DRIVERS OF ANTIBIOTIC RESISTANCE IN GRAM-NEGATIVE BACTERIA FROM THE NEUSE RIVER BASIN

Antimicrobial resistance (AMR) is the ability of infection-causing microorganisms to resist medicine normally used to treat the infections. Gram-negative bacteria are a group of bacteria responsible for some of the most clinically relevant bacteria to human health and are among the most serious AMR threats. With widespread economic, ecological, and health impacts, it is imperative to understand the factors influencing this global public health issue. This study investigates the influence of heavy metals (copper and zinc) and environmental factors (salinity, pH, temperature, and rainfall) as potential drivers AMR in Gram-negative bacteria collected from the Neuse River in North Carolina. The Neuse River Basin is one of North Carolina’s major river basins and receives runoff from urban areas, such as the highly-populated Triangle region, and hog and poultry farms. This study finds bacterial resistance to multiple metals (Cu and Zn) has significant associations to 3 or more antibiotic resistances (multidrug resistance). Furthermore, temperature, pH, rainfall, sampling locations downstream of WWTPs, and salinity are significantly associated with at least one antibiotic resistance. Temperature, pH, downstream sampling locations, and salinity were all found to have a significant association with multidrug resistance, while increased rainfall events was found to be 1.74 times more likely to lead to a 1 mm increase in Zn resistance (25 mM). Since climate change leads to increased temperatures, rainfall events, and salinity due to sea level rise, it is possible climate change may lead to increased co-resistance and AMR spread in Gram-negative bacteria. Moving forward, molecular methods and analyses should be integrated to further occurrence of and potential co-selection for metal (Cu and Zn) resistance and antibiotic resistance genes among gram negative bacteria in this setting and other estuarine and riparian systems with similar uses and influences. Overall, this study contributes to monitoring efforts of the Neuse River Basin and supports the idea of temperature as being a potential driver of co-occurrence of metals resistance and antibiotic resistance.Master of Scienc