Browsing by Author "Keppers, Adelle"

Now showing 1 - 2 of 2
  • Thumbnail Image
    Item
    Characterization of Antibiotic Resistant Genes in Two Unique City Sewer Systems
    (2020-12) Keppers, Adelle
    Sewer systems are known as point sources for the release of antibiotic resistance into the environment. Antibiotic resistance genes (ARGs) provide bacteria the ability to fight antibiotics and are viewed as emerging contaminants in environmental waterways. To minimize the spread of ARGs to the environment, this study assessed the prevalence of ARGs in upstream sewer systems that feed into wastewater treatment plants (WWTPs) so that source control strategies can be developed to mitigate the spread of antibiotic resistance. Wastewaters were examined from two unique city sewer systems containing three source types: hospital, residential, and industrial. Twenty-nine ARGs, 3 integron-intergrases, and 4 metal resistance genes were quantified using conventional and microfluidic polymerase chain reactions. Bacterial community compositions were characterized using high-throughput 16S rRNA amplicon sequencing. We found the levels of ARGs and bacterial community compositions to be dependent on the source of wastewater, the city, and the season. The abundance of ARGs in hospital wastewater were relatively constant and associated with clinically relevant antibiotics. ARG abundance in residential wastewater showed seasonal variations with high levels in winter associated with outpatient antibiotics. High levels of integron-integrase genes, a proxy for horizontal gene transfer and anthropogenic impacts, were also observed in residential wastewaters. Based on these findings we suggest satellite treatment of ARGs at hospital and residential sources to reduce their loading to WWTPs and their inevitable release to the environment.
  • Thumbnail Image
    Item
    Seasonal influence on detection probabilities for multiple aquatic invasive species using environmental DNA
    (2023-12-14) Rounds, Christopher; Arnold, Todd W; Chun, Chan Lan; Dumke, Josh; Totsch, Anna; Keppers, Adelle; Edbald, Katarina; García, Samantha M; Larson, Eric R; Nelson, Jenna KR; Hansen, Gretchen JA; round060@umn.edu; Rounds, Christopher; University of Minnesota Fisheries Systems Ecology Lab
    Aquatic invasive species (AIS) are a threat to freshwater ecosystems. Documenting AIS prevalence is critical to effective management and early detection. However, conventional monitoring for AIS is time and resource intensive and is rarely applied at the resolution and scale required for effective management. Monitoring using environmental DNA (eDNA) of AIS has the potential to enable surveillance at a fraction of the cost of conventional methods, but key questions remain related to how eDNA detection probability varies among environments, seasons, and multiple species with different life histories. To quantify spatiotemporal variation in the detection probability of AIS using eDNA sampling, we surveyed 20 lakes with known populations of four aquatic invasive species: Common Carp (Cyprinus carpio), Rusty Crayfish (Faxonius rusticus), Spiny Waterflea (Bythotrephes longimanus), and Zebra Mussels (Dreissena polymorpha). We collected water samples at 10 locations per lake, five times throughout the open water season. Quantitative PCR was used with species-specific assays to determine the presence of species DNA in water samples. Using Bayesian occupancy models, we quantified the effects of lake and site characteristics and sampling season on eDNA detection probability. These results provide critical information for decision makers interested in using eDNA as a multispecies monitoring tool and highlight the importance of sampling when species are in DNA releasing life history stages.