Bacteriology Commons^™

Vulnerability Of Pathogenic Biofilms To Micavibrio Aeruginosavorus, Daniel Kadouri, Nel C. Venzon, George A. O'Toole

Dartmouth Scholarship

The host specificity of the gram-negative exoparasitic predatory bacterium Micavibrio aeruginosavorus was examined. M. aeruginosavorus preyed on Pseudomonas aeruginosa, as previously reported, as well as Burkholderia cepacia, Klebsiella pneumoniae, and numerous clinical isolates of these species. In a static assay, a reduction in biofilm biomass was observed as early as 3 hours after exposure to M. aeruginosavorus, and an ∼100-fold reduction in biofilm cell viability was detected following a a 24-h exposure to the predator. We observed that an initial titer of Micavibrio as low as 10 PFU/well or a time of exposure to the predator as short as 30 …

Salicylic Acid Activates Sigma Factor B By Rsbu-Dependent And -Independent Mechanisms, Marco Palma, Arnold Bayer, Leon I. Kupferwasser, Tammy Joska, Michael R. Yeaman, Ambrose Cheung

Dartmouth Scholarship

Salicylic acid (SAL) may impact Staphylococcus aureus virulence by activating the sigB operon (rsbU-V-W-sigB), thus leading to reductions in alpha-toxin production and decreased fibronectin binding (L. I. Kupferwasser et al., J. Clin. Investig. 112:222-233, 2003). As these prior studies were performed in strain RN6390 (an rsbU mutant) and its rsbU-repaired variant, SH1000, the current investigation was designed to determine if the SAL effect occurs via rsbU- and/or rsbV-dependent pathways in an rsbU-intact S. aureus strain (FDA486). We thus quantified the transcription from two sigB-dependent promoters (asp23 and sarA P3) in FDA486 in response to SAL exposure in vitro, using isogenic …

Bacillus Anthracis Virulent Plasmid Px02 Genes Found In Large Plasmids Of Two Other Bacillus Species, Vicki A. Luna, Debra S. King, K. Kealy Peak, Frank Reeves, Lea Heberlein-Larson, William Veguilla, L. Heller, Kathleen E. Duncan, Andrew C. Cannons, Philip Amuso, Jacqueline Cattani

Bioelectrics Publications

In order to cause the disease anthrax, Bacillus anthracis requires two plasmids, pX01 and pX02, which carry toxin and capsule genes, respectively, that are used as genetic targets in the laboratory detection of the bacterium. Clinical, forensic, and environmental samples that test positive by PCR protocols established by the Centers for Disease Control and Prevention for B. anthracis are considered to be potentially B. anthracis until confirmed by culture and a secondary battery of tests. We report the presence of 10 genes (acpA, capA, capB, capC, capR, capD, IS1627, ORF 48, ORF 61, and repA) and the sequence for the …

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 …

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 …

Keeping Their Options Open: Acute Versus Persistent Infections, S. Furukawa, S. L. Kuchma, G. A. O'Toole

Dartmouth Scholarship

No abstract provided.

Transport Of E. Coli In Egyptian Agricultural Soils As A Result Of Reclaimed Wastewater Use For Irrigation, Aimen Badawy

Archived Theses and Dissertations

Limited water resources are one of the main constraints to socio-economic development and even a source of insecurity at national and regional levels. The increasing demand for water in the agricultural sector stimulated the use of reclaimed wastewater for irrigation. Comprehending health and environment risks resulting from contaminants that may often be associated with reclaimed wastewater will lead to the sustainable use of this resource, as well as the conservation of other water resources.

In the present study the fate and transport of one important wastewater constituent, namely E. Coli bacteria, in three Egyptian soils of typical agricultural use was …

Prevalence And Serovars Of Salmonella In The Feces Of Free-Ranging White-Tailed Deer (Odocoileus Virginianus) In Nebraska, David G. Renter, David P. Gnad, Jan M. Sargeant, Scott E. Hygnstrom

School of Natural Resources: Faculty Publications

To determine the prevalence and serovars of Salmonella in free-ranging deer, we cultured feces from white-tailed deer (Odocoileus virginianus) harvested by hunters during a regular firearm season in southeastern Nebraska (USA). We recovered Salmonella from 5 (1%; 95% confidence interval: 0.37– 2.20%) of 500 samples and identified four different Salmonella enterica serovars [Litchfield (1), Dessau (1), Infantis (2), and Enteritidis (1)]. Although the prevalence of Salmonella in free-ranging deer appears to be low, the serovars recovered are known to be pathogenic to humans and animals.

Antibiotic Resistant And Coliform Bacteria In The Ohio River; 2002 To 2004, Lisa Marie Smith

Theses, Dissertations and Capstones

During 2002 and 2003 samples, collected every five miles along the Ohio River, were analyzed for total cultivable bacteria, ciprofloxacin resistant bacteria, erythromycin resistant bacteria, tetracycline resistant bacteria, and fecal coliforms. During 2004 samples were analyzed for total cultivable bacteria, ciprofloxacin resistant bacteria, sulfamethizole resistant bacteria, tetracycline resistant bacteria, Virginiamycin resistant bacteria, total coliforms, and Escherichia coli. The objectives of this study were to systematically collect data on fecal coliforms, E. coli, and antibiotic resistant bacteria in the Ohio River and its major tributaries; to determine if antibiotic resistance populations are correlated to each other or to coliforms; and …

Concomitant Antibiotic And Mercury Resistance Among Gastrointestinal Microflora Of Feral Brook Trout, Salvelinus Fontinalis, Matt Meredith

Undergraduate Research Symposium (UGRS)

No abstract provided.

The Isolation And Characterization Of Multiply Antibiotic Resistant Strains Of Fish Pathogenic Flavobacterium Species, Sarah E. Clark, Jaehee Yun, Justin Guay

Undergraduate Research Symposium (UGRS)

Since the development of the first antibiotics in the 1940’s, there has been widespread overuse in both clinical and agricultural applications. Antibiotic resistance has become a significant problem as a result of subsequent dissemination of antibiotics into the environment, and multiply-resistant strains of bacteria are now a major pathogenic threat. In this study eight separate strains of Flavobacterium responsible for recent disease outbreaks in fish hatcheries throughout Maine were collected and analyzed. All eight strains were found to be resistant to high levels of a number of different antibiotics, including those used for aquaculture as well as human chemotherapeutic applications. …

A Broad-Spectrum Mer Operon In A Multi-Drug Resistant Strain Of The Fish Pathogen, Aeromonas Salmonicida., Erin Parry

Undergraduate Research Symposium (UGRS)

Aeromonas salmonicida AS03, a potential fish pathogen, was isolated from Atlantic salmon, Salmo salar, in 2003. This strain was found to be resistant to ≥1000 mM HgCl2 and ≥32 mM phenylmercuric acetate as well as multiple antimicrobials. Mercury (Hg) and antibiotic resistance genes are often located on the same mobile genetic elements, so the genetic determinants of both resistances and the possibility of horizontal gene transfer were examined. Specific PCR primers were used to amplify and sequence distinctive regions of the mer operon. A. salmonicida AS03 was found to have a pDU1358-like broad-spectrum mer operon, containing merB as well as …

Transposon Disruption Of The Complex I Nadh Oxidoreductase Gene (Snod) In Staphylococcus Aureus Is Associated With Reduced Susceptibility To The Microbicidal Activity Of Thrombin-Induced Platelet Microbicidal Protein 1, Arnold S. Bayer, Peter Mcnamara, Michael R. Yeaman, Natalie Lucindo, Tiffanny Jones, Ambrose L. Cheung

Dartmouth Scholarship

The cationic molecule thrombin-induced platelet microbicidal protein 1 (tPMP-1) exerts potent activity against Staphylococcus aureus. We previously reported that a Tn551 S. aureus transposon mutant, ISP479R, and two bacteriophage back-transductants, TxA and TxB, exhibit reduced in vitro susceptibility to tPMP-1 (tPMP-1(r)) compared to the parental strain, ISP479C (V. Dhawan, M. R. Yeaman, A. L. Cheung, E. Kim, P. M. Sullam, and A. S. Bayer, Infect. Immun. 65:3293-3299, 1997). In the current study, the genetic basis for tPMP-1(r) in these mutants was identified. GenBank homology searches using sequence corresponding to chromosomal DNA flanking Tn551 mutant strains showed that the fourth gene …

Densities Of Fecal Indicator Bacteria In Tidal Waters Of The Ballona Wetlands, Los Angeles County, California, John H. Dorsey

Center for Urban Resilience Scholarship

Densities of fecal indicator bacteria (FIB) represented by total coliforms, E. coli and enterococci were measured within tidal channels of the Ballona Wetlands (Los Angeles County) to see if the wetlands act as a sink or source for these bacteria and to measure increases in FIB densities during wet weather. Samples were collected on 10 days over a 1-yr period beginning February 2003 at four sites within the wetlands and one site in Ballona Creek opposite the west tide gate. Incoming flood and outgoing ebb tides were sampled during each sampling event at each station. Water from Ballona Creek may …