Microbiology Commons^™

Development Of Small Molecule Antibiotics Against A Conserved Rna Gene Regulatory Element In Gram-Positive Bacteria, Ville Yrjö Petteri Väre

Legacy Theses & Dissertations (2009 - 2024)

Bacterial infections and the rise of antibiotic resistance, especially multidrug resistant strains, have generated a clear need for discovery of novel therapeutics. Most antibiotics in use today are derivatives of previous antibiotics to which resistance mechanisms already exist, and traditionally they have a single target: either a protein or rRNA. Gram-positive bacteria regulate the expression of several essential genes or operons using a mechanism called the T-box. The T-box is a structurally conserved riboswitch-like gene regulator in the 5’-untranslated region (UTR) of numerous essential genes of Gram-positive bacteria. T-boxes are stabilized by cognate, unacylated tRNA ligands, allowing the formation of …

Improving And Modeling Bacteria Recovery In Hollow Disk System, Clifton Anderson

Theses and Dissertations

Identifying antibiotic resistance in blood infections requires separating bacteria from whole blood. A hollow spinning disk rapidly removes suspended red blood cells by leveraging hydrodynamic differences between bacteria and whole blood components in a centrifugal field. Once the red cells are removed, the supernatant plasma which contains bacteria is collected for downstream antibiotic testing. This work improves upon previous work by modifying the disk design to maximize fractional plasma recovery and minimize fractional red cell recovery. V-shaped channels induce plasma flow and increase fractional plasma recovery. Additionally, diluting a blood sample spiked with bacteria prior to spinning it increased the …

Nurse Practitioner Attitudes, Perceptions And Knowledge About Antimicrobial Stewardship, Evelyn C. Fabian

Walden Dissertations and Doctoral Studies

Resistance to antibiotics has increased dramatically in the United States, with serious associated medical, social, and economic consequences. The purpose of this project was to assess nurse practitioners' attitudes, perceptions, and knowledge about antimicrobial stewardship and knowledge in the management of anaerobic infections as well as resistant gram-negative bacteremia. Data were collected using a web-based survey in a hospital facility. The practice question explored whether nurse practitioners' attitudes, perceptions, and knowledge about antimicrobial stewardship significantly increased after an education program on antimicrobial stewardship. The project was framed by Knowles's adult learning theory. A 16-item survey was administered before and after …

A Double Humanized Blt-Mice Model Featuring A Stable Human-Like Gut Microbiome And Human Immune System, Lance Daharsh, Jianshui Zhang, Amanda E. Ramer-Tait, Qingsheng Li

Nebraska Center for Virology: Faculty Publications

Humanized mice (hu-mice) that feature a functional human immune system have fundamentally changed the study of human pathogens and disease. They can be used to model diseases that are otherwise difficult or impossible to study in humans or other animal models. The gut microbiome can have a profound impact on human health and disease. However, the murine gut microbiome is very different than the one found in humans. There is a need for improved pre-clinical hu-mice models that have an engrafted human gut microbiome. Therefore, we created double hu-mice that feature both a human immune system and stable human-like gut …

Gut Symbiont Viability In Honey Bees Exposed To Agrochemical Stressors, Bryant Justin Gabriel

Department of Entomology: Dissertations, Theses, and Student Research

The honey bee gut microbiome is essential for protecting this pollinator against abiotic and biotic stressors, including the prevention of harmful gut parasites and pathogens. Previous studies have not only demonstrated a linkage of bee gut dysbiosis to increased immunodeficiencies and pathogen sensitivities, but also report the maladaptation of the gut microbiome in bees exposed to agricultural and apicultural chemistries. There are few techniques available that allow for a simple and reliable analysis of the relative proportions of live and dead gut microbes in bees exposed to these chemistries. Previous techniques for measuring gut symbiont dysbiosis are temporally limited by …

Characterization Of Metronidazole- And Vancomycin-Resistant Clinical Isolates Of Clostridium Difficile, Chioma Odo

Dissertations and Theses (Open Access)

Characterization of Metronidazole- and Vancomycin-Resistant Clinical Isolates of Clostridium difficile

Chioma Odo, MS.

Supervisory Professor: Charles Darkoh, Ph.D.

ABSTRACT

The incidence of C. difficile infections (CDI) has been increasing at an alarming rate. This was precipitated by the emergence of strains with increased virulence, disease severity, and high recurrence rates. These strains also exhibit high propensity for resistance to antibiotics such as fluoroquinolones and beta lactams, which has made the treatment of CDI very challenging. Currently, metronidazole and vancomycin are the most commonly used drugs for the treatment of primary CDI. Metronidazole is used for the treatment of mild to …

Phaeophleospora Vochysiae Savi & Glienke Sp. Nov. Isolated From Vochysia Divergens Found In The Pantanal, Brazil, Produces Bioactive Secondary Metabolites, Daiani C. Savi, Khaled A. Shaaban, Francielly M. W. Gos, Larissa V. Ponomareva, Jon S. Thorson, Chirlei Glienke, Jürgen Rohr

Pharmaceutical Sciences Faculty Publications

Microorganisms associated with plants are highly diverse and can produce a large number of secondary metabolites, with antimicrobial, anti-parasitic and cytotoxic activities. We are particularly interested in exploring endophytes from medicinal plants found in the Pantanal, a unique and widely unexplored wetland in Brazil. In a bio-prospecting study, strains LGMF1213 and LGMF1215 were isolated as endophytes from Vochysia divergens, and by morphological and molecular phylogenetic analyses were characterized as Phaeophleospora vochysiae sp. nov. The chemical assessment of this species reveals three major compounds with high biological activity, cercoscosporin (1), isocercosporin (2) and the new compound 3-(sec-butyl)-6-ethyl-4,5-dihydroxy-2-methoxy-6-methylcyclohex-2-enone (3). …

Marine Bioactives From Saccharina Latissima, Orlaith O'Connell

Masters

Due to rapid global urbanization and therefore increased adoption of a 'Westernized' lifestyle, including decreased physical activity and increased consumption of highly processed and refined foods with a high sugar, fat and salt content, prevalence of gastrointestinal disorders are on the rise. Inflammatory bowel disease (IBD) in particular is closely associated with this type of lifestyle. IBD is a term used to describe chronic inflammatory conditions which affects all or parts of the gastrointestinal tract. It includes conditions such as Crohn's Disease, which affects all the gastrointestinal tract and Ulcerative Colitis which mainly affects the colan. Due to the role …

Optimizing Transposon Mutagenesis In Vibrio Strains To Identify Genes Involved In Antibiotic Production, Mahnur Khan

Honors Projects

Based on previous studies that have shown the competitive nature of non-pathogenic environmental strains of Vibrio, we hypothesize that environmentally derived bacteria can inhibit Vibrio pathogens, and possibly be a source of novel antibiotics. A previous experiment performed in the lab tested environmental Vibrio strains from various habitats against the pathogenic strains, Vibrio cholerae and Vibrio parahaemolyticus. Of the 3,456 strains collected, members of the Wildschutte lab identified 102 environmental strains of Vibrio that inhibited the growth of both pathogens. The data suggests that environmental Vibrio strains directly inhibit the growth of related pathogens. Our project involves the …

Comparing The Effectiveness Of Alternative And Prescription Antibiotics Against Gram-Positive Bacteria, Rachel Jenkins, Roan Dickenson, Sam Turnbull, Marcela Torres

Senior Theses

The rapid emergence of antibiotic-resistant bacteria is a global public health concern that threatens the efficacy of antibiotic drugs. We found that natural remedies, specifically coconut oil, honey and cinnamon essential oil, have the potential to be used as a clinical alternative to treat antibiotic-resistant infections. In this experiment, we performed a disk diffusion test and measured the area of inhibition of each treatment to compare the effectiveness of natural and prescription antibiotics. Cinnamon essential oil showed significantly greater antibiotic activity compared to a prescription treatment, amoxicillin. With bacterial resistance continuously expanding, more work needs to be done to determine …

Beyond The Obvious: Emerging Contaminants And Biogeochemistry As A Cause And Solution For Nitrogen Pollution, Stephanie L. Devries

Dissertations, Theses, and Capstone Projects

Following a comprehensive review of the occurrence and impacts of antibiotics and related pharmaceutical compounds on the terrestrial N-cycle, three experiments were performed to explore the topic of biogeochemistry as a source or a sink for N-pollution. The first of these experiments addresses the question of whether environmentally relevant concentrations of antibiotics (µg·kg^-1) have a significant effect on denitrification or N₂O production, a question that has not been well addressed in previous studies. Having determined that there is a significant shift, the second study aims to comprehensively follow changes to soil N pools and N_{2 …}

The Potential Stimulation Of C. Minuta Growth By Various Prebiotics, And Its Sensitivity To Various Antibiotics, Maria Elena Hakim

Wayne State University Theses

Gut microbiota play a crucial role in maintaining intestinal health and integrity; a feature that is both heritable, as well as affected by the environment and lifestyle. Probiotics are supplements containing live microorganisms that act in a similar manner to gut microflora, and maintain a balance in the latter. C. minuta is a novel bacterium in the gut that was found to be associated with reduction in body weight and adiposity. The aim of this study was to determine the possible effects of different prebiotics on C. minuta growth, and the survival of C. minuta in response to different antibiotics. …

Current Antibiotics And Future Herbal Extract Methods To Treat Methicillin-Resistant Staphylococcus Aureus (Mrsa): Focusing On Inhibition Of Penicillin-Binding Protein 2a (Pbp2a), Mgayya R. Makullah

Senior Honors Theses

Methicillin-Resistant Staphylococcus aureus (MRSA) has developed resistance towards a number of antibiotics. This resistance creates a challenge when trying to treat MRSA with a number of antibiotics. This is mainly caused by the penicillin-binding proteins 2a (PBP2a). PBP2a have significantly less affinity for beta-lactam antibiotics compared to the other penicillin-binding proteins (PBPs) expressed by non-resistant strains. New treatments involving a combination of antibiotics and herbal extracts are being developed and used to inactivate PBP2a, allowing the previous ineffective antibiotics to be more effective.

Laboratory Exercises In Microbiology: Discovering The Unseen World Through Hands-On Investigation, Joan Petersen, Susan Mclaughlin

Open Educational Resources

The exercises in this laboratory manual are designed to engage students in hand-on activities that reinforce their understanding of the microbial world. Topics covered include: staining and microscopy, metabolic testing, physical and chemical control of microorganisms, and immunology. The target audience is primarily students preparing for a career in the health sciences, however many of the topics would be appropriate for a general microbiology course as well.

Î?- Lactam-Induced Changes In Cell Wall Composition And Autolytic Properties Of Daptomycin Resistant Staphylococcus Aureus, Michael Krzyskowski

Theses and Dissertations

Staphylococcus aureus is a major human pathogen that is well known for its ability to develop resistance to antimicrobial therapies. Recent studies have identified a combination of β-lactam antibiotic and daptomycin (DAP) to be highly effective at killing single and multi-drug-resistant S. aureus. Of particular interest is this drug combinationâ??s efficiency with which it kills strains classified as DAP-resistant methicillin-resistant Staphylococcus aureus (DAP-R MRSA). The goals of the present study were two-fold: to provide a physiological profile of a DAP-R S. aureus strain undergoing beta-lactam treatment by observing changes in autolytic rate, susceptibility to lytic enzymes, levels of peptidoglycan O-acetylation, …

Antibiotic Efficacy And Interaction In Escherichia Coli During Varying Nutrient Conditions, Kristina K. Millar

Scripps Senior Theses

Due to the recent rise in antibiotic resistant pathogens, and the difficulties surrounding the quest for new antibiotics, many researchers have started revisiting antibiotic interactions in hopes of finding new treatment options. The primary outcome of this project was to examine the efficacy of concomitant antibiotic use under varying nutrient conditions, to identify variations in antibiotic interactions. Antibiotic interactions were studied, utilizing E. coli as a model bacterial system, grown in four different media types. E. coli cultures were treated with streptomycin, tobramycin, erythromycin, and amikacin individually and in a pairwise fashion at varying doses. We found that at least …

The Effect Of Antibiotics On Pseudomonas Aeruginosa Biofilm Production, Courtney Paige Turpin

Online Theses and Dissertations

Antibiotic-resistant bacteria have become an increasing burden worldwide. A highly resistant species is Pseudomonas aeruginosa, a nosocomial pathogen that produces a biofilm that enhances its resistance. This project examined the possibility of using bacteriocin, an internal protective toxin produced by some species of bacteria, as a potential treatment for resistant bacteria. In this study, standard broad spectrum antibiotics were used to treat P. aeruginosa to prevent biofilm formation. The biofilm was then analyzed to determine if the biofilm is inhibited or facilitated by each treatment. Optimal concentrations of antibiotics were determined to be effective at a concentration of 0.07mg/mL for …

Ph Dependent Antibiotic Resistance Of An Alkaliphilic, Halotolerant Bacterium Isolated From Soap Lake, Washington, Tiffany Charlynn Edwards

Masters Theses

"Soap Lake, located in Washington State, is a meromictic, soda lake. Many bacterial isolates retrieved from Soap Lake have been noted to possess resistance to multiple antibiotics. A likely explanation for the wide range of antibacterial resistance exhibited by these strains is due to the impact of high alkalinity on the antibiotics themselves and not due to the presence of antibiotic resistance genes. The aim of our study was to determine if select antibiotics are effective against Halomonas eurialkalitoleranis, a bacterium capable of growth over a wide range of neutral to alkaline pH values, to investigate the influence of alkalinity …

Fermented Food: Putting The Power Of Good Health Back Into The Hands Of The People, Marsha L. Thadison

Professional Agricultural Workers Journal

Editors’ Note: At the December 2013 Professional Agricultural Workers Conference, several women were invited to share, information about their unique businesses. One such presenter was Marsha L. Thadison, owner of Yesterday’s Kitchen 4 Today, a company that focuses on promoting functional foods. Thadison shared that food is produce and consumed differently from previous generations. Today's food, she argued, involves many more agricultural inputs that aid in food preservation, extension of shelf life, and promotion of animal health. She espoused the benefits of fermented food.

Determining The Presence Of Carbapenem Antibiotic Resistance In Clinical Isolates, Fidelis Uzoma Enyinnaya

UNLV Theses, Dissertations, Professional Papers, and Capstones

Carbapenems are β-lactam antibiotics reserved for the treatment of severe microbial infections, especially those targeting the Enterobacteriaceae. Introduced in the 1980s, carbapenems have been used successfully in hospitals, and in the 1990s resistance was discovered. Carbapenem resistance is conferred through the production of carbapenemases. In the U.S., the most common carbapenemase is Klebsiella pneumoniae carbapenemase (KPC). In 2012, the National Healthcare Safety Network reported a carbapenem resistance rate of 13.0% among Klebsiella pneumoniae infections, and indicated that the mortality rate associated with carbapenem resistant Enterobacteriaceae (CRE) infections ranged from 48.0-71.9%. According to the Food and Drug Administration (FDA), carbapenem resistance …

Remediation Of Tetracycline From Water Sources Using Vetiver Grass (Chrysopogon Zizanioides L. Nash) And Tetracycline-Tolerant Root-Associated Bacteria, Aparupa Sengupta

Dissertations, Master's Theses and Master's Reports - Open

Antibiotics are emerging contaminants worldwide. Due to insufficient policy regulations, public awareness, and the constant exposure of the environment to antibiotic sources has created a major environmental concern. Wastewater treatment plants (WWTP) are not equipped to filter-out these compounds before the discharge of the disinfected effluent into water sources (e.g., lakes and streams) and current available technologies are not equipped to remediate these compounds from environmental sources. Hence, the challenge remains to establish a biological system to remove these antibiotics from wastewater. An invitro hydroponic remediation system was developed using vetiver grass (Chrysopogon zizanioides L. Nash) to remediate tetracycline …

Lysine Biosynthesis In Bacteria: A Metallodesuccinylase As A Potential Antimicrobial Target, Danuta M. Gillner, Daniel P. Becker Ph.D., Richard C. Holz

Chemistry: Faculty Publications and Other Works

In this review, we summarize the recent literature on dapE-encoded N-succinyl-l,l-diaminopimelic acid desuccinylase (DapE) enzymes, with an emphasis on structure–function studies that provide insight into the catalytic mechanism. Crystallographic data have also provided insight into residues that might be involved in substrate and hence inhibitor recognition and binding. These data have led to the design and synthesis of several new DapE inhibitors, which are described along with what is known about how inhibitors interact with the active site of DapE enzymes, including the efficacy of a moderately strong DapE inhibitor.

Phenotypic And Genotypic Characterization Of Escherichia Coli Isolated From Untreated Surface Waters, Kai Hung, Steven Daniel, Kristopher Janezic, Blake Ferry, Eric Hendricks, Brian Janiga, Tiffany Johnson, Samantha Murphy, Morgan Roberts, Sarah Scott, Alexandra Theisen

Faculty Research & Creative Activity

A common member of the intestinal microbiota in humans and animals is Escherichia coli. Based on the presence of virulence factors, E. coli can be potentially pathogenic. The focus of this study was to isolate E. coli from untreated surface waters (37 sites) in Illinois and Missouri and determine phenotypic and genotypic diversity among isolates. Water samples positive for fecal coliforms based on the Colisure® test were streaked directly onto Eosin Methylene Blue (EMB) agar (37°C) or transferred to EC broth (44.5°C). EC broth cultures producing gas were then streaked onto EMB agar. Forty-five isolates were identified as E. coli …

Phenotypic And Genotypic Characterization Of Escherichia Coli Isolated From Untreated Surface Waters, Kai F. Hung, Steven L. Daniel, Kristopher J. Janezic, Blake Ferry, Eric W. Hendricks, Brian A. Janiga, Tiffany Johnson, Samantha Murphy, Morgan E. Roberts, Sarah M. Scott, Alexandra N. Theisen

Faculty Research & Creative Activity

A common member of the intestinal microbiota in humans and animals is Escherichia coli. Based on the presence of virulence factors, E. coli can be potentially pathogenic. The focus of this study was to isolate E. coli from untreated surface waters (37 sites) in Illinois and Missouri and determine phenotypic and genotypic diversity among isolates. Water samples positive for fecal coliforms based on the Colisure® test were streaked directly onto Eosin Methylene Blue (EMB) agar (37°C) or transferred to EC broth (44.5°C). EC broth cultures producing gas were then streaked onto EMB agar. Forty-five isolates were identified as E. coli …

Anti-Germinants As A New Strategy To Prevent Clostridium Difficile Infections, Amber Janece Howerton

UNLV Theses, Dissertations, Professional Papers, and Capstones

Clostridium difficileinfections (CDI) have emerged as a leading cause of hospital-associated complications. CDI is the major cause of antibiotic-related cases of diarrhea and nearly all cases of pseudomembranous colitis. The infective form of C. difficileis the spore, a dormant and hardy structure that forms under stress. Germination of C. difficile spores into toxin producing bacteria in the GI tract of susceptible patients is the first step in CDI establishment. Patient susceptibility occurs with a disruption of the natural gut microbiota by broad-spectrum antibiotics. Antibiotic treatments usually resolve CDI but refractory cases are on the rise. Of great concern is the …

Multiple Antibiotic Resistant Staphylococcus Spp. In Environmental Settings, Stephen Shost

Legacy Theses & Dissertations (2009 - 2024)

Ninety staphylococci carrying the mecA gene, including 17 strains of methicillin-resistant Staphylococcus aureus (MRSA), were isolated from environmental settings within New York State. Waterborne staphylococci harboring mecA were isolated from multiple sources: the Hudson River near a combined sewage overflow; urban streams; freshwater and marine beaches; a swimming pool; swimming pool decks; combined sewage; as well as wastewater treatment plant (WWTP) primary sewage influent, mixed liquor, aeration water, and final (unchlorinated) effluent. Environmental MRSA strains were isolated from beach water (n=3); swimming pool deck water (n=1); Hudson River water (n=2); combined sewage (n=3); as well as wastewater treatment plant mixed …

Discovery Of New Antimicrobial Agents Using Combinatorial Chemistry, William I. Northern

Browse all Theses and Dissertations

Combinatorial chemistry has become an important aspect of medicinal research due to its flexibility and the ability to produce large numbers of potential therapeutic agents. Once compounds are made, they must be screened to determine if there is any biological activity. This research project focused on developing a screening method for chemical agents produced by a graduate student in the chemistry department at Wright State University. After an acceptable screening method was found, the goal of the project was to determine if compounds produced had either antibacterial activity, antifungal activity, or both. Seven compounds exhibited biological activity. Two of these …

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. …

Vancomycin-Intermediate Staphylococcus Aureus In A Home Health-Care Patient, Jeffrey C. Hageman, David A. Pegues, Carrie Jepson, Rose Lee Bell, Mary Guinan, Kevin W. Ward, Martin D. Cohen, Janet A. Hindler, Fred C. Tenover, Sigrid K. Mcallister, Molly E. Kellum, Scott K. Fridkin

School of Public Health Faculty Research

To date, four of the eight cases of infection by Staphylococcus aureus with reduced susceptibility to vancomycin (vancomycin-intermediate S. aureus [VISA] or glycopeptideintermediate S. aureus [GISA]) have been reported in the United States (1-3). We report a fifth case of VISA infection in the United States, and the first to occur during home health-care therapy. While all previous VISA strains have been oxacillin resistant, one of the two VISA strains identified in this investigation was oxacillin susceptible.