Pathogenic Microbiology Commons^™

Observing Antibiotic Resistance In Bacterial Co-Cultures Under Simulated Microgravity, Tyler Jenkins, Marina Vaden

Discovery Day - Daytona Beach

Bacteria grow in complex natural environments with multiple factors affecting their growth, metabolism, and physiology. While astronauts are still preparing to travel to Mars, scientists must learn how to simulate a more realistic Martian environment. While a small volume of publications investigates the independent effects of microgravity or Martian regolith on microorganisms (Liao et al., 2025; Allen et al., 2022; Naz et al., 2023; Duri et al., 2025), to our knowledge no current experiments exist on the joint effects of microgravity and Martian simulant on a co-culture. This experiment aims to investigate the effect of a microgravity analog on the …

Evaluation Of Antimicrobial Resistance In Pathogens Relevant To Long-Duration Space Missions, Natalie Brattain, Yegor Bushnev, Mikayla M. Dutkiewicz

Discovery Day - Daytona Beach

Antimicrobial resistance is a growing global concern that necessitates the development of effective strategies for selecting appropriate antibiotics, especially in the context of future long-duration space missions, where infection control and treatment options are limited. This study employs the Kirby–Bauer disk diffusion assay to evaluate the antimicrobial susceptibility of Pseudomonas aeruginosa and other clinically and spaceflight-relevant bacterial pathogens such as Klebsiella pneumoniae, Staphylococcus aureus, and Streptococcus pneumoniae. These pathogens will be tested with commonly used antibiotics and potential natural compounds.   The pathogens will be cultured and isolated onto Mueller–Hinton agar plates. Antibiotic disks, along with various flavonoids disks, such as …

Function And Regulation Of Long Polar Fimbriae During Enterohemorrhagic Escherichia Coli Infection, Walter J. Galdamez

Dissertations and Theses (Open Access)

Enterohemorrhagic Escherichia coli (EHEC) is a foodborne pathogen that causes severe gastrointestinal disease and hemolytic uremic syndrome. EHEC employs multiple virulence factors to colonize the host intestine, including the locus of enterocyte effacement (LEE) encoded type III secretion system, intimin, and flagella, yet the role of long polar fimbriae (Lpf) in adhesions and infection remains less well understood. Long polar fimbriae can mediate bacterial attachment to host cells in vitro, yet the regulation and function of its two fimbrial operons, lpf1 and lpf2 in vivo remain poorly understood. Preliminary RNA-seq data from zebrafish infected with EHEC reveal that expression of …

Defining The Role Of Spxa1 And Spxa2 In Group A Streptococcus (Gas), Gretchen Anne Morrison

Dissertations and Theses (Open Access)

Group A Streptococcus (GAS) is a human-restricted pathogen whose global incidence has surged in the post-COVID era. The ability of GAS to shift from a colonizing to invasive phenotype depends on coordinated virulence gene regulation in response to host-imposed stressors. The paralogous global transcriptional regulators, SpxA1 and SpxA2, have emerged as central mediators of these adaptive responses; however, the mechanisms by which these regulators influence both global gene regulation in direct response to external stresses and the host response as a result of regulatory changes remain incompletely understood. Using an integrated multi-omic approach, we define the distinct yet interconnected regulatory …

Systemic Infection Of Beauveria Bassiana In A Stranded Endangered Green Turtle Chelonia Mydas: A Case Report, Ming-An Tsai, I-Chun Chen, Tsung-Hsien Li

The Thai Journal of Veterinary Medicine

The green turtle (Chelonia mydas) is the most frequently encountered marine turtle species in Taiwan. This study describes the postmortem findings of a juvenile green turtle with injuries to the right foreflipper that was rescued off the Taiwan coast and died after 3 months in rehabilitation. Necropsy revealed large, yellow, multifocal caseous lesions involving the right foreflipper, spleen, liver, kidneys, and lungs. Fungal infection of Beauveria bassiana was confirmed by culture, morphological and molecular characterization, phylogenetic analysis, and histopathological examination. This report provides evidence that B. bassiana is associated with a systemic fungal infection which can be fatal …

Dual-Action Antibacterial Agents Targeting Biofilm Reduction And Membrane Disruption In Staphylococcus Aureus, Rahmat Folashade Zakariyah, Waliyullahi Akorede Husain, Elohor Precious Samuel, Wonder Olanipekun Oloruntoba, Fatmah Opeyemi Saka, Khalid Ayinde Oyelami, Mariam Temitope Baker

Al-Bahir

Antimicrobial resistance in Staphylococcus aureus is a serious global health problem as the organism rapidly develops resistance against widely used antibiotics. This study sought to investigate the antibacterial and antibiofilm properties of γ-Tocopherol, a natural compound from Ocimum gratissimum, as well as its synergism with 5-hydroxymethylfurfural (5-HMF) against S. aureus. The antibacterial activities and minimum inhibitory concentrations of the compounds were determined using agar diffusion and microbroth dilution methods, respectively. Biofilm reduction was evaluated using 2,3,5-triphenyltetrazolium chloride (TTC) assay and membrane integrity was evaluated using the crystal violet microtiter plate assay and the ion leakage assay. The results …

An Investigation Of Entamoeba Histolytica Chitin Synthases And Other Encystation Factors In Early Encystation, John N. Talledo

All Theses

Entamoeba histolytica is a food-and-water-borne human protozoan pathogen that relies on a two-stage life cycle for successful proliferation outside of the host. E. histolytica exists in its dormant cyst form while outside of its host and converts to the motile trophozoite (amoeba) form in the small intestine. The trophozoites colonize the large intestine to cause symptomatic disease in ~10% of infections, resulting in ~100 million cases of amoebic dysentery each year. Trophozoites can convert back to the cyst form, which is shed in feces to continue the infection cycle.

Currently, there is a lack of understanding of the exact molecular …

Donor And Recipient Microbiome Interactions Determine Functional Outcomes Of Fecal Microbiota Transplantation For Clostridioides Difficile Infection, Sophie A. Millard

All Dissertations

Clostridioides difficile is a major cause of healthcare-associated diarrhea. Infection typically occurs after antibiotic treatment disrupts the gut microbiome, allowing C. difficile to colonize and produce toxins leading to disease (CDI). Standard antibiotic treatments can resolve acute infection but frequently lead to recurrence, highlighting the need for alternative strategies that restore the gut ecosystem. Fecal microbiota transplantation (FMT), the transfer of stool from a healthy donor, has emerged as an effective therapy for recurrent C. difficile infection (rCDI). Understanding the mechanisms underlying the success of FMT for treatment of rCDI could lead to safer, more defined microbial mixtures.

This dissertation …

Urea-Based Boronium Salts As Antimicrobial Agents, Gabriel Allen Merchant

Honors Theses

Quaternary ammonium compounds (QACs) are widely used in disinfectants due to their ability to inhibit the growth of and eliminate microbes. The potency, broad-spectrum activity, and low cost of QACs have made them a cornerstone of modem hygiene. In recent years, QACs have garnered many health and safety concerns due to their overuse and subsequent accumulation in the environment. The increased use of QACs has further led to an increase in antimicrobial-resistant bacteria, making the synthesis of novel antibacterial compounds vital to combat this growing threat. Recent advances in boronium salts offer a unique alternative to address these adverse effects. …

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 …

Understanding The Role Of Toxs As A Bile Sensing Component Of The Toxrs Virulence Regulatory System In Vibrio Spp., Minje Kim

Dartmouth College Ph.D Dissertations

Pathogenic Vibrio bacteria, such as V. cholerae and V. parahaemolyticus, colonize in the human small intestine to cause severe gastrointestinal disease. During the infection, these bacteria encounter bile salts, antimicrobial cholesterol metabolites secreted into the intestine. Pathogenic Vibrio species have evolved to utilize bile salts as signals to regulate virulence. The signaling depends in part on ToxRS, a conserved co-component transmembrane transcription regulator. ToxRS consists of the transcription factor ToxR and its membrane-tethered binding partner ToxS. ToxS is required for ToxR stability and full transcriptional activity. Although bile salts are known to influence ToxRS-dependent virulence gene expression, the molecular …

A Tractable Nematode Model For The Emerging Fungal Pathogen, Candida Auris, Melissa Martinez

Dissertations and Theses (Open Access)

Candida auris is an emerging multidrug-resistant opportunistic fungal pathogen. It

poses a significant threat to immunocompromised patients and those with prolonged stays in

healthcare facilities. C. auris spreads rapidly in health care facilities through enhanced

colonization of skin and abiotic surfaces. The genetic factors contributing to this ability and to

the virulence, drug resistance, and stress-tolerant nature of C. auris are largely unknown.

Current animal models of C. auris infections are not well standardized and report conflicting

results. Additional animal models of virulence are needed, especially those amenable to high-

throughput analysis. The nematode Caenorhabditis elegans has been validated as …

Characterization Of Staphylococcus Aureus Clinical Isolates From Deep Musculoskeletal Infections For An In Vitro Biofilm Model For Phage Therapy, Raquel C. Luna

Dissertations and Theses (Open Access)

The rise of multidrug-resistant (MDR) infections is a growing concern in the treatment of deep musculoskeletal infections (MSKIs) and orthopaedic device-related infections (ODRIs). Staphylococcus aureus is responsible for about one third of these infections due to its strong biofilm forming capacity, presence on human skin, and the large number of antibiotic-resistant variants. Bacteriophage (phage) therapy is now being considered as a treatment for MDR MSKIs/ODRIs. We are investigating the use of phage encapsulated into or adsorbed onto biodegradable microspheres for local delivery to the site of these MDR infections. We determined that the anti-staphylococcal phage K effectively lyses the S. …

Evaluating Elisa-Based Domoic Acid Detection Methods In Fetal And Maternal Samples Of California Sea Lions (Zalophus Californianus), Deanie Woodruff, Emily Lickiss, Samuel Gardiner, Mia Gastile, Elizabeth Sandoval, Florybeth La Valle

Seaver College Research And Scholarly Achievement Symposium

Harmful algal blooms produced by the diatom Pseudo-nitzschia regularly expose marine mammals along the California coast to domoic acid (DA), a neurotoxin that bioaccumulates in marine food webs. In California sea lions (Zalophus californianus), domoic acid exposure is associated with seizures, hippocampal injury, and maternal-fetal transfer of the toxin that can result in abortion. Bloom events have led to large numbers of stranded sea lions along the California coast. Although some clinical and neurological effects of domoic acid toxicosis have been documented, especially with regard to the hippocampus, there is limited understanding of how domoic acid concentrations fluctuate over the …

Take A Hit? Take A Hit: Quantifying Cell Death In E-Cigarette Exposed Bronchial Epithelial Cells Following Cards Toxin Treatment, Truman Havrda, Hannah Jiron, Sierra Trevino

Posters - 2026

The rapid rise of e-cigarette use among young adults has created a significant public health challenge, as the popularity of "vaping" has grown faster than our understanding of its long term cellular consequences. Current research indicates that e-cigarette vapor (ECV) induce high levels of oxidative stress and impair the lungs' ability to clear bacterial pathogens. Furthermore, ECV exposure upregulates specific receptors on the surface of airway cells, essentially making it easier for bacteria to adhere to and infect the lungs. While we know that both e-liquids and vapor trigger inflammatory responses and cytotoxicity, there is limited data on how these …

Antibiotics And You: A Comprehensive Guide, Brady Haas

Senior Theses

Antibiotic resistance is a rapidly emerging issue within public health. As resistance grows, the effectiveness of traditional antibiotic therapies diminishes while risk of treatment grows. Alongside novel therapies, public knowledge is a strong combatant of the resistance-related risks of antibiotic usage. Through a comprehensive review of current literature, this work serves as an accessible guide to the mechanisms of antibiotics, bacterial resistance, and the challenges related to current antibiotic usage. Additionally, the ability of current policy and emerging novel treatments, such as nanoparticles and bacteriophage therapy, to fight antibiotic resistance is evaluated. This analysis highlights the importance of improving public …

Evolution Of Antibiotic Responses During Chronic P. Aeruginosa Infections In The Human Lung, David Frank Ritz

Dartmouth College Ph.D Dissertations

Typical antibiotic susceptibility testing (AST) of microbial samples is performed in homogeneous cultures in batch environments, which does not account for the highly heterogeneous and dynamic nature of antibiotic responses. The most common mutation found in P. aeruginosa lineages evolved during chronic cystic fibrosis infections in the human lung, a loss of function of repressor MexZ, increases basal levels of multidrug efflux MexXY, but does not increase resistance by traditional minimal inhibitory concentration (MIC) assays. Here, we use single cell microfluidics to show that P. aeruginosa’s response to aminoglycosides is highly heterogeneous, with only a subpopulation of cells surviving exposure. …

Bio 230 - Microbiology, Sarah Moroianu

Open Educational Resources

This open educational resource (OER) syllabus is designed for BIO 230: Microbiology at Lehman College, City University of New York (CUNY), a single-semester introductory microbiology course for non-biology majors such as Nursing, Dietetics, Health Education, and Physical Education. The course reviews microbial structure, metabolism, genetics, and microbial ecology, with applied emphasis on infectious disease, antimicrobial drugs, host immune defenses, and microbial diseases. The syllabus aligns course content with the freely available OpenStax Microbiology textbook (Parker et al., CC BY 4.0) and reflects accessibility best practices consistent with CUNY guidelines.

Tlr3 Mediated Type I Interferon Response In Mammalian Cell Defense Against Cryptosporidium Parvum Infection., Anjelica Matias

Biochemistry and Molecular Biology

Cryptosporidium parvum is a major cause of a diarrheal disease which affects many children in the USA as well as the rest of the world, yet the contribution of its double stranded RNA (dsRNA) viral symbiont, Cryspovirus (CSpV1) to host innate immunity remains unclear. This study investigated whether CSpV1 activates Toll Like Receptor 3 (TLR3) signaling pathways and downstream Interferon type I (IFN I) responses in mammalian intestinal epithelial cells. Confluent Human Ileocecal Colorectal Adenocarcinoma cells (HCT8) were exposed to CSpV1, and the expression levels of Tumor Necrosis Factor Receptor-Associated Factor 3 (TRAF3), Nuclear Factor-𝜅-light chain enhancer of activated B-cells …

Activation Of Autophagy In Human Neutrophils In Response To Emerging Oral Pathogen Peptoanaerobacter Stomatis, Mya Philipose, Shikha Srivastava, Silvia Uriarte

The Cardinal Edge

Background: Periodontitis is a chronic, inflammatory disease that affects over 50% of the global population and is a leading cause of tooth loss. It is associated with the accumulation of oral pathogens that thrive in inflamed environments and contribute to the destruction of gum tissue and underlying bone. Neutrophils, the most abundant immune cells in the oral cavity, serve as the first line of defense against these pathogens. However, some bacteria can alter neutrophil responses to promote their survival, leading to sustained inflammation and tissue damage. This study focuses on Peptoanaerobacter stomatis, a Gram-positive anaerobic bacterium that is highly …