請用此 Handle URI 來引用此文件: http://hdl.handle.net/11455/21787
標題: 包氏不動桿菌臨床菌株的分子特性分析
Molecular Characterization of Clinical Acinetobacter baumannii isolates
作者: 黃崇偉
Huang, Chung-Wei
關鍵字: 包氏不動桿菌
Acinetobacter baumannii
水平傳播
抗藥性
轉位子
horizontal transfer
antibiotic resistance
integron
cassette
transposon
出版社: 生命科學系
摘要: 近年來台灣頻頻出現有最後一道防線號稱的imipenem抗生素具抗藥性的包氏不動桿菌(Acinetobacter baumannii),而且對其他抗生素抗藥性的普遍性也日益嚴重,因而喚起對包氏不動桿菌抗藥性之問題的注意與關切。包氏不動桿菌為常見的環境微生物,是人類皮膚與黏膜上的正常菌叢之一,但卻常使免疫功能缺損患者罹患許多嚴重感染疾病,如肺炎、尿道炎、心內膜炎、傷口感染、腦膜炎與敗血病等等。近年來在對於包氏不動桿菌所引發的嚴重感染疾病之治療上,常會引發多重抗藥性而使抗生素的治療失敗。 本研究以彰化基督教醫院中包氏不動桿菌臨床菌株的流行病學資料為基礎,分析其表現型與基因型的相關性,並探討其抗藥性基因是否經水平傳播的方式散佈於各菌株間之可能性,及其相關機制之解析。使用的臨床菌株以民國九十年四月一日到民國九十一年三月三十一日止,在彰化基督教醫院分離出的三十二株包氏不動桿菌為材料,以E-test與VITEK 2 Advance Expert System等抗生素藥物敏感性測試測定這32株菌株的抗生素抗藥性表現型。在這32株包氏不動桿菌中,較特別的是分別由Disk diffusion experiment與VITEK 2 AES所分別檢測出具有廣泛性抗藥性的1-43與2-45兩隻菌株。 隨即以聚合連鎖反應(PCR)方法進行抗藥性基因blaTEM-1與水平傳播單位integron的研究,發現在1-43與2-45兩菌株中,均帶有blaTEM-1基因(AY560328),經過NCBI BLAST的比對發現,也都與Escherichia coli中的blaTEM-1 基因(AF427133)達100%的相似性,就連非coding區也完全一致,這個結果顯示出菌種間水平傳播的可能性。以此為基礎,本研究再利用Mating Experiment的方法,檢討抗藥性基因水平傳播之移動性。此外,發現這兩株菌所帶有的水平移動單位integron等具cassette (AY557339),且排列方式也完全相同,經由南方墨點法與inverse PCR的結果,也發現這個integron所存在的位置具一致性,顯示抗藥性基因可經由一個比integron更大的水平移動單位進行傳播。
During the last decade, Acinetobacter baumannii strains were noticed as involving in increasingly reported of multiple-drug and imipenem resistance. Acinetobacter spp. are common environmental opportunistic pathogens, they can be found on the skin and mucosa of healthy people. But they cause lots of serious infectious disease such as pneumonia, urinary tract infection, endocarditis infection, wound infection, meningitis infection and septicemia, especially in immunocompromised patients. Antimicrobial treatment of these clinical infections, particularly those caused by A. baumannii strains, may be failed due to compromise by the multiple-resistance strains. This research was based on the epidemiological study at Changhua Christian Hospital, trying to analysis the relationship between phenotype and genotype of A. baumannii clinic isolates. And the possibility and mechanism of horizontal transfer of those involved antibiotic resistance genes. A total of 32 A. baumannii strains was isolated during April 1, 2001 through March 31, 2002 from the Microbiology Laboratory of Changhua Christian Hospital. The antibiotic resistance profile was determined by the disk diffusion experiment and VITEK 2 Advance Expert System. Two particular strains, 1-43 and 2-45, among the 32 A. baumannii isolates were identified as pan-drug resistance during the antibiotic sensitivity test and were further studied. We used the PCR method for detecting the antibiotic resistance gene blaTEM-1 and the mobile genetic unit, integron. We found that both A. baumannii strains 1-43 and 2-45 own an identical Beta-lactamase gene blaTEM-1 (AY560328). Since not only the coding region but also the non-coding region are completely the same as the blaTEM-1 gene identified in Escherichia coli (AF427133), the results strongly indicate the possibility of horizontal transfer. The result from mating experiment also suggested the occurrence of horizontal transfer. The integrons PCR experiments showed that the mobile unit, integrons, found in these two strains are identical(AY557339), and the arrangement of the included cassettes are parallel to each other. By the southern blotting experiment, we also found the two integron may locate in the same genetic structure, and suggests the involvement of transposon. Concluded all the results, we suggested that the A. baumannii may acquire the antimicrobial resistance genes through a complex horizontal gene transfer mechanisms.
URI: http://hdl.handle.net/11455/21787
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