Modified approach for investigating Prevalence of Antibiotic Resistance in the Environment (PARE)-a research project...

The Prevalence of Antibiotic Resistance in the Environment (PARE) Project utilizes standard microbiological methods to engage students in monitoring environmental soil samples for the presence of antibiotic-resistant bacteria. This initiative exemplifies a course-based undergraduate research experience (CURE) within the microbiology curriculum, which has been shown to promote student engagement and persistence in science, technology, engineering, and mathematics (STEM) disciplines by providing opportunities for authentic scientific inquiry. However, broader adoption of PARE can be limited by its requirement for microbiology specialization and biosafety level protocols. To address these barriers, we developed EcPARE (Escherichia coli [E. coli]-specific PARE), a culture-free module of PARE that focuses on detecting pathogenic E. coli in water samples using a modified IDEXX Colilert-18 method. Although IDEXX is primarily designed to detect general fecal contamination, our approach demonstrates its utility as a practical tool for screening erythromycin resistance trends in environmental water samples. In this study, undergraduate participants (n = 47) conducted hypothesis-driven research, including sample collection, laboratory analyses, data analysis, and interpretation. Our findings revealed strong positive correlations between general coliforms or E. coli counts obtained using the modified IDEXX method and total counts from Luria-Bertani plate cultures, indicating concordance between modified IDEXX and conventional plate count methods in the absence of antibiotic selection. This result validates the scientific rigor of our PARE module. Student outcomes assessed through pre- and post-course surveys indicated substantial increases in students' confidence in their scientific skills. Notably, underrepresented students reported greater gains in domains related to sense of community and career confidence, suggesting that such CUREs may be especially impactful for supporting the success and retention of diverse student populations.