Pathogenic Microbiology Commons^™

Expanding Our Grasp Of Two-Component Signaling In Clostridioides Difficile, Orlando Berumen Alvarez, Erin B. Purcell

Chemistry & Biochemistry Faculty Publications

The intestinal pathogen Clostridioides difficile encodes roughly 50 TCS, but very few have been characterized in terms of their activating signals or their regulatory roles. A. G. Pannullo, B. R. Zbylicki, and C. D. Ellermeier (J Bacteriol 205:e00164-23, 2023, https://doi.org/10.1128/jb.00164-23) have identified both for the novel C. difficile TCD DraRS. DraRS responds to antibiotics that target lipid-II molecules in the bacterial cell envelope, and regulates the production of a novel glycolipid necessary for bacitracin and daptomycin resistance in C. difficile.

Evaluating Efficacy Of Anti-Batrachochytrium Dendrobatidis Probiotic Treatment On Pacific Chorus Frogs (Pseudacris Regilla) At Current And Modeled Climate Change Temperatures, Autumn N. Holley

EWU Masters Thesis Collection

Amphibian populations are declining due to a variety of threats, including the chytrid fungal pathogen, Batrachochytrium dendrobatidis (Bd), the causative agent of the disease chytridiomycosis. Climate change and other stressors can have complicated interactions with amphibian disease. Some amphibian populations are less susceptible to chytridiomycosis due to factors such as symbiotic skin microbes that may inhibit Bd through secondary metabolites. There have been several attempts to develop probiotics from these symbiotic, antifungal bacteria to provide protection against Bd infection, but these studies have had mixed success. Our study evaluated anti-Bd bacteria isolated from the skin of Pacific chorus frogs (Pseudacris …

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 …

Survival Of Listeria Monocytogenes On Organic Honeycrisp And Fuji Apples During Storage At 5, 12 And 22.5◦C, Connor S. Freed

Graduate Theses, Dissertations, and Problem Reports (ETD)

This study aimed to evaluate and model the survival of Listeria monocytogenes on organic HoneyCrisp (HC) and Fuji (FJ) apples during storage at various temperatures. Fresh organic HC and FJ apples (without wax coating) obtained from a local wholesale market were inoculated with a 2-strain mix of L. monocytogenes followed by storage at 5.0 (22.9% RH), 12.0 (37.0% RH), and 22.5oC (50.4% RH) for 60, 35, 7 days, respectively, and periodically (day-0 to 60) analyzing microbial populations. Surviving L. monocytogenes were spread-plated on Modified-Oxford agar after 10 or 100-fold serial dilution. Data were analyzed using the mixed-model procedure of SAS …

Comparing The Microbiomes Of Dental Plaques In 19th Century Ancestral Remains, Ananya Udyaver

Undergraduate Research Posters

During the construction of VCU’s Hermes A. Kontos Medical Sciences Building in April 1994, nineteenth century ancestral remains were found in an abandoned well on the Medical College of Virginia (MCV) campus. This well, now known as the East Marshall Street Well (EMSW), is thought to have been used as a disposal location for cadaver dissection for surgical and other medical waste in the past. VCU is now seeking to use DNA sequencing technology to match and assemble bones from each individual for a proper burial, uncover the cultural and historical context in which these people lived, and bring a …

Effects Of Altering Physiologically Relevant Cholesterol Levels And Media Types On Porin Gene Expression In Klebsiella Pneumoniae And The Resulting Impact On Antibiotic Resistance, Megan R. Camden

UNF Graduate Theses and Dissertations

Klebsiella pneumoniae is a Gram-negative, non-motile bacterium belonging to the Enterobacteriaceae family. K. pneumoniae is a rising threat in the clinical setting, as there has been a large increase in the presence of antibiotic resistant isolates. While much research is conducted on laboratory and clinical strains of bacteria, not much is known regarding the impact that human physiology can have on bacterial gene expression, and in response, to antibiotic susceptibility. The goal of this study is to determine if physiologically relevant cholesterol levels and media types impact porin gene expression and antibiotic resistance in K. pneumoniae. To accomplish this, …

In Silico Analyses Of Diversity And Dissemination Of Antimicrobial Resistance Genes And Mobile Genetics Elements, For Plasmids Of Enteric Pathogens, Suad Algarni, Jing Han, Dereje D. Gudeta, Bijay K. Khajanchi, Steven C. Ricke, Young Min Kwon, Douglas D. Rhoads, Steven L. Foley

Animal Science Faculty Publications and Presentations

Introduction: The antimicrobial resistance (AMR) mobilome plays a key role in the dissemination of resistance genes encoded by mobile genetics elements (MGEs) including plasmids, transposons (Tns), and insertion sequences (ISs). These MGEs contribute to the dissemination of multidrug resistance (MDR) in enteric bacterial pathogens which have been considered as a global public health risk.

Methods: To further understand the diversity and distribution of AMR genes and MGEs across different plasmid types, we utilized multiple sequence-based computational approaches to evaluate AMR-associated plasmid genetics. A collection of 1,309 complete plasmid sequences from Gammaproteobacterial species, including 100 plasmids from each of the following …

The Type Iv Pilus Secretin Bfpb: Structural Analysis And Binding Interactions, Janay I. Little

Theses and Dissertations

Enteropathogenic Escherichia coli (EPEC) causes severe diarrhea in young children. The type IV pilus (T4P) of EPEC, known as the bundle-forming pilus (BFP), plays an important role in EPEC pathogenesis. T4Ps are a family of surface appendages that are important for adhesion, colonization, biofilm formation, virulence, twitching motility and many other functions. One essential component of the BFP system is the secretin, BfpB. Secretins are a large family of integral outer membrane proteins found in T4Ps as well as type II and type III secretion systems, and filamentous phages. Details of the secretin structure have been limited to the overall …

The Role Of Dha In The Impact Of Trem2 On Microglia Activation And Alzheimer’S Disease, Michael A. Palmieri Iii

Seton Hall University Dissertations and Theses (ETDs)

Alzheimer’s disease (AD) is a neurological disease that is associated with microglia activation. An important receptor involved in microglia activation is Triggering receptor expressed on myeloid cells 2 (TREM2). Recent studies suggest that docosahexaenoic acid (DHA) could reduce the neuroinflammation that is associated with microglia activation. We hypothesized that when DHA concentration was increased, TREM2 expression would decrease, microglia activity would be inhibited, and a resulting decrease in neuroinflammation would be observed. We examined peer-reviewed journal articles from 2017-2022 that investigated the relationship between TREM2 activation and severity of AD symptoms, the protective properties of DHA against AD, and the …

Genetic Characterization Of Resitance To Frogeye Leaf Spot Of Soybean, Gabriel D. Munoz Herrera

LSU Master's Theses

Cercospora sojina is the causal agent of the fungal disease frogeye leaf spot (FLS) in soybeans. Management of this disease consists of foliar application of fungicides and the use of resistant cultivars. However, fungicide resistance has been detected in C. sojina populations and characterization of host resistance genes is relatively limited. To overcome the latter obstacle, we aimed to identify novel resistance genes using quantitative image analysis of the SoyNAM population. Two image analysis workflows using ImageJ and PlantCV were optimized and implemented to increase reproducibility and reduce subjectivity. The quantitative measurements included disease severity, lesion count, and average lesion …

Crispr Technology As An Antiviral In Dsdna And Ssrna Viruses, Cathryn Mayes

Theses & Dissertations

The COVID-19 pandemic highlights the necessity of emergency response and pandemic preparedness, especially for emerging viral threats. Currently, virus-specific vaccines and antivirals are the primary tools to combat viral diseases; however, broad-spectrum antivirals that target more than one virus species could provide additional protection from emerging and re-emerging viral diseases (Andersen et al. 2020; Zhu et al. 2015; Hickman et al. 2022).

Clustered regulatory interspaced short palindromic repeat (CRISPR)-associated endonucleases have become recently utilized as potential antiviral strategies due to their high specificity, efficacy, and versatility (Najafi et al. 2022). While CRISPR-based antivirals have previously been used to target specific …

Effects Of Microcystin-Lr On Channel Catfish (Ictalurus Punctatus) Susceptibility To Microbial Pathogens (Aeromonas Hydrophila And Edwardsiella Piscicida), Alison Marchant

Theses and Dissertations

Microcystin-LR is a hepatotoxin produced by cyanobacteria. Aeromonas hydrophila and Edwardsiella piscicida infections are leading causes of losses in market-sized channel catfish (Ictalurus punctatus). These older fish should have natural immunity in place and a predisposing factor is likely a prerequisite for these disease outbreaks. While microcystin-LR rarely causes mortality in warm-water aquaculture, we believe it may be a predisposing factor that leads to bacterial disease outbreaks during the summer months due to its ability to damage the liver. Our study investigated microcystin-LR’s effects on channel catfish susceptibility to these pathogens. We found that a sublethal dose of microcystin-LR induced …

Molecular And Phenotypic Characterization Of Escherichia Coli Isolated From Broiler Chicken Flocks In Mississippi, Priyanka Devkota

Theses and Dissertations

Avian pathogenic Escherichia coli (APEC) is the causative agent of colibacillosis. APEC causes significant economic losses to the poultry industry. In this study, 66 E. coli isolates were collected from broiler flocks across Mississippi and categorized as clinical and non-clinical isolates. Genotypic and phenotypic characterization of virulence factors and antimicrobial resistance profiles of these E. coli were examined. The data disclosed a higher prevalence of virulence genes in clinical isolates than in non-clinical isolates. High differences on the genotypic and phenotypic antimicrobial resistance among clinical and non-clinical isolates were observed. Whole genome sequences of avian E. coli elaborated a diverse …

Alternative Precautionary Measures Yielding Lower C. Diff Infection Rates In Healthcare Facilities, Matthew Kramer

Symposium of Student Scholars

Background: An international healthcare concern is the persistent spread of Clostridium difficile, a Gram-positive spore forming bacterium that is responsible for the most common hospital-acquired infection, amongst patients.

Objective: A systematic review was performed to summarize evidence that the interventions utilized in healthcare facilities which indicate a patient’s precautionary status are insufficient, outdated, and commonly lead to infection in neighboring patient rooms. Databases such as PubMed, NCBI, Google Scholar, and APHA’s Medical Care were searched, covering the period from 2017-2022. Studies were included if their focus concentrated on C. diff and the precautionary measures taken by employees at healthcare …

Functional Analysis Of Legionella Pneumophila Effector Protein, Shreya Neupane

Masters Theses & Specialist Projects

Legionella pneumophila is a gram-negative bacterium that causes Legionnaire’s disease (a severe form of pneumonia) in humans. L. pneumophila can cause infection by utilizing its Type IV secretion system, a protein secretion system that transports proteins from the bacterial cytosol into the infected macrophage. Effectors released from the Type Iv secretion system allow L. pneumophila to create a safe environment to survive, replicate and cause infection. One such effector, RavQ, inhibits cell proliferation of mammalian HEK 293T cells and localizes to the cell’s nucleus, leading us to hypothesize that RavQ interferes with cellular activity in the nucleus. To detect its …

The Role Of Microbiota-Biotransformed Bile Acid Metabolites On Campylobacter Jejuni- And Clostridium Perfringens-Infection, Ying Fu

Graduate Theses and Dissertations

Campylobacter jejuni (C. jejuni) and Clostridium perfringens (C. perfringens) are two leading pathogenic bacteria responsible for both human and animal diseases. In chapters Ⅱ to Ⅳ, I presented an overview of current knowledge on the role of immune response, microbiota, bile acids and their microbial metabolites on campylobacteriosis, and C. perfringens induced necrotic diseases.In chapter Ⅴ, I investigated effects of deoxycholic acid-modulated anaerobes (DCA-Anaero) on attenuating chicken transmission-exacerbated campylobacteriosis. SPF Il10-/- mice were gavaged with clindamycin for 7 days followed by infected with three C. jejuni strains, Cj-P0 (C. jejuni AR101), Cj-P1 (from chicken pre-infected with C. jejuni AR101), and …

Death Of A Bacterium: Exploring The Inhibition Of Staphylococcus Aureus By Burkholderia Cenocepacia., Tiffany Brandt

Electronic Theses and Dissertations

Antimicrobial resistance is a phenomenon of increasing concern as antimicrobial overuse and misuse eliminate current therapeutic options, ushering society into a post-antimicrobial era. Antibiotic discovery and synthesis efforts are urgently needed to counter the increasing burden of antimicrobial resistance. Staphylococcus aureus is a causative agent of a variety of clinical manifestations including bacteremia, endocarditis, soft tissue infection, osteomyelitis, and device-related infections. S. aureus infection presents additional treatment challenges due to its capacity for biofilm formation, which is a mode of growth that confers protection from antibiotics and physical elimination, and the emergence of antibiotic resistant strains, including methicillin-resistant S. aureus …

Characterizing The Cutaneous Microbiome Of Eurycea Lucifuga As A Potential Defense Against Chytridiomycosis, Madeline Key

Senior Honors Theses

Chytridiomycosis is an emerging infectious disease that is significantly reducing global amphibian populations. The disease is caused by Batrachochytrium dendrobatidis (Bd), a fungus that lethally modifies amphibian skin. Recent research has suggested that the cutaneous microbiome of individual amphibians may play a role in susceptibility to the pathogen. In this study, twelve cave salamanders (Eurycea lucifuga) were collected. Cutaneous bacteria from each salamander were isolated and identified using Sanger Sequencing. Additionally, a Bd-challenge assay was performed to determine each isolate’s antifungal activity. Results indicated many microbial isolates possessed inhibitory capabilities against Bd, which may …

The Antimicrobial Resistance Plasmid Mobilome Of Salmonella Enterica And Related Enteric Species And Factors That Influence The Transfer Efficiency., Suad Algarni

Graduate Theses and Dissertations

The dynamic distribution of antimicrobial resistance genes in Salmonella enterica is considered a public health risk. S. enterica is one of the most important etiological agents of foodborne illness and has a critical impact on global human health. In S. enterica and related species, mobile genetic elements (MGEs) serve as primary vehicles for the dissemination of antibiotic resistance genes in the bacterial evolution. This dissemination can be impacted by different selective pressures that leads to diverse antibiotic response phenotypes. This project focusses on the dynamics of antimicrobial resistance genes, particularly exploring the transfer efficiency of multidrug resistance plasmids in S. …

An Active Biodegradable Layer-By-Layer Film Based On Chitosan-Alginate-Tio2 For The Enhanced Shelf Life Of Tomatoes, Kalpani Y. Perera, Shubham Sharma, Brendan Duffy, Shiviani Pathania, Amit K. Jaiswal, Swarma Jaiswal

Articles

This work aims at developing biodegradable active chitosan-alginate layer-by-layer bio-nanocomposite film with TiO₂NPs using the solvent casting method followed by CaCl₂ crosslinking for food packaging applications. The developed films enhanced the tensile strength and elongation at break by 14.76 and 2 folds (p < 0.05) respectively. The UV barrier properties of CH-SA-0.3%TiO₂ film increased by 88.6%, while the film transparency decreased by 87.23%. All films showed antimicrobial activity against foodborne pathogens E. coli, S. aureus, S. typhi, and L. monocytogene. The film with 0.1%TiO₂ showed the complete killing of gram-positive bacteria. The CH-SA-0.1%TiO₂ film was completely biodegraded during the …