Organisms Commons^™

A Potential Klebsiella Bacteriocin With Efficacy Toward The Enterbacteriaceae Family, Kasey Barber

Undergraduate Honors Theses

Drug resistance is unfortunately becoming a prevalent issue in the course of patient treatment, ranging from chemotherapy resistance to antimicrobial resistance. The Centers for Disease Control and Prevention (CDC) estimated in 2016 that at least 23,000 people die every year in the United States from an infection with an antibiotic-resistant organism (Munita, et al, 2016). Carl Friedlander was the first scientist to describe Klebsiella pneumoniae in 1882 as an encapsulated bacillus after isolating the bacterium from the lungs of patients who had died from pneumonia (Ashurst and Dawson, 2022). Klebsiella pneumoniae is the type species for the Klebsiella genus and …

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 …

Analyzing Pseudomonas Aeruginosa With Bacteriophage Tags Using Photoacoustic Flow Cytometry, Jennifer C. Schinke

Electronic Theses and Dissertations

The number of daily bacterial infections is climbing and the CDC explains that this is due to the antibiotic-resistant threat in the United States. Finding a faster way of bacterial identification is necessary as it currently takes 1-4 days for a medical lab to culture and identify bacteria. Photoacoustic flow cytometry (PAFC) can be used as an alternative method resulting in swift identification within an hour (Edgar, 2019). Pseudomonas aeruginosa, cell line PA01, will be coated in up to a few hundred red dyed phages making it detectible by the photoacoustic flow cytometry system. Bacteriophages (phages) are viruses that …

The Effects Of Light Intensity And Cell Structure On The Cultivation Of Arthrospira Platensis, Taylor Barnhart

Honors Theses

As scientists explore further into space, more cost-effective resources are needed for long-term space travel. An interesting solution is Arthrospira platensis, a filamentous cyanobacteria high in proteins and nutrients, and known for its helical structure. In unfavorable conditions, coiled spirulina cells become straight. Spirulina converts carbon dioxide gas into pure oxygen and the different cell structures stimulate different responses in oxygen production and cultivation. In these experiments, 2.3 L containers of pure coiled spirulina and mixed (coiled and straight) spirulina were placed into 3 incubators with different light intensities: 51μmol/m2/s, 25μmol/m2/s, 12μmol/m2/s. Each experiment length was 72 hours and the …

Effect Of Temperature On The Microbiome Of A Laboratory-Reared Colony Of Haemaphysalis Longicornis Ticks, Brianna L. Mitchell

Undergraduate Honors Theses

Haemaphysalis longicornis ticks are invasive to the United States with potential to transmit several tick-borne pathogens that are native to the United States. Based on existing locations of H. longicornis in its native regions in Asia, as well as its invasive populations that are established in the United States, several geographic range prediction models have been produced to help understand future range expansion and distribution of this invasive tick in North America. Unfortunately, these models do not all agree and there is uncertainty associated with the potential geographic range expansion of H. longicornis ticks in North America. Climate can affect …

Leptospira Seroprevalence In Companion Animals In Tennessee, Kellie Anne Mccreight

Masters Theses

Leptospirosis is a re-emerging zoonotic disease in humans and animals. The bacteria Leptospira spp. causing this disease is maintained in the kidneys of animals such as rodents and cattle as well as in the environment. Animals harboring Leptospira spp. in the kidneys frequently shed the bacteria in their urine, contaminating the environment. Contact with contaminated soil and water may result in infection. Animals and humans may develop serious life threatening disease from Leptospira infection. Approximately 1 million new human cases and over 50,000 deaths are reported worldwide. Numerous animal species including rodents, cattle, and dogs may serve as reservoir …

The Effect Of Fluorouracil On Pathogenic And Non-Pathogenic Oral Microorganisms And Microbial Interactions With Preventative Measures: A Preliminary Study, Valeria Ortiz Jimenez, Lynn Lewis

Student Research Submissions

Cancer chemotherapy compromises the patient’s oral health through dysbiosis of oral microbiota and increases the prevalence of dental cavities, gingivitis, oral mucositis, and xerostomia. This research aimed to evaluate the effect of a common chemotherapeutic agent, Fluorouracil (5-FU), on certain microorganisms that are common within the oral cavity. Varying concentrations (50 μM, 75 μM and 100μM) of 5-FU were used to simulate the dosage that reaches the oral cavity after intravenous delivery. The microorganisms tested were Pseudomonas aeruginosa, Staphylococcus aureus, Enterococcus faecalis, Streptococcus mutans, Lactobacillus rhamnosus and Streptococcus salivarius. These are some of the most common ones found in 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 …

Alzheimer’S Disease Genetics And Short-Chain Fatty Acid Treatment In Studies Of The Murine Gut Microbiome, Diana Zajac

Theses and Dissertations--Physiology

Elucidating the relationship of the gut microbiome in Alzheimer's Disease (AD) risk and pathogenesis is an area of intense interest. Since 60 to 80% of AD risk is related to genetics and APOE alleles represent the most impactful genetic risk factors for AD, their mechanism(s) of action are under intense scrutiny.

First, I conducted a study on APOE targeted replacement mice to investigate the impact of APOE alleles on the murine gut microbiome. The relative abundance of bacteria from the family Ruminococacceae and related genera increased with APOE2 status. The relative abundance of the class Erysipelotrichia increased with APOE4 status, …

Expansion On The Use Of The Novel Compound, Elp-004, Using A Mycobacterium Tuberculosis Experimentation Model, Kendyl Marie Berry

Graduate Theses, Dissertations, and Problem Reports

Osteoarticular tuberculosis (OAT) is a bone degenerative disease that results in bone erosion, joint effusion, joint swelling, and sometimes, nerve compression. OAT occurs from the hematogenous dissemination of Mycobacterium tuberculosis (Mtb) bacilli spreading from the primary site of infection to the bones and joints; the primary site of infection tends to be the lungs as pulmonary tuberculosis infections are the most common. OAT can occur as the result of an active or latent infection. Latent infections result in OAT when bacilli are able to escape granulomas. The incidence of OAT is not as high as pulmonary infections, making up about …

An Epidemiological And Pharmacokinetic-Pharmacodynamic Investigation Into The Impact Of Carbapenem-Resistant Enterobacterales, Justin Clark

Theses and Dissertations--Pharmacy

Background: According to the 2019 CDC Antibiotic Resistance Threats Report, more than 2.8 million antibiotic-resistant infections occur in the United States each year, leading to more than 35,000 deaths. Among the most urgent threats identified by the CDC are carbapenem-resistant Enterobacterales (CRE). Despite efforts to control the spread of these organisms, the number of estimated cases between 2012 and 2017 remained stable. In 2017, an estimated 13,100 hospitalized cases of CRE led to approximately 1,100 deaths and $130 million attributable healthcare costs. This dissertation seeks to address this issue from both a pharmacokinetic/pharmacodynamic and epidemiological perspective.

Methods: We evaluated the …

Exploring The Effects Of Fatty Acids (Pufas) On The Antimicrobial Resistance In Vibrio Cholerae, Naina Patel

Honors Theses

As antibiotic resistance becomes a major challenge for public health professionals, our research objectives aimed to investigate the potential for polyunsaturated fatty acids (PUFAs) to create membrane vulnerability in the gram-negative pathogen Vibrio cholerae to help improve the efficacy of several antibiotics. V. cholerae, normally residing in aquatic environments, is capable of altering its phospholipid composition through the uptake and assimilation of exogenous polyunsaturated fatty acids. The purpose of this study was to measure PUFA-mediated changes in the membrane permeability and antibiotic resistance of Vibrio cholerae. The three physiologically relevant PUFAs used were linoleic acid [18:2], arachidonic acid [20:4], and …

Comparison Of The Humoral Immune Response Following Both Bacterial Challenge And Rnai Of Major Factors On Proliferation Of Bartonella Quintana In The Human Louse, Jake Zina

Masters Theses

Human body lice, Pediculus humanus humanus, and head lice, Pediculus humanus capitis, have been hematophagous ectoparasites of humans for thousands of years. Despite being ecotypes, only body lice are known to transmit bacterial diseases to humans, and it appears that lower humoral and cellular immune responses allow body lice to possess a higher vector competence. We previously observed that the transcription level of the defensin 1 gene was up-regulated only in head lice following oral challenge of Bartonella quintana, a causative agent of trench fever, and also that body lice excreted more viable B. quintana in their …

Tracking The Source Of Helicobacter Pylori In Watersheds Of San Juan, Puerto Rico, Mary Elizabeth Sailors

Biology Theses

Helicobacter pylori is a pathogenic bacterium that infects more than half of the world’s population. The large number of H. pylori infections in Puerto Rico could be related to the waterborne transmission of the pathogen. While the San Juan Bay Estuary (SJBE) system is home to over three million people, water quality studies in this area of Puerto Rico are lacking. The goal of this study is to determine seasonal and yearly (2020-2021) shifts and relationships between the presence of H. pylori and host-specific (human and dog) Bacteroides in streams that flow through the northern coastal zone of Puerto Rico …

Flippase Inhibitors As Antimicrobial Agents, Robert Tancer

Seton Hall University Dissertations and Theses (ETDs)

Drug resistant microbes are a considerable challenge for modern medicine to overcome. The research described in this dissertation involved development of lipid flippase inhibitors and investigating their potential as antimicrobial agents against various drug resistant microbes. The microbes primarily investigated were methicillin resistant Staphylococcus aureus (MRSA) & Cryptococcus neoformans. Chapter 1 reviews the historical perspective and summarizes the current state of the field of research. In Chapter 2, the design space of an antimicrobial peptide known as humimycin was explored and the effects of modifications on its structure were observed against MRSA. Several key observations resulted. Most notably, the …

Bacteriophages: Paving The Road For The Future Of Medicine, Luke Brinkerhoff

Honors Theses

Bacteriophages are a possible solution to antibiotic resistance, which is predicted to be detrimental world-wide by the year 2050. Personal field research was also conducted for a project studying the characteristics of two bacteriophages on a single bacterial host.

Investigation On Bacterial Signaling Through Generation Of A Ppgpp Biosensor, Andrew Robinson

Undergraduate Honors Theses

Guanosine tetraphosphate (ppGpp) is a bacterial signaling molecule involved in activating the stringent response, a cellular reaction to environmental stress that downregulates cell division and metabolism processes to conserve nutrients. The stringent response is implicated in some instances of antibiotic persistence, so broadening the current understanding of ppGpp signaling is useful. This thesis seeks to generate a ppGpp biosensor that will bind ppGpp and emit fluorescent light in its presence, which will allow for improved research into the pathways and functions of the signaling molecule. To generate a novel ppGpp biosensor, I converted a biosensor previously used to detect cyclic …

Cyclic-Di-Gmp-Binding Proteins Regulate Acinetobacter Baumannii Motility, Gabriel Smith

Undergraduate Honors Theses

Acinetobacter baumannii is a prevalent nosocomial pathogen where, like many other infectious bacteria, A. baumannii is increasingly considered a multi-drug resistant pathogen. This research study was designed to find a way to affect the persistence of A. baumannii such that it can be applied to a hospital setting to prevent further nosocomial infections. One regulatory mechanism potentially used by A. baumannii to persist on hospital surfaces is through the use of the bacterial second messenger cyclic-di-GMP (c-di-GMP). This nucleotide signal is regulated in response to environmental conditions, and then activates c-di-GMP-binding proteins that induce phenotypic changes. One c-di-GMP-regulated phenotype is …

Diversity Of Bacteriophage In Burkholderia Species, Abigail Price

Honors Projects

Bacteriophages are viruses that infect and replicate within bacteria and offer the potential of a therapeutic alternative to chronic infections that do not respond to antibiotic-based therapies. B. vietnamiensis is one of a number of Burkholderia species involved with chronic drug resistant infections in the lungs of individuals with compromised respiratory systems, as found in those with chronic obstructive pulmonary disease and, most especially, are of particular significance in patients with cystic fibrosis. The diversity of the Burkholderia species is explored by using online databases and looking at bacteriophage or phage-encoding viruses found in B. vietnamiensis. The open reading frames …

An Antimicrobial Polydopamine Surface Coating To Reduce Biofouling On Telemetry Tags Used In Marine Conservation Practices, Ariana Smies

Dissertations, Master's Theses and Master's Reports

Satellite telemetry tags are used to track the migration patterns of large cetaceans. These tags penetrate the dermis and remain embedded in the underlying blubber tissue. As the dermis of cetaceans is host to a diverse microbiome, and it is impossible to clean the skin before implanting the devices, the potential for infection is increased when the tags penetrate through the skin. H₂O₂ is a potential antimicrobial agent that, in addition to showing broad-spectrum efficacy against gram-negative and gram-positive bacteria, can promote wound healing outcomes by promoting proliferative factors and peptides that protect against oxidative stress. However, …

The Influence Of Hydrogen Peroxide On The Enrichment Of Fe(Iii) Reducing Bacteria From Acid Mine Drainage, Susami Seth

Williams Honors College, Honors Research Projects

It is hypothesized that the ocean of Europa, a Jupiter moon, hosts bacteria on its oceanic floor. Understanding how Fe(III) reducing bacteria (FeRB) from AMD utilize organic materials within its surrounding environment outlines how FeRB could thrive and tolerate extreme conditions. FeRB are known to tolerate metals and highly reactive oxidants species (ROS), but in this experiment, H₂O₂ was the experimental factor to further test FeRB tolerance. H₂O₂ is a common ROS and is damaging to living material such as proteins, DNA, and RNA. A range of H₂O₂ concentrations were fed …

Effectiveness Of Stabilized Hypochlorous Acid In Acute Peritonitis Treatment: A Murine Surgical Study, Benjamin Michael Pomeroy

MSU Graduate Theses

Peritonitis is an inflammatory condition affecting the mesothelial cells that line the peritoneal cavity and is commonly induced by bowel perforations. This medical emergency is treated through antibiotic therapy and surgical intervention followed by tissue irrigation (lavage). Acute treatments aim to remove the bacterial burden, however recurring peritoneal infections occur at high rates and contribute to patient morbidity. These recurring infections are likely due to the inability of lavage solutions to remove the entire massive intra-abdominal bacterial load due to intestinal perforation. Numerous antiseptic solutions and antibiotic additives have been evaluated in their ability to improve source control by abdominal …

Genital Chlamydia Infection Is Influenced By The Female Sex Hormones Estrogen And Progesterone In Vivo, Amy Gail Gravitte

Electronic Theses and Dissertations

Chlamydia is the most common bacterial sexually transmitted infection in the United States and worldwide. It often goes unnoticed due to lack of symptoms and left untreated it can ascend the female genital tract to cause sequelae like pelvic inflammatory disease and irreversible tubal infertility. In reproductive-aged women, female sex hormones estrogen (E2) and progesterone (P4) concentrations fluctuate during the menstrual cycle and are influenced by hormonal contraceptives and hormone replacement therapy. E2 and P4 influence genital Chlamydia infection in women and mice, but these multifactorial interactions are not entirely mapped out. The complex interplay of E2 and P4 with …

Disruption Of Insertion Sequence 200 (Is200) Leads To A Premature Induction Of The Cysteine Regulon In Salmonella Typhimurium, Naomi-Jean Q. Scherba

Electronic Thesis and Dissertation Repository

Salmonella Typhimurium is a leading contributor to non-typhoid diseases with complex regulatory networks that are key to understanding its pathogenicity and virulence. I explore the role of the sRNA IS200, where its deletion in Salmonellaleads to premature induction of the Cys regulon. The premature induction in ∆IS200 was validated through qRT-PCR and GFP transcriptional fusions and occurs at late exponential to early stationary phase. In addition, ∆IS200 leads to increased sensitivity to oxidative stress. The focus of this work has been to understand how ∆IS200 leads to premature Cys regulon induction, and I present three models: the futile import/export, …

Assesment Of Antibiotic Resistant Gene Expression In Clinical Isolates Of Pseudomonas Aeruginosa, Dustin Esmond

Biology Theses

Increasing prevalence of nosocomial infections by antimicrobial resistant pathogens resulting in higher mortality rates and financial burden is of great concern. Pseudomonas aeruginosa represents one of six highly virulent “ESKAPE” pathogens that exhibit considerable intrinsic drug resistance as well as mechanisms for acquiring further resistance. As many of these mechanisms are regulated through gene expression, we sought to identify regulatory strategies and patterns at play in 23 clinical isolates collected from Baku, Azerbaijan and Tyler, Texas, USA. Real-time quantitative polymerase chain reaction was performed on six gene targets implicated in resistance and contrasted with antibiotic phenotypes. We found AmpC cephalosporinase …

Identification And Characterization Of Butyrate-Producing Species In The Human Gut Microbiome, Grace Maline

Theses/Capstones/Creative Projects

Inflammatory Bowel Diseases (IBD) including ulcerative colitis, indeterminate colitis, and Crohn’s disease are increasingly common conditions that places a high physical and financial burden on individuals and global healthcare systems. Though many treatments exist for these conditions, their unpredictable nature and causation make them difficult to manage across the variety of IBD patients. Additionally, many of these treatments come with undesirable side effects or modes of delivery. Therefore, it is worthwhile to explore the use of Short Chain Fatty Acids (SCFAs) such as butyrate whose affects in the human gut include decreased inflammation and decreased risk of colorectal cancer. As …

Hemin Utilization In Rhizobium Leguminosarum Atcc 14479, John Lusby

Electronic Theses and Dissertations

Rhizobium leguminosarum is a Gram negative, motile, nitrogen-fixing soil bacterium. Due to the scarcity of iron in the soil bacteria have developed a wide range of iron scavenging systems. The two types of iron scavenging systems used are indirect and direct. In-silico analysis of the genome identified a unique direct iron scavenging system the Hmu operon. This system has been identified in other closely related rhizobium species and is believed to be involved in utilizing heme compounds as a sole source of iron. We have attempted to characterize the role of the Hmu operon in iron utilization by monitoring the …

Deciphering The Mechanisms Of Alcaligenes Faecalis’ Inhibition Of Staphylococcus Aureus And Synergism With Antibiotics, Cortlyn Holdren

Undergraduate Honors Theses

Staphylococcus aureus has developed resistance to several antibiotics including vancomycin, which is often used as a “last resort” treatment. There is an ever-increasing need to develop novel antimicrobial treatments to combat S. aureus and other drug resistant bacteria. Microorganisms are most often found in polymicrobial communities where they either exhibit synergistic or antagonistic relationships. Competition between microorganisms can lead to the discovery of new antimicrobial targets as the specific mechanisms of resistance are elucidated. In addition, synergistic treatments are being evaluated for their combined effect and potential to decrease the concentration of drugs needed, and thus the side effects also. …

The Migration Of Carbapenem-Resistant Acinetobacter Baumannii From The Battlefields Of Iraq And Afghanistan To The Healthcare Facilities Of The Veterans Health Administration, Jeffery Rogers

Capstone Experience

Multidrug-resistant organisms (MDRO) pose a great threat to health across the globe. That threat is also felt in the Veterans Health Administration (VHA). Wounded warriors returning home from the battlefields of Iraq and Afghanistan may have brought with them MDROs, such as the bacterium Acinetobacter baumannii, as they have transitioned from military service into the VHA facilities. This study investigates the interconnectedness of military service in the Department of Defense (DoD) and a lifetime of care at VHA through a longitudinal tracking of a linked cohort of combat veterans with battlefield injuries and subsequent MDR infections of A. baumannii. …

Characterizing The Physiology And Genetics Of Contact Dependent Growth Inhibiton Systems In Burkholderia Species, Alice Elizabeth Oates

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

Contact-dependent growth inhibition (CDI) systems mediate interbacterial competition. The genes encoding these systems are widespread among Gram-negative bacteria, including Burkholderia pathogens. CDI systems of Burkholderia species are composed of two-partner secretion pathway proteins and function to deliver the toxic C-terminus of a polymorphic surface-exposed exoprotein BcpA (Burkholderia CDI protein A) to the cytoplasm of neighboring recipient bacteria upon cell-cell contact. Specific outer and inner membrane proteins facilitate BcpA translocation both out of the donor bacterium and into the recipient cell cytoplasm. Most Burkholderia species-specific CDI translocation factors in recipient cells are unknown. BcpA intoxication functions as a mechanism by …