Medical Microbiology Commons^™

Structure And Activity Of A Selective Antibiofilm Peptide Sk-24 Derived From The Nmr Structure Of Human Cathelicidin Ll-37, Yingxia Zhang, Jayaram Lakshmaiah Narayana, Qianhui Wu, Xiangli Dang, Guangshun Wang

Journal Articles: Pathology and Microbiology

The deployment of the innate immune system in humans is essential to protect us from infection. Human cathelicidin LL-37 is a linear host defense peptide with both antimicrobial and immune modulatory properties. Despite years of studies of numerous peptides, SK-24, corresponding to the long hydrophobic domain (residues 9–32) in the anionic lipid-bound NMR structure of LL-37, has not been investigated. This study reports the structure and activity of SK-24. Interestingly, SK-24 is entirely helical (~100%) in phosphate buffer (PBS), more than LL-37 (84%), GI-20 (75%), and GF-17 (33%), while RI-10 and 17BIPHE2 are essentially randomly coiled (helix%: 7–10%). These results …

Immunopathogenesis Of Craniotomy Infection And Niche-Specific Immune Responses To Biofilm, Sharon D.B. De Morais, Gunjan Kak, Joseph P. Menousek, Tammy Kielian

Journal Articles: Pathology and Microbiology

Bacterial infections in the central nervous system (CNS) can be life threatening and often impair neurological function. Biofilm infection is a complication following craniotomy, a neurosurgical procedure that involves the removal and replacement of a skull fragment (bone flap) to access the brain for surgical intervention. The incidence of infection following craniotomy ranges from 1% to 3% with approximately half caused by Staphylococcus aureus (S. aureus). These infections present a significant therapeutic challenge due to the antibiotic tolerance of biofilm and unique immune properties of the CNS. Previous studies have revealed a critical role for innate immune responses …

Crosstalk Between Staphylococcus Aureus And Innate Immunity: Focus On Immunometabolism, Christopher M. Horn, Tammy Kielian

Journal Articles: Pathology and Microbiology

Staphylococcus aureus is a leading cause of bacterial infections globally in both healthcare and community settings. The success of this bacterium is the product of an expansive repertoire of virulence factors in combination with acquired antibiotic resistance and propensity for biofilm formation. S. aureus leverages these factors to adapt to and subvert the host immune response. With the burgeoning field of immunometabolism, it has become clear that the metabolic program of leukocytes dictates their inflammatory status and overall effectiveness in clearing an infection. The metabolic flexibility of S. aureus offers an inherent means by which the pathogen could manipulate the …

The Role Of Neutrophils Against Pythium Insidiosum, Apichaya Sriwarom

Chulalongkorn University Theses and Dissertations (Chula ETD)

Pythium insidiosum (P. insidiosum) is an oomycetes fungus-like microorganism causing pythiosis infection in humans. The zoospores (infective stage) of this pathogen contaminate aquatic environments such as moist soil and swampy area, which is a natural habitiat. Humans are infected with P. insidiosum via cutaneous route which is the main entry of the zoospores. Recent studies have shown that patients with pythiosis shows high morbidity and mortality rates particularly those with hematologic diseases. As neutrophils are the first line of immune defense during fungal infections, this study therefore investigated the activity of neutrophils in response to P. insidiosum. The neutrophil killing …

Mechanisms Of Colistin Resistance And The Antimicrobial Effects Of Antibiotic And Adjuvant Combination On Colistin-Resistant Klebsiella Pneumoniae, Aye Mya Sithu Shein

Chulalongkorn University Theses and Dissertations (Chula ETD)

The prevalence of colistin-resistant Klebsiella pneumoniae (ColRkp) has progressively increased globally. The purposes of this study were to characterize the molecular mechanisms responsible for colistin resistance among ColRkp clinical isolates in Thailand, to determine the expression levels of virulence factors associated with ColRkp clinical isolates, and to evaluate in vitro and in vivo synergistic activities of novel combination of antibiotic and adjuvant against ColRkp clinical isolates. A total of 165 carbapenem-resistant K. pneumoniae clinical isolates were obtained from King Chulalongkorn Memorial Hospital between 2016 and 2021. We discovered a rising trend of ColRkp displaying extensively drug-resistant (XDR) and pandrug-resistant (PDR) …

S. Gordonii-Produced Hydrogen Peroxide Modulates Mir-663a And Ccl20 Expression In Oral Epithelial Cells, Marshall Houston Maynard

Theses and Dissertations--Medical Sciences

The mechanisms through which a persistent recognition of commensal bacteria by oral epithelial cells (OECs) mitigates an uncontrolled inflammatory response of the oral mucosa remain unknown. CCL20 secretion by OECs in response to pathogenic bacteria is regulated by S. gordonii (Sg)-induced miR-663a; nevertheless, the mechanisms involved in these Sg-modulated responses remain to be elucidated. Since Sg is a hydrogen peroxide (H₂O₂) producer, and H₂O₂ has been shown to stimulate miRNA expression, we hypothesized that H₂O₂ could be involved in Sg-induced miR663a and CCL20 responses. Expression of miR663a …

Comparisons Of Oral, Intestinal, And Pancreatic Bacterial Microbiomes In Patients With Pancreatic Cancer And Other Gastrointestinal Diseases, Mei Chung, Naisi Zhao, Richard Meier, Devin C. Koestler, Guojun Wu, Erika De Castillo, Bruce J. Paster, Kevin Charpentier, Jacques Izard, Karl T. Kelsey, Dominique S. Michaud

Department of Food Science and Technology: Faculty Publications

Background: Oral microbiota is believed to play important roles in systemic diseases, including cancer. Methods: We collected oral samples (tongue, buccal, supragingival, and saliva) and pancreatic tissue or intestinal samples from 52 subjects, and characterized 16S rRNA genes using high-throughput DNA sequencing.

Results: Bray–Curtis plot showed clear separations between bacterial communities in the oral cavity and those in intestinal and pancreatic tissue samples. PERMANOVA tests indicated that bacterial communities from buccal samples were similar to supragingival and saliva samples, and pancreatic duct samples were similar to pancreatic tumor samples, but all other samples were significantly different from each …

Utilizing The Coughing Rat Model Of Pertussis To Improve Vaccine Efficacy, Jesse M. Hall

Graduate Theses, Dissertations, and Problem Reports (ETD)

Pertussis, also known as whooping cough, is a respiratory disease caused by the highly contagious, Gram-negative pathogen Bordetella pertussis (Bp). Infection occurs through inhalation of aerosolized droplets containing Bp, which then colonizes ciliated epithelial cells of the respiratory tract. Here, Bp expresses toxins and virulence factors that lead to leukocyte recruitment, paroxysmal cough, and impairment of host innate responses. Currently, in developed countries, acellular pertussis vaccines (aP; DTaP; Tdap) are used to prevent Bp infection and whooping cough disease. However, we currently realize that the aP vaccine efficacy quickly wanes resulting in a reemergence of pertussis. Recent …

Pseudomonas Aeruginosa Vaccine Development Using Dual-Species Whole Cell And Subunit Vaccines, Catherine Bell Blackwood

Graduate Theses, Dissertations, and Problem Reports (ETD)

Pseudomonas aeruginosa is a Gram-negative opportunistic pathogen which can cause severe, recurrent, and chronic infections. The pathogen is highly adaptable, and pneumonia caused by it is associated with high morbidity and mortality, especially in individuals with the genetic disorder cystic fibrosis. Antibiotic resistance amongst clinical isolates of P. aeruginosa is steadily increasing, and multi-drug resistant strains are prevalent. There is currently no vaccine available for commercial use against P. aeruginosa. For these reasons, we sought to understand the immunity to P. aeruginosa induced by whole cell vaccination and identify antigens for development of future subunit vaccines. In this dissertation, …

Conservation Of Epithelial-To-Mesenchymal Transition Process In Neural Crest Cells And Metastatic Cancer, April Zhang, Hira Aslam, Neha Sharma, Aryeh Warmflash, Walid D Fakhouri

Faculty, Staff and Student Publications

Epithelial to mesenchymal transition (EMT) is a highly conserved cellular process in several species, from worms to humans. EMT plays a fundamental role in early embryogenesis, wound healing, and cancer metastasis. For neural crest cell (NCC) development, EMT typically results in forming a migratory and potent cell population that generates a wide variety of cell and tissue, including cartilage, bone, connective tissue, endocrine cells, neurons, and glia amongst many others. The degree of conservation between the signaling pathways that regulate EMT during development and metastatic cancer (MC) has not been fully established, despite ample studies. This systematic review and meta-analysis …

Development Of A Human Viable Heavy Chain Antibody Against The Alpha Folate Receptor As A Molecule For Targeted Application By Phage Display Technology, Nattihda Parakasikron

Chulalongkorn University Theses and Dissertations (Chula ETD)

Alpha folate receptor (FRα) is currently under investigation as a target for the treatment of patients with non-small-cell lung cancer (NSCLC), since it is highly expressed in tumor cells but is largely absent in normal tissue. In this study, a novel human variable domain of a heavy-chain (VH) antibody fragment specific to FRα was enriched and selected by phage bio-planning. The positive phage clone (3A102 VH) is specifically bound to FRα and also cross-reacted with FRβ, as tested by ELISA. Clone 3A102 VH was then successfully expressed as a soluble protein in an E. coli shuffle strain. The obtained soluble …

A Comparative Study Of Gut Microbiota In The Healthy Elderly And The Elderly With Colorectal Cancer, Nutta Iadsee

Chulalongkorn University Theses and Dissertations (Chula ETD)

Colorectal cancer is one of the third most common cancer worldwide. Dysbiosis of the human gut microbiota has been linked to sporadic colorectal cancer (CRC). This study aimed to compare the gut microbiota profile of a total of 80 Thai volunteers, who were above 50 years old, among 25 CRC patients, 33 adenoma patients, and 22 healthy controls (HC). The 16S rRNA sequencing was utilized to characterize the gut microbiome in both mucosal tissue and stool samples. Moreover, absolute quantitative PCR (qPCR) assay was conducted to quantify six CRC-associated bacteria including Fusobacterium nucleatum (FN), Parvimonas micra (PM), colibactin positive strains …

The Effect Of Xylitol And Erythritol In The Presence Of Sucrose On Single And Mixed-Species Biofilm Of Early Colonizer And Cariogenic Streptococci, Panadda Yuapibanrak

Chulalongkorn University Theses and Dissertations (Chula ETD)

Dental caries is caused by multiple factors. An essential factor is sucrose. Dental caries is the result of an imbalance between early colonizers and cariogenic bacteria in biofilms. Sugar alcohols, xylitol and erythritol, become more popular because they do not cause cavities and are also effective at preventing caries. In everyday life, however, sucrose consumption is unavoidable. Thus, the aim of this study was to investigate the effect of xylitol and erythritol in the presence of sucrose on single- and mixed-species biofilm of early colonizers and cariogenic bacteria. Bacteria were cultured in broth containing 1% sucrose compared to broth containing …

Comparative Response Of Dendritic Cells To Pathogenic And Non-Pathogenic Leptospira Spp., Pratomporn Krangvichian

Chulalongkorn University Theses and Dissertations (Chula ETD)

Leptospirosis is a zoonotic disease caused by pathogenic Leptospira species, which consist of three groups and contain 4 subclades: pathogenic strains (P1), intermediate strains (P2), and non-pathogenic strains (S1 and S2). Infection of pathogenic leptospires occurs through contact with contaminated environments. Then, leptospires present in the bloodstream disseminate to target organs. Nowadays, the knowledge of the immune response to pathogenic and non-pathogenic leptospires during early infection is still limited. Due to the limitation of a susceptible host, immunological reagents for hamsters and strains of mice are limited and not available. Dendritic cells are the first cells to encounter leptospires found …

Designing An Extracorporeal Plasma Filtration Column With Specific Binding To Dengue Virions, Sasiwimon Thonghong

Chulalongkorn University Theses and Dissertations (Chula ETD)

Dengue infection is one of the major public health concerns and no specific treatment is currently available. An extracorporeal system is one of the alternative treatment in severe dengue patients with impending shock. However, the commercial immunoadsorption devices were size-exclusive, non-selective designed for multipurpose thus not specific for dengue syndrome. This study focuses on establishing the flavivirus-specific (4G2) antibody entrapped into the alginate bead. Results showed that the viral titer reduced more than 90 % after 3 h running on a simulated circuit quantified by reverse transcription qPCR and plaque titration assay. The experiments were repeated with two biological replicates …

The Synergistic Activity Of Antibiotic Combinations Against Colistin-Resistant Acinetobacter Baumannii Clinical Isolates And Its Mechanisms Related To Colistin Resistance, Sukrit Srisakul

Chulalongkorn University Theses and Dissertations (Chula ETD)

The increasing development of colistin resistance in Acinetobacter baumannii clinical isolates is a global concern. Due to the limitation of effective antibiotics, the antibiotic combination therapies are the alternative choices. Here, we investigated the prevalence of colistin resistant A. baumannii (CoR-AB) clinical isolates and their resistance mechanisms, and examined the in vitro synergistic activities of the antibiotic combinations against CoR-AB. Among 341 carbapenem-resistant Acinetobacter spp., 317 (92.0%) were identified as A. baumannii by gyrB multiplex PCR. The rate of colistin resistance was 15.1% in A. baumannii isolates with MIC range of 0.125 – 64 mg/L. A total of 30 representative …

Endotoxemia From Nsaids-Induced Gut-Leakage Enhanced Lupus Characteristics In Fc Gamma Receptor Iib Deficient Lupus Mice, Thansita Bhunyakarnjanarat

Chulalongkorn University Theses and Dissertations (Chula ETD)

High dose of non-steroidal anti-inflammatory drugs (NSAIDs), the common analgesia, might induce lupus activity through NSAIDs-induced gastrointestinal permeability defect (gut leakage) that causes endotoxemia. Indomethacin (25 mg/day) was orally administered for 7 days in 24-week-old Fc gamma receptor IIb deficient (FcgRIIb-/-) mice, an asymptomatic lupus model, and age-matched wild-type (WT) mice. The severity of indomethacin-induced enteropathy in FcgRIIb-/- mice was higher than WT mice as demonstrated by intestinal injury (histology, immune-deposition and intestinal cytokines), gut leakage (FITC-dextran assay and endotoxemia) and serum cytokines. In addition, higher responses against endotoxemia in indomethacin-administered FcgRIIb-/- mice was also supported by the prominent responses …

Impact Of Bacterial Dna In Severity Of Sepsis, Warerat Kaewduangduen

Chulalongkorn University Theses and Dissertations (Chula ETD)

Bacterial sepsis can be caused by intestinal damage, leading to the passage of viable bacteria and their components into the circulatory system. Bacterial-free DNA in the blood during sepsis can be derived from bacterial death and intestinal translocation of free DNA in the gut contents. The presence of bacterial DNA in combination with lipopolysaccharide (LPS) can lead to more serious outcomes of sepsis. To explore the impact of bacterial-free DNA in sepsis, animal and macrophage experiments were performed. Firstly, the appearance of bacterial-free DNA and bacteriome in the blood was presented in mice with cecal ligation and puncture sepsis. Secondly, …

Specimens, Sara Kapadia

The Transdisciplinary STEAM+ Journal

A short rumination on specimens

The Cardiac Neural Crest Cells In Heart Development And Congenital Heart Defects, Eileen M Burd, Ahmed Babiker, Jessica K Fairley, Divya Bhamidipati, Laila E Woc-Colburn, Blaine A Mathison

Faculty, Staff and Student Publications

No abstract provided.