Broad spectrum antibiotics, such as Tylosin (naturally synthesized by Streptomyces fradiae) are used to treat infections in farm animals and are often administered at sub-therapeutic levels along with feed rations. The presence of bacteria resistant to antimicrobials in animal waste has raised concern related to their transport to surface and groundwater. Previous studies have shown that cells preferentially attach to sediments affecting their transport in overland flow; however, a lack of quantitative understanding exists regarding the attachment mechanisms such as extracellular organelles and the relationship between these and virulence factors in humans. In a preliminary study, the presence of Tylosin resistant bacteria have been enumerated in tile drainage samples collected beneath no-till plots. While this study shows the transport potential of resistant bacteria, the method of transport, the relationships between transport and resistance, and attachment and virulence factors is unknown. The objective of this research is to study these relationships in Escherichia coli collected from swine manure. Cultures will be screened for antibiotic resistance, and multiple antibiotic resistances. Resistant and nonresistant cultures will be grown in a chemostat environment to mimic a low nutrient environment. Relationships will be studied in vitro using an attachment assay and PCR. This study will be important in determining the relationship between antibiotic resistant bacteria and their ability to move within the environment and impact human health.
Available at: http://works.bepress.com/michelle_soupir/7/