Medical Microbiology Commons^™

Dengue Cases In Hanoi, Vietnam: Unseasonal Surge Foreshadows Increased Incidence That Demands Organized Preventive Action, Andrew W. Taylor-Robinson

Chulalongkorn Medical Journal

Letter to the Editor - Abstract not required.

Evaluation Of Leptospirosis Vaccine Efficacy After Modifications Of N-Linked Glycosylation In Liga Mrna Vaccines., Rampapat Phaetthayanan

Chulalongkorn University Theses and Dissertations (Chula ETD)

Leptospirosis, caused by pathogenic Leptospira species, is a widespread zoonotic disease, particularly prevalent in developing countries in tropical areas. Commercially available bacterins have several limitations. A previous study developed a messenger RNA (mRNA) vaccine encoding the carboxy-terminal domain 7-13 of LigA (LigAc) that was expressed with glycosylation in mammalian cells and elicited high humoral immune response in a hamster model but failed to provide protection against lethal challenge. To improve the protective efficacy, this study aimed to develop LigAc-mRNA vaccines with minimal glycosylation. Three mRNA constructs were developed based on two strategies: modifying the potential N-glycosylation sites (from asparagine to …

Trends Of Methicillin-Resistant Staphylococcus Aureus Infections Among Thai Pediatric Patients, Pintip Suchartlikitwong, Nopphon Wuthinantiwong, Watsamon Jantarabenjakul, Noppadol Wacharachaisurapol, Jiratchaya Sophonphan, Tanittha Chatsuwan, Thanyawee Puthanakit

Chulalongkorn Medical Journal

Background While reductions in methicillin-resistant Staphylococcus aureus (MRSA) infections have been reported, vancomycin prescription rates have remained high.

Objectives We aimed to update trends in pediatric prevalence and antibiotic susceptibilities of MRSA infections.

Methods We conducted a retrospective study in patients aged S. aureus infections during 2016-2022 at a Thai tertiary-care hospital. MRSA was defined when resistant to cefoxitin or oxacillin MIC of >4 µg/mL. Patients with MRSA infections and their first isolates were classified into HA-MRSA or CA-MRSA based on surveillance definitions. Antibiotic susceptibilities were tested using the VITEK 2XL automated system and disk diffusion. The annual prevalence of …

Effects Of Stat3 Variant On Stat1 And Stat5b In Fibroblasts From Mice With Stat3 Gain-Of-Function Variant, Natthakan Thareram

Chulalongkorn University Theses and Dissertations (Chula ETD)

STAT mutations cause immune system dysfunction and many diseases, such as autoimmune cytopenias, lymphoproliferative disorders, susceptibility to infections, endocrinopathies, and growth defects. However, the molecular activity of these proteins remains unclear. Here, we investigated the phosphorylation, nuclear translocation, and gene expression levels of Stat1, Stat3, and Stat5b, as well as downstream target genes of these proteins, using mouse fibroblasts with Stat3 wild type and Stat3 L387R gain-of-function (GOF) variant edited by CRISPR-Cas9 technique as a model. In fibroblasts of Stat3 L387R GOF animals, the expression of downstream target genes of STAT1, Cxcl10 and Irf7 were significantly decreased compared with Stat3 …

Development Of 3d Cell Culture Model For Graves’ Ophthalmopathy, Rajit Chompoowong

Chulalongkorn University Theses and Dissertations (Chula ETD)

Orbital tissue fibrosis and remodeling contribute to the development of exophthalmos, a hallmark symptom of Graves’ ophthalmopathy (GO). The central pathogenesis to this process are orbital fibroblasts (GOF), which express autoantigen, thyroid-stimulating hormone receptor (TSHR). However, there are limitations in preclinical models for studying the pathogenesis and drug discovery of GO, which poses challenges for developing effective treatment options. This study aimed to identify markers of GOF, explore epigenetic alteration, and develop a scaffold-free 3D cell culture model for GO. The novel results from immunohistochemical analysis showed that vimentin was uniquely expressed in GO but absent in control samples. Additionally, …

The Antibacterial And Anti-Inflammatory Properties Of Probiotics Against Methicillin-Resistant Staphylococcus Aureus (Mrsa), Punploy Klawkla

Chulalongkorn University Theses and Dissertations (Chula ETD)

Background: Dysbiosis refers to an imbalance in the types of microorganisms in a person’s natural f lora, associated with several diseases like asthma, type 2 diabetes, and atopic dermatitis (AD). Reports indicate that Staphylococcus aureuscolonizes about 60%-100% of AD skin, causing barrier dysfunction through virulence factors such as superantigens, enzymes, and other proteins. These factors disrupt skin homeostasis by affecting keratinocytes and immune cells. Additionally, dysbiosis in AD skin is marked by a reduction in commensal microbes like Staphylococcus epidermidis and Corynebacterium spp. In recent years, probiotics have been studied in both live bacteria and bacterial lysate forms. Most studies …

The Comparison Between Alternative And Standard Methods For Quality Control Of Diphtheria Toxoid In Thai-Gpo’S Dtp And Dt Vaccines (Adsorbed), Wanlop Leeden

Chulalongkorn University Theses and Dissertations (Chula ETD)

In response to the country's vaccine security policy and to make Thailand self-reliant in vaccine supply, the Government Pharmaceutical Organization has been successfully established he the production process of dT and DTP vaccine (Adsorbed). According to WHO recommendation, the quality control scheme for dT, DTP vaccines (adsorbed) includes identity test, toxicity and reversion to toxicity test, potency test, and antigen content and degree of absorption. Therefore, it is of interest to study and develop appropriate methods for use in quality control and for inclusion in the product registration application process. The comparison study of the quality testing methods can categorized …

The Development Of Novel Chimeric Antigen Receptor T Cell Targeting B7h3 For Common Solid Cancers, Thananya Inthanachai

Chulalongkorn University Theses and Dissertations (Chula ETD)

Chimeric antigen receptor (CAR-T cells) have shown a prominent success in hematologic malignancies and are being widely investigated to overcome heterogeneity and immune suppressive environment in solid tumors. B7 homolog 3 (B7H3), an overexpressed antigen across multiple cancers with restricted expression on normal tissues, serves as a potential target for CAR T cells therapy. This study, Gene Expression Profiling Interactive Analysis 2 (GEPIA 2) was used to evaluate CD276 gene upregulation and using flow cytometric staining to investigate an expression of B7H3 across various solid tumors. As a potential antigen targeting cancers, novel B7H3 CAR-T cells were developed from new …

The More Severe Adverse Effect Of Alcohol In Fc Gamma Receptor Iib Deficient (Fcgrllb-/-) Lupus Mice Than In Wild-Type Due To The More Profound Responses Against Alcohol-Induced Leaky Gut, Phatcharapon Yiengwattananon

Chulalongkorn University Theses and Dissertations (Chula ETD)

Consuming alcoholic beverages is well-known to have a part in causing inflammation and obstructing the function of the digestive system, and it may lead to leaky intestines. However, the relationship between alcohol consumption and Systemic Lupus Erythematosus (SLE) remains a subject of controversy continued. In general, alcohol can promote intestinal bacterial dysbiosis and also result in endotoxin release by Gram-negative bacteria. This stimulates many immune cells to produce inflammatory cytokines in the gut. This study focuses on the inflammatory response effect of FcgRIIb-/- mice upon loss of FcgRIIb receptors in which alcohol-induced leaky gut can occur. In 8-week-old mice lacking …

Efficiency Of Mrna Vaccine Against House Dust Mite Allergy In Mouse Model, Chanatip Thanasarnthungcharoen

Chulalongkorn University Theses and Dissertations (Chula ETD)

Through the capacity to mediate Th1-biased immune responses and the induction of neutralizing antibodies, the mRNA-lipid nanoparticle (LNP) platform could represent an innovative approach for shorter, safer, and more effective treatment of house dust mite (HDM) allergy. Our previous study showed that nucleoside-modified mRNA encoding recombinant forms of HDM allergens Der p 1 and Der p 2 (ProDer p 1 and Der p 2 K96A) and formulated with ionizable LNP, induced Th1-biased immune responses and potent specific blocking IgG responses, while being non-reactogenic in sensitized mice. This present study evaluated the immunotherapeutic efficacy of HDM-specific mRNA-LNP-based AIT in a mouse …

The Effect Of Efflux Pumps On Yeast Susceptibility To Chitosan, Sureeporn Muangsawat

Chulalongkorn University Theses and Dissertations (Chula ETD)

Mucocutaneous and life-threatening systemic fungal infections by Candida is a critical problem worldwide, especially with rising prevalence of antifungal drug resistance. Novel alternative or adjunctive antifungal agents with low toxicity is thus in great need. Because drug-efflux pump overexpression is a common mechanism conferring multi-drug resistance, we investigated the effects of drug-efflux pumps on antifungal activity of chitosan, a natural polymer with promising antifungal activity. The minimal fungicidal concentration (MFC) of oligomer (7-9 kD) and polymer (900-1,000 kD) chitosan against Saccharomyces cerevisiae and Candida albicans were evaluated by broth and agar dilution methods. To examine the roles of efflux pumps, …

Development Of A Latex Agglutination Test Based On Vh Antibody Fragment For Detection Of Streptococcus Suis Serotype 2, Kiratika Chidkoksung

Chulalongkorn University Theses and Dissertations (Chula ETD)

Streptococcus suis serotype 2 (S. suis 2) is an important porcine pathogen that causes diseases in both swine and humans. For rapid S. suis 2 identification, a novel latex agglutination test (LAT) based on heavy-chain variable domain antibody (VH) was developed. Firstly, the soluble 47B3 VH antibody fragment from a phage display library, in which cysteine residues were engineered at the C-terminus, was expressed in Escherichia coli. The purified protein was then gently reduced to form monomeric soluble 47B3 VH subsequently used to coat with latex beads by means of site-specific conjugation. The detection sensitivity was found to be as …

Inhibition Of Chondrocyte Apoptosis Via Fas/Fasl System In Knee Osteoarthritis Patients, Ousakorn Kamenkit

Chulalongkorn University Theses and Dissertations (Chula ETD)

Osteoarthritis (OA) is a degenerative rheumatic disease characterized by articular cartilage degeneration. This articular cartilage degradation is positively correlated with chondrocyte apoptosis. The Fas/Fas ligand (FasL) system is part of the extrinsic apoptosis pathway that regulates cell death through the binding of Fas on target cells to FasL on effector cells. Although Fas+ chondrocytes have been identified and the Fas/FasL system has been implicated in this apoptotic process, the apoptosis through chondrocyte-to-FasL+ cell interaction remains unclear. Therefore, this study aims to investigate Fas/FasL-mediated chondrocyte apoptosis focusing on cell-to-cell interactions. In our study, we conducted ex vivo experiments using flow cytometry …

Metagenomic Analysis Using Oxford Nanopore For Fungal Identification In Hemoculture Sample, Nattapong Langsiri

Chulalongkorn University Theses and Dissertations (Chula ETD)

Currently, with advancements in medical technology, the mortality rate from fungal infections has also increased, particularly since the late 20th century. The incidence of invasive fungal infections, especially bloodstream fungal infections, is rising. However, laboratory diagnosis of fungi from clinical specimens still faces significant limitations. Diagnosing fungi based on morphological characteristics to identify species level can take weeks, which is not aligned with the severity of the disease. Current molecular biology techniques also have limitations, such as PCR success rates and mixed infections. With significant advancements in sequencing technology leading to third-generation sequencing, there are notable benefits. Third-generation sequencing, or …

Factors Associated With Hpv16 Cervical Precancerous Stage : Microbiome/Virome And Hpv16 E1, Thanayod Sasivimolrattana

Chulalongkorn University Theses and Dissertations (Chula ETD)

The human papillomavirus type 16 (HPV16) and/or high-risk (Hr-) HPV are the main causes of cervical cancer. The viral factors, such as the E6 and E7 oncogenes, have been recognized as the major factors of carcinogenesis. However, it is currently unknown how other HPV genes, particularly E1, contribute to the development of cancer. Beside HPV, another element that may contribute to the development of cervical cancer is the microbiota in the cervix. Cervical bacteriome and mycobiome have been the focus of numerous investigations; less is known about cervical virome, particularly when HPV is present. No study has investigated the entire …

Effects Of Different Serum Supplements On Piggybac Cd19 Chimeric Antigen Receptor T Cells, Mulita Sanyanusin

Chulalongkorn University Theses and Dissertations (Chula ETD)

Chimeric Antigen Receptor (CAR) T cell is a novel therapy for relapse and refractory hematologic malignancy. Characteristics of CAR T cells is associated with clinical efficacy and toxicity. Type of serum supplements used during cultivation affect the immunophenotype and function of viral-based CAR T cells. This study explores the effect of serum supplements on non-viral piggyBac transposon CAR T cell production. PiggyBac CD19 CAR T cells were expanded in cultured conditions containing either fetal bovine serum, human AB serum, human platelet lysate or xeno-free serum replacement. Then, the effect of different serum supplements on cell expansion, transfection efficiency, immunophenotypes and …

Functional Analysis Of Laminin Subunit Beta-3 (Lamb3) In Hpv16 Positive Cervical Cancer Cell Lines, Warattaya Wattanathavorn

Chulalongkorn University Theses and Dissertations (Chula ETD)

Nearly 100% cervical cancer cases are infected with high-risk (HR) HPV types, in which HR-HPV16 is found in >50%. The mechanism of cervical cell transformation is related to the powerful activity of viral E6 and E7 oncoproteins. The aim of this study is to identify key genes and their associated pathways through comprehensive bioinformatics analysis as well as to explore the effects of a significant gene in cervical cancer carcinogenesis. In this study, the transcriptome sequencing (RNA-seq) of HPV16 positive cervical cancer cell lines (SiHa and CaSki) was compared to HPV negative cervical cancer cell lines (C33A) to identify significant …

Synthetic Flavonoid Derivatives With Antiviral Activity Against Dengue And Chikungunya Viruses, Van Cao

Chulalongkorn University Theses and Dissertations (Chula ETD)

Dengue infection is one significant global health issue, as climate change exacerbated the spread of mosquito vectors. The Chikungunya virus is also a re-emerging arbovirus infection, which is transmitted by some similar vectors. Currently, no commercial antiviral drug is available to treat them. Previous reports suggested that several flavonoid derivatives inhibited mosquito-borne flaviviruses even at submicromolar levels, and one of them is a halogenated flavone derivative, 8-bromobaicalein, was a potential dengue and Zika replication inhibitor targeting flaviviral polymerase and also 3CLpro of SARS-CoV-2. This study characterized that 8-bromobaicalein inhibited chikungunya virus replication with EC50 of 0.49 ± 0.11 µM in …

The Effect Of Histone Methylation In Trained Innate Immunity Of Cord Blood Monocytes In Newborn Infants Of Chronic Hbv-Infected Mothers, Pennapa Plypongsa

Chulalongkorn University Theses and Dissertations (Chula ETD)

Newborns contract Hepatitis B virus (HBV) through exposure in utero from mothers who are infected with HBV. In newborn infant from chronic HBV-infected mothers, the immune system displays innate immune cell maturation and enhances immune response upon restimulation with unrelated pathogens such as bacteria. This pattern is called “trained immunity” or “innate immune memory”. Trained immunity is regulated by epigenetic programming, especially histone modification. To date, there is not report on the epigenetics to regulate trained immunity in HBV. Therefore, this study investigated the cytokines levels and expression levels of histone modification enzyme genes in HBV-exposed cord blood monocytes. Moreover, …

Study Of Thermodynamic Binding Between Ader And Ades In Two-Component Antibiotic Sensor Of Antibiotic Resistant Strains Of Acinetobacter Baumannii, Konrawee Thananon

Chulalongkorn University Theses and Dissertations (Chula ETD)

The proteins AdeR (response regulator) and AdeS (histidine kinase sensor) play a crucial role in regulating the efflux pump, which is responsible for removing antibiotics from bacterial cells. This regulation occurs through a two-component regulatory system (TCS) involving autophosphorylation. Upon receiving external signals, AdeS undergoes autophosphorylation, leading to the activation of AdeR, which in turn initiates the expression of target genes related to the efflux pump. In this study, both enzymes from the reference strain of Acinetobacter baumannii (ATCC19606) and antibiotic resistant strains (H1074 and G560) were cloned and expressed in E. coli. The enzymes were purified using an immobilized …

Effect Of Candida Glabrata Β-Glucans On Immunosuppressive Properties Of Dendritic Cells, Phawida Tummamunkong

Chulalongkorn University Theses and Dissertations (Chula ETD)

β-glucan is a polysaccharide and consists of the backbone of β-(1, 3)-glucan and/or β-(1, 6)-glucan structures. β-glucans are extracted from the cell wall of Candida sp, including Candida glabrata. Interestingly, the biological activity of Candida β-glucan has been represented as a stimulator in the mechanism of immune responses. Dendritic cells are powerful antigen-presenting cells that play a significant role in both innate and adaptive immunity. In the present study, we evaluated the effect of C. glabrata β-glucans on dendritic cell (DC) immunologic responses. Firstly, bone marrow-derived DCs (BMDCs) were induced with C. glabrata β-glucans in a dose-dependent manner. The expression …

Generation Of Tolerogenic Dendritic Cells From Fcgr2b Deficient Lupus-Prone Mice For The Model Of Sle Therapy, Phuriwat Khiewkamrop

Chulalongkorn University Theses and Dissertations (Chula ETD)

Tolerogenic dendritic cells (tolDCs) are DCs with an immunoregulatory function, which can induce regulatory T cells (Tregs) and suppress the immune response. Currently, tolDCs-based treatment has become a promising therapeutic approach for organ transplantation and autoimmune disease. FcgRIIB is an inhibitory receptor widely expressed in B cells, myeloid cells, and DCs. The ablation of FcgRIIB in the murine model shows a spontaneous development of a lupus-like disease and might affect other immune cell regulation. There was limited information on tolDC induction in FcgRIIB defective mice. Thus, in this study, we studied the generation of tolDCs from the bone marrow-derived dendritic …

Macrophage Depletion Enhances Gut Dysbiosis And Severity In Sepsis Mouse Model, Pratsanee Hiengrach

Chulalongkorn University Theses and Dissertations (Chula ETD)

Macrophage is vital players in the responsiveness of the innate immune system against injury or infection. Although macrophage depletion is well-known for some emerging therapies, such as osteoporosis, osteopenia, and decreasing tumor-associated macrophages in melanoma, dysfunction of macrophages leads to an inability of an appropriate immune response and implicated in various disease processes, especially intestinal macrophages that play a key role in the gut immune system and the regulation of gastrointestinal physiology. To obtain an understanding of the role of sepsis-associated macrophages, clodronate was used for the dysfunction of mouse macrophages with and without cecal ligation and puncture (CLP) sepsis. …

The Inhibitory Effect Of Combined Human Cathelicidin With Antibiotics On Antibiotic-Resistant Cutibacterium Acnes, Rakwaree Sriharat

Chulalongkorn University Theses and Dissertations (Chula ETD)

Cutibacterium acnes is one of the major factors involved in the pathogenesis of acne vulgaris which sometimes develops antibiotic resistance particularly clindamycin- and doxycycline-resistant C. acnes. In this study, human cathelicidin (LL-37) which is a type of human antimicrobial peptide against a wide range of microorganisms was used. We investigated the antimicrobial activity of LL-37 on C. acnes isolated from patients with acne at the King Chulalongkorn Hospital using broth microdilution. Moreover, the synergistic effects of LL-37 with clindamycin and doxycycline were investigated using checkerboard microdilution, and time-killing assays. The cytotoxicity of LL-37 was also evaluated by MTT assay. The …

Epigenetic Regulation In Trained And Tolerized Macrophages, Salisa Benjaskulluecha

Chulalongkorn University Theses and Dissertations (Chula ETD)

Innate immune memory is the phenomenon that can either enhance (trained) or suppress (tolerized) immune response by innate immune cells during the second encounter of the stimuli such as pathogens. Previous studies reported that epigenetic regulations critically regulate both types of innate immune memory. However, a complete understanding of the underlying mechanisms is still lacking. In this study, we performed a screening of an epigenetics compound library to identify inhibitors that affect ß-glucan (BG)-trained or LPS-tolerized macrophages. Among 181 compounds tested, various inhibitors targeting Aurora kinase, histone methyltransferase PRMT and EZH2, histone demethylase LSD1 and JMJD2, histone deacetylase 6 and …

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 …

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) …

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 …

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 …