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Date of Graduation
Bachelor of Science (BS)
Department of Biology
James B. Herrick
Steven G. Cresawn
Staphylococcus is comprised of 41 known species, of which 18 can colonize humans. Despite the prevalence of infectious Staphylococcus within hospital settings and agriculture, there are few reports of Staphylococcus in natural bodies of water. A recent study by the US Food and Drug Administration found substantial contamination of poultry and other meats with Staphylococcus. We hypothesized that intensive farming of poultry adjacent to streams would result in contaminated runoff, resulting in at least transient occurrence of Staphylococcus spp. in stream waters and sediments. In this study, we sought to determine whether Staphylococcus occurs and persists within Muddy Creek, a stream located in Hinton, Virginia that originates at the Appalachian Mountains of Virginia and runs through various agricultural fields and adjacent to a poultry processing plant in the central Shenandoah Valley. Five different Staphylococcus spp. were detected in water and sediment from Muddy Creek. Mannitol Salt Agar (MSA) was used to isolate eleven Staphylococcus from both water and sediment. These isolates were Gram-positive, catalase-positive, and oxidase-negative cocci that were capable of fermenting mannitol. In addition, a method for screening putative staphylococci species from stream water and sediment was developed. Ten out of the eleven tested isolates were oxacillin resistant (now used to identify phenotypic methicillin-resistance) using a Kirby Bauer disc diffusion test. Furthermore, the isolates were susceptible to trimethoprim/sulfamethoxazole, tetracycline, and gentamicin while two of the isolates were resistant to erythromycin. Additionally, the BOX-PCR repetitive sequence fingerprinting method verified the presence of nine different strains among the isolates. Sequencing of the 16S rRNA gene identified five of the isolates as Staphylococcus equorum. The Biolog identification protocol further identified the remaining isolates as Staphylococcus xylosus, Staphylococcus lentus, Staphylococcus succinus, and Staphylococcus sciuri. Finally, polymerase chain reaction amplification (PCR) confirmed that ten of the eleven isolates harbored the mecA gene known to confer methicillin-resistance. Overall, the occurrence of coagulase-negative staphylococci (MRCoNS) in stream water and sediment represents a potential environmental and human health concern.
Partin, Michael Timothy, "Isolation of Methicillin-Resistant Coagulase-Negative Staphylococcus (MRCoNS) from a fecal-contaminated stream in the Shenandoah Valley of Virginia" (2014). Senior Honors Projects, 2010-current. 459.