2011-08-012024-05-13https://scholars.lib.ntu.edu.tw/handle/123456789/642539摘要：幽門螺旋桿菌為一重要致病菌，目前已知其感染會引發慢性胃炎，並與消化性潰瘍、胃癌和胃黏膜相關淋巴瘤有高度相關性。抑酸劑加上多重抗微生物藥物療程常用於治療幽門螺旋桿菌所引起的疾病。然而抗生素的廣泛使用導致抗藥性持續增加而根除率不斷下降。氟化奎林酮類藥物(fluoroquinolones），如環丙沙星(ciprofloxacin)近年來開始用於在第三線療程時取代克拉黴素(clarithromycin)或甲硝唑(metronidazole)。而隨著使用率的增加，幽門螺旋桿菌對於氟化奎林酮類藥物具有抗藥性的比例也逐年上升。過去的研究發現氟化奎林酮類藥物抗藥性是由於幽門螺旋桿菌gyrA的氟化奎林酮類藥物抗藥性決定區的氨基酸突變所導致。在台大醫院近年所收集的臨床菌株中，有10%具有環丙沙星抗藥性，然而其中67%的環丙沙星抗藥菌株不具有gyrA的點突變，因此很可能存在未知的機制使這些菌株具有抗藥性。因此，我們計劃（1）利用表現基因庫、DNA微陣列、二維差異凝膠電泳或突變株庫尋找抵抗環丙沙星的抗藥基因（2）初步分離的抗藥基因將以基因剔除突變株及互補株證實其對於環丙沙星的抗藥功能（3）分析此抗藥基因在臨床菌株中的分佈（4）表現與純化此一基因所轉譯之蛋白質，並解析其結構，了解其抗藥機制，以期篩選可能的抑制劑。希望此計劃能更進一步了解幽門螺旋桿菌的抗藥機制而有助未來新藥的開發。<br> Abstract: Helicobacter pylor is the important cause of chronic gastritis, and is highly associated with peptic ulcer, gastric adenocarcinoma and mucosa-associated lymphoid tissue lymphoma. Regiments of acid-suppressive reagents plus multiple antimicrobial agents are commonly used to cure the disorders caused by H. pylori. However, widespread use of antibiotics leads to increasing antibiotic resistance and decreasing eradication rates. Fluoroquinolones are recommended as drugs for third-line therapy. In recent years, the preference rate of fluoroquinolones resistance is increasing. Amino acid mutation in the quinolone resistance-determining regions (QRDR) of gyrA is a well-known mechanism for the fluoroquinolones resistance of H. pylori. In clinical isolates of H. pylori collected in National Taiwan University Hospital, 10% of strains have ciprofloxacin resistance, however, 67% of ciprofloxacin resistance strains do not have mutations in the QRDR of gyrA. We hypothesized that there should be an unknown mechanism in these strains contributing to the ciprofloxacin resistance. Therefore, we plan (1) to search genes which contribute to resistance against ciprofloxacin other than gyrA by expression library, DNA microarray, two-dimensional differential in-gel electrophoresis (2D-DIGE), or mutant library (2) to characterize the genes function involved in resistance to ciprofloxacin by deletion mutant and complementation strains (3) to determine the preference rate of the ciprofloxacin-resistant gene in resistance strains without gyrA mutation (4) To express and purify the protein encoded by ciprofloxacin resistance gene, and to resolve crystal structure for screening new inhibitor. The results of this project might find a new mechanism of ciprofloxacin resistance and will be helpful for the eradication of H. pylori.