Medical Microbiology Commons^™

The Prospect Of Nanoparticle Systems For Modulating Immune Cell Polarization During Central Nervous System Infection, Lee E. Korshoj, Wen Shi, Bin Duan, Tammy Kielian

Journal Articles: Pathology and Microbiology

The blood-brain barrier (BBB) selectively restricts the entry of molecules from peripheral circulation into the central nervous system (CNS) parenchyma. Despite this protective barrier, bacteria and other pathogens can still invade the CNS, often as a consequence of immune deficiencies or complications following neurosurgical procedures. These infections are difficult to treat since many bacteria, such as Staphylococcus aureus, encode a repertoire of virulence factors, can acquire antibiotic resistance, and form biofilm. Additionally, pathogens can leverage virulence factor production to polarize host immune cells towards an anti-inflammatory phenotype, leading to chronic infection. The difficulty of pathogen clearance is magnified by …

Intracranial Mycoplasma Hominis Infection Following Emergent Craniectomy, Zahra Qamar, Stavropoula Tjoumakaris, Matthew Pattengill, Maliha Ahmed, Bryan Hess

Division of Infectious Diseases and Environmental Medicine Faculty Papers

We present a case of a young healthy female who developed recurrent cranial wound infections after a traumatic injury, the etiologic organism finally identified as Mycoplasma hominis, an uncommon and difficult to isolate bacterium.

Report Of The Pathogenesis And Pathophysiology Of Lyme Disease Subcommittee Of The Hhs Tick Borne Disease Working Group, Sam T. Donta, Leith J. States, Wendy A. Adams, Troy Bankhead, Nicole Baumgarth, Monica E. Embers, Robert B. Lochhead, Brian Stevenson

Microbiology, Immunology, and Molecular Genetics Faculty Publications

An understanding of the pathogenesis and pathophysiology of Lyme disease is key to the ultimate care of patients with Lyme disease. To better understand the various mechanisms underlying the infection caused by Borrelia burgdorferi, the Pathogenesis and Pathophysiology of Lyme Disease Subcommittee was formed to review what is currently known about the pathogenesis and pathophysiology of Lyme disease, from its inception, but also especially about its ability to persist in the host. To that end, the authors of this report were assembled to update our knowledge about the infectious process, identify the gaps that exist in our understanding of …

Antibiotic Tolerance And Heteroresistance: Associated Fitness Costs And Potential In Evading Antibiotic Killing, Tina H. Dao

Theses and Dissertations (ETD)

Streptococcus pneumoniae is a prominent human pathogen that causes both invasive and non-invasive diseases, such as otitis media, pneumonia, meningitis, and bacteremia. Although it is frequently an asymptomatic colonizer of the human nasopharynx, S. pneumoniae is a major cause of morbidity and mortality in the immune compromised population, young children, and the elderly. Up until the 1970s, S. pneumoniae was susceptible to almost all antibiotics. Since then, this pathogen has gained resistance to a variety of antibiotic treatments, including beta-lactams, macrolides, and fluoroquinolones.

In the first chapter, we focused on fluoroquinolone resistance in S. pneumoniae. Fluoroquinolones are one of the …

Identification Of Effectors Of Synergistic Lethality In Candida Albicans-Staphylococcus Aureus Polymicrobial Intra-Abdominal Infection, Olivia Adele Todd

Theses and Dissertations (ETD)

Candida albicans, an opportunistic fungal pathogen, and Staphylococcus aureus, a ubiquitous pathogenic bacterium, are among the most prevalent causes of nosocomial infections and cause severe morbidity and mortality. Moreover, they are frequently coisolated from central venous catheters and deep-seated infections, including intra-abdominal sepsis. Relatively little is known about the complex interactions and signaling events that occur between microbes and even less so how microbial “cross-talk” shapes human health and disease.

Using a murine model of polymicrobial intra-abdominal infection (IAI), we have previously shown that coinfection with C. albicans and S. aureus leads to synergistic lethality whereas monomicrobial infection is nonlethal. …

Insights Into The Packaging Of Mouse Mammary Tumor Virus (Mmtv) Genomic Rna By Identifying Pr77ᴳᴬᴳ Binding Sites Involved During Its Selective Encapsidation, Akhil Chameettachal

Dissertations

Selective encapsidation and/or packaging of retroviral genomic RNA (gRNA) by Gag during retrovirus assembly is a crucial step for generating infectious virus particles. Despite having been studied extensively, the mechanism by which the retroviral Gag precursor selects and packages the retroviral genome remains largely unclear. Therefore, to understand the molecular mechanism(s) of mouse mammary tumor virus (MMTV) gRNA packaging, as a first step, expression of full-length recombinant Pr77^Gag -His6-tag fusion protein in bacteria was done. The recombinant Gag protein was then purified from the soluble fractions of bacterial cultures using immobilized metal affinity chromatography (IMAC) and size exclusion chromatography …

Effect Of Serine-Dipeptide Bacterial Lipid Treatment On Gene Expression In Hepg2 Liver Cells, Shaharia Ferdus

Honors Scholar Theses

While greater abundances of Bacteroidetes are associated with better health outcomes, this phylum is a major producer of serine-dipeptide lipids, which are thought to promote inflammation via Tolllike receptor (TLR) stimulation. Lipid 654 (L-654) is one class of serine-dipeptide lipids that has been isolated from arterial plaques and is thought to contribute to atherogenesis. Recent evidence shows that not only does long-term L-654 exposure attenuate atherosclerosis, it also significantly reduces hepatic lipid levels and markers of inflammation in mice. To better understand the impact on the human liver, L-654 was administered to HepG2 hepatocytes at concentrations of 0.5 μg/mL or …

Resistance To Lethal Ectromelia Virus Infection Requires Type I Interferon Receptor In Natural Killer Cells And Monocytes But Not In Adaptive Immune Or Parenchymal Cells., Carolina R Melo-Silva, Pedro Alves-Peixoto, Natasha Heath, Lingjuan Tang, Brian Montoya, Cory J Knudson, Colby Stotesbury, Maria Ferez, Eric B. Wong, Luis J. Sigal

Department of Microbiology and Immunology Faculty Papers

Type I interferons (IFN-I) are antiviral cytokines that signal through the ubiquitous IFN-I receptor (IFNAR). Following footpad infection with ectromelia virus (ECTV), a mouse-specific pathogen, C57BL/6 (B6) mice survive without disease, while B6 mice broadly deficient in IFNAR succumb rapidly. We now show that for survival to ECTV, only hematopoietic cells require IFNAR expression. Survival to ECTV specifically requires IFNAR in both natural killer (NK) cells and monocytes. However, intrinsic IFNAR signaling is not essential for adaptive immune cell responses or to directly protect non-hematopoietic cells such as hepatocytes, which are principal ECTV targets. Mechanistically, IFNAR-deficient NK cells have reduced …

Clinical Consequences And Determinants Of False Positive Blood Cultures In Adult Hospitalized Patients, Sidra Liaquat

Theses & Dissertations

Blood cultures are the gold standard for detecting blood stream infections. However, in the US, 0.6-6% of all blood cultures get contaminated leading to adverse clinical outcomes such as unnecessarily prolonged hospital stay and antibiotic therapy. Using electronic medical records, we explored the clinical outcomes and patient-specific risk factors of contaminated blood cultures in an era where rapid blood culture testing was being utilized to provide blood culture results within hours. Rapid blood culture test results can help clinicians in early and more effective management of patients with contaminated blood cultures, thus improving clinical outcomes. We also studied the impact …

Identification Of The E3 Ligase That Directs The Degradation Of Proteins That Control Cell Fate Decisions In Yeast, Prasanna Tati, Stephen D Willis, Katrina F. Cooper

Rowan-Virtua Research Day

The ubiquitin–proteasome system (UPS) and autophagy pathways are distinct, highly conserved proteolytic systems that play important roles in maintaining cellular homeostasis in response to environmental cues [1]. The goal of this project is to identify the E3 ligase that mediates the degradation of cyclin C following nitrogen starvation in yeast using quantitative Western blot analysis of cyclin C-myc following nitrogen starvation in mutants of known Ubc4/5 interacting E3 ligases. No potential E3 ligases were identified as stable after 4 hours of nitrogen starvation, suggesting redundancy in function.

Molecular Interactions Of Human Cell Proteins With Sars-Cov-2 Versus Influenza Viruses, Linze Cowman

Honors Thesis

Molecular Interactions of Human Cell Proteins with SARS-CoV-2 versus Influenza

Viruses

Linze Cowman

Director: Victor Huber, Ph.D.

The novel Coronavirus Disease 2019, or COVID- 19, shows considerable similarity to a common influenza infection. Over the past year, innumerable studies have been investigating the Vitus in various capacities, from big-picture public health repercussions to the virus' biochemical interactions with human cells for infection. This research provides invaluable information in the ongoing war against infectious diseases. While the influenza virus is fairly well-understood, much surrounding the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) remains unclear, including its longevity, long-term health effects, methods …

Developing A Microdialysis Sampling-Based Biofilm/Macrophage Co-Culture Model, Alda Diaz Perez

Graduate Theses and Dissertations

The host immune system and bacterial cells are known to interact during the human lifetime. Bacteria secrete a wide variety of signaling molecules, known as quorum sensing (QSC) molecules, that modulate the host immune system. While immune-biofilm interactions involve this chemical signaling network, the mechanisms through which this occurs are not well understood. This work aimed to develop a new method that can be used not only in vitro settings but also in vivo. The microdialysis sampling technique has widely been used in in vitro and in vivo settings in humans, mice, and rats for the collection of neuropeptides, cytokines, …

The Importance Of Noncapped Viral Genomic Rna To Alphaviral Infection And Pathogenesis., Autumn Lapointe

Electronic Theses and Dissertations

Alphaviruses are mosquito-borne arboviruses that have a positive sense, single-stranded RNA genome, which are capable of causing severe disease and thus pose a significant burden to public health. During alphaviral replication, significant quantities of viral genomic RNAs that lack the canonical alphaviral 5’ cap structure are produced and packaged into viral particles, despite the fact that these noncapped genomes cannot be translated and are essentially noninfectious. The production and packaging of the noncapped genomes has been found to be true for infections across multiple vertebrate and invertebrate cell lines and alphavirus species, although the proportion of ncgRNA produced differs. Despite …

Delineating The Upc2a Regulon In Candida Glabrata, Yu Li

Theses and Dissertations (ETD)

Candida glabrata is the second most common cause of invasive candidiasis. Intrinsic resistance has greatly limited the utility of the triazole antifungal, fluconazole, in the treatment of invasive fungal infection. The transcription factor Upc2 regulates the expression of sterol biosynthesis genes in yeast. Disrupting UPC2A in C. glabrata greatly increases its susceptibility to fluconazole (FLU) in both FLU-susceptible and -resistant clinical isolates. Therefore, the Upc2A and its target genes represent a potential pathway for overcoming FLU resistance in C. glabrata. We aimed to delineate the Upc2A regulon to determine its target genes involved in FLU resistance. Transcriptome sequencing (RNA-seq) analysis …

A New All-Natural Wound Treatment Gel Shows Strong Inhibitory Activity Against Staphylococcus Aureus And Other Wound Pathogens, Tasha K. Nelson

Electronic Theses and Dissertations

Skin related injuries are some of the most dangerous forms of wounds. In addition to treating the wound itself, health care providers must be cautious of microbial infections. In this study, we evaluate a novel all-natural antimicrobial gel compound (AMG) designed to kill planktonic bacteria, penetrate bacterial biofilms, and accelerate wound healing. In -vitro experiments demonstrate that AMG is effective in inhibiting planktonic growth and biofilm development of eight common pathogens. LIVE/DEAD staining and confocal microscopy reveal that planktonic growth and three-dimensional structure of biofilms were significantly reduced. Reverse Transcriptase Polymerase Chain Reaction (RT-PCR) was used to investigate a small …

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: Master of Public Health

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. …

A Novel Application Of Galleria Mellonella Larvae To Study Pathogenesis Of Rickettsia Rickettsii Infection, Jacob M. Jones

Honors College Theses

Rickettsia are obligate intracellular tick-borne bacteria that cause acute undifferentiated febrile illness accompanied by headache, malaise, myalgias, and disseminated endothelial infection. Immune responses to Rickettsia and pathogenesis of rickettsioses are not fully understood. Current work with Rickettsia is limited to vertebrate models that are strictly regulated and have low throughput. Since the innate immune system of vertebrates retains striking similarities with the immune response in insects, invertebrates are being used to study host responses to various pathogens. The purpose of this study was to evaluate if larvae of the greater wax moth Galleria mellonella (GML) can be used as an …

Categorization Of Orthologous Gene Clusters In 92 Ascomycota Genomes Reveals Functions Important For Phytopathogenicity, Daniel Peterson, Tang Li, Ana M. Calvo, Yanbin Yin

Food for Health: Publications

Phytopathogenic Ascomycota are responsible for substantial economic losses each year, destroying valuable crops. The present study aims to provide new insights into phytopathogenicity in Ascomycota from a comparative genomic perspective. This has been achieved by categorizing orthologous gene groups (orthogroups) from 68 phytopathogenic and 24 non-phytopathogenic Ascomycota genomes into three classes: Core, (pathogen or non-pathogen) group-specific, and genome-specific accessory orthogroups. We found that (i) ~20% orthogroups are group-specific and accessory in the 92 Ascomycota genomes, (ii) phytopathogenicity is not phylogenetically determined, (iii) group-specific orthogroups have more enriched functional terms than accessory orthogroups and this trend is particularly evident in phytopathogenic …

Streptococcus Anginosus Lung Infection And Empyema: A Case Report And Review Of The Literature, Nishita Tripathi, Kuldeep Ghosh, Anupama Raghuram

The University of Louisville Journal of Respiratory Infections

Streptococcus milleri group (SMG) also referred to as the Streptococcus anginosus group. These are Gram-positive, variable hemolysis, catalase negative, microaerophilic, non-motile facultative anaerobes which have been known to cause abscesses in humans. We report a case of empyema caused by Streptococcus anginosus in a patient with an unresolved pneumonia for over a month. In early October 2018, the patient presented to an emergency room with the complaints of shortness of air, productive cough, chills, subjective fever and weight loss for 4 weeks. A chest X-ray revealed a left lower lobe pneumonia. He was treated with 250 mg of azithromycin for …

Viral Infection Modulates Qa-1b In Infected And Bystander Cells To Properly Direct Nk Cell Killing., Maria Ferez, Cory J. Knudson, Avital Lev, Eric B. Wong, Pedro Alves-Peixoto, Lingjuan Tang, Colby Stotesbury, Luis J. Sigal

Department of Microbiology and Immunology Faculty Papers

Natural killer (NK) cell activation depends on the signaling balance of activating and inhibitory receptors. CD94 forms inhibitory receptors with NKG2A and activating receptors with NKG2E or NKG2C. We previously demonstrated that CD94-NKG2 on NK cells and its ligand Qa-1b are important for the resistance of C57BL/6 mice to lethal ectromelia virus (ECTV) infection. We now show that NKG2C or NKG2E deficiency does not increase susceptibility to lethal ECTV infection, but overexpression of Qa-1b in infected cells does. We also demonstrate that Qa-1b is down-regulated in infected and up-regulated in bystander inflammatory monocytes and B cells. Moreover, NK cells activated …