Submitted to: Sustainability
Publication Type: Peer reviewed journal
Publication Acceptance Date: 3/5/2014
Publication Date: 3/12/2014
Publication URL: http://handle.nal.usda.gov/10113/58665
Citation: Mclain, J.E., Williams, C.F. 2014. Sustainability of water reclamation: long-term recharge with reclaimed wastewater does not enhance antibiotic resistance in sediment bacteria. Sustainability. 6:1313-1327. Interpretive Summary: The development of antibiotic resistance is of great concern due to the potential associated health risks. The application of reclaimed municipal waste water containing antibiotics may lead to the development of increased antibiotic resistance in soil microorganisms receiving these waters. Using soil organisms isolated from the top 30 cm of a groundwater recharge facility it was found that antibiotic resistance was present. However, the level of resistance in the recharge basins was statistically similar to organisms from a recharge facility that only receives ground water for recharge. Surprisingly, it was found that antibiotic resistance in Enterococcus for four antibiotics was higher in the control soils that had only received groundwater than the soils receiving treated effluent. Comparing the development of antibiotic resistance in soil bacteria at these two sites will increase awareness of the environmental and public health impacts of using reclaimed water for groundwater recharge and irrigation of municipal areas.
Technical Abstract: Wastewater reclamation for municipal irrigation is an increasingly attractive option for extending water supplies. However, public health concerns include the potential for development of antibiotic resistance (AR) in soil bacteria after exposure to residual pharmaceuticals in reclaimed water. Though scientific studies have reported high levels of AR in soils irrigated with wastewater, these works often fail to address the natural occurrence of AR, the soil resistome. This study compared AR patterns in sediment Enterococcus isolated from water storage basins recharged with either reclaimed water or groundwater in central Arizona. Resistance to 16 antibiotics was quantified in isolates to a depth of 30 cm. Results reveal that high levels of resistance to multiple antibiotics, including lincomycin, ciprofloxacin, and erythromycin, exists in soils regardless of the water source (groundwater, reclaimed water), and that AR is not increased in soils exposed to reclaimed water. Furthermore, multiple-antibiotic-resistance (MAR) was substantially reduced in isolates from reclaimed water sediments, compared to isolates from freshwater sediments. Comparing the development of AR in soil bacteria at these two sites will increase awareness of the environmental and public health impacts of using reclaimed water for irrigation of municipal areas, and illustrates the necessity for control sites in studies examining AR development.