Saudi Cultural Missions Theses & Dissertations
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Item Restricted Antifungal tolerance in clinical isolates during the development of drug resistance(University of Birmingham, 2024-08-27) Alnafisi, Bassam; Ji Tsai, HungThe increasing prevalence of fungal diseases, particularly those caused by Candida albicans, presents a significant challenges for healthcare due to the rising number of immunocompromised individuals. C. albicans, an opportunistic pathogen, often transitions from a harmless commensal organism to a virulent pathogen under conditions of immune suppression, leading to a spectrum of infections from superficial to life-threatening systemic diseases. Despite advancements in antifungal therapies, infections caused by C. albicans remain associated with high mortality rates, highlighting the organism's complex mechanisms for evading host immune responses and developing drug resistance. This study investigates the evolution of drug tolerance and resistance in C. albicans clinical isolates, particularly in the context of fluconazole treatment. The research focuses on understanding the role of aneuploidy, heat shock response, and subpopulation dynamics in the development of tolerance. Through a series of experiments involving clinical isolates, the study tracks how C. albicans adapts over time in response to antifungal treatment. The results indicate that tolerance mechanisms are more pronounced at 37°C, a temperature reflective of the human body, underscoring the importance of thermal adaptation in the pathogenicity of C. albicans. Additionally, C. albicans clinical isolates exhibit tolerance in both broth and agar plate assays, a phenomenon attributed to a combination of specific genotypic and phenotypic characteristics. Our data support the initial hypothesis that the drug tolerance of C. albicans varies over different time points, reflecting the fungus's adaptive response to fluconazole exposure, particularly as influenced by temperature and subpopulation dynamics.44 0Item Restricted Standardising Methodology and Evaluating the Efficacy of C. Myrrh(Saudi Digital Library, 2023-11-28) Alsulami, Afnan; Makrish, Nujud; Tyrrell, Jon; Hugh Gong, RIn ancient times, medicinal plants have been recorded throughout in history. One of these is Commiphora myrrh. This plant is commonly found in the southern part of Arabia, the northeastern part of Africa, in Somalia, and Kenya. It has been used traditionally for treating wounds, mouth ulcers, microbial infections, and inflammatory diseases, and as an antiseptic. This study evaluates in vitro the antimicrobial activity of C. myrrh in various forms, including parchment with Polyethylene Oxide (PEO) combined with C. myrrh, PEO alone, C. myrrh powder, PEO solution, and C. myrrh/PEO solution. A diverse panel of gram-negative E. Coli strains were employed to comprehensively evaluate their responses to these agents. A combination of diffusion assays, broth micro-dilution and time kill assays were used. While the diffusion assays revealed no zones of inhibition, suggesting a lack of antimicrobial activity, Broth micro- dilution and Time-kill assays demonstrated that C. myrrh exhibited antimicrobial potential, particularly at a concentration of 400 mg/ml. their MIC and MBC value was 400 mg/ml. This study suggests that C. myrrh may be found to act as a bacteriostatic agent rather than a bactericidal agent. In addition, this study introduces the novel application of Polyethylene Oxide (PEO) combined with C. myrrh nanofibers as antimicrobial agents. The results of the experiments provide valuable information about C. myrrh's function as an inhibitor of bacterial growth. Also, it emphasises the need for more research and development to uncover the antimicrobial properties of this natural compound. As well as investigations at higher concentrations of C. myrrh. In addition, testing C. myrrh against gram-positive such as Staphylococcus aureus strains to define the efficacy and expand our understanding of myrrh's antimicrobial potential is recommended.23 0