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Medical Microbiology

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Full-Text Articles in Organisms

Validation Of A Real-Time Pcr Laboratory Developed Test For The Detection Of Pneumocystis Jirovecii In Bronchoalveolar Lavage Samples, Caitlyn Moon May 2026

Validation Of A Real-Time Pcr Laboratory Developed Test For The Detection Of Pneumocystis Jirovecii In Bronchoalveolar Lavage Samples, Caitlyn Moon

Honors Scholar Theses

Pneumocystis jirovecii is an opportunistic, host-obligate fungal pathogen responsible for causing P. jirovecii pneumonia (PJP) in humans. PJP is treated with trimethoprim-sulfamethoxazole (TMP-SMX), a strong broad-spectrum antibiotic that carries risk of renal and hepatotoxicity. Therefore, rapid diagnosis or exclusion of PJP is crucial to ensure PJP-positive patients receive effective treatment and PJP-negative patients avoid unnecessary antibiotics. Unlike most microorganisms, P. jirovecii cannot be cultured, presenting complications for the typical methods of diagnosing fungal pathogens. Historically, the gold standard for diagnosis was direct microscopic examination with stains such as methenamine silver and calcofluor white, but this diagnostic technique requires highly skilled …


Investigating Corollaries Between Streptococcus Gallolyticus Subsp. Gallolyticus Virulence And Colorectal Cancer, Tyler G. Myers Mar 2026

Investigating Corollaries Between Streptococcus Gallolyticus Subsp. Gallolyticus Virulence And Colorectal Cancer, Tyler G. Myers

Pursuit - The Journal of Undergraduate Research at The University of Tennessee

Streptococcus gallolyticus subsp. gallolyticus (Sgg) is a gram-positive, non-beta-hemolytic bacterium that belongs to the Lancefield group D of streptococcal pathogens. For the past several decades, associations between Sgg bacteremia and colorectal cancer (CRC) have been apparent, with gastroenterologists routinely recommending colonoscopies for positive cases of Sgg in either blood or stool samples. However, current research has not wholly established whether Sgg acts as a causative agent of CRC or if pre-existing cancers make the lumen of the colon more hospitable to its colonization. Regardless, Sgg has been implicated in the modulation of host inflammatory pathways and subsequent remodeling …


The Structure, Dynamics, And Impact Of An Interbacterial Weapon Encoded By Human Gut Bacteria, Casey John Latario Jan 2026

The Structure, Dynamics, And Impact Of An Interbacterial Weapon Encoded By Human Gut Bacteria, Casey John Latario

Dartmouth College Ph.D Dissertations

The human gut is densely colonized by diverse bacteria. Over a human’s growth, the GI tract becomes a dynamic community that is subjected to a continual in-flow of nutrients and would-be colonizers and an out-flow of microbes and waste products. Despite these dynamics, the bacterial community often displays stability, with particular strains persisting over decades. These stable colonizers have evolved mechanisms to bolster their colonization, resist disruption by other microbes, and persist through environmental flux.

Both interbacterial competition and horizontal gene transfer (HGT) contribute to colonization and survival within the GI tract. A major mechanism for interbacterial competition is the …


Light-Induced Oslike1 Phosphorylation Enhances Rice Resistance Against Blast Disease, Jiangtao Liu, Lei Su, Wenya Wang, Jintao Wang, Weizhong Chen, Zhixiang Yang, Leiyun Yang, Gang Li, Xinyu Liu, Haifeng Zhang, Zhongqiang Qi, Yongfeng Liu, Yuqiang Liu, Ping Wang, Muxing Liu, Zhengguang Zhang Dec 2025

Light-Induced Oslike1 Phosphorylation Enhances Rice Resistance Against Blast Disease, Jiangtao Liu, Lei Su, Wenya Wang, Jintao Wang, Weizhong Chen, Zhixiang Yang, Leiyun Yang, Gang Li, Xinyu Liu, Haifeng Zhang, Zhongqiang Qi, Yongfeng Liu, Yuqiang Liu, Ping Wang, Muxing Liu, Zhengguang Zhang

School of Graduate Studies Faculty Publications

Rice blast caused by Magnaporthe oryzae poses a major threat to world food supply. Conditions conducive to the disease include insufficient light. Our previous studies found that light-dependent phosphorylation of light-harvesting complex II protein (LHCB5) mediates rice immunity; however, the underlying mechanisms, in particular, the upstream regulators of LHCB5 phosphorylation, remain unknown. Here, we show that OsLIKE1 functions as a lectin receptor-like kinase (LecRLK) to play a critical role in rice resistance against M. oryzae. OsLIKE1 interacts with and phosphorylates LHCB5. In addition, we find two phosphorylation sites in the kinase domain of OsLIKE1 important for its auto-phosphorylation and phosphorylation …


Elucidating The Relationship Between Water Quality And Antibiotic Resistance Of Rainwater Microbes Across Western Humboldt County, Theo P. Murphy, Eve Wendley, Justice Laskowski, Tyler Paredes Nov 2025

Elucidating The Relationship Between Water Quality And Antibiotic Resistance Of Rainwater Microbes Across Western Humboldt County, Theo P. Murphy, Eve Wendley, Justice Laskowski, Tyler Paredes

Humboldt Journal of Microbiology

Limited studies have been conducted regarding the fecal contamination and microbial dispersal through rainwater, with no known studies investigating the potential connection between antibiotic resistant microbes and water quality in rainwater. This study seeks to identify the presence of a correlation between water quality and incidence of antibiotic resistance in rainwater microbes. We hypothesize that there will be a correlation between these two variables. We additionally anticipate a high incidence of fecal contamination across rural and urban collection sites alike, with fecal contamination being more prevalent in rural areas than urban locals. To determine water quality, we measured the concentration …


Advancing Peptide-Based Vaccines Against Candida: A Comparative Perspective On Liposomal And Synthetic Formulations, Hong Xin Oct 2025

Advancing Peptide-Based Vaccines Against Candida: A Comparative Perspective On Liposomal And Synthetic Formulations, Hong Xin

School of Graduate Studies Faculty Publications

The growing threat of multidrug-resistant fungal pathogens, especially Candida auris, has underscored the need for effective antifungal vaccines. This commentary highlights recent advances in peptide-based vaccination using the SNAP (Spontaneous Nanoliposome Antigen Presentation) platform, focusing on the FM-SNAP vaccine, a bivalent liposomal formulation targeting the surface-expressed peptides fructose bisphosphate aldolase (Fba) and methionine synthase (Met6). Compared to earlier constructs such as MP12, FM-SNAP achieves superior immunogenicity and long-lasting protection at lower antigen doses. It elicits balanced Th1/Th2 cytokine responses and demonstrates durable efficacy in both immunocompetent and complement-deficient mouse models. The platform's compatibility with clinically approved adjuvants (MPLA and QS-21), …


Bcg Vaccine-Induced Innate And Adaptive Pulmonary Immunity Correlating With Protective Efficacy Against Mycobacterium Tuberculosis In The Lungs, Mayank Khanna, Alistair J. Ramsay Aug 2025

Bcg Vaccine-Induced Innate And Adaptive Pulmonary Immunity Correlating With Protective Efficacy Against Mycobacterium Tuberculosis In The Lungs, Mayank Khanna, Alistair J. Ramsay

School of Graduate Studies Faculty Publications

Background/Objectives: Effective prophylaxis for Mycobacterium tuberculosis (Mtb) requires greater understanding of immune correlates of protection. With renewed interest in BCG as an Mtb vaccine, particularly via the intravenous (IV) route, our objective was to characterize both innate and adaptive immune correlates of vaccine-induced pulmonary immunity as potential biomarkers for protective efficacy in a murine model of Mtb infection. Methods: Mice were given BCG via different routes and some boosted with recombinant virus constructs encoding Mtb Ag85B. Responding innate lymphoid cell (ILC) populations, T cells and B cells were analyzed by fluorescence activated cell sorting (FACS) for surface markers and by …


Distinct Echinocandin Responses Of Candida Albicans And Candida Auris Cell Walls Revealed By Solid-State Nmr, Malitha C. Dickwella Widanage, Kalpana Singh, Jizhou Li, Jayasubba Reddy Yarava, Faith J. Scott, Yifan Xu, Neil A.R. Gow, Frederic Mentink-Vigier, Ping Wang, Frederic Lamoth, Tuo Wang Jul 2025

Distinct Echinocandin Responses Of Candida Albicans And Candida Auris Cell Walls Revealed By Solid-State Nmr, Malitha C. Dickwella Widanage, Kalpana Singh, Jizhou Li, Jayasubba Reddy Yarava, Faith J. Scott, Yifan Xu, Neil A.R. Gow, Frederic Mentink-Vigier, Ping Wang, Frederic Lamoth, Tuo Wang

School of Graduate Studies Faculty Publications

Invasive candidiasis affects 1.6 million people annually, with high mortality among immunocompromised and hospitalized patients. Echinocandins are frontline antifungals, but rising resistance limits their efficacy. Here, we show that Candida albicans and multidrug-resistant Candida auris share a conserved cell wall architecture yet differ markedly in their adaptive responses to echinocandins. Solid-state NMR reveals that both species possess a rigid inner layer of tightly associated chitin microfibrils and β−1,3-glucans, supported by a flexible matrix of β−1,6-glucans and additional β−1,3-glucans. Outer mannan fibrils rely on α−1,2-linked sidechains to maintain contact with the inner wall. In both species, caspofungin rigidifies β−1,6-glucans and mannan …


Exploring The Role Of Lysine Acetylation During Biofilm Formation In Bacillus Subtilis, Jennifer Nguyen, Briana Ericka Reid, Valerie Carabetta May 2025

Exploring The Role Of Lysine Acetylation During Biofilm Formation In Bacillus Subtilis, Jennifer Nguyen, Briana Ericka Reid, Valerie Carabetta

Rowan-Virtua Research Day

Biofilms are structured communities of bacterial cells encased in a self-produced extracellular matrix, composed of polysaccharides, extracellular DNA, and proteins. Bacteria in a biofilm pose significant challenges in healthcare due to their resistance to disinfectants and tolerance to antibiotics. In some species, histone-like proteins were found to be important structural components of the biofilm. Nε-Lysine acetylation is a widespread post-translational modification (PTM) in bacteria, which can alter a protein’s function. The histone-like protein HBsu in Bacillus subtilis is acetylated at seven sites in vivo. We hypothesized that the acetylation state of HBsu may alter biofilm structure or the genetic programming, …


Mechanisms Of Behavioral Change In Hosts Of Toxoplasma Gondii: A Review, Olivia Grimsley May 2025

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 …


The Role Of Horizontal Gene Transfer In Antibiotic Resistance Amidst Prevalent Community And Healthcare-Associated Mrsa Rates, Gabrielle Nascimento Jan 2025

The Role Of Horizontal Gene Transfer In Antibiotic Resistance Amidst Prevalent Community And Healthcare-Associated Mrsa Rates, Gabrielle Nascimento

Honors College Theses

In recent decades, cases of community-acquired MRSA (CA-MRSA) and healthcare-associated MRSA (HA-MRSA) have been on the rise. The ability of antibiotic resistance to transfer between microorganisms greatly expands its threat to the effective treatment and containment of bacterial infections. The mecA gene is found on a mobile cassette within the Staphylococcal cell and encodes for PBP2a, an alternate version of penicillin-binding protein (PBP) with less binding affinity for β-lactam antibiotics, increasing resistance to the effects of antibiotics. The goal of this research is to investigate the horizontal transfer of the mecA gene between various Staphylococcus species as well as to …


Investigating Regulation And The Regulome Of The Nucleic Acid Binding Protein Spovg Within Borrelia Burgdorferi, Timothy C. Saylor Jan 2025

Investigating Regulation And The Regulome Of The Nucleic Acid Binding Protein Spovg Within Borrelia Burgdorferi, Timothy C. Saylor

Theses and Dissertations--Medical Sciences

Prior studies indicated Borrelia burgdorferi SpoVG protein was regulated, SpoVG binds specifically to a number of nucleic acids, and SpoVG binds to the non-variable section of the major virulence factor vlsE. Although a direct transcriptional activator or inhibitor was not elucidated, it is shown that SpoVG is regulated based on cell culture density independent of the growth rate of B. burgdorferi, indicating that SpoVG regulation is outside the scope of the alternative sigma factor RpoS. Using a dCas9 CRISPRi construct to target SpoVG resulted in protein expression trending towards upregulation of the BosR-RpoS regulon, and a marked decrease …


Blood Culture Utilization: How Many Follow-Up Cultures Are Needed?, George Jones, Jennifer Hanrahan Jan 2025

Blood Culture Utilization: How Many Follow-Up Cultures Are Needed?, George Jones, Jennifer Hanrahan

Department of Medicine Faculty Publications

Background: Follow-up blood cultures (BCx) are ordered after an initial positive culture in many instances. The number of follow-up cultures needed is not clear. Obtaining unnecessary BCx may cause unintended consequences. The optimal balance between stewardship and patient safety warrants investigation. We sought to assess the frequency with which a third set is positive after a negative second BCx. Methods: We conducted a retrospective study of BCx submitted to the microbiology laboratory from 1/1/18-11/1/23. We included all patients ≥18 years who had at least two follow-up BCx drawn 24-72 hours after an initial positive culture. Data were collected from electronic …


Improving Treatment Outcomes For Bacterial Vaginosis By Affecting The Vaginal Microbiome, Aleya Devries, Jyotsna Chawla Assistant Professor, Microbiology, Jackeline Moljo Assistant Professor, Family Medicine Nov 2024

Improving Treatment Outcomes For Bacterial Vaginosis By Affecting The Vaginal Microbiome, Aleya Devries, Jyotsna Chawla Assistant Professor, Microbiology, Jackeline Moljo Assistant Professor, Family Medicine

HCA-NSU MD Research Day

Objective: The goal of this review is to educate providers about the importance of maintaining the balance of the vaginal microbiome (VMB) and how modifiable factors may be used to improve treatment outcomes of patients with bacterial vaginosis. Background: Bacterial vaginosis (BV) is the most common vaginal infection in women of reproductive age and is treated with Metronidazole, which has a high recurrent infection rate. Preliminary studies highlighted the balance of VMB species affects the development of BV and therapeutic outcomes of Metronidazole. Furthermore, previous studies have described how VMB composition can be shaped by various factors. Methods: Here, we …


Investigating The Role Of The Gut Microbiota On Immune Checkpoint Inhibitor-Mediated Colitis, Taylor Halsey, Robert Jenq May 2024

Investigating The Role Of The Gut Microbiota On Immune Checkpoint Inhibitor-Mediated Colitis, Taylor Halsey, Robert Jenq

Dissertations and Theses (Open Access)

Immune checkpoint inhibitors (ICIs) have been revolutionary in the fight against cancer by recruiting the host immune system as an agent for attack on malignant cells. Unfortunately, immune-related adverse events (irAEs), including ICI-mediated colitis (IMC), are common side effects that result from immune cell mediated damage on healthy tissues. Recent studies have highlighted a role for the gut microbiota in modulating ICI-mediated anti-tumor responses, but less is known regarding how the gut microbiota may impact on irAEs. Considering that the gastrointestinal tract harbors thousands of unique microbial species, many of which are known to modulate the immune system, microbes and …


Headache And Vision Loss As Initial Symptoms For An Acute Invasive Rhino-Orbital-Cerebral Mucormycosis, Thanh Le Od, Gregg Wentworth Od Apr 2024

Headache And Vision Loss As Initial Symptoms For An Acute Invasive Rhino-Orbital-Cerebral Mucormycosis, Thanh Le Od, Gregg Wentworth Od

Optometric Clinical Practice

Background: Acute invasive rhino-orbital-cerebral mucormycosis (ROCM) is a rare fungal infection commonly caused by Rhizopus species. It occurs in immune- compromised individuals who have acquired immune deficiency syndrome (AIDS), leukemia, uncontrolled diabetes mellitus, or organ transplant patients who are on immunosuppressive therapy. Diagnosing invasive ROCM is challenging because its clinical presentation can be nonspecific, and it is not frequently observed in ophthalmic practices. Case Report: A 66-year-old Hispanic male with poorly controlled diabetes mellitus presented with the complaint of severe headache and retrobulbar pain in the right eye. An ophthalmic examination revealed normal ocular health in both eyes. Computerized tomography …


Typhlitis In A Neutropenic Patient, Alice He Bs, Wern Lynn Ng Md, Lay She Ng Md, Si Yuan Khor Md, Chandi Garg Md Apr 2024

Typhlitis In A Neutropenic Patient, Alice He Bs, Wern Lynn Ng Md, Lay She Ng Md, Si Yuan Khor Md, Chandi Garg Md

Tower Health Research Day

No abstract provided.


The Impact Of Gestational Diabetes Mellitus And Maternal Oral Microbiome: A Scoping Review, Jaclyn P. Langan Jan 2024

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 …


Unraveling The Effects Of The Covid-19 Pandemic On Staphylococcus Aureus Carriage: A Comparative Research Of Pre- And Post-Pandemic Samples, Catherine G. Johnston Jan 2024

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 …


Clostridioides Difficile: Identification Of Rival Organisms & Evaluation Of Non-Antibiotic Treatment Implementation, Justin Davis Jan 2024

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 Jan 2024

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 …


Catheter-Associated Urinary Tract Infections: Patient Characteristics, Treatment, And Clinical Outcomes In One South Texas Acute Care Hospital, Kimberly A. Ambrosini, Jose Campo Maldonado Oct 2023

Catheter-Associated Urinary Tract Infections: Patient Characteristics, Treatment, And Clinical Outcomes In One South Texas Acute Care Hospital, Kimberly A. Ambrosini, Jose Campo Maldonado

Research Colloquium

Background: Catheter-associated urinary tract infections (CA-UTIs) account for 40 percent of nosocomial infections worldwide. Their elimination is at the forefront of quality improvement in one South Texas acute care hospital.

Methods: Over a period of 6 months, five CA-UTIs occurred in one South Texas acute care hospital. These cases were identified via regular surveillance by Infection Prevention staff and the Laboratory Department of the hospital. This research reviews patient age, sex, length of stay, bacteria contracted, appropriate antibiotic use, patient characteristics, and overall outcomes.

Results: Between the months of July and December 2021, 5 CAUTIs were contracted. Patients ranged in …


Oral Dosages Of The Nsaid Aspirin Decreased The Growth Rate Of Species Found In The Human Gut Microbiome Including Akkermansia Muciniphila, Bacteroides Fragilis, Clostridium Sordellii, And Clostridium Difficile, Wyatt H. Greenbaum, Garrett J. Greenbaum, Anna Spiezio Sep 2023

Oral Dosages Of The Nsaid Aspirin Decreased The Growth Rate Of Species Found In The Human Gut Microbiome Including Akkermansia Muciniphila, Bacteroides Fragilis, Clostridium Sordellii, And Clostridium Difficile, Wyatt H. Greenbaum, Garrett J. Greenbaum, Anna Spiezio

PANDION: The Osprey Journal of Research and Ideas

Over past few decades, new insight has been revealed in the scientific community about the importance of the human gut microbiome relating to general health. It is known that imbalances in the species that reside in the human gut can cause organism-wide problems in humans. When prescribing or injecting oral medications, the thought of the downstream effects on the gut microbiome are not always considered. By exposing known healthy members of the gut; Akkermansia muciniphila, Bacteroides fragilis, Clostridium sordellii, and Clostridium difficile to the Aspirin, this study attempted to provide insight into the effects of the drug on bacterial growth. …


Molecular Characterization Of Streptococcus Pneumoniae Causing Disease Among Children In Nigeria During The Introduction Of Pcv10 (Gsk), Stephanie W. Lo, Paulina A. Hawkins, Binta Jibir, Fatimah Hassan-Hanga, Mahmoud Gambo, Rasaq Olaosebikan, Grace Olanipekun, Huda Munir, Nicholas Kocmich, Amy Rezac-Elgohary, Safiya Gambo, Danstan Bagenda, Paul Fey, Robert F. Breiman, Lesley Mcgee, Stephen D. Bentley, Stephen K. Obaro, Community Acquired Pneumonia And Invasive Bacterial Disease Capibd Consortium Sep 2023

Molecular Characterization Of Streptococcus Pneumoniae Causing Disease Among Children In Nigeria During The Introduction Of Pcv10 (Gsk), Stephanie W. Lo, Paulina A. Hawkins, Binta Jibir, Fatimah Hassan-Hanga, Mahmoud Gambo, Rasaq Olaosebikan, Grace Olanipekun, Huda Munir, Nicholas Kocmich, Amy Rezac-Elgohary, Safiya Gambo, Danstan Bagenda, Paul Fey, Robert F. Breiman, Lesley Mcgee, Stephen D. Bentley, Stephen K. Obaro, Community Acquired Pneumonia And Invasive Bacterial Disease Capibd Consortium

Student Papers, Posters & Projects

Streptococcus pneumoniae (pneumococcus) is a leading vaccine-preventable cause of childhood invasive disease. Nigeria has the second highest pneumococcal disease burden globally, with an estimated ~49 000 child deaths caused by pneumococcal infections each year. Ten-valent pneumococcal conjugate vaccine (GSK; PCV10) was introduced in December 2014 in a phased approach. However, few studies have characterized the disease-causing pneumococci from Nigeria. This study assessed the prevalence of serotypes, antibiotic susceptibility and genomic lineages using whole genome sequencing and identified lineages that could potentially escape PCV10 (GSK). We also investigated the potential differences in pneumococcal lineage features between children with and without sickle …


Two Structurally Defined Aβ Polymorphs Promote Different Pathological Changes In Susceptible Mice, Ruben Gomez-Gutierrez, Ujjayini Ghosh, Wai-Ming Yau, Nazaret Gamez, Katherine Do, Carlos Kramm, Hamid Shirani, Laura Vegas-Gomez, Jonathan Schulz, Ines Moreno-Gonzalez, Antonia Gutierrez, K Peter R Nilsson, Robert Tycko, Claudio Soto, Rodrigo Morales Aug 2023

Two Structurally Defined Aβ Polymorphs Promote Different Pathological Changes In Susceptible Mice, Ruben Gomez-Gutierrez, Ujjayini Ghosh, Wai-Ming Yau, Nazaret Gamez, Katherine Do, Carlos Kramm, Hamid Shirani, Laura Vegas-Gomez, Jonathan Schulz, Ines Moreno-Gonzalez, Antonia Gutierrez, K Peter R Nilsson, Robert Tycko, Claudio Soto, Rodrigo Morales

Faculty, Staff and Student Publications

Misfolded Aβ is involved in the progression of Alzheimer's disease (AD). However, the role of its polymorphic variants or conformational strains in AD pathogenesis is not fully understood. Here, we study the seeding properties of two structurally defined synthetic misfolded Aβ strains (termed 2F and 3F) using in vitro and in vivo assays. We show that 2F and 3F strains differ in their biochemical properties, including resistance to proteolysis, binding to strain-specific dyes, and in vitro seeding. Injection of these strains into a transgenic mouse model produces different pathological features, namely different rates of aggregation, formation of different plaque types, …


Impacts Of A Duf2207 Family Protein On Streptococcus Mutans Stress Tolerance Responses And Biofilm Formation, Xiaochang Huang, Camile G. Laird, Paul P. Riley, Zezhang Tom Wen Aug 2023

Impacts Of A Duf2207 Family Protein On Streptococcus Mutans Stress Tolerance Responses And Biofilm Formation, Xiaochang Huang, Camile G. Laird, Paul P. Riley, Zezhang Tom Wen

School of Dentistry Faculty Publications

Locus SMU.243 in Streptococcus mutans was annotated as a member of the DUF2207 family proteins highly conserved in all bacteria but with unknown function. To investigate its role in S. mutans physiology, a SMU.243-deficient mutant was constructed using allelic exchange mutagenesis, and the impacts of SMU.243 deletion on bacterial growth, stress tolerance response, and biofilm formation were analyzed. Compared to the wild-type UA159, S. mutans lacking SMU.243 displayed a reduced growth rate and a reduced overnight culture density (p < 0.01) when grown at low pH and in the presence of methyl viologen. Relative to the parent strain, the deficient mutant also had a reduced survival rate following incubation in a buffer of pH 2.8 (p < 0.01) and in a buffer containing hydrogen peroxide at 58 mM after 60 min (p < 0.001) and had a reduced capacity in biofilm formation especially in the presence of sucrose (p < 0.01). To study any ensuing functional/phenotypical links between SMU.243 and uppP, which is located immediately downstream of SMU.243 and encodes an undecaprenyl pyrophosphate phosphatase involved in recycling of carrier lipid undecaprenyl phosphate, a uppP deficient mutant was generated using allelic exchange mutagenesis. Unlike the SMU.243 mutant, deletion of uppP affected cell envelope biogenesis and caused major increases in susceptibility to bacitracin. In addition, two variant morphological mutants, one forming rough colonies and the other forming mucoid, smooth colonies, also emerged following the deletion of uppP. The results suggest that the SMU.243-encoded protein of the DUF2207 family in S. mutans plays an important role in stress tolerance response and biofilm formation, but unlike the downstream uppP, does not seem to be involved in cell envelope biogenesis, although the exact roles in S. mutans’ physiology awaits further investigation.


Species Delineation And Comparative Genomics Within The Campylobacter Ureolyticus Complex, Joel J Maki, Mondraya Howard, Sara Connelly, Matthew Pettengill, Dwight J Hardy, Andrew Cameron May 2023

Species Delineation And Comparative Genomics Within The Campylobacter Ureolyticus Complex, Joel J Maki, Mondraya Howard, Sara Connelly, Matthew Pettengill, Dwight J Hardy, Andrew Cameron

Department of Pathology, Anatomy, and Cell Biology Faculty Papers

Campylobacter ureolyticus is an emerging pathogen increasingly appreciated as a common cause of gastroenteritis and extra-intestinal infections in humans. Outside the setting of gastroenteritis, little work has been done to describe the genomic content and relatedness of the species, especially regarding clinical isolates. We reviewed the epidemiology of clinical C. ureolyticus cultured by our institution over the past 10 years. Fifty-one unique C. ureolyticus isolates were identified between January 2010 and August 2022, mostly originating from abscesses and blood cultures. To clarify the taxonomic relationships between isolates and to attribute specific genes with different clinical manifestations, we sequenced 19 available …


Aging Manuka Honey Improves Antimicrobial Activity Against Pathogenic Bacteria, Rayna M. Carlson May 2023

Aging Manuka Honey Improves Antimicrobial Activity Against Pathogenic Bacteria, Rayna M. Carlson

2023 Symposium

Manuka honey (MH) has been documented to possess powerful anti-microbial properties through multiple mechanisms. These mechanisms include a low pH, high osmolarity, iron chelation, and its unique manuka factor (UMF), methylglyoxal (MGO). Although MGO is purported to be a major pillar in the honey’s antimicrobial properties, its activity is variable against different bacterial species. We hypothesize that MH’s other antimicrobial mechanisms may also exhibit variable activity against different bacterial species. Preliminary experiments to determine the Manuka honey minimum inhibitory concentrations (MIC) for bacterial species, Escherichia coli, Pseudomonas aeruginosa, and Staphylococcus aureus, suggested that some Manuka honey antimicrobial mechanisms …


Elucidating The Impact Of Sos-Response Timing In On Escherichia Coli Survival Following Treatment With Fluoroquinolone Topoisomerase Inhibitors, Stephanie Schofield May 2023

Elucidating The Impact Of Sos-Response Timing In On Escherichia Coli Survival Following Treatment With Fluoroquinolone Topoisomerase Inhibitors, Stephanie Schofield

Honors Scholar Theses

Antibiotic treatment failure is a public health crisis, with a 2019 report stating that roughly 35,000 deaths occur in the United States yearly due to bacterial infections that are unresponsive to antibiotics (1). One complication in the treatment of bacterial infection is antibiotic persistence which further compromises our battle to effectively treat infection. Bacterial persisters can exist in clonal bacterial cultures and can tolerate antibiotic treatment by undergoing reversible phenotypic changes. They can survive drug concentrations that their genetically identical kin cannot. Some persisters remain in a slow growing state and are difficult to target with current antibiotics. A specific …


Effect Of Temperature On The Microbiome Of A Laboratory Reared Colony Of Haemaphysalis Longicornis Ticks, Brianna Mitchell May 2023

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

Poster Presentations

Honors research poster.

Haemaphysalis longicornis is a species of tick native to eastern Asia, including eastern China, Japan, eastern Russia, and Korea. To date, it has invaded and has now established its existence in Australia, New Zealand, and several of the Pacific Islands. This species of tick has recently been introduced to the United States, having a confirmed sighting in November 2017 on a sheep farm in New Jersey and since establishing populations in 18 states along the east coast and Appalachia. Based on the existing locations of H. longicornis in its native regions, as well as in the United …