MDPI and ACS Style

Hellweger, F.L.; Ruan, X.; Sanchez, S. A Simple Model of Tetracycline Antibiotic Resistance in the Aquatic Environment (with Application to the Poudre River). Int. J. Environ. Res. Public Health 2011, 8, 480-497.

AMA Style

Hellweger FL, Ruan X, Sanchez S. A Simple Model of Tetracycline Antibiotic Resistance in the Aquatic Environment (with Application to the Poudre River). International Journal of Environmental Research and Public Health. 2011; 8(2):480-497.

Chicago/Turabian Style

Hellweger, Ferdi L.; Ruan, Xiaodan; Sanchez, Sarah. 2011. "A Simple Model of Tetracycline Antibiotic Resistance in the Aquatic Environment (with Application to the Poudre River)." Int. J. Environ. Res. Public Health 8, no. 2: 480-497.

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