Microbiology Commons^™

Microevolution In Staphylococcus Aureus: Does Exposure To Sub-Lethal Levels Of Cinnamon Bark Oil Lead To Changes In Antimicrobial Susceptibility?, Heather Sandra Schuettner

Graduate College Dissertations and Theses

The emergence of antibiotic-resistant and multi-drug resistant bacteria presents a growing global health issue recognized by the World Health Organization and the Centers for Disease Control and Prevention. Infections caused by drug-resistant bacteria are associated with longer hospital stays, higher treatments costs, and increased mortality compared to infections caused by antibiotic-susceptible pathogens. The global increase in antibiotic resistance is driven in part by the misuse and overuse of antibiotics in healthcare and agriculture. Staphylococcus aureus can infect humans and animals, and strains that are resistant to one or more antibiotics are common. Many plant essential oils have antimicrobial properties. Essential …

Microevolution In Staphylococcus Aureus: Does Exposure To Sub-Lethal Levels Of Cinnamon Bark Oil Lead To Changes In Antimicrobial Susceptibility?, Heather Sandra Schuettner

Graduate College Dissertations and Theses

The emergence of antibiotic-resistant and multi-drug resistant bacteria presents a growing global health issue recognized by the World Health Organization and the Centers for Disease Control and Prevention. Infections caused by drug-resistant bacteria are associated with longer hospital stays, higher treatments costs, and increased mortality compared to infections caused by antibiotic-susceptible pathogens. The global increase in antibiotic resistance is driven in part by the misuse and overuse of antibiotics in healthcare and agriculture. Staphylococcus aureus can infect humans and animals, and strains that are resistant to one or more antibiotics are common. Many plant essential oils have antimicrobial properties. Essential …

Biofilm Sanitizer Tolerance Of Vermont Dairy Listeria Monocytogenes, Emily C. Forauer

Graduate College Dissertations and Theses

Listeria monocytogenes is a foodborne pathogen found in biofilms on surfaces and equipment in the food processing environment. Sodium hypochlorite (SH) and quaternary ammonium compounds (QAC) are readily available and commonly used sanitizers. However, due to the structure and additional organic material produced in a biofilm, killing bacteria within the biofilm may be a challenge for one or both of these sanitizers.

The objective of this work was to determine if immature and mature biofilms from L. monocytogenes isolated from Vermont artisan dairy environments were more tolerant to QAC and SH compared to planktonic cultures’ tolerance. To determine sanitizer minimum …

Metarhizium Anisopliae, Metarhizium Brunneum And Beauveria Bassiana Formulations For Biological Control Of Larval Winter Ticks, Dermacentor Albipictus, Cheryl Sullivan

Graduate College Dissertations and Theses

There is a critical need to develop effective, high-quality, fungal-based biopesticides for use against ticks. Dermacentor albipictus Petch (Acari: Ixodidae), the winter tick, is a one-host tick. They commonly infest large ungulates, particularly moose, Alces alces L. (Artiodactyla: Cervidae) on which they cause significant physiological and metabolic stress on densely parasitized individuals. Heavily infested calves can be killed. Entomopathogenic fungi in the genera Metarhizium (Hypocreales: Clavicipitaceae) and Beauveria (Hypocreales: Cordycipitaceae) are promising tick biological control agents. The larval stage of D. albipictus aggregates on the ground in a prolonged, quiescent state during the summer and then quests for hosts in …

Characterization Of Higher Order Chromatin Structures And Chromatin States In Cell Models Of Human Herpesvirus Infection, Michael Mariani

Graduate College Dissertations and Theses

Human herpesviruses are ubiquitous pathogens worldwide with 90% of the global population infected with one or more Human herpesviruses (HHV’s) by adulthood. All herpesviruses have three unique life cycle stages. Upon resolution of a primary acute stage infection, they can establish a latent stage infection within the host cell nucleus. This stage is characterized primarily by transcriptional quiescence of the viral genome. Specific physiological conditions (e.g., cell stress) can cause the latent virus to enter the reactivation stage, often many years after resolution of the acute infection, in which the virus becomes replicationally active again. HHV’s are known to cause …

Sarracenia Purpurea As A Model System For Aquatic Ecosystem State Changes And Their Impact On Bacterial Communities, Amanda Claire Northrop

Graduate College Dissertations and Theses

Aquatic ecosystems can undergo abrupt and long-lasting transitions from one state to another, often with negative ecological and economic consequences. With anthropogenic enrichment, aquatic ecosystems such as lakes and ponds may shift rapidly from an oligotrophic, clear water state to a eutrophic, turbid state. These shifts, or state changes, generally occur due to a phenomenon called hysteresis in which the relationship between a driving variable and ecosystem variable depend on the current state of the ecosystem. Such dynamics often make recovery difficult or impossible. Though state changes in aquatic ecosystems have been studied extensively since the 1970s, there have been …

Network And Ecological Methods To Study Enteric Pathogen Co-Infections, Connor L. Klopfer

Graduate College Dissertations and Theses

Diarrhea remains a leading cause of childhood morbidity and mortality, especially inchildren under 5 years of age. Enteric pathogen co-infection has been found to cause increased diarrheal severity and some pathogens may work in tandem to enhance infection. It is important to identify patterns of pathogen co-infection and their impact on diarrhea to inform intervention strategies for improving child health. In this thesis, I use data from the MAL-ED and PROVIDE birth cohort studies in Bangladesh to generate bipartite networks that represent the relationship between stool samples and pathogens. I randomly rewire the network while preserving connectivity to randomize the …

Analysis Of Host Factors Involved In Regulating Hiv-1-Induced Syncytium Formation, Emily Elizabeth Whitaker

Graduate College Dissertations and Theses

Human Immunodeficiency Virus type 1 (HIV-1) is a retrovirus and the causative agent of Acquired Immunodeficiency Syndrome (AIDS). HIV-1 can spread through multiple modes of transmission including cell-to-cell transmission between CD4+ T cells at a transient junction known as the virological synapse (VS). The VS forms upon HIV-1 Envelope (Env) on the surface of an infected (producer) cell binding CD4 on an uninfected (target) cell. While the VS typically resolves with complete cell separation and transfer of virus particles, Env can occasionally facilitate cell-cell fusion at this site, forming a multinucleated infected cell (syncytium). Excessive syncytium formation is prevented by …