Pathogenic Microbiology Commons^™

Potency Of Novel Anti-Toxoplasmic Compounds, Matthias Walters

Theses/Capstones/Creative Projects

Toxoplasma gondii, the causative agent of toxoplasmosis, is an intracellular apicomplexan parasite. Toxoplasmosis is often asymptomatic, though, it can be debilitating or fatal to immunocompromised individuals and fetuses, being one of the leading causes of fetal mortality and birth defects. Toxoplasmosis is treated with a synergistic combination of drugs pyrimethamine and sulfadiazine; however, these drugs are only effective against the acute stage of infection, and the pyrimethamine is relatively cytotoxic, damaging bone marrow and causing noxious side effects. Due to these limitations, a safer alternative that targets the chronic stage of infection is needed. In this study, we tested …

The Effect Of Different Types Of Plastic And Rubbers Often Found In Healthcare Facilities On The Survival Of Potentially Pathogenic Bacteria, Ashely George

Honors Theses

This study focused on the survival of different species of bacteria on different types of plastics and rubbers found in healthcare facilities. The gram-positive coccus Staphylococcus aureus and the gram negative bacillus Escherichia coli, known to have importance as potential pathogens in healthcare facilities, were tested on two types of plastic (polyurethane and Polyvinyl Chloride (PVC)) and two types of rubbers (latex and nitrile) typically found on reusable healthcare surfaces. Known quantities of bacteria were aseptically placed on disinfected plastic surfaces in triplicate, air-dried, and then incubated at room temperature for 30 minutes, 20 hours, and 40 hours. After incubation, …

The Stringent Response In Pseudomonas Aeruginosa Influences The Phenotypes Controlled By The Gac/Rsm System, Michael Shawn Hooker

Electronic Theses and Dissertations

Pseudomonas aeruginosa is a ubiquitous, opportunistic pathogen that causes acute and chronic infections. Infection is typically initiated via motile and virulent strains. After exposure to stressors, acute infections make both genotypic and phenotypic switches to a chronic, sessile strain. This is due to intricate regulatory networks directing gene expression in response to stressors. One network, GacA/GacS, has been established to control virulence factors. The stringent response of bacteria is mediated by alarmones produced primarily by RelA which responds to starvation.

To study the effect of the stringent response on the virulence switch. A series of experiments were run in both …

Diagnosis Of Urinary Tract Infections And Rapid Molecular Characterization Of Antibiotic Resistance, Mohammed Harris

All Dissertations

Urinary tract infections (UTIs) are one of the most common infectious clinical entities in both community and hospital settings. They have a broad range of clinical severity yet inflict large epidemiological burden of morbidity and mortality on patients and the healthcare system with billions of dollars in cost of treatment. Understanding what methods are optimal for diagnosing UTIs are critical to mitigate the marked impact and cost of these infections.

Chapter 1 and 2 in this work surveys the broad array of diagnostic modalities for UTIs and highlights their advantages and limitations in the context of the current standard of …

The Effects Of Specialized Pro-Resolving Mediator Lipoxin A4 On Pseudomonas Aeruginosa Biofilms And Interactions With Monocytes, Julianne M. Thornton

Graduate School of Biomedical Sciences Theses and Dissertations

Pseudomonas aeruginosa (P. aeruginosa) is an opportunistic pathogen known as a major cause of hospital-acquired secondary infections, commonly causing chronic respiratory infections in immunocompromised individuals, especially those with cystic fibrosis, and often found in wound infections. P. aeruginosa uses the quorum sensing pathway to readily form protective biofilms, which reduce the efficacy of antibiotics and access by host immune cells to eradicate the pathogen. Specialized pro-resolving mediators (SPMs) are lipids endogenously produced by the host immune response to infection to aid in infection resolution. One SPM, Lipoxin A4 (LxA4), has been shown to be a robust quorum sensing inhibitor.

The …

Investigating The Antibacterial And Immunomodulatory Properties Of Lactobacillus Acidophilus Postbiotics, Rachael M. Wilson

Graduate School of Biomedical Sciences Theses and Dissertations

Probiotics are nonpathogenic microorganisms that have been extensively studied for their ability to prevent various infectious, gastrointestinal, and autoimmune diseases. The mechanisms underlying these probiotic effects have not been elucidated. However, we and other researchers have evidence suggesting that probiotic bacteria secrete metabolites that are antimicrobial and anti-inflammatory. As such, we developed a methodology to collect the secreted metabolites from a probiotic bacterium, Lactobacillus acidophilus, and tested this cell free filtrate (CFF) both in vitro and in vivo. Using this CFF, we have demonstrated that L. acidophilus secretes a molecule(s) that has specific bactericidal activity against the opportunistic pathogen, Pseudomonas …

Accelerating Biosafety Capacity Building To Ensure National Biosecurity, Peipei Liu, Jiafu Jiang, Hao Lu, Peilei Cong, Lilin Zhao, Gexia Qiao, Dongsheng Zhou, Guizhen Wu

Bulletin of Chinese Academy of Sciences (Chinese Version)

Biosafety is an essential part of the national security system, which is related to people's lives and health, the country's longterm stability, and sustainable development, which is the bottom line that must be guaranteed. The international biosafety situation is grim and complex, while domestic biosafety faces challenges. Therefore, biosafety capacity building has become an international hot spot, among which scientific and technological innovation, talent training, and infrastructure platform construction are the top priorities. Although China has achieved strategic results in the rapid identification of pathogens, research, and development of specific vaccines and medicine in fighting against COVID-19 by relying on …

Syndemics And Social Factors: Infectious Disease Patterns Within The Population Of People Experiencing Homelessness In The United States, Kathleen Berzonsky

Honors Program: Senior Projects (Public)

Individuals experiencing homelessness are at increased risk of suffering from infectious diseases. This is due to a number of social factors and healthcare disparities, as well as the idea of syndemics, by which diseases cluster together to worsen disease burden. Current intervention strategies approach treatment from a post-infection perspective, but reducing transmission rates of infectious diseases within the population of people experiencing homelessness will require a shift in the healthcare framework. The issue of people experiencing homelessness must be viewed through a biosocial lens, focusing on preventative care and treatment. I provide an overview of the social factors governing infectious …

Conformational Rearrangements In The Sensory Rcsf/Omp Complex Mediate Signal Transduction Across The Bacterial Cell Envelope, Sarah Rosemarie Lach Phd

Dissertations and Theses (Open Access)

Timely detection and repair of envelope damage are paramount for bacterial survival. The Regulator of Capsule Synthesis (Rcs) stress response is a complex signaling cascade that monitors gram-negative cell envelope integrity and can transduce the stress signals across the multilayered envelope to regulate gene expression in the cytoplasm. The outer membrane (OM) lipoprotein RcsF is the sensory component, but how RcsF functions remains elusive. RcsF interacts with the β-barrel assembly machinery (Bam) complex, which assembles RcsF in complex with OM proteins (OMPs), resulting in RcsF’s partial cell surface exposure. RcsF can also interact with the periplasmic domain of the negative …

The Immunomodulating Effects Of Delta-9 Tetrahydrocannabinol (Thc) And Cannabidiol (Cbd) In The Context Of Infection, Rose D. Goodman, Kate Rouse, Victor Jimenez

Annual Research Symposium

No abstract provided.

A Systematic Review: Toxoplasma Gondii Infection And Drugs Of Abuse, Amani Sastry

Annual Research Symposium

No abstract provided.

Genetic Determinants Involved In Acquisition Of Iron In The Opportunistic Pathogen Mycobacterium Abscessus, Manal F. Farhat

Dissertations, Theses, and Capstone Projects

The opportunistic pathogen Mycobacterium abscessus subsp. abscessus (Mab) has become an emerging public health threat due to the increasing number of Mab-associated chronic pulmonary disease cases. Infection cure rates are only 50% due to the complex resistance of Mab to most antimicrobial drugs and chemotherapy.

Deeper knowledge of Mab biology is needed to illuminate potential candidates for development of improved therapeutics against Mab infections. The ESX-3 type VII protein secretion system of Mab plays an important role in host inflammatory and pathological responses during infection.

In this study, we demonstrate a functional link between the ESX-3 secretion …

The Immune Modulation On Innate Immunity, From Pathogen Recognition To Fungal Clearance., Ko-Wei Liu

Dartmouth College Ph.D Dissertations

The human lung is not sterile but a complex environment with various microorganisms. Besides commensals in the lung, hundreds to thousands of individual microbiomes enter the lung every day but without causing the symptom. Host innate immunity plays an important role in maintaining homeostasis of the lung environment and as the first defense line against pathogens. Aspergillus fumigatus (A. fumigatus) is a saprophytic filamentous fungus that can cause human disease in immune compromised patients. However, with functional innate immunity, immune cells can quickly recognize pathogen associated molecular patterns (PAMPs) from A. fumigatus through pattern recognition receptors (PRRs). The activation of …

Using Nspefs To Sensitize Mrsa To Vancomycin Treatment, Areej Malik, Alexandra E. Chittams-Miles, Claudia Muratori, Erin B. Purcell

The Graduate School Posters

Staphylococcus aureus (S. aureus) is a biofilm-forming pathogen. S. aureus treatment is marked by the development of antibiotic resistance. The public health impact has increased since the emergence of methicillin-resistant S. aureus (MRSA), which has started to show intermediate resistance to vancomycin in MRSA. Nano-second pulse electric fields (nsPEFs) are low-energy and high-power electric pulses, which have been suggested to sensitize pathogens to antibiotics by creating transient pores in the cell membrane. Our combinatorial treatment includes nsPEF pre-treatment and vancomycin post-treatment of MRSA cells. Our results show that MRSA log phase cells had the highest susceptibility to vancomycin. …

Analysis Of A Cathepsin Protease In Normal Development And Tumor Metastasis In Drosophila Melanogaster, Lindsey Fannin

Mahurin Honors College Capstone Experience/Thesis Projects

Cysteine cathepsins are an important class of fifteen proteases with involvement in normal development and tumor progression. To better understand their contribution to these processes, the cathepsin L protease in Drosophila melanogaster was studied. In part one of this project, the role of this cathepsin in the normal development of Drosophila wings was analyzed. The GAL4/UAS-system and RNAi were used to downregulate this cathepsin in various regions of the wing and progeny were inspected for phenotypic irregularities. An abnormal phenotype of curved wings was found and hypothesized to be a result of apoptosis. Further experimentation will be required to prove …

Clonal Diversity, Antibiotic Resistance, And Virulence Factor Prevalence Of Community Associated Staphylococcus Aureus In Southeastern Virginia, Katelyn D. Cranmer, Mohan D. Pant, Suzanne Quesnel, Julia A. Sharp

EVMS School of Health Professions Faculty Publications

Staphylococcus aureus is a significant human pathogen with a formidable propensity for antibiotic resistance. Worldwide, it is the leading cause of skin and soft tissue infections (SSTI), septic arthritis, osteomyelitis, and infective endocarditis originating from both community- and healthcare associated settings. Although often grouped by methicillin resistance, both methicillin-resistant (MRSA) and methicillin-sensitive (MSSA) strains are known to cause significant pathologies and injuries. Virulence factors and growing resistance to antibiotics play major roles in the pathogenicity of community-associated strains. In our study, we examined the genetic variability and acquired antibiograms of 122 S. aureus clinical isolates from SSTI, blood, and urinary …

Distribution Patterns Of Allorhizobium Vitis In Missouri Vineyards And Non-Vineyard Soils, Jacquelyn M. Wray

Graduate Theses/Dissertations

Crown gall disease causes significant economic loss to the grape and wine industry. Preventive strategies are most effective for mitigating the loss of grapevines in vineyards, as there is no known cure for this disease. The bacterium Allorhizobium vitis carrying a tumor-inducing (Ti) plasmid is the causative agent. A. vitis bacteria live systemically in the grapevine before causing visible symptoms and can survive in residual plant tissues and soil for more than two years. Diagnostic methods have been developed to detect A. vitis bacteria in grapevines and soil. However, more reliable, specific, and high-throughput diagnostics are still needed for screening …

Marineepi: A Gui-Based Matlab Toolbox To Simulate Marine Pathogen Transmission, Gorka Bidegain, Tal Ben-Horin, Eric N. Powell, John M. Klinck, Eileen E. Hofmann

CCPO Publications

The Graphical User Interface (GUI) MarineEpi is presented as a Matlab toolbox for easily (i) constructing disease transmission models for different marine host-pathogen systems, (ii) running simulations by specifying initial conditions and model parameters, and (iii) interpreting the resulting time series of the host and pathogen population dynamics. MarineEpi users can generate models for systems in which pathogen transmission occurs through contact with infected individuals (SI), contact with dead infected individuals (SID), contact with environmental pathogens released by infected individuals (SIP), and contact with environmental pathogens released by dead infected individuals (SIPD). MarineEpi is a freely available GUI that provides …

Multipatch Stochastic Epidemic Model For The Dynamics Of A Tick-Borne Disease, Milliward Maliyoni, Holly D. Gaff, Keshlan S. Govinder, Faraimunashe Chirove

Biological Sciences Faculty Publications

Spatial heterogeneity and migration of hosts and ticks have an impact on the spread, extinction and persistence of tick-borne diseases. In this paper, we investigate the impact of between-patch migration of white-tailed deer and lone star ticks on the dynamics of a tick-borne disease with regard to disease extinction and persistence using a system of Itô stochastic differential equations model. It is shown that the disease-free equilibrium exists and is unique. The general formula for computing the basic reproduction number for all patches is derived. We show that for patches in isolation, the basic reproduction number is equal to the …

Substrate Selection And Effector Gating In The Helicobacter Pylori Cag Type Iv Secretion System, Mackenzie E. Ryan

Theses and Dissertations--Microbiology, Immunology, and Molecular Genetics

Helicobacter pylori is a recognized carcinogen and gastric colonization by strains that harbor the cag type IV secretion system (1) is the strongest known risk factor for stomach malignancy. Gastric adenocarcinoma is the fourth leading cause of cancer-related deaths world-wide ( > 700,000 deaths annually), with H. pylori directly contributing to the development of more than one million new cases of cancer per year accounting for 5.5% of all malignancies. H. pylori exploits cag T4SS activity to alter the mucosal microenvironment by delivering diverse immunostimulatory cargo into target gastric epithelial cells. Currently, the mechanisms by which the cag T4SS …