Environmental Antibiotic Resistance Associated with Land Application of Biosolids

The extent to which human activities in general and the application of biosolids to agricultural lands in particular, contribute to the maintenance of environmental reservoirs of antibiotic resistance is poorly understood. Concerns are fueled by a lack of knowledge of the effects of trace antibiotics on ecosystem processes, by questions related to the survival of enteric bacteria in the soil, and by an absence of critical information regarding the movement of resistance genes within and between microbial populations in the environment. This chapter summarizes the known connections between biosolids application and antibiotic resistance, and highlights multiple areas in which additional research is needed. Multiple studies have demonstrated amplification of antibiotic resistance genes during biological wastewater treatment. Although quantitative microbial risk assessment (QMRA) has evolved rapidly over the last decade, a definitive QMRA has not yet been performed for biosolids-borne pathogenic antibiotic-resistant bacteria with regard to human exposure.