Honors Students' Abstracts
Analysis of the abundance and distribution of resistance genes in bacteria in the Ballona Wetlands.
Sarah Patno, Daniel Garcia, Samantha Hurndon, Kevin Ramirez
Antibiotic resistance genes (ARG) have been classified as a biological pollutant, which poses both a public health risk and environmental threat. The presence of these genes in coastal wetlands in Southern California has been documented but determining the extent of their influence on human health and ecosystems depends on an assessment of their presence, persistence and dissemination properties as well as the host bacteria which harbor them. As a first step in assessing whether they pose a threat in the Ballona Wetlands, we conducted studies to quantitatively measure their relative abundance. Using replica-plating techniques, six thousand bacteria colonies were screened for multiple-antibiotic insensitivities resulting in approximately 150 strains with 5 or more antibiotic insensitivities being isolated for further molecular probing. Since these strains are more likely to carry ARG, we developed qualitative molecular methods to detect the presence of ARGs within our isolates of interest. A library of different validated tetracycline ARG primer pairs has been constructed to screen DNA from the isolates and a number of strains have been shown to carry different tetracycline resistance genes. We will report on the results of our testing these isolates, the progress in creating libraries for other common antibiotic resistances and the identification of possible human pathogens harboring multi-drug resistance genes.