Microbiology Commons^™

Evolution And Clinical Relevance Of Vaginal Bifidobacterium Breve In The Vaginal Environment, Nicole R. Jimenez

Theses and Dissertations

The vaginal microbiome is important in reproductive health and disease and is often dominated by lactobacilli. However, there are many other community state types dominated by single species that are still not well characterized. Bifidobacterium species such as Bifidobacterium breve and Bifidobacterium longum have been observed to dominate vaginal profiles. Bifidobacteria are important in infant gut development, but little is known about their role in vaginal health. Thus, we sought to use a multisystem approach to better characterize Bifidobacterium species present in the vaginal microbiome with an emphasis on B. breve. Eight strains of B. breve were isolated from vaginal …

Targeting Transferrin Binding Protein A For Vaccine Development In Neisseria Gonorrhoeae, Ashley Greenawalt

Theses and Dissertations

Neisseria gonorrhoeae, the causative agent of the sexually-transmitted infection gonorrhea, has recently been labeled a superbug. With dwindling treatment options, there is urgent need for a gonococcal vaccine. TonB-dependent transporters (TDTs) are important gonococcal virulence factors that allow the gonococcus to pirate metals directly from host proteins. The TDTs, TbpA and TbpB, are promising vaccine targets because both proteins are expressed and highly conserved in gonococcal strains, and they are not subject to high-frequency antigenic variation. Because the Tbps bind to host protein as their natural function, our immune system does not recognize them as foreign antigens; thus, immunogenicity is …

Il-36g Cytokine Induction In Oral Epithelial Cells Triggered By Treponema Denticola And Their Role In Chronic Periodontitis, Christopher Blake

Theses and Dissertations

Periodontal disease is a polymicrobial disease affecting 10-15% of the population. Periodontal disease affects the quality of life by reducing mastication and potentially causing tooth loss. Periodontal disease is also linked to more severe, systemic diseases such as cardiovascular disease and rheumatoid arthritis. Development of the diseased state occurs when the plaque biofilm shifts from healthy to dysbiotic. The shift to a dysbiotic biome brings with it a shift in bacterial presence, specifically an increase in gram-negative bacteria, such as T. denticola. T. denticola is a gram-negative, anaerobic spirochete whose relationship with oral epithelial cells is poorly understood. Preliminary data …

Mass Spectrometry Based Lipidomic Investigation Of Staphylococcus Aureus Lipid Metabolism And Characterization Of Lipase A, Naren Gajenthra Kumar

Theses and Dissertations

Staphylococcus aureus produces an arsenal of virulence factors and is adept at colonizing multiple hosts by employing specific processes to persist at different sites of infection. Infections caused by this pathogen range from self-limiting infections of the skin like folliculitis to life threatening and chronic conditions like infective endocarditis, non-healing diabetic foot ulcers and atopic dermatitis. As the field continues to expand its understanding of the mechanisms by which this pathogen rapidly develops resistance to new antibiotics, the underlying mechanisms that facilitates niche adaptation and host colonization among healthy individuals remain elusive.

Bacterial and host lipid metabolism presents and area …

The Role Of Manganese In Streptococcus Sanguinis, Tanya M. Puccio

Theses and Dissertations

Streptococcus sanguinis is primarily associated with oral health as a commensal bacterium. As an opportunistic pathogen, S. sanguinis is capable of colonizing heart valve vegetations, leading to the disease infective endocarditis. Previous studies from our lab have identified the high-affinity manganese transporter SsaACB as important for endocarditis virulence. The impact that manganese depletion has on S. sanguinis had never been evaluated and a secondary manganese transporter has not been identified. Thus, we employed the use of a fermentor to control large-scale growth over time and depleted manganese in an ΔssaACB mutant using a metal chelator, EDTA. The changes in …

Dna Analysis And The Postmortem Submersion Interval From The Microbiome Of Waterlogged Sus Scrofa Skeletal Remains, Claire Cartozzo

Theses and Dissertations

Following water-related deaths, soft tissue on victims’ remains may be entirely absent after a temperature dependent period of time. Due to their physical and chemical components, which protect them from environmental deterioration and biological attack, bones preserve DNA for longer periods of time. Therefore, the ability to both identify an individual and estimate the postmortem submersion interval (PMSI) may depend on DNA obtained from skeletal remains. The goals of the dissertation were to examine differences in both the degradation of skeletal DNA and the microbiome inhabiting bone in freshwater aquatic environments (e.g., Henley Lake and the James River). At each …

The Pseudomonas Aeruginosa Interactome: Insights Into Srna-Mediated Regulatory Networks, Christine M. Van Duyn

Theses and Dissertations

Pseudomonas aeruginosa is a Gram-negative bacterium found in various environmental niches including soil, water, hospital environments, and within a broad range of hosts. It is well known for its metabolic versatility and intrinsic and acquired resistance to a variety of antimicrobial agents. Moreover, this bacterium has a remarkable ability to adapt and survive in suboptimal environments by altering its transcriptional profile in response to nutrient deprivation, changes in temperature and pH, osmotic stress, the presence of reactive oxygen species (ROS), and exposure to antibiotics and host defenses. P. aeruginosa colonizes individuals with compromised immune systems and severe burn injuries and …

Development Of A Screening Assay For Type Iii Secretion System Inhibitors And High Throughput Screening Campaign Of Inhibitors Of Prp Of Staphylococcus Aureus, Heather A. Pendergrass

Theses and Dissertations

Antibiotics inhibit the growth or survival of bacteria by targeting their essential functions.¹ Due to weaknesses in traditional antibiotics and the increasing prevalence of antibiotic resistance genes, virulence factors are being targeted for therapeutic treatment of bacterial infection.² We have developed an assay to quantify and observe type III secretion system (T3SS) activity. The type III secretion system (T3SS) is a virulence factor present in some Gram-negative pathogens including enteropathogenic and enterohemorrhagic E. coli (EPEC and EHEC, respectively),³ and others.^4–9 The T3SS between EPEC and EHEC are highly conserved and share over 90% sequence identity with …

Characterization Of Plasmids Harbored By Vibrio Cholerae Isolates Endemic To The Rio Grande Delta, Viviana Trevino

Theses and Dissertations

Cholera is a diarrheal disease responsible for considerable morbidity and mortality globally. Epidemics along the Rio Grande Delta were reported during the 1850s, and the etiological agent Vibrio cholerae, remains endemic, thus presenting a unique opportunity for a study of historical and biological relevance. V. cholerae strains were isolated from two locations: the Rio Grande River under a bridge linking Brownsville to Matamoros (site 21) and where the river empties into the Gulf of Mexico (site 42). Two strains from site 21, and one from site 42 were selected to isolate, subclone, sequence, assemble and annotate extra-chromosomal elements. Results …

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 …

Bioaerosols Associated With Evaporative Cooler Use In Low-Income Homes In Semi-Arid Climates, Ashlin Elaine Cowger

Theses and Dissertations

Asthma is the leading chronic illness in children in the United States. Since children in the U.S. spend a majority of their time indoors there is an increased need to understand key sources of daily asthma triggers in the home. Bacterial endotoxin, dust mite allergens and β-D-glucan have been shown to be potent inducers of asthma attacks, and high levels of these allergens in homes can trigger attacks in those with asthma. We aim to better understand the risks to those with asthma that might be associated with evaporative cooler (EC) use in low-income homes. ECs are often promoted because …

Heterotrophic Protists As Useful Models For Studying Microbial Food Webs In A Model Soil Ecosystem And The Universality Of Complex Unicellular Life, Andrew Robert Thompson

Theses and Dissertations

Heterotrophic protists, consisting largely of the Cercozoa, Amoebozoa, Ciliophora, Discoba and some Stramenopiles, are a poorly characterized component of life on Earth. They play an important ecological role in soil communities and provide key insights into the nature of one of life’s most enigmatic evolutionary transitions: the development of the complex unicell. Soil ecosystems are crucial to the functioning of global biogeochemical cycles (e.g. carbon and nitrogen) but are at risk of drastic change from anthropogenic climate change. Heterotrophic protists are the primary regulators of bacterial diversity in soils and as such play integral roles in biogeochemical cycling, nutrient mobilization, …

Bottom-Up Controls (Micronutrients And N And P Species) Better Predict Cyanobacterial Abundances In Harmful Algal Blooms Than Top-Down Controls (Grazers), Scott Andrew Collins

Theses and Dissertations

The initiation, bloom, and bust of harmful Cyanobacteria and algae blooms (HAB) in lakes are controlled by top-down and bottom-up ecological controls. Excess phosphorous and nitrogen inputs from anthropogenic sources are primary to blame, but eukaryotic grazers may also promote or curb Cyanobacteria dominance. We tracked shifts in bacterial composition, lake chemistry, and eukaryotic grazing community weekly or bi-weekly through spring and summer and modeled the causes of specific Cyanobacterial species blooms and busts across three lakes in Utah, USA, with differing lake trophic states. Regardless of trophic status, all three lakes experienced blooms of varying composition and duration. Aphanizomenon …

Isolation, Genetic Characterization And Clinical Application Of Bacteriophages Of Pathogenic Bacterial Species, Trever Leon Thurgood

Theses and Dissertations

Bacteriophages (phages) are the smallest biological entity on the planet. They provide vast amounts of valuable knowledge to biologists. Phage genomes are relatively simple compared to the organisms they infect (prokaryotes) and yet continually point to the complexity surrounding molecular- and microbiological mechanisms of life. By studying phages we can learn of the systems of gene expression, protein interaction and DNA organization. Phages are useful not only from an academic perspective, but may also have useful clinical applications. In the face of the rise of antibiotic-resistant bacterial “super pathogens”, scientists and researchers turn to phages as alternative treatments to these …

Isolation, Characterization, And Genomic Comparison Of Bacteriophages Of Enterobacteriales Order, Ruchira Sharma

Theses and Dissertations

According to CDC, every year at least 2 million people are affected and 23,000 dies as a result of antibiotic resistance in U.S. It is considered one of the biggest threats to global health. More and more bacterial infections are becoming harder to treat. One such infection is fire blight, one of the most destructive disease of apple and pear trees. It is caused by bacteria Erwinia amylovora and its outbreaks have been known to destroy entire orchards in a single season. The conventional method of treatments includes use of antibiotics like streptomycin and oxytetracycline but the incidences like presence …

Geological And Geochemical Controls On Non-Tuberculous Mycobacterium Transmission: Examples From Hawaii, Schuyler Thomas Robinson

Theses and Dissertations

The opportunistic environmental microbes, non-tuberculous Mycobacterium (NTM), pose an increasing risk of disease and death in both immunodeficient and immunocompetent individuals in the USA and across the world. NTM lung disease is particularly prevalent in Hawaii, although the modes of NTM acquisition and transport in Hawaii are not fully understood. This study evaluated 149 soil and 50 water samples across the Hawaiian Islands to determine geochemical factors controlling NTM. Non-metric multidimensional scaling (NMDS) and principal component analyses (PCA) of modern soils show variables such as Total Organic Carbon (TOC), pH, P, mafic silicate minerals, and Pb seem to control NTM …

Evaluating Fungal Pathogen Inoculum Loads In Field Seed Banks, Taryn Lori Williamson

Theses and Dissertations

Quantification of soilborne pathogen inoculum loads is important in both agricultural and wildland settings. Quantitative Polymerase Chain Reaction (qPCR) methods using SYBR Green chemistry have been shown to be useful for quantifying fungal inoculum loads in environmental samples. The purpose of this study was to develop a method to quantify fungal pathogen inoculum loads in soil seed banks using a qPCR method with SYBR Green chemistry. The invasive annual grass Bromus tectorum was chosen for this seed bank study. There were three objectives: 1) to design target-specific primers for three fungal pathogens known to be important in Bromus tectorum seed …

Pas Kinase And Tor, Controllers Of Cell Growth And Proliferation, Brooke Jasmyn Cozzens

Theses and Dissertations

Nutrient sensing kinases lie at the heart of cellular health and homeostasis, allowing cells to quickly adapt to changing environments. Target of Rapamycin (TOR) and PAS kinase (PASK, or PASKIN) are two such nutrient kinases, conserved from yeast to man. In yeast, these kinases each have paralogs. The two TOR paralogs in yeast mimic the mammalian TORC1 and TORC2 complexes, except both Tor1 and Tor2 may contribute to TORC1 or TORC2 function. The two PAS kinase paralogs are paired with the TOR paralogs, meaning that both Psk1 and Psk2 regulate TORC1, while Psk2 suppresses a temperature-sensitive allele of Tor2. Herein …

The Anaplasma Phagocytophilum Adhesin Asp14 Directs Pdi-Mediated Disulfide Reduction To Promote Infection, Ryan S. Green

Theses and Dissertations

Obligate intracellular pathogens must invade host cells to survive and pose a global health risk. As such, internalization is a critical life stage and represents an excellent therapeutic target. Oxidoreductase exploitation is a thematic invasion strategy among obligate intracellular pathogens. Delineating the mechanisms and proteins mediating this exploitation could identify novel therapeutic targets for many important pathogens. Anaplasma phagocytophilum infects neutrophils by an incompletely defined mechanism, resulting in the emerging potentially fatal disease, human granulocytic anaplasmosis. The bacterial adhesin, Asp14, contributes to invasion by virtue of its C-terminus engaging an unknown receptor. Yeast two-hybrid analysis identified protein disulfide isomerase (PDI) …

Illumination Of The Golgi Apparatus Of Pathogenic And Nonpathogenic Naegleria Species, Tyler M. Poe

Theses and Dissertations

In this study, Naegleria fowleri, a pathogenic amoeba and the causative agent of Primary Amebic Meningoencephalitis (PAM), was utilized to determine the presence or absence of classically conserved Golgi molecules featured in the expression of a Golgi apparatus. Previous studies concluded no Golgi expression via light microscopy and transmission electron microscopy, but a recent report on Naegleria gruberi indicated the presence of dispersed Golgi tubules. Non-pathogenic species of the Naegleria genus such as Naegleria gruberi 30540 and Naegleria lovaniensis 30569 were utilized in Western immunoblot analysis compared to reduced whole-cell lysate proteins of two strains of N. fowleri and …

Preconditioning Of The Tumor Microenvironment By Means Of Low Dose Chemotherapies For An Effective Immunotherapy Of Breast Cancer, Hussein F. Aqbi

Theses and Dissertations

Breast cancer mortality is mainly due to distant recurrence of the disease arising from dormant tumor cells established by cancer therapies. Patients who initially respond to cancer therapies often succumb to distant recurrence of the disease. It is not clear why people with the same type of breast cancer respond to treatments differently; some escape from dormancy and relapse earlier than others. In addition, some tumor clones respond to immunotherapy while others do not. We investigated how autophagy plays a role in accelerating or delaying recurrence of neu overexpressing mouse mammary carcinoma (MMC) following adriamycin (ADR) treatment, and in affecting …

Response And Recovery Of Syntrophic And Methanogenic Activity To Saltwater Intrusion In A Tidal Freshwater Marsh Soil, David J. Berrier Jr.

Theses and Dissertations

Tidal freshwater wetland soils contain large amounts of organic carbon, some of which is mineralized to carbon dioxide (CO₂) and methane (CH₄) by a diverse consortium of anaerobic microorganisms that includes fermenters, syntrophs, and methanogens (MG). These microbial groups are tightly linked and often rely on cooperative interspecies metabolisms (i.e., syntrophy) to survive. Environmental perturbations can disrupt these interactions and thus alter the rates and pathways of carbon cycling. One environmental change of particular concern in coastal wetlands is sea level rise, which can result in increased episodic saltwater intrusion events into these ecosystems. These events …

The Infectivity Of Naegleria Fowleri Cysts In Vivo And In Vitro, And Mediation Of Encystment By Camp, Anna L. Evdokiou

Theses and Dissertations

The free-living amoeba and causative agent of Primary Amoebic Meningoencephalitis, Naegleria fowleri, has three life stages: the trophozoite, the flagellate, and the cyst. This study examined the ability of the cyst to attach to, excyst upon, and destroy cell cultures grown to confluent monolayers, and to cause Primary Amoebic Meningoencephalitis in a murine animal model. The co-culture of cysts with P388D.1, CHME3, Vero, human nasal epithelial, and rat primary mixed glial cells resulted in destruction of the monolayer of all cell types once the cysts attached and excysted. One day post exposure to cysts, the mixed glial cells exhibited …

The Antimicrobial Properties Of Honey And Their Effect On Pathogenic Bacteria, Shreena Himanshu Mody

Theses and Dissertations

Honey has been used to heal wounds since ancient times. There are many references in ancient literature that cite honey for its medicinal uses. It is used as an alternative agent to cure infections of wounds, burns, ulcers etc. Researchers have shown some of the antimicrobial properties of honey when used as an ointment. When applied to an affected area, it helps to promote the growth of healthy tissue. One of the factors on which the quality of the honey depends, is its geographical origin. Based on the location, honey types can vary as much as 100-fold from each other …

Galleria Mellonella As An Alternate Infection Model For Burkholderia Species And A Comparison Of Suspension And Surface Test Methods For Evaluating Sporicidal Efficacy, Joseph D. Thiriot

Theses and Dissertations

Melioidosis is a neglected tropical disease that continues unabated in many countries, particularly in Southeast Asia. There is no vaccine and antimicrobial treatment is expensive and complicated. Virulence models are important tools used to investigate genes involved in pathogenesis. Galleria mellonella is the larvae of the wax worm moth that has been used to model various infections. Based on previous studies, we attempted to establish an infection model using Burkholderia pseudomallei and Burkholderia thailandensis, a related species which is avirulent in humans. Injections of various forms of these species (fresh and frozen) were used to develop Kaplan-Meier plots. We …

The Diversity Found Among Carbapenem-Resistant Bacteria, Galen Edward Card

Theses and Dissertations

This work will look at two factors that add to the diversity of carbapenem resistant bacteria. First, it focuses on the diversity of carbapenemase resistance plasmids. 446 plasmids were characterized by size, gene content and replicon groups. We identified that on average, over 30% of the encoded proteins on each plasmid have an unknown function. Plasmid sizes ranged from 1.6kb to 500kb, with an average of around 100kb and median of 80kb. Additionally, six replicon groups account for 80% of all the carbapenemase resistance plasmids. We also highlight the lack of data available for carbapenemase carrying plasmids from bacterial genera …

Bacteriophages For Treating American Foulbrood And The Neutralization Of Paenibacillus Larvae Spores, Thomas Scott Brady

Theses and Dissertations

The causative agent of the most devastating honeybee disease, American foulbrood (AFB), is the spore-forming bacterium Paenibacillus larvae. To prevent AFB outbreaks beekeepers prophylactically treat their hives with antibiotics even though it decreases the overall health of uninfected hives. A new treatment for AFB is needed due to recent legislation against using antibiotics, antibiotic resistance developing in P. larvae, and the resilience of P. larvae spores. Bacteriophages, or phages, are an attractive alternative to traditional antibiotics because of their specificity and ability to evolve alongside their target bacterium. In this study, two phage cocktails were developed for the …

The Ability Of Novel Phage To Infect Virulent Bacillus Anthracis Isolates, Hyrum Smith Shumway

Theses and Dissertations

Bacillus anthracis is a soil dwelling microbe with pronounced pathogenic potential. Historically, anthrax has infected livestock and man. In the modern-age, anthrax is a bioterrorism concern with major incidents every decade. While the threat of large scale attacks is currently viewed as unlikely, the threat is consistent and constant. Current methods to defend against such an attack focus on antibiotics and containment of public panic. Antibiotic resistance, while not currently an issue for anthrax, could easily become so with genetically engineered weaponized strains created by rogue states or independent actors. This project evolved from collaborations between the Grose lab and …

Biomarker Analysis And Clinical Relevance Of Thymidine Kinase 1 In Solid And Hematological Malignancies, Evita Giraldez Weagel

Theses and Dissertations

Despite the global effort to discover and improve ways to detect, treat, and monitor cancer, it still remains the second leading cause of death in the United States and poses a major health and economic burden worldwide. While traditional treatments like surgery, chemotherapy, radiation therapy, and hormone therapy have been successful and have decreased cancer mortality, cancer incidence in all sites continues to rise. Consequently, there is an immediate need to find new therapeutics for the treatment of cancer. In recent years, and with the continuing push towards personalized medicine, cancer biomarkers have become crucial to detect, treat, and monitor …

Hospital And Meat Associated Staphylococcus Aureus And Their Biofilm Characteristics, Trevor Michael Wienclaw

Theses and Dissertations

Biofilm phenotypes were studied in 32 Staphylococcus aureus strains isolated from store-bought meats and 22 from diseased patients in hospitals. Of the meat-associated strains, 21 were methicillin-resistant Staphylococcus aureus (MRSA) and 11 were methicillin-susceptible Staphylococcus aureus (MSSA). The hospital-associated strains included 15 MRSAs and 7 MSSAs. We studied the robustness and composition of the biofilms produced by these strains. We found that on average hospital-associated strains form more robust biofilms than meat associated strains. The model often used to describe S. aureus biofilm composition includes two biofilm types defined by the presence or absence of polysaccharide intercellular adhesin (PIA), PIA-dependent …