Bacteriology Commons^™

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 …

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 …

Elucidation Of Gene Essentiality And Genetic Determinants Of Intrinsic P-Aminosalicylic Acid Resistance In Mycobacterium Kansasii, Keith J. Levendosky

Dissertations, Theses, and Capstone Projects

Mycobacterium kansasii (Mk) is an opportunistic pathogen capable of causing tuberculosis-like pulmonary disease in immunocompromised individuals and those with other risk factors including chronic obstructive pulmonary disease or malignancy. Mk is frequently isolated from man-made water sources where it forms resilient biofilms, posing a health risk to these susceptible individuals. Despite its medical relevance as an environmental pathogen, and a close phylogenetic relationship with the obligate pathogen Mycobacterium tuberculosis (Mtb), few studies to date have probed the molecular biology and genetics of Mk. Here, we sought to apply a transposon (Tn) mutagenesis tool to dissect …

Genetic Determinants Of Carotenoid Pigmentation In The Opportunistic Pathogen Mycobacterium Kansasii, Niklas Janisch

Dissertations, Theses, and Capstone Projects

Mycobacterium kansasii (Mk) is an opportunistic pulmonary pathogen causing infections, predominantly in immunocompromised people, with symptoms similar to those caused by its close relative Mycobacterium tuberculosis (Mt). In contrast to the latter, little work has been done on Mk genetics and even less on its defining characteristic of photochromogenicity, the controlled expression of carotenoid pigments in response to light exposure.

This work represents major progress in the investigation of pigmentation-related genetic factors in Mk. We report the creation of a large-scale, random transposon-insertion mutant library of Mk and its subsequent screening for mutants with an aberration in the …

Comparative Genomics And Virulence Studies Of Streptomyces Soil Rot And Scab Pathogen Species, Natasha Soares

LSU Doctoral Dissertations

Comparative genomic analyses were performed to gain insights into the organization and content of the genome of Streptomyces ipomoeae, the soil rot pathogen that infects sweetpotatoes. Unlike Streptomyces scab pathogens, the thaxtomin phytotoxin gene cluster (txt) in S. ipomoeae does not appear to reside within a genomic island and has diverged from its scab pathogen counterparts. Increased usage of the rare TTA codon, particularly for the txt cluster, suggests greater translational control by the bldA tRNA in S. ipomoeae. Orthologous gene searches and secondary metabolite profiling yielded ortholog groups and metabolite gene clusters that were exclusive …

Novel Signal Sequences And Fusion Partners For Paratransgenesis In Asaia, Christina Grogan

Electronic Theses and Dissertations

Mosquitoes transmit many pathogens that cause human disease. One such disease, malaria, is caused by parasites in the genus Plasmodium, infecting over 200 million people and killing over 600,000 per year. Current strategies to control vector-transmitted diseases are increasingly undermined by mosquito and pathogen resistance. Research has turned to additional and novel methods of control, such as altering the microbiota of the vectors. In this method, called paratransgenesis, symbiotic bacteria are genetically modified to affect the mosquito’s phenotype by engineering them to deliver antiplasmodial molecules into the midgut to kill parasites. These molecules must be released by the …

Cyclic Di-Gmp Regulates Motility, Biofilm Formation, And Desiccation Tolerance In Acinetobacter Baumannii, Garrett Reynolds

Electronic Theses and Dissertations

Acinetobacter baumannii is an increasingly multidrug-resistant pathogen contributing to hospital-acquired infections necessitating the discovery of novel treatments. A bacterial second messenger, cyclic diguanosine monophosphate (cyclic di-GMP), can regulate various persistence factors that are potentially advantageous for survival in hospital environments. Cyclic di-GMP–modulating enzymes and cyclic di-GMP–binding effectors predictively are encoded in the Acinetobacter baumannii genome. I hypothesized that cyclic di-GMP controls motility, biofilm formation, and desiccation tolerance in Acinetobacter baumannii. Disrupting cyclic di-GMP–modulating enzymes or cyclic di-GMP–binding effectors should alter the regulatory effectiveness of these phenotypes. I tested the multidrug-resistant isolate Acinetobacter baumannii strain AB5075 and identified several transposon …

The Effects Of Short Chain Fatty Acids On Clostridioides Difficile Growth, Sporulation, And Toxin Production, Michelle Baldassare

All Theses

Short chain fatty acids (SCFAs) are products of bacterial fermentation that help maintain important gut functions such as the intestinal barrier, signaling, and immune homeostasis. The main SCFAs acetate, propionate, and butyrate have demonstrated beneficial effects for the host, including importance in combatting infections caused by pathogens such as Clostridioides difficile. C. difficile infection (CDI) is a public health concern and causes 30,000 deaths each year mainly due to the overuse of antibiotics. Despite the potential role of SCFAs in mitigating C. difficile infection, their direct effect on C. difficile remains unclear. Through a set of in-vitro experiments, we …

Investigation Of The Urobiome For The Production Of Novel Antimicrobials Against Uropathogenic E. Coli (Upec), Jennifer Jones

ORBioM (Open Research BioSciences Meeting)

BACKGROUND: Urinary tract infections (UTIs) are one of the most common bacterial infections globally with antibiotic treatment becoming increasingly less effective. The urobiome remains a relatively understudied niche as a source of potentially novel antimicrobials (e.g., bacteriocins). Improvements to bacterial culturing and sequencing techniques have highlighted the potentially rich source of alternative treatments and control strategies to target uropathogenic E. coli (UPEC).

MATERIALS AND METHODS: (a) BAGEL 4 was used for bioinformatic screening of the genomes of urobiome isolates to identify bacteriocin gene clusters (BGC).

(b) Expanded quantitative urine culture (EQUC) was used to culture mid-stream urine samples to isolate …

Resolving The Repression Pathway Of Virulence Gene Hila In Salmonella, Alexandra King, Lon Chubiz Phd, Brenda Pratte, Lauren Daugherty

Undergraduate Research Symposium

Salmonella is a relatively abundant, virulent species of bacteria that is most known for spreading gastrointestinal diseases through food. These illnesses result in approximately 1.35 million infections, including over 25,000 hospitalizations each year, in the U.S. alone (CDC.gov). As antibiotic resistance becomes an increasingly urgent public health problem, the importance of developing alternative treatment methods is only becoming more crucial. One of the genes responsible for this virulence is known as hilA. HilA is the main transcriptional regulator of Salmonella Pathogenicity Island-1 gene (UniProt). SPI-1 plays an important role in the invasion of Salmonella into epithelial cells. The proteins encoded …

An Investigation On The Impact Of Intestinal Oxygen Availability On Survival And Regulation Of Virulence In Listeria Monocytogenes, Damayanti Chakravarty

Dissertations

The deadly foodborne pathogen Listeria monocytogenes is a gram positive facultative anaerobic bacterium. It is the third leading cause of death from food-borne illnesses. Once ingested, it encounters various stressors in the gastrointestinal (GI) tract, including acidic pH, bile, and alterations in oxygen availability. Various studies have been done regarding the pathogen’s survival mechanism against acid and bile. Since the lower parts of the GI tract are anaerobic, it is imperative to investigate how physiologically relevant anaerobic conditions impact L. monocytogenes’s survival. Transcriptomic analysis of L. monocytogenes under conditions mimicking the GI tract was performed. A large number of genes …

Eskape Pathogens: The Clinical Prevalence And Molecular Mechanisms Of Antibiotic Resistance, Anusha Attre

Honors Scholar Theses

The ESKAPE pathogens (Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, and Enterobacter species) are the leading cause of all nosocomial, or healthcare-associated (HAI), infections (Navidinia, 2016). The purpose of this research study is to determine the burden of ESKAPE infections on healthcare and study the antibiotic resistance in these high-risk pathogens to provide direction for researchers to develop new antimicrobial innovations to reduce ESKAPE infectivity and improve patient outcomes. To study the burden of ESKAPE infections, this review analyzes the current statistics explaining the clinical prevalence of each pathogen in causing HAIs. Additionally, each pathogen is …

Characterizing The Interaction Between Candida Albicans And Two Enterobacter Species, Abigail Cornett

Electronic Theses and Dissertations

Candida albicans is the most common human fungal pathogen. The relationship between C. albicans and Enterobacter bacteria have yet to be explored. The hypothesis of this study is that C. albicans and both E. aerogenes and E. cloacae have a positive relationship and work together to infect the host. In this study, the physical cell-to-cell interaction, molecular components of said interaction, and the impact of the interaction on a live organism were explored. Results indicate that Enterobacter adheres to C. albicans and inhibits growth with unidentified secreted molecules. Als1p has potential involvement in the attachment of E. cloacae to C. …

The Microbiome Characterization And Comparison Of Loggerhead (Caretta Caretta) And Green (Chelonia Mydas) Sea Turtle Eggs In Broward County, Florida, Colleen Mcmaken

All HCAS Student Capstones, Theses, and Dissertations

All seven extant species of sea turtles are classified as threatened or endangered due to natural and anthropogenic impacts. Sea turtle conservation efforts are largely dedicated to ensuring healthy nesting activity. Hatching success of sea turtle eggs can be affected by several factors including the proliferation of pathogenic microbes. However, it is unclear as to which microbes have the most impact on hatching success and how they are transmitted into the eggs. The primary aims of this study characterized and compared the bacterial communities (microbiomes) from the i) cloaca of nesting sea turtles; ii) sand within and surrounding the nests …

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 …

Investigating Alternative Induction Of The S. Aureus 80a Prophage, Jody Caretti

Student Scholar Showcase

Widespread antibiotic resistance has quickly become one of the most concerning crises affecting modern medicine, especially in cases of Staphylococcal infections, which have become resistant to all ��-lactam antibiotics. As a result, research into alternative forms of treatment for bacterial infections is a top priority. Bacteriophage therapy is a popular candidate for replacing antibiotics, due to the way the viruses interact with the bacteria. The 80�� prophage integrates its DNA into Staphylococcus aureus strain 10616 via the lysogenic cycle, and replicates with the bacterial cell. When stressed, the bacteria stop replicating and the prophage stimulates the lytic cycle, activating transcription …

Sars-Cov-2 Reveals That Chimeric Agents Are The Bioweapons Of The Future, Rachel Craig

Senior Honors Theses

Bioweapons programs have existed since their development during the Cold War. These biowarfare programs initially utilized naturally occurring pathogens capable of infecting crops, livestock populations, and human populations. Anthrax is a widely exploited bioagent responsible for attacks ranging from the Germans’ deployment in World War I to the mailing of anthrax through the postal service in attempts on U.S. senators’ lives. With the development of genetic manipulations, the Soviet Union began modifying anthrax to resist detection and treatment. With the continued advancement of science and technology, a new bioagent has entered the scene – the man-made chimeric virus. Chimeric viruses …

The Coxsackievirus And Adenovirus Receptor Has A Short Half-Life In Epithelial Cells, Poornima Kotha Lakshmi Narayan, James M. Readler, Mahmoud S. Alghamri, Trisha L. Brockman, Ray Yan, Priyanka Sharma, Vladislav Snitsarev, Katherine J.D.A Excoffon, Abimbola O. Kolawole

Department of Biology Faculty Scholarship and Creative Works

The coxsackievirus and adenovirus receptor (CAR) is an essential cellular protein that is involved in cell adhesion, cell signaling, and viral infection. The 8-exon encoded isoform (CAREx8) resides at the apical surface of polarized epithelia, where it is accessible as a receptor for adenovirus entering the airway lumen. Given its pivotal role in viral infection, it is a target for antiviral strategies. To understand the regulation of CAREx8 and determine the feasibility of receptor down regulation, the half-life of total and apical localized CAREx8 was determined and correlated with adenovirus transduction. Total and apical CAREx8 has a relatively short half-life …

The Role Of The Skin Microbiome In Amphibian Pathogen Susceptibility In Turnbull National Wildlife Refuge, Krista S. Dodd

EWU Masters Thesis Collection

The fungal pathogen, Batrachochytrium dendrobatidis (Bd), has led to the decline and extinction of many amphibian populations, but some bacteria in the skin microbiome can inhibit its growth. In Turnbull National Wildlife Refuge (TNWR) in eastern Washington, Bd is highly prevalent, but the role of the skin microbiome in Bd infection dynamics have not been examined in this region. We hypothesized that frogs with lower Bd infection intensities would have higher skin bacterial diversity and more abundant anti-Bd bacteria, indicative of a more protective function. Our study combined cultureindependent and culture-dependent methods to assess the relationship between Bd and the …

Evaluate The Efficacy Of A Mixture Of Peroxyacetic Acid And H2o2 Against The Survival And Cross-Contamination Of The Salmonella Surrogate Enterococcus Faecium On Tomatoes During Triple-Wash, Corey Waitman Coe

Graduate Theses, Dissertations, and Problem Reports (ETD)

Triple-wash with a mixture of peroxyacetic acid and H2O2 (SaniDate-5.0) during post-harvest processing of fresh produce has been recommended by West Virginia Small Farm Center to improve microbial safety. It has been well recognized that the washing of produce is more important for preventing cross-contamination than reducing foodborne pathogens. Furthermore, it may help improve public confidence in that the produce they obtain from locally grown farmers is safe for their consumption. determine the efficacy of SaniDate-5.0 for reducing the survival and preventing cross-contamination of the Salmonella surrogate Enterococcus faecium on tomatoes during triple-wash.

E. faecium ATCC-8459 (resistant to 100-ppm nalidixic-acid) …

An Investigation Into The Prevalence Of Vancomycin-Resistant Enterococci Within An Irish Hospital, Dylan Casey

International Undergraduate Journal of Health Sciences

Vancomycin-resistant enterococci (VRE) are well-recognised nosocomial pathogens that pose a significant threat to public health. Associated with poorer clinical outcomes than their vancomycin-sensitive counterparts, the prevalence of VRE in Ireland has increased in recent times, with the European Antimicrobial Resistance Surveillance Network reporting that out of 29 countries, Ireland demonstrated the highest rates of vancomycin resistance among invasive Enterococcus faecium isolates between 2011 and 2014 (2011; 34.9%, 2012; 44.0%, 2013; 42.7%, 2014; 45.1%). Herein, we investigate VRE prevalence in the Mercy University Hospital (MUH) – an acute care hospital in southern Ireland. A total of 21 first-time VRE infections were …

Enzymatic Degradation Of Microcystin-Lr By Microcystinase (Mlra), Faisal Alqhtani

Graduate Theses and Dissertations

Microcystin-LR (MC-LR) is affecting the water supply worldwide. Hence, a way to eliminate this toxin is an essential target. In this study, successful cloning of the mlrA gene and producing MlrA enzyme that can degrade the cyclic MC-LR to linearized MC-LR was done. MlrA protein was expressed in Escherichia coli BL-21 (E. coli). Also, enhancing the MlrA yield by adding nickel to LB media was a success in producing more MlrA enzyme from the same volume. Even though the enzyme showed no activity after adding Ni, the enzyme was expressed at a higher yield. Furthermore, it was to investigate adding …

Lyme Arthritis: A Primer For Primary Care, Ganesh Arun, Farhan Ali, Sowmya Srinivas, Justin Nistico, Pranav Nair

Advances in Clinical Medical Research and Healthcare Delivery

Lyme disease is caused by a bacteria belonging to the Borreliaceae family. Wooded forests and terrains are affected, including those in the Northeastern United States. Teenage ticks are most commonly discovered on humans as those ticks need to satisfy their nutritional requirements for growth. They bite warm, moist areas of the body and take 24 to 48 hours to transmit the Borrelia Burgdorferi infection. Lyme disease manifests as a multisystem disorder in humans, and is known for its dermatological, neurological and rheumatological findings. For the primary care provider, Lyme disease should be on the differential in multisystem diseases. Our case …

The Sterilization Of Escherichia Coli With Black Diamond-Coated Silicon, Sarah M. Cawthon, Jesse L. Rozsa, Mark P. Running

The Cardinal Edge

In order to combat increasing levels of antimicrobial resistance, new antimicrobials are needed to successfully kill microbes. Silicon coated in black diamond is a material that is hypothesized to have antimicrobial properties. To test this hypothesis, Escherichia coli cells were placed on different black diamond-coated silicon surfaces and allowed to rest on each surface for 15 minutes, 30 minutes, and 1 hour. Cells were collected, and growth was assessed by counting colonies on plates or spectrophotometry growth curves. The results of this study indicated that the experimental samples have some antimicrobial or growth inhibition properties, but they may not be …

Editorial: Pathogens, Pathobionts, And Autoimmunity, Linda A. Spatz, Gregg J. Silverman, Judith A. James

Publications and Research

No abstract provided.

Mara Repression Of Virulence Gene Hila In Salmonella, Alexandra King, Lauren Daugherty, Lon Chubiz Phd

Undergraduate Research Symposium

Salmonella is a bacteria most commonly known for causing the eponymous food-related illness. Due to their rapid reproduction rate and their ability to be propogated and maintained in a lab setting, they are commonly used in lab studies so that we can better understand how Salmonella causes disease in organisms that are more difficult to study. One area of interest is analyzing how Salmonella controls expression of the mechanisms that actually cause disease, called virulence traits, in response to the environment. In this study, antibiotic stress was used to analyze virulence gene expression. MarA is a gene that regulates ampicillin …

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 …

Examining Effects Of The Dna Regulator Lrp On Quorum Sensing Gene Expression In Pseudomonas Aeruginosa, Bradley Lumsden

Symposium of Student Scholars

Pseudomonas aeruginosa is an opportunistic human pathogen that has the capacity to express multiple virulence factors that are regulated through an extensive quorum sensing network. Three major quorum sensing systems have been identified in Pseudomonas species: the acyl homoserine lactones of las and rhl, and the Pseudomonas Quinolone Signal (PQS). We seek to investigate the involvement of a global regulator, Lrp with the expression of these three networks. Specifically, we will compare expression levels of las, rhl, and pqs in wild type P. aeruginosa (MPAO1) with an lrp transposon insertion mutant using quantitative PCR. Through this comparative …

The Role Of The Msaabcr Operon In Cell Wall Integrity And Programmed Cell Death During Biofilm Development, Bibek G C

Dissertations

Staphylococcus aureus is an important human pathogen in both community and health care settings. Biggest challenges with S. aureus as a pathogen is its ability to acquire antibiotic resistance and produce robust biofilms. In this work, we investigated the nature of the cell wall defect in the msaABCR operon mutant in the Mu50 (VISA) and USA300 LAC methicillin-resistant Staphylococcus aureus (MRSA) strains. Results showed that msaABCR-mutant cells had decreased cell wall thickness and cell wall crosslinking in both strains. These defects are most likely due to increased murein hydrolase activity and/or nonspecific processing of murein hydrolases mediated by increased …

Directed Genome Evolution To Identify Genes For Macrophage Survival By Staphylococcus Agnetis, Sonali Lakshika Anne Lenaduwe Lokuge

Graduate Theses and Dissertations

Bacterial Chondronecrosis with Osteomyelitis (BCO) is a debilitating infection that negatively impacts animal welfare and costs the broiler industry billions of dollars annually. We have previously isolated Staphylococcus agnetis 908 from BCO samples obtained from broilers at the University of Arkansas research farm. This isolate can induce BCO lameness at greater than 50% in broilers exposed to the pathogen in drinking water. We found that S. agnetis 908 is capable of surviving and escaping macrophages compared to a closely related cattle isolate,1379. Through Directed Genome Evolution (DGE) we identified that this difference is at least partially associated with an alanine …