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Full-Text Articles in Life Sciences

The Cost Of Mupirocin Resistance In Staphylococcus., Susan D. Reynolds May 2006

The Cost Of Mupirocin Resistance In Staphylococcus., Susan D. Reynolds

Electronic Theses and Dissertations

Control of antibiotic resistance in bacteria is based on the concept that resistance incurs a fitness cost in non-selective conditions. Fitness costs were assessed for low- and high-level mupirocin resistance in locally-derived Staphylococcus aureus and S. epidermidis. Costs of resistance were assessed in pure cultures by comparing growth curve characteristics and in mixed culture as the proportion of resistant cells surviving. Costs were not present in comparisons of growth rates among groups of naturally-occurring isolates from the different resistance categories. However, in S. aureus, growth rates within resistance categories differed by approximately 30 – 90%. Among near-isogenic pairs …


Conjugative Transfer Pathways Of High-Level Mupirocin Resistance And Conjugative Transfer Genes In Staphylococcus., Danielle Barnard May 2006

Conjugative Transfer Pathways Of High-Level Mupirocin Resistance And Conjugative Transfer Genes In Staphylococcus., Danielle Barnard

Electronic Theses and Dissertations

To combat widespread infections caused by Staphylococcus aureus, mupirocin was introduced at the Veterans Affairs Medical Center, Mountain Home, Tennessee. Soon after introduction, high-level mupirocin-resistance emerged. The rapid emergence was hypothesized to be due to conjugative transfer of the mupA resistance gene from S. epidermidis to S. aureus. Results have shown that transfer of high-level mupirocin-resistance from S. aureus donors commonly occurs. However, transfer from naturally-occurring S. epidermidis donors was not attainable. Staphylococcus epidermidis transconjugants, however, were capable of serving as donors. Further examination of non-transmissibility included PCR analysis of conjugative transfer genes (tra genes) in capable …


Comparison Study Of Sediment Microbial Enzyme Activities To Biochemical Oxygen Demand, Nitrate Concentration, Phosphate Concentration In The Sediments Of A Fecally-Contaminated Stream In Northeast Tennessee Relative To Season And Land Use, Brian G. Evanshen, Kurt J. Maier, Phillip R. Scheuerman Jan 2006

Comparison Study Of Sediment Microbial Enzyme Activities To Biochemical Oxygen Demand, Nitrate Concentration, Phosphate Concentration In The Sediments Of A Fecally-Contaminated Stream In Northeast Tennessee Relative To Season And Land Use, Brian G. Evanshen, Kurt J. Maier, Phillip R. Scheuerman

ETSU Faculty Works

Microbial metabolism reacts quickly to environmental conditions. These reactions are dependent on the need for nutrients and respiration and can be measured using an assay of individual microbial enzyme activities (MEA’s). In this study, we measured MEA’s in the sediments of a stream in northeast Tennessee that had an approved fecal coliform Total Maximum Daily Load (TMDL). These values were compared to biochemical oxygen demand (BOD), phosphate concentration and nitrate concentration in the water column of this stream. Comparisons were grouped by season and land use. Stream sediments and water were collected monthly for one year and then quarterly for …


Comparison Of Microbial Water Quality Parameters Of Four Geographically Similar Creeks In Northeast Tennessee, Kimberlee K. Hall, L. K. Gallagher, Brian G. Evanshen, Kurt J. Maier, Phillip R. Scheuerman Jan 2006

Comparison Of Microbial Water Quality Parameters Of Four Geographically Similar Creeks In Northeast Tennessee, Kimberlee K. Hall, L. K. Gallagher, Brian G. Evanshen, Kurt J. Maier, Phillip R. Scheuerman

ETSU Faculty Works

Four creeks within the Watauga River watershed in Northeast Tennessee are routinely monitored for water quality assessments. To identify sources and monitor remediation, Sinking Creek, Cash Hollow Creek, Buffalo Creek and Boones Creek are monitored for chemical and microbial parameters. These parameters include phosphates, nitrates, BOD and fecal coliforms. Sinking Creek is a tributary of the Watauga River with 10 miles of impaired water. Cash Hollow Creek enters the Watauga River at river mile 11.4 with 3.4 miles of impaired water. Boones Creek contains 18.6 impaired miles while the status of water quality in Buffalo Creek is not yet determined. …