Theses and Dissertations from UMD

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New submissions to the thesis/dissertation collections are added automatically as they are received from the Graduate School. Currently, the Graduate School deposits all theses and dissertations from a given semester after the official graduation date. This means that there may be up to a 4 month delay in the appearance of a give thesis/dissertation in DRUM

More information is available at Theses and Dissertations at University of Maryland Libraries.

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    Assessing the Presence of Antibiotic-Resistant Enterococcus in Reclaimed Water Used for Spray Irrigation
    (2013) Carey, Stephanie Ann; Sapkota, Amy R; Turner, Paul; Maryland Institute for Applied Environmental Health; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)
    Reclaiming wastewater is increasing in the US to combat dwindling freshwater supplies. This water potentially contains pathogenic bacteria; therefore, we evaluated the occurrence, concentration, and antimicrobial susceptibilities of Enterococcus spp.--an important opportunistic pathogen that remains a leading cause of nosocomial infections--in reclaimed water used for spray irrigation (SI). A total of 48 wastewater effluent and SI samples were collected in 2009 and 2010 from the Mid-Atlantic and Midwest regions of the US. Enterococci were isolated using membrane filtration, confirmed using biochemical tests and PCR, and tested for antimicrobial susceptibility using the Sensititre® dilution system. We detected total enterococci and vancomycin-resistant enterococci (VRE) in 68% (27/40) and 8% (3/40), respectively, of all SI samples. VRE and vancomycin-intermediate enterococci (VIE) represented 2% (1/41) and 10% (4/41), respectively, of the total enterococci recovered from all SI sites. Our findings show that SI workers may be exposed to enterococci during spray irrigation activities.
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    ISOLATION, IDENTIFICATION, AND ANTIMICROBIAL SUSCEPTIBILITY ANALYSIS OF ENTEROCOCCCUS SPP. AND SALMONELLA SPP. FROM CONVENTIONAL POULTRY FARMS TRANSITIONING TO ORGANIC FARMING PRACTICES
    (2009) Kinney, Erinna Lea; Sapkota, Amy R.; Public and Community Health; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)
    This baseline study evaluated prevalence and antibiotic resistance of food-borne bacteria as conventional poultry facilities transition to organic practices. Poultry litter, feed, soil, water samples and poultry questionnaire responses were collected from 10 conventional and 10 organic-transitioning poultry houses from March to June 2008. Enterococcus spp. (n=260) and Salmonella spp. (n=100) isolates were identified to species level and antimicrobial susceptibility testing was performed using the Sensititre® system. Statistical analyses were performed using STATA 10. Prevalence of Enterococcus spp. on organic-transitioning and conventional poultry farms was 100%; and prevalence of Salmonella spp. was 100% and 40%, respectively. Enterococcus isolates from conventional poultry houses displayed significantly higher percentages of resistance for 9 antibiotic agents compared to organic-transitioning isolates. Conversely, Salmonella spp. isolated from both conventional and organic-transitioning poultry houses exhibited similar antibiotic resistance patterns. Baseline findings suggest importance of poultry production practice in prevalence and antibiotic resistance patterns of food-borne bacteria.