Transport of Antibiotic Resistant Escherichia Coli in Soil and Sediment.

The widespread use of antibiotics in the treatment of human diseases and in the animal farm environments led to the selection and spread of antibiotic resistant bacteria. Of great concern is the occurrence of the antibiotic resistant bacteria in groundwater, which represents a major source of drinking water supply. The use of treated wastewater for irrigation purpose and the application of manure as fertilizers in agricultural fields represent one of the major pathways that can lead to the contamination of groundwater by antibiotic resistant bacteria. Although many studies have documented the existence of antibiotic resistant bacteria in groundwater, little is known regarding the transport behavior of antibiotic resistant bacteria in the soil and groundwater system. In this research,  the transport of antibiotic resistant Escherichia coli in soil and sediment under varying conditions of water chemistry and moisture contents was investigated using flow-through columns packed with silica sands . Our results indicated that 1) antibiotic susceptible and antibiotic resistant bacteria can display distinct mobilty in the subsurface system, and 2) the transport of antibiotic resistant bacteria was influenced by water chemistry and flow conditions. Various surface properties of the bacterial cells were determined and related to the observed difference in microbial mobility.