【摘要】： 目的監(jiān)測(cè)大腸埃希菌臨床分離株的耐藥性，了解大腸埃希菌中Ⅰ類整合子的存在頻率，以及基因盒的種類和排列，分析細(xì)菌攜帶基因盒與耐藥表型的關(guān)系以及Ⅰ類整合子與大腸埃希氏菌多重耐藥性的關(guān)系，探討整合子——基因盒系統(tǒng)介導(dǎo)和傳播細(xì)菌耐藥性的分子機(jī)制。 方法利用全自動(dòng)細(xì)菌分析儀，對(duì)114株大腸埃希菌臨床分離株進(jìn)行確認(rèn)、產(chǎn)ESBLs判讀和22種抗生素敏感性測(cè)定，紙片擴(kuò)散法對(duì)另外4種抗生素進(jìn)行敏感性測(cè)定，應(yīng)用PCR方法，擴(kuò)增質(zhì)粒DNA上Ⅰ類整合酶基因(IntⅠ1)，并對(duì)IntⅠ陽(yáng)性的標(biāo)本進(jìn)行Ⅰ類整合子(int1)的擴(kuò)增；對(duì)大小相同的Ⅰ類整合子進(jìn)行酶切分析；對(duì)純化后的Ⅰ類整合子進(jìn)行DNA測(cè)序，將DNA序列在GenBank中搜索，確定Ⅰ類整合子可變區(qū)基因盒的種類和排列。 結(jié)果細(xì)菌對(duì)12種抗生素的耐藥率超過(guò)50％，耐藥率高的抗生素包括氨芐青霉素(100％)、復(fù)方新諾明(80％)、頭孢曲松(60％)、慶大霉素(60％)等，46株(40.4％)細(xì)菌產(chǎn)ESBLs，，80株(70.2％)細(xì)菌為多重耐藥菌(耐受3種以上抗生素)。在62株細(xì)菌的質(zhì)粒DNA上檢測(cè)到Ⅰ類整合酶基因陽(yáng)性，整合酶基因陽(yáng)性的菌株擴(kuò)增Ⅰ類整合子得到58株陽(yáng)性，大小約600bp-3500bp，58株細(xì)菌各含1-2個(gè)Ⅰ類整合子。細(xì)菌的多重耐藥率與Ⅰ類整合子的陽(yáng)性率存在相關(guān)。大小相同的Ⅰ類整合子有相同的酶切圖譜，據(jù)此認(rèn)為它們有相同序列。整合子中最常見(jiàn)的基因盒為dfr17(甲氧芐啶耐藥基因)、aadA5(鏈霉素、壯觀霉素耐藥基因)，最主要的基因盒排列為dfr17-aadA5。攜帶甲氧芐啶耐藥基因盒的絕大多數(shù)菌株對(duì)復(fù)方新諾明耐受，攜帶鏈霉素、壯觀霉素耐藥基因盒的大多數(shù)菌株對(duì)鏈霉素不敏感。 結(jié)論大腸埃希菌臨床分離株的耐藥性強(qiáng)，Ⅰ類整合子在大腸埃希菌中廣泛存在，耐藥基因盒與甲氧芐啶、早期使用的氨基糖苷等傳統(tǒng)抗生素有著密切的聯(lián)系，菌株攜帶基因盒和耐藥表型之間有較好的對(duì)應(yīng)關(guān)系，基因盒介導(dǎo)了細(xì)菌耐藥性。
[Abstract]:Objective to monitor the drug resistance of clinical isolates of Escherichia coli and to understand the frequency of class I integron and the type and arrangement of gene boxes in Escherichia coli. The relationship between bacterial cassette and drug resistance phenotype and the relationship between class I integron and multidrug resistance of Escherichia coli were analyzed, and the molecular mechanism of integron gene box system mediated and transmitted bacterial drug resistance was discussed. Methods 114 clinical isolates of Escherichia coli were identified by automatic bacterial analyzer, ESBLs interpretation and 22 antibiotic sensitivity tests were performed, and 4 other antibiotics were tested by disk diffusion method. PCR method was used. The class I integrase gene (Int 鈪

本文編號(hào)：2155155