Developing a Novel Antibiotic Resistance Detection Method for Water Systems using IDEXX TECTA Technologies

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Cole, Allison
AMR , Antibiotic Resistance Detection , Ampicillin Resistance , E. coli resistance
Regular surveillance of water in the environment is essential for identifying hazardous contaminants, including antimicrobial-resistant (AMR) bacteria. These bacteria not only present a significant risk to public health but also impose considerable economic costs. Traditional methods for detecting resistance, though effective, are hindered by slow results, the need for intensive labor, specialized training, costly equipment, and a lack of portable, dependable alternatives 26. Consequently, there exists a substantial gap in our understanding of current AMR prevalence in natural settings, which obscures the levels of human exposure. This thesis presented an adaptation of the IDEXX TECTA system, a device already instrumental in identifying fecal bacteria within 18 hours, bypassing the need for preliminary bacterial culture steps. By evaluating its capability to detect resistance in typical fecal indicators like E. coli and coliforms, specifically against the widely used antibiotic ampicillin, this research aimed to pioneer a novel, readily deployable approach. The TECTA was used to explore viable E. coli concentrations at varying antibiotic concentrations and to analyze different growth kinetics according to the degree of resistance. Compared to conventional tests, the TECTA device showed highly agreeable results, with simplified steps and turnaround times of 18 hours. The TECTA used with ampicillin was able to discriminate the relative resistance of three E. coli strains using the time-to-detection values provided by the device, as well as bacteria concentration and fraction of inhibition. The TECTA device also shows potential for use in real-world samples as determined by mixed culture experiments.
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