Organisms Commons^™

Nanosecond Pulsed Electric Fields Increase Antibiotic Susceptibility In Methicillin-Resistant Staphylococcus Aureus, Alexandra E. Chittams-Miles, Areej Malik, Erin B. Purcell, Claudia Muratori

Bioelectrics Publications

Staphylococcus aureus is the leading cause of skin and soft-tissue infections (SSTIs). SSTIs caused by bacteria resistant to antimicrobials, such as methicillin-resistant S. aureus (MRSA), are increasing in incidence and have led to higher rates of hospitalization. In this study, we measured MRSA inactivation by nanosecond pulsed electric fields (nsPEF), a promising new cell ablation technology. Our results show that treatment with 120 pulses of 600 ns duration (28 kV/cm, 1 Hz), caused modest inactivation, indicating cellular damage. We anticipated that the perturbation created by nsPEF could increase antibiotic efficacy if nsPEF were applied as a co-treatment. To test this …

Diel Vertical Migration Rates Of The Dinoflagellate Species Margalefidinium Polykrikoides In A Lower Chesapeake Bay Tributary, S. Clayton, Jacqueline B. Chrabot, Michael Echevarria, Leah Gibala-Smith, Kathryn Mogatas, Peter Bernhardt, Margaret R. Mulholland

OES Faculty Publications

Margalefidinium polykrikoides is a mixotrophic dinoflagellate harmful algal bloom (HAB) species that blooms annually in the lower Chesapeake Bay. M. polykrikoides undertakes a diel vertical migration (DVM) which may give it a competitive advantage over purely phototrophic organisms who cannot access deeper nutrient pools and allow it to form large toxic blooms. Laboratory-based estimates of M. polykrikoides’ DVM rates suggest that it is one of the fastest known dinoflagellate swimmers and understanding this behavior is likely important for modeling and predicting M. polykrikoides blooms. However, to date, no field-derived estimates of M. polykrikoides’ DVM rates have been made in the …

Exploration Of Potential Broad-Spectrum Antiviral Targets In The Enterovirus Replication Element: Identification Of Six Distinct 5' Cloverleaves, Morgan G. Daniels, Meagan E. Werner, Rockwell T. Li, Steven M. Pascal

Chemistry & Biochemistry Faculty Publications

Enterovirus genomic replication initiates at a predicted RNA cloverleaf (5′CL) at the 5′ end of the RNA genome. The 5′CL contains one stem (SA) and three stem-loops (SLB, SLC, SLD). Here, we present an analysis of 5′CL conservation and divergence for 209 human health-related serotypes from the enterovirus genus, including enterovirus and rhinovirus species. Phylogenetic analysis indicates six distinct 5′CL serotypes that only partially correlate with the species definition. Additional findings include that 5′CL sequence conservation is higher between the EV species than between the RV species, the 5′CL of EVA and EVB are nearly identical, and RVC has the …

Estradiol Signaling Improves Extinction Memory Recall To Combat Cue-Induced Heroin Relapse In Rats, Jordan S. Carter

MUSC Theses and Dissertations

We are in the midst of an opioid use disorder (OUD) epidemic. While several treatments mitigate a range of factors contributing to return to use, or relapse, the power of drug-conditioned environmental cues to precipitate relapse have not been adequately addressed. One treatment modality targeting cue reactivity, cue exposure therapy (CET), exacerbated relapse in individuals with OUD, perhaps due to a deficit in extinction memory recall (EMR). Here, EMR is the ability to override the drug-cue association and prevent relapse. Interest remains in combatting cue-induced relapse, potentially by introducing a pharmacologic adjunct with CET to enhance EMR. In the following …

Contributions Of The Replication Initiator Protein Dnaa To Physiology And Virulence Of The Lyme Disease Spirochete, Andrew Krusenstjerna

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

Borrelia burgdorferi, the etiological agent of Lyme disease, is the most prevalent vector-borne disease in the United States. The spirochetal population is naturally maintained by consistently cycling between Ixodid ticks and small vertebrates. To survive within these diverse niches, B. burgdorferi has evolved a unique physiology and regulatory network to sense and respond to environmental fluxes. Replication is a hallmark of the Lyme spirochete’s enzootic life cycle, specifically at the nymphal tick-to-vertebrate interface. The mechanisms and regulatory schema for the basic cellular processes in B. burgdorferi, or indeed any member of the phylum spirochaetota, are largely unknown. The central hypothesis …

The Oral-Microbiome-Brain Axis: A Thorough Review On The Relationship Between Periodontitis And Alzheimer’S Disease And A Proposed Innovative Application Of Biomagnetism As A Means Of Alternative Therapy., Taha Al Hassan, Noah Al-Hassan, Maria Quiñones-Peña, Juan Lopez-Alvarenga, Seratna Guadarrama-Beltran

MEDI 9331 Scholarly Activities Clinical Years

The relationship between periodontitis and Alzheimer's disease (AD) has garnered significant attention due to the potential influence of chronic oral inflammation on neurodegenerative processes. Our hypothesis is supported by the oral-microbiome-brain axis and highlights the possibility that chronic periodontitis contributes to cognitive decline by promoting systemic inflammation and neuroinflammation, mediated by specific pathogenic microorganisms within the oral microbiome. Our findings reveal a strong association between elevated levels of Porphyromonas gingivalis and Treponema denticola, red complex bacteria, and markers of systemic inflammation, such as C-reactive protein (CRP) and pro-inflammatory cytokines. Additionally studies have demonstrated that beta amyloid plaque in rat …

The Impact Of Gestational Diabetes Mellitus And Maternal Oral Microbiome: A Scoping Review, Jaclyn P. Langan

Honors Undergraduate Theses

Background: Gestational diabetes mellitus (GDM) is a common pregnancy-related metabolic disorder associated with adverse maternal and fetal outcomes. Recent research has highlighted the potential role of the oral microbiome in the pathophysiology of various systemic conditions, including diabetes mellitus. However, the impact of GDM on the maternal oral microbiome remains relatively understudied. Understanding alterations in the oral microbiome during pregnancy complicated by GDM could provide valuable insights into the mechanistic links between systemic metabolic disorders and oral health.

Objective: The objective of this scoping review was to comprehensively examine the existing literature on the relationship between GDM and maternal oral …

Genetic And Biochemical Analysis Of Novel Borrelia Burgdorferi Genes Bb0244 And Bb0246, Christian J. Ruiz-Rodriguez

Honors Undergraduate Theses

As the cause of the most common vector-borne disease in the US, Borrelia burgdorferi continues to affect an estimated hundreds of thousands of patients each year. The spirochete boasts one of the most complex genomes in comparison to all other prokaryotes as it is fragmented across up to 21 different replicons. Moreover, the functions of a majority of the encoded genes remain unknown. Gene of unknown function, bb0244, along with putative co-transcribed genes bb0245, and bb0246 are hypothesized to be involved in the vital functions of cell division and cell wall biogenesis. B. burgdorferi lacking bb0244 demonstrate a significant growth …

The Effect Of Mating Pheromone 2,6-Dichlorophenol On Gene Expression In Male Lone Star Ticks (Amblyomma Americanum), Mitchell E. Dyen

Honors Undergraduate Theses

Lone star ticks (Amblyomma americanum) are tick species known for their generalist feeding habits, pursuing blood meals with little preference for specific host species. They are found in the southern and midwestern United States but have been rapidly expanding northward due to climate change and white-tailed deer population expansion. Since they are a zoonotic disease vector, their increased abundance has caused the concurrent increased prevalence of a variety of tick-borne illnesses such as tularemia, heartland virus disease, alpha-gal syndrome, ehrlichiosis, and southern tick-associated rash illness (STARI), which effect both humans and animals alike. This increased prevalence of tick-borne …

Unraveling The Effects Of The Covid-19 Pandemic On Staphylococcus Aureus Carriage: A Comparative Research Of Pre- And Post-Pandemic Samples, Catherine G. Johnston

Honors Undergraduate Theses

The COVID-19 pandemic brought about significant changes in the epidemiology of Staphylococcus aureus carriage and disease. This study aims to assess these changes by leveraging respiratory samples collected from a longstanding cohort, comparing the genomic characteristics of S. aureus isolates from pre- and post-pandemic periods. We analyzed S. aureus genomes and phenotypically determined macrolide resistance to characterize population structure, antibiotic resistance, and virulence profiles. Changes in S. aureus carriage rates, macrolide resistance, disease occurrence, and population structure between samples collected pre- and post-pandemic were examined. By using respiratory samples, chart reviews, and risk factor questionnaires of 498 children from a …

Genome-Based Pathogenicity Potential Of Salmonella Isolated From Diverse Sources, Jared Mr Crocco

Theses and Dissertations (Comprehensive)

Bacterial human pathogens are among the leading causes of death around the world, especially in low income and developing countries. One important element in a bacterium’s ability to cause disease are genes that directly contribute to pathogenicity called virulence factors. A second significant aspect are antimicrobial resistance genes which allow microorganisms to persist in the presence of antimicrobial agents. In this project I aimed to determine if Salmonella isolated from different sources differed in pathogenicity profiles based on the complement of genes identified through genomic analysis. Accordingly, Salmonella genomes were organized into 8 groups: animal, clinical, human, environmental, food, water …

Harnessing Antagonistic Pleiotropy: Tolc-Dependent Coliphages Can Drive Reduced Antibiotic Resistance In E. Coli, Cooper Mckenna

CMC Senior Theses

The rise of multidrug-resistant (MDR) bacterial pathogens has been a growing concern in healthcare around the world, and bacteriophage (phage) therapy is a promising method to combat MDR infections. One defense mechanism of E. coli against antibiotics is the TolC-AcrAB efflux pump. At the same time, some phages use TolC as a surface receptor to infect the cell. This puts TolC at a crossroads in which it is beneficial to the bacteria to protect against antibiotics but harmful by allowing phage infection, creating the potential for evolutionary trade-offs. Previous research has identified only three TolC-dependent phages and shown phage-resistant E. …

Gut Dysbiosis Correlates With Covid-19 Severity, Ednita Escobar

CMC Senior Theses

Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) impacts not only respiratory but also gut and oral microbiomes, influencing the manifestations of COVID-19. Each person’s unique microbiome consists of microorganisms such as bacteria, fungi, and viruses, some of which are symbiotic and others potentially harmful. Alterations in the gut microbiome, specifically, can affect the severity and symptoms of COVID-19. A review of studies indicate a pattern of gut dysbiosis in COVID-19 patients characterized by a decrease in beneficial microbiota and/or an increase in opportunistic pathogens. This gut imbalance correlates with disease severity, suggesting that the gut microbiome plays a significant role …

Advancing Small Molecule Therapies For Myotonic Dystrophy Type 1, Sawyer M. Hicks

Electronic Theses & Dissertations (2024 - present)

Myotonic dystrophy type 1 (DM1) is a multisystemic disorder caused by the expression of expanded CUG (CUG^exp) repeat RNA from the myotonic dystrophy protein kinase (DMPK) gene. This CUG^exp repeat RNA’s gain-of-function mechanism leads to the sequestration of muscleblind-like (MBNL) proteins, resulting in widespread alternative splicing dysregulation across tissues. Despite significant research, there are currently no approved therapeutics targeting the underlying causes of DM1. This dissertation explores the development and optimization of a novel class of small molecules, Modified Polycyclic Compounds (MPCs), designed to address splicing dysregulation in DM1. MPCs were designed from previously published …

Implementing A Nurse-Driven Clostridium Difficile Screening Protocol, Sandrela Magnuson

Graduate Theses, Dissertations, and Problem Reports (ETD)

ABSTRACT

Background: Clostridium difficile infection (CDI) is a prevalent infection often contracted in hospitals. CDI is also increasingly originating from community settings. In addition to the health risks associated with CDI, diagnosis of a hospital-acquired CDI can have a significant financial impact on hospital systems. When hospital acquired, hospital systems are no longer reimbursed by payers. Secondary to the increasing prevalence of community-acquired CDI, mechanisms for early detection and isolation are warranted.

Local Problem: J.W. Ruby Memorial Hospital has an integrated Clostridium difficile (C. difficile) electronic health record (EHR) screening questionnaire that requires updating to align with current guidelines.

Purpose: …

Clostridioides Difficile: Identification Of Rival Organisms & Evaluation Of Non-Antibiotic Treatment Implementation, Justin Davis

Honors Undergraduate Theses

Clostrioides difficile is a common cause of nosocomial (hospital-acquired) infections. Patients receiving antibiotic treatment experience dysbiosis of gut microbiota, and C. difficile, normally held in check by the various other organisms, takes this opportunity to propagate. Symptoms of infection generally include diarrhea, colitis, dehydration, and fever. Understanding that C. difficile generally only causes illness when it is the dominant bacterium (i.e. when growth is relatively unchecked by other microbes), it is appropriate to investigate potential competitive organisms that may be introduced after antibiotic courses or during active C. difficile infection to effectively displace it. Fecal samples from the University …

Tim/Tam Receptors: A Potential Biomarker For Predicting Sensitivity To Zika Virus-Induced Oncolysis In Non-Small Cell Lung Cancers, Shankari Somasekar

Honors Undergraduate Theses

Non-small cell lung cancers (NSCLC) constitute 80-85% of lung cancers and are the leading cause of cancer-related deaths globally. The most common cause is prolonged smoking. Current treatment options for NSCLC include surgery, radiation, chemotherapy, targeted drug therapy, and immunotherapy. Although these medications are effective in the short term, patients often face issues of drug resistance and debilitating side effects with prolonged use. Currently, the use of Zika virus (ZIKV) is being researched as a possible alternative treatment for cancer, which minimizes side effects and the risk of drug resistance. TIM/TAM proteins are identified as the putative ZIKV receptors on …

Invasion Of Superbugs: Cockroach-Driven Outbreak Of Multidrug-Resistant Enterobacter In An Icu, Jennifer Hanrahan, Nicholas Schouten, Steven H. Fyffe, Annette Jencson, Stephanie Stroever

Department of Medicine Faculty Publications

Objective: To describe factors in an outbreak of multidrug-resistant Enterobacter cloacae (MRE) in an intensive care unit (ICU) over a 20-month period including the likely contribution of cockroaches to the outbreak.

Design: This is a retrospective descriptive study.

Setting: ICU in an urban hospital.

Patients: All patients admitted to the ICU during the 20-month outbreak period were included in the study.

Interventions: Infection prevention interventions included contact isolation, hand hygiene, dedicated patient equipment, environmental cultures, and pest control.

Results: 25 patients were identified as being colonized or infected with MRE. Relatedness of the outbreak strain and strains found in cockroaches …

Intra-Decadal Increase In Globally-Spread Magallana Gigas In Southern California Estuaries, Marah L Wolfe, Chelsea M Bowers-Doerning, Anabell Espinosa, Ty Frantz, William J Hoese, Joann G Lam, Kailee R Lamp, Rachael A Lyons, Justin K Nguyen, Bryce D Keyes, Jada Smith, Holly L Suther, Meaghan Swintek, Juliann C Vannordstrand, Danielle C Zacherl

Faculty, Staff and Student Publications

Introduction and establishment of non-indigenous species (NIS) has been accelerated on a global scale by climate change. NIS Magallana gigas' (formerly Crassostrea gigas') global spread over the past several decades has been linked to warming waters, specifically during summer months, raising the specter of more spread due to predicted warming. We tracked changes in density and size distribution of M. gigas in two southern California, USA bays over the decade spanning 2010-2020 using randomly placed quadrats across multiple intertidal habitats (e.g., cobble, seawalls, riprap) and documented density increases by 2.2 to 32.8 times at 7 of the 8 sites surveyed …

Resilience And Associated Factors In Orphaned And Separated Adolescents In Kenya: Understanding The Relationship With Care Environment And Hiv Risks., Sarah Sutherland, Harry Shannon, David Ayuku, David Kleiner, Olli Saarela, Lukoye Atwoli, Joseph Hogan, Paula Braitstein

Internal Medicine, East Africa

Orphans are at higher risk of HIV infection and several important HIV risk factors than non-orphans; however, this may be due to a combination of related social, psychological, and economic factors, as well as care environment, rather than orphan status alone. Understanding these complex relationships may aid policy makers in supporting evidence-based, cost-effective programming for this vulnerable population. This longitudinal study uses a causal effect model to examine, through decomposition, the relationship between care environment and HIV risk factors in orphaned and separated adolescents and youths (OSAY) in Uasin Gishu County, Kenya; considering resilience, social, peer, or family support, volunteering, …