Publications by authors named "Shawn D Siefring"
Antimicrobial resistance (AR) is a serious global problem due to the overuse of antimicrobials in human, animal, and agriculture sectors. There is intense research to control the dissemination of AR, but little is known regarding the environmental drivers influencing its spread. Although AR genes (ARGs) are detected in many different environments, the risk associated with the spread of these genes to microbial pathogens is unknown.
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- The U.S. EPA established calibrator cell equivalent (CCE) densities for enterococci in recreational waters using a qPCR method, which influences water quality criteria for public health.
- Recent research indicates that CCE estimates can vary due to differences in the gene copy recovery during DNA extraction from cultured Enterococcus samples.
- To ensure consistent results, this study estimated target sequence recoveries and developed a modified calibration model for better alignment of enterococci quantities in water samples from eight U.S. rivers with EPA's recommended values.
Gulls are often cited as important contributors of fecal contamination to surface waters, and some recreational beaches have used gull control measures to improve microbial water quality. In this study, gulls were chased from a Lake Michigan beach using specially trained dogs, and water quality improvements were quantified. Fecal indicator bacteria and potentially pathogenic bacteria were measured before and during gull control using culture methods and quantitative polymerase chain reaction (qPCR).
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