Brandon Schultz, “Impact of Low Concentrations of Ciprofloxacin on Mutation Rates in the Genus Aeromonas”
Mentor: Troy Skwor, Biomedical Sciences

According to the Center for Disease Control and Prevention, each year within the United States more than 2.8 million people are infected with antibiotic-resistant microorganisms. To fully understand antibiotic resistance, we must recognize the role of human, animal, and environmental habitats on the evolution and current rise of antibiotic resistance. Wastewater and recipient natural aquatic environments commonly contain antibiotics and other chemicals as long-term contaminants. One genus that exists within these ecosystems is Aeromonas. This genus is a Gram-negative bacterium that are associated with numerous animal and human diseases such as gastroenteritis, wound infections, and pneumonia. The purpose of this study was to assess if sub-inhibitory concentrations of the antibiotic ciprofloxacin antibiotic will increase mutation rates within the bacterial species, Aeromonas hydrophila. To perform these experiments, the minimum inhibitory concentration (MIC) of A. hydrophila ATCC 7966 was determined for ciprofloxacin and nalidixic acid. We focused on sub-inhibitory concentrations of ciprofloxacin considering its frequent use and presence within healthcare facilities, wastewater, and other natural aquatic environments. Bacterial cultures were inoculated into Luria broth media with and without sub-inhibitory concentrations of ciprofloxacin (≤ 7.8ng/mL). Mutation rates were determined by plating on TSA media containing 4x (4.16 mcg/mL) and 16x (16.64 mcg/mL) concentrations of nalidixic acid to identify mutant colonies, those that became resistant. Parallel cultures were performed, and mutation rates were determined by dividing the number of colony-forming units (CFU’s) on the nalidixic acid plates compared with the CFU’s of the total culture. Our findings highlight the risk associated with the presence of sub-inhibitory concentrations of antibiotics within the environment on causing mutations that could lead to increased resistance levels, making treatment processes more difficult to establish.

Synchronous Presentation April 16th at 2:30pm

Phone Conference ID: 655 025 361#