Decomposition of Antibiotics in Water Systems and the Impact on Microbial Communities

Primary Submission Contact

Abby Beavan

Faculty Sponsor

Julie Peller

Faculty Sponsor Email Address



Arts and Sciences



Document Type

Poster Presentation


Fall 10-28-2016


Penicillin is one of the most prescribed antibiotics for humans and animals. As a result, unmetabolized penicillin is discharged into water systems, and bacteria in those water systems can become resistant. To better understand the lifetime of penicillin in water systems, the decomposition of Penicillin G (Pen G) in water solutions was studied. Simultaneously, the behavior of Staphylococcus aureus in these same solutions was analyzed. Four different aqueous solutions of 50 uM Pen G were studied: 1) water, 2)10 ppm Dissolved Organic Material (DOM), 3) 5mM NaHCO3, and 4) both DOM and NaHCO3. These solutions were analyzed weekly for 13 weeks using Ultra High Performance-Liquid Chromatography-Mass Spectrometry (UHPLC). Pure Pen G in water decomposed completely within two weeks. The solution containing NaHCO3 showed similar results, although decomposition was slower. The rate of decomposition of Pen G in the DOM solutions was even slower, as Pen G remained in solution after thirteen weeks. The bacteria plates exposed to the Pen G and Pen G in NaHCO3 solutions showed that after time the antibiotic was less effective against the bacteria. The bacteria plates exposed to the Pen G in DOM solutions showed that the antibiotic was still effective against the bacteria. Pen G resistant colonies of the bacteria were found on almost all of the plates tested.

Biographical Information about Author(s)

Abby Beavan is a senior Chemistry Major with aspirations to go to pharmacy school. Ashita Bhatnagar is a junior Psychology, Biology, and Chemistry triple Major with aspirations to go to medical school. These researchers became interested in this project because of the medical applications that this project has on both of their careers. Abby and Ashita feel that studying the decomposition of antibiotics will help decrease the spread of antibiotic resistant bacteria which will lead to viable treatments for their future patients.

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