The Transformation and Conjugation of Ampicillin-Resistant Escherichia coli

William J Gannon, Nicholas G Stapleton


There is growing concern regarding the development of anticiotic resistance in clinical and agricultural settings due to the prevalence of antibiotics that exist there. However, antibiotic resistant traits areused extensively in researc labs and even in undergraduate classrooms. We aimed to determine whether undergraduate laboratory transformation experiments could contribute to the spread of antiviotic resistance. Studies have been done on antibiotic resistance in large scale hospial and waste-treatment environments; we applied similar methods to an undergraduate laboratory. We first examined whether ampicillin-resistant E. coli were left in the laboratory ater the General Bioloy freshmen performed a transformation lab. In addition, we tested how efficiently ampicillin-resistant bacteria could transfer its resistance to other bacterial genra. The undergraduate lab was swabbed in five highly trafficked areas; swabs of the undersides of work tables, sides of chairs, and doorknob produced no resistant cultures, while swabs of the sink and table tops contained some resistant bacteria. These E. coli were plated with various strains of batera, including several other Enterobacteriaceae as well as gram positive genra with clinical relevance. We then used selective and differential media to determine if ampicillin-resistance was transferred. The results were assessed by the colony counting plate method. Our findings could have immediate implications for the safety and cleaning procedures used by undergraduate labs and could provide incentive to test this hypothesis more thoroughly in clinical environments in the future. In addition, the results indicate the possible contaminaton of sewage water and the release of resistant bacteria into the environment. Further experimentation could better determine the clinical and environmental consequences of the spread of antibiotic resistance in an aquatic environment.


ampicillin-resistanc, bacteria, transformation

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