Pathogenic Microbiology Commons^™

Role Of Growth Factors In The Pathogenesis Of Systemic-Sclerosis-Associated Fibrosis, Fabian A. Mendoza, Sonsoles Piera-Velazquez, Sergio A. Jimenez

Jefferson Institute of Molecular Medicine Papers and Presentations

Systemic Sclerosis (SSc) is a systemic autoimmune disease of unknown etiology characterized by a severe fibroproliferative vasculopathy and frequently progressive cutaneous and internal organ fibrosis. The small-vessel vasculopathy and the tissue fibrotic alterations are responsible for the most serious clinical and pathological manifestations of the disease and for its high mortality. Despite the high severity and frequent mortality, there are currently no optimal therapeutic approaches for SSc, and its complex pathogenesis has not been fully elucidated. Numerous studies have suggested that growth factors and related regulatory macromolecules released from inflammatory and other cells present in the affected tissues play a …

Detection Method For Escherichia Coli Using Real-Time Polymerase Chain Reaction Targeting The Yhav Gene, Muktiningsih Nurjayadi, Anisa Fitriyanti, Royna Rahma Musie, Gusti Angieta Putri, Puan Aqila Azizah, Helzi Angelina, Grace Grace, Ananda Indah Putri Sihombing, Agus Setiawan, Jefferson Lynford Declan, Gladys Indira Putri, Dandy Akbar Juliansyah, Siti Fatimah, Ayu Berkahingrum, Irma Ratna Kartika, Fera Kurniadewi, Vira Saamia, Shyi-Tien Chen, Bassam Aboemolak, Hesham Ali El Enshasy

Makara Journal of Science

Escherichia coli is a foodborne pathogenic bacterium that can cause diarrhea, while yhaV is a virulence-associated gene linked to the toxin–antitoxin system in E. coli. This study was aimed at evaluating the confirmation, specificity, and sensitivity of a yhaV gene primer using real-time polymerase chain reaction. The yhaV-targeting PCR successfully amplified a DNA fragment with an amplicon length of 207 bp (base pairs) under an annealing temperature optimized to a range of 54 °C to 62 °C via gradient PCR. The PCR using the primer pair produced a consistent Ct (cycle threshold) of 14.14 ± 0.05 and showed …

The Role Of Liver Macrophages In Viral Liver Pathogenesis, Alexis Brantly, Kyle Yeakle, Michael J. Bouchard, Peter J. Gaskill, Michael R. Nonnemacher

Kimmel Cancer Center Faculty Papers

Liver macrophages play important roles in the pathophysiology of liver fibrosis and hepatocellular carcinoma. However, liver macrophages are a heterogenous population and have differing roles in maintenance of liver function and response in disease. In a healthy liver, macrophages play a critical role in antigen processing, maintaining tolerance to the high levels of gut-derived bacterial products, and regulating inflammation through cytokine response. However, macrophages also play a critical role in liver pathology, specifically in the context of viral infection. The liver is targeted by multiple viruses, including human immunodeficiency virus, hepatitis B virus, and hepatitis C virus, which dysregulate macrophage …

Enhancing Preparedness: A Genetic Study Of Sar-Cov-2 And Other Microbial Public Health Threats In Wastewater From A College Town, Christian N. Hutchinson

Master's Theses

Problem

The SARS-CoV-2 (COVID-19) pandemic revealed both the systemic vulnerabilities of our healthcare system as well as the importance of timely, localized data for informing public health responses. Traditional testing approaches were essential but often failed to capture the full extent of viral spread, especially in those with mild or asymptomatic conditions that relied on at home testing. This underreporting hindered effective allocation of resources and made developing effective intervention strategies difficult. We also realized the potential for wastewater surveillance to be applied to tracking antimicrobial resistance gene markers. Taken together, this approach should have important implications for improving public …

Synergistic Cefiderocol-Containing Antibiotic Combinations Active Against Highly Drug-Resistant Acinetobacter Baumannii Patient Isolates With Diverse Resistance Mechanisms, Justin Halim, Andrew P. Keane, Jeannete Bouzo, Tope Aderibigbe, Jessica A. Chicola, Katie T. Nolan, Keertana Jonnalagadda, Jason X. Tran, Valerie J. Carabetta

Rowan-Virtua School of Osteopathic Medicine Departmental Research

BACKGROUND: Acinetobacter baumannii is a nosocomial pathogen known for rapidly developing resistance to nearly all antibiotics, including last-line agents. Cefiderocol, a novel siderophore cephalosporin, has shown in vitro activity against A. baumannii and is now used clinically, but resistance is emerging. Data on cefiderocol-based antibiotic combinations are limited.

OBJECTIVES: To evaluate the in vitro activity of cefiderocol alone and in combination with other antibiotics against XDR and PDR A. baumannii clinical isolates, and to explore resistance mechanisms underlying cefiderocol synergy.

METHODS: We tested 21 XDR/PDR clinical isolates and one NDM-1-producing strain using broth microdilution and checkerboard assays with cefiderocol and …

Effect Of Histidine Tag On The Enzymatic Activity Of Pseudolysin And Its Interaction With The Streptomyces Metalloprotease Inhibitor (Smpi) Protein, Adewale Adeboye Adewole

Electronic Theses and Dissertations

Pseudolysin (PLN) protein is a major virulent factor in Pseudomonas aeruginosa infection. PLN belongs to the family of zinc-dependent metalloproteases. It is naturally inhibited by a smaller protein called streptomyces metalloprotease inhibitor (SMPI), secreted by Streptomyces nigrescens. Previous and current studies demonstrate that the interaction between PLN and SMPI offers unique mechanistic insights for drug development against infections caused by P. aeruginosa. This study investigated the effect of N-terminal Histidine (His) tag on the enzymatic activity of PLN and its interaction with SMPI. His-tagged PLN and SMPI proteins were expressed in bacteria and purified by affinity chromatography …

Adiponectin-Regulated Macrophage Responses In Aspergillus Fumigatus Infection: Mechanisms Of Uptake And Killing, Sri Harshini Goli

All-Inclusive List of Electronic Theses and Dissertations

Invasive aspergillosis (IA), caused by Aspergillus fumigatus, is a life-threatening infection in immunocompromised individuals, necessitating novel host-directed therapies. Macrophages are pivotal in antifungal defense, yet their function can be dysregulated; the influence of the adipokine adiponectin (APN) on this process is not fully understood. This thesis investigated the role of APN signaling in alveolar macrophage (AM) and bone marrow-derived macrophage (BMDM) responses to A. fumigatus and assessed the therapeutic potential of the APN receptor agonist, AdipoRon. Initial studies revealed that genetic deficiency in APN or its receptors renders AMs intrinsically pro-inflammatory and significantly impaired fungicidal activity against A. fumigatus. Subsequent …

Orchestrated Architecture Dismantling: Borrelia Burgdorferi’S Coordinated Destruction Of Adaptive Immune Responses, Craig A. Land

Electronic Theses and Dissertations

Borrelia burgdorferi represents the most prevalent vector-borne bacteria in North America, affecting ~476,000 Americans annually yet persisting despite robust immune responses. This project reveals spirochetes target adaptive immunity through coordinated lymphatic colonization and precision immune dysregulation.

Using comparative host models (C57BL/6 vs. reservoir Peromyscus leucopus), we demonstrate lymph node colonization within 48-hours, with spirochetes exploiting LYVE-1-positive lymphatic structures as dissemination highways while avoiding the interior of follicular regions. Critically, we identify targeted CD4+ T-cell elimination in germinal center border zones at 21-DPI, precisely when these cells should be coordinating protective immunity. Concurrent upregulation of inhibitory receptor CD32b creates molecular …

Elucidation Of A Role In Biofilm Production For The Tyrosine Catabolism Pathway In Vibrio Cholerae And Analysis Of Reversible Phase Variation In Vibrio Vulnificus, Aheli S. Mukerji

LSU Doctoral Dissertations

Biofilms produced by the cholera pathogen Vibrio cholerae not only enhance its ability to survive in the environment but also allow pathogenic success of the bacterium. This organism also undergoes phase variation, switching between smooth and rugose colonial phenotypes, the latter forming much more vibrio polysaccharide (VPS) resulting in more robust biofilms and subsequently having an increased level of persistence. In a previous study, many genes were found to be upregulated in the transition from the smooth to the rugose phenotype. Here, several of these upregulated genes were investigated for their potential role in biofilm production, and an additional gene, …

The Impact Of Polymycovirus 1 On Aspergillus Fumigatus Pathogenesis During Lung Infection, Alexander W. Rapp

Dartmouth College Ph.D Dissertations

The genus Aspergillus comprises over 250 species of fungi. Within this genus, only a handful of species cause disease in humans. One species is Aspergillus fumigatus (A.f.), an environmentally ubiquitous, saprophytic fungal pathogen. Lung infections due to A.f. range from invasive infection to allergic forms of the disease. Allergic bronchopulmonary aspergillosis (ABPA) is one of the most severe forms and presents as a hypersensitivity that often results in off-target damage to the surrounding airways. Patients with ABPA are sensitized to fungal antigens and this is commonly seen in cystic fibrosis and genetic predispositions. Recent data from our lab shown how …

From Epidemics To Experimental Treatments: Amphibian Mass Mortality Events And A Potential Treatment For Chytridiomycosis, Daniel Callahan

Graduate Masters Theses

Worldwide, amphibian populations have experienced dramatic declines due to a variety of threats. Among them, disease has been particularly deleterious and continues to impact populations. In the United States and Canada, the three leading causes of amphibian mass mortality events are ranavirosis, chytridiomycosis, and severe perkinsea infection, all caused by infectious pathogens. While research and policy have helped populations recover from these diseases, more work needs to be done to develop practical and efficient treatments for these infections. Of these three diseases, chytridiomycosis has had the most devastating effects on amphibian populations globally. Caused by the chytrid fungi Batrachochytrium dendrobatidis …

Characterization Of Sars-Cov-2 Replication And Transcription Complexes Via Structural And Evolutionary Approaches, Amelie Ghirardo, Ben Shabatian, Avishai Aghelian, Kyle Tau, Eleonora Gianti

Undergraduate Research

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) caused around 700M cases and over 7M COVID-19-related deaths recorded worldwide (World Health Organization, March 2025). Aiming to effectively combat this and other disease-causing Coronaviruses (CoV), unprecedented research efforts led to the development of new vaccines and antiviral therapies. Due to emergence of variants of concern (VOCs) with increased transmissibility, immune evasion from vaccination, and potential to resist the available treatments, SARS-CoV-2 continues to represent a major threat to global health. Hence, there is a pressing need to discover new antivirals with broad-spectrum efficacy against multiple SARS-CoV-2 variants and related CoVs. This project …

A Complete Transfer Learning-Based Pipeline For Discriminating Between Select Pathogenic Yeasts From Microscopy Photographs, Ryan A. Parker, Danielle S. Hannagan, Jan H. Strydom, Christopher J. Boon, Jessica Fussell, Chelbie A. Mitchell, Katie L. Moerschel, Aura G. Valter-Franco, Christopher Cornelison

Faculty Articles

Pathogenic yeasts are an increasing concern in healthcare, with species like Candida auris often displaying drug resistance and causing high mortality in immunocompromised patients. The need for rapid and accessible diagnostic methods for accurate yeast identification is critical, especially in resource-limited settings. This study presents a convolutional neural network (CNN)-based approach for classifying pathogenic yeast species from microscopy images. Using transfer learning, we trained the model to identify six yeast species from simple micrographs, achieving high classification accuracy (93.91% at the patch level, 99.09% at the whole image level) and low misclassification rates across species, with the best performing model. …

Coxiella Burnetii Manipulation Of Membrane Contact Sites In The Intracellular Niche, Margaret F. Sladek

Theses & Dissertations

Coxiella burnetii is a highly infectious and environmentally persistent bacterium that causes the disease Q Fever. Its intracellular home, the Coxiella-Containing Vacuole (CVV), is formed from fusion of host-derived vesicles and is rich in sterols - yet cholesterol accumulation in the CCV is bacteriolytic. Our lab’s goal is to understand how Coxiella manages intracellular cholesterol levels and survives within the host. One way Coxiella may modulate CCV cholesterol is through membrane contact sites (MCS), areas where molecular complexes bridge two organelles and exchange lipids. This thesis explores how Coxiella uses both a mammalian lipid transfer protein and bacterially-encoded effector …

Decoding Bacterial Resilience: Srnas And Sigma Factors In Stress Adaptation And Persistence Of Salmonella, Anita Nguyen

Poster Presentations

Small RNAs (sRNAs) are noncoding RNA molecules in bacteria that function primarily to regulate gene expression, including those associated with stress. The Borchert Lab has identified 173 sRNAs and > 500 sRNAs that are responsive to desiccation and carbon starvation (c-starvation), respectively. Prokaryotic transcription involves an RNA Polymerase (RNAP) that transcribes DNA into RNA. RNAP involves sigma factors, which recognize promoters for the initial steps of RNA synthesis. The Borchert Lab has determined that there are significant overlaps between sRNAs expressed in cells subjected to both short-term durations and long-term durations of carbon starvation. Salmonella enterica serovars can have outbreaks associated …

Phosphatase Activity And Structure Of The Spoiie Protein In Clostridioides Difficile, Kathryn Wootten

Biological Sciences Undergraduate Honors Theses

Clostridioides difficile is a major cause of severe gastrointestinal infections and diseases, particularly in healthcare settings. Because of its ability to produce infectious endospores by sporulation, the protein SpoIIE, which is known to play a role in the regulation of this process, is being explored as a potential therapeutic target. In order to gain better insight into the structure and function of this protein, a concentrated and purified sample of the protein must be obtained. The goal of this study was to determine the conditions that would yield the highest amount of SpoIIE. The density of the cultures of bacteria …

Toxicity And Biodegradability Of Novel Boronium Vs Conventional Ammonium-Based Antimicrobial Compounds In Wastewater Treatment Systems, Noor Shalan

Honors Theses

Quaternary ammonium compounds (QACs) are highly effective as disinfectants, herbicides, and pesticides; thus, overuse causes elevated levels of residual toxicity in domestic and industrial wastewater. QACs can be toxic to essential bacteria breaking down pollutants in wastewater treatment plants (WWTPs) and can remain untreated in effluent, harming the environment, and contributing to antibiotic resistance, posing risks to human health. Novel boronium-based antimicrobial compounds have demonstrated efficacy in eliminating bacteria, fungi, and viruses. If the boronium compounds exhibit lower residual toxicity, they could offer a promising alternative to QACs. Because these compounds are still in development, their potential toxicity to the …

Impact Of Temperature And Microbial Infection On The Honey Bee Hemocytes, Michael E. Oeth

Master's Theses

Introduction

Honey bees (Apis mellifera) rely on hemocytes for immunity, wound healing, and hemolymph homeostasis. While 32°C reflects optimal hive conditions, suboptimal temperatures (22°C) and stressors like pathogens (Varroa destructor, bacteria) or pesticides impair hemocyte function. Using clodronate liposomes (CLD) to deplete hemocytes, we assessed how immune suppression interacts with these stressors.

Methods

Newly emerged (5-day-old) and older (15-day-old) bees were assigned to: CLD, control liposomes (LP), PBS, injection wound, or no treatment. Cohorts were exposed to 32°C (optimal) or 22°C (stressful for non-immunosuppressed bees). Fifteen-day-old bees were challenged with Escherichia coli or Staphylococcus aureus. Survival, hemolymph volume, and hemocyte …

Serological Evaluation For Leptospirosis On Samples Received By The Connecticut Veterinary Medical Diagnostic Laboratory (Cvmdl), Hayden R. Samuels

Honors Scholar Theses

Leptospirosis is a globally distributed zoonotic disease caused by pathogenic species of Leptospira, motile spirochetes capable of infecting humans and animals. Transmission typically occurs through contact with water or soil contaminated by the urine of reservoirs or infected animals. Although leptospirosis is considered a neglected tropical disease, its geographic range is expanding due to climate change and urbanization. Surveillance remains limited in many regions, especially in the United States. This study aimed to assess the seroprevalence and serovar diversity of Leptospira exposure in a variety of domestic and wild animals submitted to the Connecticut Veterinary Medical Diagnostic Laboratory (CVMDL). …

Thymosin Beta-4: A Novel Treatment For Acanthamoeba Keratitis, Victoria A. Murphey

All Theses

Acanthamoeba keratitis (AK) is a severe corneal infection caused by the free-living amoeba, Acanthamoeba. Both stages of its life cycle (trophozoite and cyst) cause infection, primarily in contact lens wearers. It is often misdiagnosed, leading to delayed treatment and poor clinical outcomes. Current treatment options for AK rely on anti-amoebic agents that are toxic to corneal epithelial cells. Further, no single drug can eliminate both forms of the amoeba. Approximately 30% of all AK infections require a corneal transplant.

Thymosin beta-4 (Tβ4) is a G-actin binding protein synthesized in almost all human cells, including corneal epithelial cells. Tβ4 exhibits …

Mechanisms Of Behavioral Change In Hosts Of Toxoplasma Gondii: A Review, Olivia Grimsley

Senior Honors Theses

The parasite Toxoplasma gondii is a highly ubiquitous parasite that latently infects an estimated 33% percent of the global population. Toxoplasmosis is of obvious clinical significance due to the extremely high risks to the unborn who contract it congenitally. Less attention has been given to a more subtle aspect of latent infection, which is the behavioral alterations that are commonly experienced by those who contract the parasite. Infected individuals commonly display a variety of altered behaviors, such as increased aggression and risk-seeking behaviors, depression, higher tendency towards suicide and self-directed violence, a loss of fear response, and a greatly increased …

Genome Analysis Of Aeromonas Hydrophila Strain S14-452, Zarin Tasnim Raya

Undergraduate Research Conference

The Aeromonas hydrophila are gram-negative, opportunistic bacteria that can infect many groups of organisms, mainly fish and amphibians. In channel catfish, A. hydrophila causes fatal bacterial septicemia, leading to massive economic losses for catfish farmers. Therefore, an understanding of its genome will aid in identifying its virulence factors, metabolic pathways and survival mechanisms within the host. This study details the draft genome sequence of A. hydrophila strain S14-452, isolated from channel catfish exhibiting bacterial septicemia during a disease outbreak at a catfish farm.

A. hydrophila strain S14-452 was sequenced using the Illumina iSeq 100 System. Assembly was performed with SPAdes, …

Biochemical And Structural Insights Into The Yersinia Effector Yopm And Its Negative Regulation Of The Pyrin Inflammasome, Bethany Wairimu Mwaura

Dartmouth College Ph.D Dissertations

Bacteria utilize sophisticated secretion systems to inject effectors into host cells in order to facilitate their survival and replication in the host. Some pathogenic species of Gram-negative bacteria use a conserved contact-dependent T3SS to inject a wide array of effectors. While the effectors diverge in their structures, functions and cell-localization, the T3SS is well conserved. Several effectors discussed in this thesis target key host inflammasome responses. The focus of this work is how the Yersinia effector YopM inhibits the pyrin inflammasome. During Yersinia infection, two effectors, YopE and YopT inadvertently activate the pyrin inflammasome while targeting RhoA to avoid phagocytosis. …

Neutrophil Inflammatory Death Regulation By Bacterial Type Iii Secreted Effectors, Arianna D. Reuven

Dartmouth College Ph.D Dissertations

Yersinia and Pseudomonas use a T3SS to secrete effectors into host cells that inhibit phagocytosis and modulate immune responses, such as inflammasome activation. Inflammasomes promote the activation of the proinflammatory protease caspase-1. The activation of an inflammasome sensor in response to a signal or ligand initiates the assembly of the inflammasome leading to activation of caspase-1 which cleaves GSDMD and pro-inflammatory cytokines IL-1β and IL-18 into their mature forms. As neutrophils are recruited in large quantities to sites of infection, they are excellent candidates to drive inflammasome dependent responses. Neutrophils have been shown to produce multiple inflammasomes, like pyrin and …

The Isolation And Characterization Of Acidovorax And Brevundimonas Bacteriophages With Preliminary Biocontrol Study On Arabidopsis Thaliana, Minh Quynh N. Vu

Senior Theses

As antibiotic-resistance becomes an increasing global concern, researchers are looking for alternatives to combat phytopathogenic rhizobacteria – one of which is through the application of phage biocontrol. To elucidate the complex tripartite relationships between phage, bacteria and plant interactions, nine novel phages were isolated from potential phytopathogenic strains of Acidovorax (RBW13) and Brevundimonas (RBW18). These phages were isolated from root samples obtained from the Rocky Branch Creek and the Broad River located in Columbia, SC. Using Pulsed-Field Gel Electrophoresis (PFGE), we identified seven “medium sized” phages (~40 kbp), one “large-sized” phage (~200 kbp), and one “small-sized” phage ( < 25 kbp). Three phages were determined to be lambda-like due to their “ladder-building” patterns on PFGE. Although spot-tests revealed that all phages seemed to have broad host ranges that spanned over multiple genera, plaque-formations must be observed in future experiments to determine if these phages can infect their hosts productively. Preliminary in planta experiments were performed on Arabidopsis thaliana …