Pathogenic Microbiology Commons^™

Evaluating Vaccine Management Strategies For Edwardsiella Ictaluri Infections In Zebrafish (Danio Rerio), Brandy Malbrough

LSU Master's Theses

Aquaculture is a globally important industry that faces significant challenges due to infectious diseases, which can result in substantial financial losses. In 2011, a new strain of Edwardsiella ictaluri emerged as a major pathogen affecting zebrafish in the ornamental fish industry, leading to high mortality rates and posing a severe threat to the sector. Vaccines provide potential benefits for disease prevention in aquaculture, particularly live-attenuated vaccines (LAVs), which induce strong host immune responses. Bacterial attenuation for vaccine development has evolved from serial passage to more targeted genetic modification techniques. However, regulatory constraints limit the availability of licensed LAVs for aquaculture. …

Horizontal Transfer Of Probable Chicken-Pathogenicity Chromosomal Islands Between Staphylococcus Aureus And Staphylococcus Agnetis, Douglas D. Rhoads, Jeff Pummil, Nnamdi S. Ekesi, Adnan A.K. Alrubaye

Cell and Molecular Biology Faculty Publications and Presentations

Staphylococcus agnetis is an emerging pathogen in chickens but has been most commonly isolated from sub-clinical mastitis in bovines. Previous whole-genome analyses for known virulence genes failed to identify determinants for the switch from mild ductal infections in cattle to severe infections in poultry. We now report identification of a family of 15 kbp, 17–19 gene mobile genetic elements (MGEs) specific to chicken osteomyelitis and dermatitis isolates of S. agnetis. These MGEs can be present in multiple copies per genome. The MGE has been vectored on a Staphylococcus phage that separately lysogenized two S. agnetis osteomyelitis strains. …

Characterization Of Antimicrobial Properties Of Excrement And Functional Microbiome Of Black Vultures (Coragyps Atratus), Bridgette Gray

Theses

Black vultures, Coragyps atratus, are obligate scavenging birds that consume and dispose of decaying carcasses and carrion. They fulfill a key ecological niche in the environments in which they live. It has been observed that these vultures sometimes excrete bodily waste onto their legs. This adaptive behavior could help aid them in controlling bacteria and other microbes they encounter while stepping into a carcass to eat. This study directly examined the antimicrobial properties of the excrement of black vultures across various bacterial species utilizing a zone of inhibition test and a nematode species utilizing a survival assay. The black vulture …

A Review On Antibiotic Resistance And The Use Of Medicinal Plants In The Management Of Uropathogenic Bacteria, Hubza Ruatt Khan, Mehvish Javeed, Iqra Batool, Rabeea Anwar, Asma Ashraf, Sara Janiad

Journal of Bioresource Management

UTIs are the most prevalent infections and are caused by uropathogenic microbes such as Escherichia coli, Klebsiella pneumoniae, Proteus mirabilis, Pseudomonas aeruginosa, Staphylococcus aureus, and Enterococcus spp. Antibiotic resistance has hampered the management of UTIs over the years, with direct repercussions on the treatment cost, the infection severity, and the duration of hospitalization. This review discussed the route of infections, risk factors connected to UTIs, antibiotic resistance issues as well as an alternative therapy to overcome the problem of antibiotic resistance. The medicinal plants, which have been utilized for thousands of years to cure a variety of ailments, represent a …

Investigating The Mammillary Bodies As An Early Target Of Alzheimer's Disease, Cole Martinson

University Honors Theses

Alzheimer's disease (AD) is the most common form of dementia. With minimal treatment options and no cure, developing a deeper understanding of the pathology of the disease is crucial. For nearly four decades, the accumulation of beta-amyloid (Aβ) plaques has been correlated with the disease and its progression. Previous studies mapping this accumulation show that the mammillary bodies (MB) are an early target of the disease. Glutamatergic neurons are of key interest due to their prevalence in the central nervous system, specifically the MB. To understand the effects of AD on the glutamatergic system, we used vesicular glutamate transporter 2 …

Understanding Ubiquitin-Like Signaling At The Host-Pathogen Interface, Danna Eloisa Guzman Gonzalez

University Honors Theses

Research on pathogen intervention and ubiquitin modification has increased over the last few years but a lot is still unknown about ubiquitin-like modifiers (Ubl) and how or if they are modified by pathogens in the same way as Ubiquitin. In this work, two different studies conducted over the course of 2 years are highlighted. The first study focused on purifying and synthesizing four activity based probes in order to study enzymatic activity in the Ubl-modification systems. These probes were reacted with virulence factors isolated from different bacteria and it was concluded that there were unexpected bands formed between some of …

​ Soilborne Pathogens Of Strawberry In The Central Coast Region Of California: ​ Survey And Cover Cropping With Wheat For Management Of Macrophomina Phaseolina, Mary Steele

Master's Theses

Surveys of the four major soilborne pathogens of strawberry (Fusarium oxysporum f. sp. fragariae, Macrophomina phaseolina, Phytophthora spp., and Verticillium dahliae) to determine their relative prevalence were conducted in Watsonville-Salinas, CA in 2021 and in Santa Maria, CA in 2022. All four major pathogens were detected at relatively similar prevalence in Watsonville-Salinas, between 22% and 31% of sampled fields. In Santa Maria, M. phaseolina was far more prevalent at 52% of sampled fields, the other three falling between 14% and 17%. Additionally replicated greenhouse and field trials were conducted to evaluate the effects of wheat as …

Development Of Novel Nanocarbon Based Materials And Membranes With Enhanced Biocidal Capabilities For Clean Water Generation, Indrani Gupta

Dissertations

Water scarcity is one of the major challenges facing humanity today, driven by population growth, economic development, and dietary shifts towards more water-intensive animal products. To address this issue, efficient water resource management and recycling of wastewater are essential. However, around 80% of wastewater globally is discharged into water bodies without treatment, posing a risk to ecosystems and human health. Pathogens, or harmful microorganisms, are a primary cause of water impairment and the transmission of waterborne diseases, leading to increased mortality rates. Traditional methods of treating pathogens involve the use of radiation or chemical disinfectants. Nonetheless, these methods have drawbacks, …

Overexpressing Two Helicobacter Pylori Small Rnas From A Bacterial Pathogenicity-Related Chromosomal Region To Investigate Their Regulation Of Virulence Genes, Roxanne N. Mcpeck, Olivia F. Morgan, Andrea R. Castillo Phd

2023 Symposium

The bacterial pathogen Helicobacter pylori infects the stomachs of approximately 50% of humanity, causing symptomatic disease (e.g., stomach ulcers, gastric cancer, and MALT lymphoma) in 10-15% of the infected. Colonizing the acidic, inhospitable stomach requires H. pylori to tightly regulate gene expression despite lacking many common bacterial genetic regulatory elements. The pathogen may compensate by using abundant non-protein-coding small RNAs (sRNAs) to regulate gene expression, including of infection-intensifying virulence genes. Additionally, severe disease and cancer correlate with infection by H. pylori strains that contain a nonessential chromosomal region, the cytotoxin-associated gene pathogenicity island (cagPAI). This encodes powerful virulence …

Characterization Of Lps As A Virulence Factor In Burkholderia Cepacia During Plant And Human Infection, Jack Klahr, Elizabeth Danka

Biology Senior Theses

Burkholderia cepacia is a gram-negative bacterium first characterized as the causative agent of sour skin in onion crops. More recently, B. cepacia has become a clinical concern as an opportunistic pathogen that can colonize the upper respiratory tract of cystic fibrosis patients and increase mortality in these patients. Infection is exacerbated by the intrinsic resistance to antibiotics found in this genus of organisms. Additional virulence factors help the bacteria persist in the host during infection. However, few of these factors have been described. In this work, we characterized a putative virulence factor that was first identified through an onion infection …

The Development Of A Primer Payload With Microparticles For Uti Pathogen Identification Using Polythymidine- Modified Lamp Primers In Droplet Lamp, Jonas Otoo

KGI Theses and Dissertations

Nucleic acid amplification tests (NAATs) are among the diagnostic tests with the highest sensitivity and specificity. However, they are more complex to develop than other diagnostic tests such as biochemical tests and lateral flow immunoassay tests. Polymerase chain reaction (PCR) is the gold standard for NAATs. PCR requires thermal cycling to achieve clonal amplification of the target pathogen DNA for diagnosis. Thermal cycling poses a challenge in the development of PCR diagnostics for point-of-care (POC) settings. Loop-mediated isothermal amplification (LAMP) offers an isothermal method for NAATs diagnostics. The advancement of the microfluidics field significantly enhances the development of LAMP diagnostics …

Causes And Consequences Of Lasr Mutant Selection In Pseudomonas Aeruginosa Populations, Dallas L. Mould

Dartmouth College Ph.D Dissertations

Change is the only constant in life, and these changes, though random in nature, can have consequences. Quorum sensing is heterogeneous in phenotype and prone to negative selection. In P. aeruginosa, the regulator LasR is frequently non-functional in phylogenetically diverse isolates. Through repeated experimental evolution and mathematical modeling, we show that differences in growth enable lasR mutant evolutionary success and this requires a system enabling metabolic choices, known as carbon catabolite repression (or catabolite repression). The differences in catabolite repression between wild type and lasR mutants enable altered metabolite preferences, and the resulting differences in metabolic states enable intraspecies …

Elucidating The Impact Of Sos-Response Timing In On Escherichia Coli Survival Following Treatment With Fluoroquinolone Topoisomerase Inhibitors, Stephanie Schofield

Honors Scholar Theses

Antibiotic treatment failure is a public health crisis, with a 2019 report stating that roughly 35,000 deaths occur in the United States yearly due to bacterial infections that are unresponsive to antibiotics (1). One complication in the treatment of bacterial infection is antibiotic persistence which further compromises our battle to effectively treat infection. Bacterial persisters can exist in clonal bacterial cultures and can tolerate antibiotic treatment by undergoing reversible phenotypic changes. They can survive drug concentrations that their genetically identical kin cannot. Some persisters remain in a slow growing state and are difficult to target with current antibiotics. A specific …

A Critical Assessment Of The Role Of Clpxp-Mediated Proteolysis In The Development And Differentiation Of Chlamydia Trachomatis, Nicholas A. Wood

Theses & Dissertations

Chlamydia trachomatis, an obligate intracellular human pathogen, is the etiological agent of the most commonly reported bacterial sexually transmitted infection and the leading cause of preventable infectious blindness worldwide. In adapting to an intracellular niche, Chlamydia has evolved to eliminate superfluous genes from its chromosome. Despite its highly reduced genome, Chlamydia undergoes a complex developmental cycle in which the bacteria differentiate between two functionally and morphologically distinct forms: the infectious, non-replicative elementary body (EB) and the non-infectious, replicative reticulate body (RB). An EB initiates infection by binding to and inducing uptake into a host cell. Within the cell, the EB …

Immunomodulatory Effects Of Resolvin D2 In A Model Of Infection, Prem Yugandhar Kadiyam Sundarasivarao

Graduate School of Biomedical Sciences Theses and Dissertations

Dysregulated hyperinflammatory host immune response to underlying bacterial infections is a characteristic of sepsis. In sepsis, bacteria often trigger abnormal hyperinflammatory responses which can cause multiple organ failure and if sustained can lead to an immunosuppressive phase where the host is susceptible to secondary infections caused by opportunistic bacteria like Pseudomonas aeruginosa (P. aeruginosa). In our studies, we used a 2-hit model of cecal ligation and puncture (CLP) followed by P. aeruginosa secondary lung infection to investigate cellular and molecular mechanisms in the beneficial action of resolvin D2 (RvD2). Resolvins of the D-series are a group of fatty acids known …

Impacts Of Bacterial Evolution On Host Lethality In Drosophila, Andrew Preston

College of Arts & Sciences Senior Theses

Evolution is the process by which species change their genetic traits, such as the pathogenicity of bacteria, over time in response to changes in their environment. Although the genetic mechanisms underlying many evolutionary processes have been revealed, it is still not well understood how opportunistic pathogens, such as Pseudomonas aeruginosa, become virulent. The overall goal of this thesis is to test the Coincidental Evolution Hypothesis, which proposes that the virulence of opportunistic pathogens evolves coincidentally as a by-product of their interaction with their natural predators. I hypothesized that the virulence of ancestral Pseudomonas aeruginosa changes over time if it co-evolves …

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 …

Identification Of A Role Beyond Iron Acquisition For Yersiniabactin During Yersinia Pestis Infection., Sarah Price

Electronic Theses and Dissertations

Yersinia pestis is a Gram-negative re-emerging bacterial pathogen that is responsible for bubonic, septicemic, and pneumonic plague. Y. pestis and other bacteria require transition metals, such as iron, zinc, and manganese, to maintain intermediary metabolism, transcriptional regulation, and virulence. To inhibit infection, eukaryotic organisms have developed distinct mechanisms, called nutritional immunity, to sequester these important nutrients from invading bacteria. For pathogens to colonize the vertebrate host, they have evolved dedicated acquisition systems for transition metals. During infection, Y. pestis overcomes iron limitation by secreting the siderophore yersiniabactin. Additionally, Y. pestis requires zinc for infection and utilizes high affinity transporters to …