目的：包氏不動桿菌（Acinetobacter baumannii) 為喜好潮濕的革蘭氏陰性球桿菌，普遍存在於人體 皮膚、黏膜以及環境中。能廣泛的利用各種碳源， 常在加護病房以及燒烫傷病房内免疫力較弱的病人 身上引起各種症狀，包括敗血症、心内膜炎、腦 膜炎、尿道炎等，但是最主要的，還是在院内感 染的肺炎[1,2]。包氏不動桿菌廣泛帶有對多種抗 生素的抗藥性，甚至陸續出現對多種抗生素具抗藥 性的菌株（Multidrug-resistant Acinetobacter baumannii;MDR-Ab)，使得我們在臨床上治療它們 所引發的感染疾病更加困難。因此，我們針對MDR-Ab進行integrase聚合酶反應之分子研究，分析可 能的抗藥性基因之水平傳播方式。
方法：本研究以中部某區域醫院中所收集的MDR-Ab臨 床菌株之流行病學資料為基礎，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。 使用的臨床菌株是民國九十一年六月一日到民國 九十二年五月三十一日止，在中部某區域醫院分離 出的12株Multidrug-resistant包氏不動桿菌為材 料，分別再以Disk diffusion experiment與VITEK 2 Advance Expert System等抗生素藥物敏感性測 試來測定這12株菌株的抗生素抗藥性表現型。此 外，以聚合酶連鎖反應（PCR)方法進行水平傳播 平台Integron内含的integrase基因來分析。
最後，以南方墨點法來確認這12株MDR-Ab臨床 菌株的Integron序列是否相同。
結果：PCR結果顯示這12株MDR-Ab菌株均帶有一個約 160-bp fragment的第一類integrase gene。南方 墨點法結果發現這12株MDR-Ab菌株均帶有一個約
2.5Kb的第一類integron，其中的 gene cassette 排列方式也完全相同，這結果顯示出抗藥基因有水 平傳播的可能。
結論：這12株MDR-Ab菌株均帶有一個約160-bp fragment的第一類integrase gene，所以都具有第 一類integron，integron是一種基因水平傳播單 位，能幫助抗藥基因在不同細菌中散播，這結果 顯示出這12株MDR-Ab菌株的抗藥基因有水平傳播 的可能性。從integron的定序結果發現，這12株 菌株的gene cassettes排列完全相同，推測可能原 因有二，一為這12株菌株剛好都得到相同的gene cassettes，另一個可能為這12株菌株的integron 位在一個更大的水平移動單位，如轉位子上。

Objectives：Acinetobacter baumannii, a type of gram-negative coccobacilli which prefers a a moist environment, is commonly found on the skin and mucosa of human beings. Capable of utilizing various carbon sources, Acinetobacter baumannii frequently induces septicemia, endocarditis, meningitis and urethritis in intensive care or severely burned patients because of their weaker immunity. Among all hospital-acquired infections, pneumonia caused by Acinetobacter baumannii is primary. Acinetobacter baumannii i is resistant to numerous antibiotics, and several strains of multidrug-resistant Acinetobacter baumannii (MDR-Ab) have been discovered. This makes Acinetobacter baumannii induced infections more difficult to treat. The aim of this study was to analyze the horizontal transfer of possible drug-resistant genes in the integrase polymerase chain reaction of MDR-Ab.
Methods：This study utilized epidemiologic data about 12 strains of MDR-Ab collected by a regional hospital in central Taiwan between June 1, 2002 and May 31, 2003. Two drug sensitivity tests, a disk diffusion experiment and the VITEK 2 Advanced Expert System, were used to determine the antibiotic-resistant phenotype of the 12 strains. In addition, a polymerase chain reaction (PCR) was conducted to analyze integrase genes in the integron, a horizontal transfer platform. A southern blot was also used to verify whether these 12 clinical strains of MDR-Ab had an identical integron sequence.
Results：PCR results revealed that a class 1 integrase gene about 160-bp fragment was common among these 12 strains of MDR-Ab. The southern blot also showed the existence of a class 1 integron about 2.5Kb in all 12 strains of MDR-Ab; moreover, their gene cassette sequences were identical.
Conclusions：These 12 strains of MDR-Ab all had a fragment of class 1 integrase gene about 160-bp, and therefore, they all had a class 1 integron, a gene horizontal transfer unit enabling the spread of drug-resistant genes among bacteria. This finding demonstrated the possibility of a horizontal transfer of the drug resistant genes of these 12 strains of MDR-Ab. Results from integron sequencing showed that the gene cassettes of these 12 strains of MDR-Ab were completely identical. This may have been because these 12 strains of bacteria happened to have identical gene cassettes, or the integron of these 12 strains of bacteria was located at a larger horizontal transfer unit, e.g.,the transposon.